Nature & Animals, News & Press - A Blog by F.Intilla (WWW.OLOSCIENCE.COM)

Wild Crows Reveal Tool Skills.

2010-01-17T05:13:00.000-08:00

A new study using motion sensitive video cameras has revealed how New Caledonian crows use tools in the wild. (Credit: Copyright University of Oxford.
Source: ScienceDaily
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ScienceDaily (Jan. 17, 2010) — A new study using motion sensitive video cameras has revealed how New Caledonian crows use tools in the wild.

Previous work has shown the sophisticated ways in which crows can use tools in the laboratory, but now a team of scientists from Oxford University and the University of Birmingham have investigated tool use in its full ecological context. The researchers recorded almost 1,800 hours of video footage for the study and published their findings in Proceedings of the Royal Society B.
In the wild, New Caledonian crows use tools for many purposes, including 'fishing out' large beetle larvae from holes in dead wood. In the new study, the team was able to show for the first time that more larvae were extracted by crows using tools than with their beaks.
They also discovered that adult crows appeared to be much more skilled at obtaining larvae than juvenile crows, suggesting that considerable learning -- possibly from copying more experienced 'larvae fishers' -- is required for crows to become competent at this task.
Aside from recording the video footage the team also collected a large sample of tools that crows had left inserted into larvae burrows. By comparing the length of the tools to the burrows, they found that, on average, longer tools are found in deeper burrows -- suggesting that wild crows, like their cousins in the laboratory, are able to match the 'right' tool to the task. The collection also showed that wild crows do not select tools randomly, from debris on the forest floor, but are more likely to choose leaf-stems than twigs, and are more likely to use tools of a certain size range.
The research team included Dr Lucas Bluff, Dr Christian Rutz, Dr Alex Weir and Professor Alex Kacelnik from Oxford University's Department of Zoology, and Jolyon Troscianko from the University of Birmingham.
The work was funded by the UK's Biotechnology and Biological Sciences Research Council (BBSRC).

Story Source:
Adapted from materials provided by University of Oxford.
Journal Reference:
Bluff et al. Tool use by wild New Caledonian crows Corvus moneduloides at natural foraging sites. Proceedings of The Royal Society B Biological Sciences, 2010; DOI: 10.1098/rspb.2009.1953

Polar Bear Droppings Advance Superbug Debate.

2010-01-17T04:49:00.001-08:00

Researchers found little sign of superbugs in the droppings of polar bears that have had limited or no contact with humans, suggesting that the spread of antibiotic resistance genes seen in other animals may be the result of human influence. (Credit: iStockphoto/David Yang)

Source: ScienceDaily

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ScienceDaily (Jan. 15, 2010) — Scientists investigating the spread of antibiotic-resistant superbugs have gone the extra mile for their research -- all the way to the Arctic. Researchers writing in the open access journal BMC Microbiology found little sign of the microbes in the droppings of polar bears that have had limited or no contact with humans, suggesting that the spread of antibiotic resistance genes seen in other animals may be the result of human influence.

Trine Glad, from the University of Tromsø, Norway, led a study that examined feces samples from five polar bears and rectal swabs from another five polar bears between 2004 and 2006. She said, "The presence of antibiotic resistance genes has previously been described in bacteria taken from the feces of deer, foxes, pigs, dogs and cats. The Barents Sea population of polar bears is located in an area that is sparsely populated by humans. This enables us to study an ecosystem with little human impact and should allow us to determine whether these genes are naturally occurring or are caused by exposure to human antibiotics."
The researchers found that there was scant evidence of antibiotic resistance genes in the bacteria taken from these isolated bears. Overall, the bacterial diversity in the bears' feces was low. Speaking about these results, Glad said "Our analysis of polar bear feces showed a homogenous microbial flora dominated by Clostridia, most of them well characterized as they are also dominant in the human gut. These findings fit nicely with previous studies of the gut microbial ecology in mammals, indicating that bacterial diversity is lower in carnivores, such as polar bears that feed mostly on seals, than herbivores."

Story Source:
Adapted from materials provided by BioMed Central, via EurekAlert!, a service of AAAS.
Journal Reference:
Trine Glad, Pal Bernhardsen, Kaare M Nielsen, Lorenzo Brusetti, Magnus Andersen, Jon Aars and Monica A Sundset. Bacterial diversity in faeces from polar bear (Ursus maritimus) in Arctic Svalbard. BMC Microbiology, (in press) [link]

New System Helps Explain Salmon Migration.

2010-01-15T03:55:00.001-08:00

DOE/Pacific Northwest National Laboratory researchers helped develop the Juvenile Salmon Acoustic Telemetry System to study the migration of juvenile salmon through fast-moving rivers. (Credit: Pacific Northwest National Laboratory)

Source: ScienceDaily

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ScienceDaily (Jan. 15, 2010) — A new acoustic telemetry system tracks the migration of juvenile salmon using one-tenth as many fish as comparable methods, suggests a paper published in the January edition of the American Fisheries Society journal Fisheries. The paper also explains how the system is best suited for deep, fast-moving rivers and can detect fish movement in more places than other tracking methods.

The Juvenile Salmon Acoustic Telemetry System (JSATS) estimated the survival of young, ocean-bound salmon more precisely than the widely used Passive Integrated Transponder (PIT) tags during a 2008 study on the Columbia and Snake rivers, according to the results of a case study discussed in the paper. The paper also concludes that fish behavior is affected least by light-weight JSATS tags compared to larger acoustic tags.
"Fisheries managers and researchers have many technologies to choose from when they study fish migration and survival," said lead author Geoff McMichael of the Department of Energy's Pacific Northwest National Laboratory.
"JSATS was specifically designed to understand juvenile salmon passage and survival through the swift currents and noisy hydroelectric dams on the Columbia River," McMichael continued. "But other systems might work better in different circumstances. This paper demonstrates JSATS' strengths and helps researchers weigh the pros and cons of the different fish tracking methods available today."
Scientists at PNNL and the U.S. Army Corps of Engineers' Portland District co-authored the paper. PNNL and NOAA Fisheries began developing JSATS for the Corps in 2001.
JSATS is an acoustic telemetry system that includes the smallest available acoustic transmitting tag, which weighs 0.43 grams. Its battery-powered tags are surgically implanted into juvenile salmon and send a uniquely coded signal every few seconds. Receivers are strategically placed in waterways to record the signal and track when and where tagged fish travel. A computer system also calculates the precise 3-D position of tagged fish using data gathered by the receivers.
PIT tags are also implanted into juvenile salmon for migration and survival studies, but don't use batteries to actively transmit signals. Instead, PIT tags send signals when they become energized while passing by PIT transceiver antennas.
For the paper's case study, researchers implanted 4,140 juvenile Chinook salmon with both JSATS and PIT tags. They also placed just PIT tags inside another 48,433 juveniles. All of the case study's tagged fish were released downstream of Lower Granite Dam on the Snake River in April and May 2008.
A significantly greater percentage of JSATS tags were detected than PIT tags, the case study demonstrated. For example, about 98 percent of JSATS-tagged fish were detected at Ice Harbor Dam on the Snake River. About 13 percent of PIT-tagged fish were detected in the same stretch of river. As a result, studies using JSATS require using roughly one-tenth as many fish as those employing PIT tags, which helps further conserve the salmon population.
Survival estimates were similar between JSATS and PIT tags. Forty-eight percent of the JSATS-tagged fish were estimated to have survived migration between Lower Granite Dam and Bonneville Dam, which is the last dam on the Columbia before the Pacific Ocean. For PIT-tagged fish, 43 percent were estimated to have reached the same area.
Having flexibility in where receivers can be placed is advantageous, the authors reported. JSATS receivers can be located in both rivers and dams, while PIT antennas usually can only go inside fish bypasses at dams. Researchers can estimate fish survival for an entire river system when receivers are placed in more locations, the paper explains.
The team also compared JSATS' technical features with those of another acoustic telemetry system, the VEMCO system being used for the Pacific Ocean Shelf Tracking (POST) project along North America's West Coast. The VEMCO system is best suited for use in the slow-moving, open ocean when observing small numbers of large fish, the authors wrote. In contrast, JSATS was developed to study the migration of larger quantities of small juvenile fish in fast-moving rivers.
A key difference between the JSATS and VEMCO systems is dry tag weight. JSATS tags weigh 0.43 grams and are the smallest acoustic tags available. VEMCO tags that have been used in Columbia River juvenile salmon weighed 3.1 grams. Previous research shows fish can bear a tag that weighs up to 6.7 percent of their body weight without significant adverse survival effects. That means JSATS tags can be implanted into fish as light as 6.5 grams, while VEMCO tags should be used in fish that weigh no less than 46.3 grams.
Another advantage of JSATS is that it is non-proprietary and available for anyone to manufacture or use. Because several companies have been able to competitively bid for the opportunity to produce the system's components, its cost has dropped in recent years. JSATS tags, for example, have gone from $300 per tag in 2005 to $215 in 2008. And JSATS tags cost $40 to $135 less than other commercially available acoustic tags in 2008. Proprietary interests have hindered the development of acoustic telemetry equipment in certain areas, the team wrote.
"JSATS has helped us get a clearer, more complete picture of how salmon migrate and survive through the Columbia and Snake rivers to the Pacific Ocean," McMichael said. "But we're continuing to develop JSATS and hope others will find it useful in studies of other aquatic animals. There's an opportunity for all aquatic telemetry technologies to be improved."

Story Source:
Adapted from materials provided by DOE/Pacific Northwest National Laboratory.
Journal Reference:
G.A. McMichael, M.B. Eppard, T.J. Carlson, J.A. Carter, B.D. Ebberts, R.S. Brown, M. Weiland, G.R. Ploskey, R.A. Harnish and Z.D. Deng. The Juvenile Salmon Acoustic Telemetry System: A New Tool. Fisheries, Vol. 35, No. 1, January 2010

'World's Least Known Bird' Discovered Breeding in Afghanistan.

2010-01-15T03:40:00.001-08:00

Researchers from the Wildlife Conservation Society have discovered the only known breeding area for the large-billed reed warbler, once called "the world's least known bird species." (Credit: WCS-Afghanistan)

Source: ScienceDaily

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ScienceDaily (Jan. 15, 2010) — Researchers for the Wildlife Conservation Society have discovered for the first time the breeding area of the large-billed reed warbler -- dubbed in 2007 as "the world's least known bird species" -- in the remote and rugged Wakhan Corridor of the Pamir Mountains of north-eastern Afghanistan.

Using a combination of astute field observations, museum specimens, DNA sequencing, and the first known audio recording of the species, researchers verified the discovery by capturing and releasing almost 20 birds earlier this year, the largest number ever recorded.
A preliminary paper on the finding appears in the most recent edition of BirdingASIA. The authors include: Robert Timmins, Naqeebullah Mostafawi, Ali Madad Rajabi, Hafizullah Noori, Stephane Ostrowski and Colin Poole, of the Wildlife Conservation Society; Urban Olsson of Göteborg University, Sweden; and Lars Svensson.
The recent discovery of large-billed reed warblers in Afghanistan represents a watershed moment in the study of this bird, called in 2007 the world's least known bird species by BirdLife International. The first specimen was discovered in India in 1867, with more than a century elapsing before a second discovery of a single bird in Thailand in 2006.
"Practically nothing is known about this species, so this discovery of the breeding area represents a flood of new information on the large-billed reed warbler," said Colin Poole, Executive Director of WCS's Asia Program. "This new knowledge of the bird also indicates that the Wakhan Corridor still holds biological secrets and is critically important for future conservation efforts in Afghanistan."
The find serves as a case study in the detective work needed to confirm ornithological discoveries. The story begins in 2008, when Timmins was conducting a survey of bird communities along the Wakhan and Pamir Rivers. He immediately heard a distinctive song coming from a small, olive-brown bird with a long bill. Timmins taped the bird's song. He later heard and observed more birds of the same species.
Initially, Timmins assumed these birds to be Blyth's reed warblers, but a visit to a Natural History Museum in Tring, United Kingdom to examine bird skins resulted in a surprise: the observed birds were another species. Lars Svensson -- an expert on the family of reed warblers and familiar with their songs -- then realized that Timmins' tape was probably the first recording of the large-billed reed warbler.
The following summer (June 2009), WCS researchers returned to the site of Timmins' first survey, this time with mist nets used to catch birds for examination. The research team broadcast the recording of the song, a technique used to bring curious birds of the same species into view for observation and examination. The recording brought in large-billed reed warblers from all directions, allowing the team to catch almost 20 of them for examination and to collect feathers for DNA. Later lab work comparing museum specimens with measurements, field images, and DNA confirmed the exciting finding: the first-known breeding population of large-billed reed warblers.
WCS is currently the only organization conducting ongoing scientific conservation studies in Afghanistan -- the first such efforts in over 30 years -- and has contributed to a number of conservation initiatives and activities in partnership with the Afghanistan Government, with support from USAID (United States Agency for International Development). In 2009, the government of Afghanistan gazetted the country's first national park, Band-e-Amir, established with technical assistance from WCS's Afghanistan Program. WCS also worked with Afghanistan's National Environment Protection Agency (NEPA) in producing the country's first-ever list of protected species, an action that now bans the hunting of snow leopards, wolves, brown bears, and other species. In a related effort, WCS now works to limit illegal wildlife trade in the country through educational workshops for soldiers at Bagram Air Base and other military bases across Afghanistan.
Situated between the mountainous regions of the Pamirs in Tajikistan, Pakistan, and China, the Wakhan Corridor supports a surprisingly wide range of large mammal species, including Marco Polo sheep (or argali), ibex, lynx, wolf, and the elusive snow leopard.

Story Source:
Adapted from materials provided by Wildlife Conservation Society, via EurekAlert!, a service of AAAS.

Alligators Breathe Like Birds, Study Finds.

2010-01-15T03:34:00.000-08:00

Computerized tomographic (CT) X-ray images of side and top views of a 24-pound American alligator, with 3-D renderings of the bones and of airways or bronchi within the lungs. The windpipe and first-tier of bronchi are not shown. A University of Utah study found that air flows in one direction through a gator's lungs. It flows from the first-tier bronchi through second-tier bronchi (blue), then through tube-like third-tier parabronchi (not shown) and then back through other second-tier bronchi (forest green). (Credit: C.G. Farmer and Kent Sanders, University of Utah.)

Source: ScienceDaily

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ScienceDaily (Jan. 15, 2010) — University of Utah scientists discovered that air flows in one direction as it loops through the lungs of alligators, just as it does in birds. The study suggests this breathing method may have helped the dinosaurs' ancestors dominate Earth after the planet's worst mass extinction 251 million years ago.

Before and until about 20 million years after the extinction -- called "the Great Dying" or the Permian-Triassic extinction -- mammal-like reptiles known as synapsids were the largest land animals on Earth.
The extinction killed 70 percent of land life and 96 percent of sea life. As the planet recovered during the next 20 million years, archosaurs (Greek for "ruling lizards") became Earth's dominant land animals. They evolved into two major branches on the tree of life: crocodilians, or ancestors of crocodiles and alligators, and a branch that produced flying pterosaurs, dinosaurs and eventually birds, which technically are archosaurs.
By demonstrating one-way or "unidirectional" airflow within the lungs of alligators, the new study -- published in the Jan. 15 issue of the journal Science -- means that such a breathing pattern likely evolved before 246 million years ago, when crocodilians split from the branch of the archosaur family tree that led to pterosaurs, dinosaurs and birds.
That, in turn, means one-way airflow evolved in archosaurs earlier than once thought, and may explain why those animals came to dominance in the Early Triassic Period, after the extinction and when the recovering ecosystem was warm and dry, with oxygen levels perhaps as low as 12 percent of the air compared with 21 percent today.
"The real importance of this air-flow discovery in gators is it may explain the turnover in fauna between the Permian and the Triassic, with the synapsids losing their dominance and being supplanted by these archosaurs," says C.G. Farmer, the study's principal author and an assistant professor of biology at the University of Utah. "That's the major reason this is important scientifically."
Even with much less oxygen in the atmosphere, "many archosaurs, such as pterosaurs, apparently were capable of sustaining vigorous exercise," she adds. "Lung design may have played a key role in this capacity because the lung is the first step in the cascade of oxygen from the atmosphere to the animal's tissues, where it is used to burn fuel for energy."
Farmer emphasized the discovery does not explain why dinosaurs, which first arose roughly 230 million years ago, eventually outcompeted other archosaurs.
Farmer conducted the study -- funded by the National Science Foundation -- with Kent Sanders, an associate professor of radiology at the University of Utah School of Medicine. They performed CT scans of a 4-foot-long, 24-pound alligator.

'The Great Dying' -- Decline of the Synapsids, Rise of the Archosaurs:
The synapsids -- which technically include modern mammals -- occupied ecological niches for large animals before the Permian-Triassic extinction.
"Some got up to be bear-sized," says Farmer. Some were meat-eaters, others ate plants. They were four-footed and had features suggesting they were endurance runners. Their limbs were directly under their body instead of sprawling outward like a lizard's legs. There is evidence they cared for their young.
The cause of the mass extinction 251 million years ago is unknown; theories include massive volcanism, an asteroid hitting Earth and upwelling of methane gas that had been frozen in seafloor ice.
"A few of the synapsids survived the mass extinction to re-establish their dominance in the early Triassic, and the lineage eventually gave rise to mammals in the Late Triassic," says Farmer. "However, the recovery of life in the aftermath of the extinction involved a gradual turnover of the dominant terrestrial vertebrate lineage, with the archosaurs supplanting the synapsids by the Late Triassic."
From then until the dinosaurs died out 65 million years ago, any land animal longer than about 3 feet was an archosaur, says Farmer, while mammal-like synapsid survivors "were teeny little things hiding in cracks. It was not until the die-off of the large dinosaurs 65 million years ago that mammals made a comeback and started occupying body sizes larger than an opossum."
No one knows much about the archosaur that was the common ancestor of crocodilians and of pterosaurs, dinosaurs and birds, Farmer says.
It probably was "a small, relatively agile, insect-eating animal," Farmer says. Illustrations of early archosaurs look like large lizards.
"Our data provide evidence that unidirectional flow [of air in the lungs] predates the origin of pterosaurs, dinosaurs and birds, and evolved in the common ancestor of the crocodilian and bird [and pterosaur and dinosaur] lineages," Farmer says.

Cul-de-sacs or Loops for Airflow:
In the lungs of humans and other mammals, airflow is like the tides. When we inhale, the air moves through numerous tiers of progressively smaller, branching airways, or bronchi, until dead-ending in the smallest chambers, cul-de-sacs named alveoli, where oxygen enters the blood and carbon dioxide moves from the blood into the lungs.
It long has been known that airflow in birds is unidirectional, and some scientists suggest it also was that way in dinosaurs.
In modern birds, the lungs' gas exchange units are not alveoli, but tubes known as "parabronchi," through which air flows in one direction before exiting the lung. Farmer says this lung design helps birds fly at altitudes that would "render mammals comatose."
Some researchers have argued that unidirectional airflow evolved after crocodilians split from the archosaur family tree, arising among pterosaurs and theropod dinosaurs, the primarily meat-eating group that included Tyrannosaurus rex. Others have argued it arose only among coelurosaurs, a group of dinosaurs that also includes T. rex and feathered dinosaurs.
Unidirectional air flow in birds long has been attributed to air sacs in the lungs. But Farmer disagrees, since gators don't have air sacs, and says it's due to aerodynamic "valves" within the lungs. She believes air sacs help birds redistribute weight to control their pitch and roll during flight. Farmer says many scientists simply assume air sacs are needed for unidirectional airflow, and have pooh-poohed assertions to the contrary.
"They cannot argue with this data," she says. "I have three lines of evidence. If they don't believe it, they need to get an alligator and make their own measurements."

Assessing Airflow in Alligators:
Farmer did three experiments to demonstrate one-way airflow in alligators' lungs:
-She performed surgery on six anesthetized alligators and inserted flow meters called thermistors into the lungs to measure airflow speed and direction.
-Farmer pumped air in and out of lungs removed from four dead alligators sent to her by a wildlife refuge in Louisiana. The flow was monitored, showing the air kept going the same direction to loop through various tiers of bronchi and back to the trachea.
-Using lungs from another dead gator, she pushed and pulled water with tiny fluorescent beads through the lungs, making movies showing the unidirectional flow.
Farmer says the fact gator lungs still had unidirectional flow after being removed shows unidirectional airflow is caused by aerodynamic valves within the lungs, and not by some other factor, like air sacs or the liver, which acts like a piston to aid breathing.
How does air loop through an alligator's multichambered lungs?
Inhaled air enters the trachea, or windpipe, and then flows into two primary bronchi, or airways. Each of those primary bronchi enters a lung.
From those primary airways, the bronchi then branch into a second tier of narrower airways. Inflowing air jets past or bypasses the first branch in each lung because the branch makes a hairpin turn away from the direction of airflow, creating an aerodynamic valve. Instead, the air flows into other second-tier bronchi and then into numerous, tiny, third-tier airways named parabronchi, where oxygen enters the blood and carbon dioxide leaves it.
The air, still moving in one direction, then flows from the parabronchi into the bypassed second-tier bronchi and back to the first-tier bronchi, completing a one-way loop through the lungs before being exhaled through the windpipe.

Story Source:
Adapted from materials provided by University of Utah.

Unlocking the mystery of the duck-billed platypus' venom.

2010-01-14T07:21:00.000-08:00

Despite its cuddly look, the male duck-billed platypus has stingers on its hind limbs that can deliver a painful venom. Scientists are unraveling its chemical composition. Credit: Wikimedia Commons.

Source: Physorg.com

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Abandon any notion that the duck-billed platypus is a soft and cuddly creature -- maybe like Perry the Platypus in the Phineas and Ferb cartoon.

This platypus, renowned as one of the few mammals that lay eggs, also is one of only a few venomous mammals. The males can deliver a mega-sting that causes immediate, excruciating pain, like hundreds of hornet stings, leaving victims incapacitated for weeks. Now scientists are reporting an advance toward deciphering the chemical composition of the venom, with the first identification of a dozen protein building blocks. Their study is in the Journal of the American Chemical Society.
Masaki Kita, Daisuke Uemura, and colleagues note that spurs in the hind limb of the male platypus can deliver the venom, a cocktail of substances that cause excruciating pain. The scientists previously showed that the venom triggers certain chemical changes in cultured human nerve cells that can lead to the sensation of pain. Until now, however, scientists did not know the exact components of the venom responsible for this effect.
To unlock its secrets, the scientists collected samples of platypus venom and used high-tech analytical instruments to separate and characterize its components. They identified 11 new peptides, or protein subunits, in the venom. Studies using nerve cells suggest that one of these substances, called Heptapeptide 1, is the main agent responsible for triggering pain. The substance appears to work by interacting with certain receptors in the nerve cells, they suggest.
More information: "Duck-Billed Platypus Venom Peptides Induce Ca2+ Influx in Neuroblastoma Cells", http://pubs.acs.org/doi/full/10.1021/ja908148z
Provided by American Chemical Society.

From the Ancient Amazonian Indians: 'Biochar' as a Modern Weapon Against Global Warming.

2010-01-14T01:09:00.000-08:00

Unlike familiar charcoal briquettes, above, biochar is charcoal made from wood, grass and other organic matter, and has the potential to help slow climate change. (Credit: iStockphoto/Don Nichols)

Source: ScienceDaily

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ScienceDaily (Jan. 14, 2010) — Scientists are reporting that "biochar" -- a material that the Amazonian Indians used to enhance soil fertility centuries ago -- has potential in the modern world to help slow global climate change. Mass production of biochar could capture and sock away carbon that otherwise would wind up in the atmosphere as carbon dioxide, the main greenhouse gas.

Their report appears in ACS' Environmental Science & Technology, a bi-weekly journal.
Kelli Roberts and colleagues note that biochar is charcoal produced by heating wood, grass, cornstalks or other organic matter in the absence of oxygen. The heat drives off gases that can be collected and burned to produce energy. It leaves behind charcoal rich in carbon.
Amazonian Indians mixed a combination of charcoal and organic matter into the soil to improve soil fertility, a fact that got the scientists interested in studying biochar's modern potential.
The study involved a "life-cycle analysis" of biochar production, a comprehensive cradle-to-grave look at its potential in fighting global climate change and all the possible consequences of using the material. It concludes that several biochar production systems have the potential for being an economically viable way of sequestering carbon -- permanently storing it -- while producing renewable energy and enhancing soil fertility.

Story Source:
Adapted from materials provided by American Chemical Society, via EurekAlert!, a service of AAAS.
Journal Reference:
Roberts et al. Life Cycle Assessment of Biochar Systems: Estimating the Energetic, Economic, and Climate Change Potential. Environmental Science & Technology, 2010; 44 (2): 827 DOI: 10.1021/es902266r

Raft or Bridge: How Did Iguanas Reach Tiny Pacific Islands?

2010-01-14T01:06:00.000-08:00

The Fijian crested iguana. (Credit: iStockphoto/Michelle Cottrill)

Source: ScienceDaily

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ScienceDaily (Jan. 14, 2010) — Scientists have long puzzled over how iguanas, a group of lizards mostly found in the Americas, came to inhabit the isolated Pacific islands of Fiji and Tonga. For years, the leading explanation has been that progenitors of the island species must have rafted there, riding across the Pacific on a mat of vegetation or floating debris. But new research in the January issue of The American Naturalist suggests a more grounded explanation.

Using the latest genetic, geological and fossil data, biologists Brice Noonan of the University of Mississippi and Jack Sites of Brigham Young University have found that iguanas may have simply walked to Fiji and Tonga when the islands were still a part of an ancient southern supercontinent.
The two islands, located about 2000 miles east of Australia, are home to several iguana species, and their presence there is "one of the most perplexing scenarios in island biogeography," Noonan says. The other islands in the region, and closest continental landmass, Australia, have no iguanid species at all. In fact the closest iguanids are found about 5,000 miles away in the Americas. So how did these species get to these remote islands?
Some scientists have hypothesized that they must have rafted there -- a journey of around 5,000 miles from South America to the islands. There is some precedent for rafting iguanas. There are documented cases of iguanas reaching remote Caribbean islands and the Galapagos Islands on floating logs. But crossing the Pacific is another matter entirely. Noonan and Sites estimate the trip would take six months or more -- a long time for an iguana to survive on a log or vegetation mat.
So Noonan and Sites tested the possibility that iguanas simply walked to the islands millions of years ago, before the islands broke off from Gondwana -- the ancient supercontinent made up of present-day Africa, Australia, Antarctica and parts of Asia. If that's the case, the island species would need to be old -- very old. Using "molecular clock" analysis of living iguana DNA, Noonan and Sites found that, sure enough, the island lineages have been around for more than 60 million years -- easily old enough to have been in the area when the islands were still connected via land bridges to Asia or Australia.
Fossil evidence backs the finding. Fossils uncovered in Mongolia suggest that iguanid ancestors did once live in Asia. Though there's currently no fossil evidence of iguanas in Australia, that doesn't necessarily mean they were never there. "[T]he fossil record of this continent is surprisingly poor and cannot be taken as evidence of true absence," the authors write.
So if the iguanas simply migrated to Fiji and Tonga from Asia or possibly Australia, why are they not also found on the rest of the Pacific islands? Noonan and Sites say fossil evidence suggests that iguana species did once inhabit other islands, but went extinct right around the time humans colonized those island. That's an indication that iguanas were on the menu for the early islanders. But Fiji and Tonga have a much shorter history of human presence, which may have helped the iguanas living there to escape extinction.
The molecular clock analysis combined with the fossil evidence suggests a "connection via drifting Australasian continental fragments that may have introduced [iguanas] to Fiji and Tonga," Noonan says. "The 'raft' they used may have been the land."
The researchers say that their study can't completely rule out the rafting hypothesis, but it does make the land bridge scenario "far more plausible than previously thought."

Story Source:
Adapted from materials provided by University of Chicago Press Journals, via EurekAlert!, a service of AAAS.
Journal Reference:
Brice P. Noonan and Jack W. Sites Jr. Tracing the Origins of Iguanid Lizards and Boine Snakes of the Pacific. The American Naturalist, 2010; 175 (1): 61 DOI: 10.1086/648607

Understanding Why Leopards Can't Change Their Spots.

2010-01-14T01:03:00.001-08:00

Leopard. The leopard cannot change its spots, nor can the tiger change its stripes, but new research tells us something about how cats end up with their spots and stripes. (Credit: iStockphoto/Dmitry Ersler)

Source: ScienceDaily

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ScienceDaily (Jan. 14, 2010) — The leopard cannot change its spots, nor can the tiger change its stripes, but a new research report published in the January 2010 issue of the journal Genetics tells us something about how cats end up with their spots and stripes. It demonstrates for the first time that at least three different genes are involved in the emergence of stripes, spots, and other markings on domestic cats.

Researchers have also determined the genomic location of two of these genes, which will allow for further studies that could shine scientific light on various human skin disorders.
"We hope that the study opens up the possibility of directly investigating the genes involved in pattern formation (i.e., the establishment of stripes, spots, and other markings) on the skin of mammals, including their structure, function, and regulation," said Eduardo Eizirik, a researcher involved in the work from the Pontifical Catholic University of Rio Grande do Sul, Brazil. "From these studies, we hope to understand how the different coat patterns have evolved in different mammalian groups, and to be able to investigate their roles in adaptation to different environments, such as their importance for camouflage in wild cat species."
Scientists crossed domestic cats with different coat patterns, such as stripes and blotches, and tracked the inheritance of these patterns among their offspring. Genetic samples were collected and used to type various molecular markers. Results showed that specific markers were inherited by a kitten every time a given coat pattern appeared, suggesting that the marker and the gene causing the coat pattern were located in the same region of the genome. Using statistical procedures called linkage mapping, scientists determined the genomic location of two genes involved in these traits. By clarifying the inheritance of markings in one mammalian species, researchers hope to identify and characterize the implicated genes and then determine if they apply to other mammals, such as humans. The hope is that this discovery will shed new light on human skin diseases that appear to follow standardized patterns.
"Coat color and markings of animals are obvious traits that have long attracted the interest of geneticists" said Mark Johnston, Editor-in-Chief of the journal GENETICS, "and this study in cats may ultimately help us better understand the genetics behind hair and skin color in other mammals. In turn, this understanding could lead to new therapeutic strategies to correct skin problems in people."

Story Source:
Adapted from materials provided by Genetics Society of America, via EurekAlert!, a service of AAAS.
Journal Reference:
Eizirik et al. Defining and Mapping Mammalian Coat Pattern Genes: Multiple Genomic Regions Implicated in Domestic Cat Stripes and Spots. Genetics, 2010; 184 (1): 267 DOI: 10.1534/genetics.109.109629

Sunflower Genome Holds the Promise of Sustainable Agriculture.

2010-01-14T01:00:00.000-08:00

Field of sunflowers. (Credit: iStockphoto)

Source: ScienceDaily

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ScienceDaily (Jan. 14, 2010) — As agricultural land becomes increasingly valuable, the need to maximize its utilization increases and decisions about what crops to plant and where, become paramount.

The sunflower family includes a number of valuable food crops, with sunflower seed production alone valued at about $14 billion annually. Yet the sunflower family is the only one of a handful of economically important plant families where a reference genome is not available to enable the breeding of crops better suited to their growing environment or consumers tastes.
A new research project, largely funded by Genome Canada, Genome BC, the US Departments of Energy and Agriculture, and France's INRA (National Institute for Agricultural Research), will create a reference genome for the sunflower family -- currently the world's largest plant family, containing 24,000 species of plants, including many crops, medicinal plants, horticulture plants and noxious weeds.
The US$10.5 million research project titled, Genomics of Sunflower, will use next-generation genotyping and sequencing technologies to sequence, assemble and annotate the sunflower genome and to locate the genes that are responsible for agriculturally important traits such as seed-oil content, flowering, seed-dormancy, and wood producing-capacity.
"The intent is to have the basis for a breeding program within four years," says project leader, Dr. Loren Rieseberg (University of British Columbia).
One of the potential applications of this research includes a hybrid variety of sunflower, grown as a dual-use crop. The wild Silverleaf species of sunflower, known for its tall, woody stalks that grow 10 to 15 feet tall and up to 4 inches in diameter in a single season, could be crossbred with the commercially valuable sunflower plant that produces high quality seeds, capitalizing on the desirable traits of both species.
"The seeds would be harvested for food and oil, while the stalks would be utilized for wood or converted to ethanol. As a dual-use crop it wouldn't be in competition with food crops for land," says project leader, Dr. Loren Rieseberg (University of British Columbia).
In addition, this fast growing annual crop will be highly drought resistant, thanks to desirable traits from the Silverleaf variety, and would therefore be suitable for use in subsistence agriculture in places like Sub-Saharan Africa, as well as in much of North America.
Dr. Nolan Kane (University of British Columbia) is one of the co-investigators on the project and together with colleagues at INRA in France, is doing much of the bioinformatics for the genome project.
"The sunflower genome is 3.5 billion letters long -- slightly larger than the human genome. The sunflower family is the largest plant family on earth -- encompassing several important crops and weeds. Mapping its genome will create a very useful reference template for the entire plant family, which will enable us to work on closely related species," says Kane.
Dr. Steve Knapp (University of Georgia) is another co-investigator on the project, whose work includes genetic mapping for desirable traits such as wood formation, as well as the development of germplasm for breeding. "The complete sequence will give us a full draft of the genome and eliminate the arduous one at a time process that we have been using up until this point," he says.
"Genome BC is very pleased to support this innovative project, which will capitalize on Canada's strong genomics infrastructure and leadership in Sunflower genomics, in collaboration with other experts worldwide," says Dr. Alan Winter, President and CEO of Genome BC. "The potential applications of this research are extremely important, both globally and locally."

Story Source:
Adapted from materials provided by Genome BC.

Northern Forests Do Not Benefit from Lengthening Growing Season, Study Finds.

2010-01-13T12:03:00.001-08:00

Forest in Finland. (Credit: iStockphoto/David Navrátil)

Source: ScienceDaily

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ScienceDaily (Jan. 13, 2010) — Forests in northern areas are stunted, verging on the edge of survival. It has been anticipated that climate change improves their growth conditions. A study published in Forest Ecology and Management journal shows that due to their genetic characteristics trees are unable to properly benefit from the lengthening growing season.

Furthermore, the researchers were surprised to find that the mortality of established trees considerably promotes the adaptation of forests to the changing environment.
In cooperation with colleagues at the Universities of Oulu and Potsdam, Anna Kuparinen, Docent at the University of Helsinki's Faculty of Biological and Environmental Sciences, simulated forest growth from southern to northern Finland. A meteorological dispersal model was applied to describe the spread of pollen and seeds in the atmosphere. Above all, the results illustrate the slowness of the adaptation process.
Generally, trees stop growing before the frosts and this cessation of growth has been programmed in their genotype. Therefore, trees are unable to effectively follow the increasing environmental growing season. Instead, they cease growth as dictated by their genotype. It is estimated that after hundred years from now northern forests will substantially lag behind the speed of growth that would be enabled by their environment.

Evolution is promoted by the mortality of established trees:
The researchers assumed that demographic characteristics of the trees would have a notable impact on their adaptability. Tree species differ for example so that birch matures at a considerably younger age than pine, and birch seeds spread more effectively than pine seeds. However, the results showed that these differences had only minor impacts. Instead, the mortality of established trees played a large role in the evolutionary adaptation.
The existing trees in northern forests will survive in a warmer climate better than before but, at the same time, they prevent genetically better adapted individuals from becoming more common. In a dense stand, old trees cast a shadow and prevent new seedlings from establishing. In this way, younger seedlings, which would be more suitable to warmer conditions, cannot easily progress beyond the sapling state.
A question closely related to environmental changes is, whether humans should help the populations to adapt? For forests, possible means of human aid include thinning and planting southern seeds to more northern locations.

Scientists Find Amazing New Pondlife on Nature Reserve.

2010-01-13T01:23:00.001-08:00

The single-celled Plagiopyla. (Credit: Copyright B.J. Finlay)

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Source: ScienceDaily

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ScienceDaily (Jan. 13, 2010) — One year in to a project to save one of the UK's top sites for pondlife, amazing new species are being revealed for the first time.

Scientists from Queen Mary, University of London working with Dorset Wildlife Trust have discovered an astonishing variety of minute aquatic organisms, so small as to be invisible to the naked eye.
East Stoke Fen nature reserve is coming under the microscope of scientists from Queen Marys' School of Biological and Chemical Sciences, based at the Freshwater Biological Association's River Laboratory. They have already found over 30 species of invertebrates smaller than half a millimetre (so called meiofauna) and over 100 single-celled species (ciliates) in less than two months.
The reserve's reed fen, on the floodplain of the River Frome near Wool, is a rare and declining habitat in Dorset. Now, with funding from the Esmée Fairbairn Foundation, the Wet Fens Project is being launched to study 'cryptic biodiversity' (biodiversity invisible to the naked eye) and raise awareness so that it can be protected in pond and fen management.
Dr Genoveva Esteban of Queen Mary's School of Biological and Chemical Sciences, said: "Cryptic biodiversity helps natural ecosystems to bounce back in response to environmental change. The Wet Fens Project in partnership with Dorset Wildlife Trust and the Freshwater Biological Association is pioneer work in the UK, to link research with conservation practice with the aim of incorporating small organisms into wetland conservation management. Local biodiversity conservation will become all-embracing by covering the full range of aquatic organisms that contribute to the proper functioning of an ecosystem -- not just those judged as 'charismatic'."
Dr Rachel Janes, Dorset Wildlife Trust's Pond Project Co-ordinator, said: "It is very exciting to learn about these incredible animals on our reserve, thanks to the work of the scientific team. The Wet Fens Project will help to protect them for the future, alongside the more visible aquatic wildlife."
The Wet Fens Project will be launched this month at a seminar to celebrate the first year of the two-year Purbeck Important Ponds Project, which was launched in January 2009 by Dorset Wildlife Trust and funded by Biffaward -- a multi-million pound environment fund which utilises landfill tax credits donated by Biffa Waste Services, the Environment Agency and the Dorset AONB (Area of Outstanding Natural Beauty), to safeguard one of the UK's foremost regions for pond biodiversity. Purbeck ponds are an aquatic hotspot for wildlife, including nearly all of the known British dragonfly species as well as the rare great crested newt.

Story Source:
Adapted from materials provided by Queen Mary, University of London.

Tilapia Feed on Fiji's Native Fish.

2010-01-13T01:20:00.001-08:00

The poster child for sustainable fish farming -- the tilapia -- is actually a problematic invasive species for the native freshwater fish species of the Fiji Islands. (Credit: Aaron P. Jenkins)

Source: ScienceDaily

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ScienceDaily (Jan. 13, 2010) — The poster child for sustainable fish farming -- the tilapia -- is actually a problematic invasive species for the native fish of the islands of Fiji, according to a new study by the Wildlife Conservation Society and other groups.

Scientists suspect that tilapia introduced to the waterways of the Fiji Islands may be gobbling up the larvae and juvenile fish of several native species of goby, fish that live in both fresh and salt water and begin their lives in island streams.
The recently published paper appears in Aquatic Conservation: Marine and Freshwater Ecosystems. The authors include: Stacy Jupiter and Ingrid Qauqau of the Wildlife Conservation Society; Aaron P. Jenkins of Wetlands International-Oceania; and James Atherton of Conservation International.
"Many of the unique freshwater fishes of the Fiji Islands are being threatened by introduced tilapia and other forms of development in key water catchment basins," said Dr. Jupiter, a co-author of the study and one of the investigators examining the effects of human activities on the native fauna. "Conserving the native fishes of the islands will require a multi-faceted collaboration that protects not only the waterways of the islands, but the ecosystems that contain them."
The most surprising finding of the study centers on the tilapia, a member of the cichlid family of fishes from Africa that has become one of the most important kinds of fish for aquaculture, due in large part to its rapid rate of growth and palatability. Aside from its value as a source of protein, the tilapia is sometimes problematic to native fish species in tropical locations.
To gauge the impacts of tilapia and other human activities on native fish species in the Fiji Archipelago, researchers surveyed the fish species and other denizens of 20 river basins on the major islands of Vitu Levu, Vanua Levu, and Taveuni. In addition to catching and identifying fishes with gill and seine nets, the scientists also rated other environmental factors such as: the potential of erosion due to loss of forest cover and riparian vegetation; road density near rivers and streams; the distances and complexity of nearby mangroves and reefs; and the presence or absence of invasive species (tilapia mainly).
The team found that streams with tilapia contained 11 fewer species of native fishes than those without; species most sensitive to introduced tilapia included the throat-spine gudgeon, the olive flathead-gudgeon, and other gobies. In general, sites where tilapia were absent had more species of native fish.
Since tilapia are known to consume the larvae and juvenile fish, the researchers assume that the introduced species may be consuming the native ones as they make their way upstream and down. Absence of forest cover adjacent to streams was also correlated to fewer fish species.
Based on the spatial information compiled in the study, the researchers found that remote and undeveloped regions -- with waterways containing a full complement of native species and no tilapia -- on the three islands should be considered priority locations for management. The main management activities, the authors recommend, should include conserving forests around waterways and keeping the tilapia out.
"Protecting marine and aquatic biodiversity takes more than managing isolated rivers or coral reefs," said Dr. Caleb McClennen, Director of the Wildlife Conservation Society's Marine Program. "A holistic conservation approach is needed, one that incorporates freshwater systems, the surrounding forest cover, coastal estuaries and seaward coral reefs. As aquaculture continues to develop worldwide, best practices must include precautionary measures to keep farmed species out of the surrounding natural environment."

Story Source:
Adapted from materials provided by Wildlife Conservation Society.

Green sea slug makes chlorophyll like a plant.

2010-01-12T04:47:00.000-08:00

Source: Physorg.com

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The photosynthetic sea slug Elysia chlorotica appears like a dark green leaf as a result of retaining chloroplasts from its algal prey, Vaucheria litorea, in cells lining its digestive tract. Image credit: Mary S. Tyler/PNAS.

Scientists from the University of South Florida in Tampa have found a green sea slug is able to synthesize chlorophyll like a plant, which makes it the first animal known to be capable of the feat.

Researcher Sidney K. Pierce said the super green sea slug, Elysia chlorotica, which lives in waters on the east coast of the USA and Canada, is known to steal genes and photosynthesizing organelles called chloroplasts from its favorite intertidal algae species, Vaucheria litorea, but it now seems it has developed an entire chemical pathway to manufacture the green pigment "chlorophyll a" itself.
Chlorophyll is the pigment that captures energy from sunlight in photosynthesis. Pierce and his team used radioactive tracing techniques to determine the slugs were manufacturing the chlorophyll themselves and it did not originate in the algae they ate.
A number of animals (such as corals) host microbes and algae and benefit from their photosynthesis, but in most of these associations the cells remain whole. In Elysia chlorotica, in contrast, the cells are broken down and chloroplasts are extracted and held inside the slug's own cells, where they remain active for the slug's lifetime of almost a year. Researchers have shown that once a young slug has eaten a meal of Vaucheria algae it never has to eat again as long as it has access to light and supplies of chlorophyll and other chemicals used in photosynthesis.
In 2007 scientists, including Pierce and his team, found genes related to photosynthesis in the slugs, and these genes, apparently originally from the algae, were even found in unhatched slugs that had never eaten algae. In the latest research Pierce found more algal genes, and some of them were for enzymes required for the chemical process manufacturing chlorophyll.
Pierce and his team studied slugs that had not eaten anything for at least five months and had stopped eliminating waste digestive products. They contained chloroplasts taken from the algae, but Pierce said that any other part of the algae should have long ago been digested. They gave the slug an amino acid labeled with radioactive carbon and found that the radioactive carbon turned up in the chlorophyll a molecule after the slugs had been sunbathing, but not if they had been in the dark.
The findings were reported at the annual meeting of the Society for Integrative and Comparative Biology in Seattle, Washington on 7 January and will be published in the journal Symbiosis.

Melting Tundra Creating Vast River of Waste Into Arctic Ocean.

2010-01-12T00:11:00.001-08:00

Source: ScienceDaily

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ScienceDaily (Jan. 12, 2010) — The increase in temperature in the Arctic has already caused the sea-ice there to melt. According to research conducted by the University of Gothenburg, if the Arctic tundra also melts, vast amounts of organic material will be carried by the rivers straight into the Arctic Ocean, resulting in additional emissions of carbon dioxide.

Several Russian rivers enter the Arctic Ocean particularly in the Laptev Sea north of Siberia. One of the main rivers flowing into the Laptev Sea is the Lena, which in terms of its drainage basin and length is one of the ten largest rivers in the world. The river water carries organic carbon from the tundra, and research from the University of Gothenburg shows that this adds a considerable amount of carbon dioxide to the atmosphere when it is degraded in the coastal waters.

Increased temperatures:
The increase in temperature in the Arctic, which has already made an impact in the form of reduced sea-ice cover during the summer, may also cause the permafrost to melt. "Large amounts of organic carbon are currently stored within the permafrost and if this is released and gets carried by the rivers out into the coastal waters, then it will result in an increased release of carbon dioxide to the atmosphere," says Sofia Hjalmarsson, native of Falkenberg and postgraduate student at the Department of Chemistry.

Study of two areas:
In her thesis, Sofia Hjalmarsson has studied the carbon system in two different geographical areas: partly in the Baltic Sea, the Kattegat and the Skagerrak, and partly in the coastal waters north of Siberia (the Laptev Sea, the East Siberian Sea and the Chukchi Sea). The two areas have in common the fact that they receive large volumes of river water containing organic carbon and nutrients, mainly nitrogen.
The thesis Carbon Dynamics in Northern Marginal Seas was publicly defended on 18 December.

Story Source:
Adapted from materials provided by University of Gothenburg.

Butterflies Reeling from Impacts of Climate and Development.

2010-01-12T00:08:00.001-08:00

Source: ScienceDaily

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ScienceDaily (Jan. 12, 2010) — California butterflies are reeling from a one-two punch of climate change and land development, says an unprecedented analysis led by UC Davis butterfly expert Arthur Shapiro.

The new analysis, scheduled to be published online the week of January 10 in the journal Proceedings of the National Academy of Sciences, gives insights on how a major and much-studied group of organisms is reacting to the Earth's warming climate.
"Butterflies are not only charismatic to the public, but also widely used as indicators of the health of the environment worldwide," said Shapiro, a professor of evolution and ecology. "We found many lowland species are being hit hard by the combination of warmer temperatures and habitat loss."
The results are drawn from Shapiro's 35-year database of butterfly observations made twice monthly at 10 sites in north-central California from sea level to tree line. The Shapiro butterfly database is unique in science for its combination of attributes: one observer (which reduces errors), very long-term, multiple sites surveyed often, a large number of species (more than 150), and attendant climatological data.
Shapiro's co-authors include three other UC Davis researchers and two former Shapiro graduate students, including lead analyst Matthew Forister, now an assistant professor of biology at the University of Nevada, Reno.
Their most significant findings:
Butterfly diversity (the number of different species present) is falling fast at all the sites near sea level. It is declining more slowly or holding roughly constant in the mountains, except at tree line.
At tree line, butterfly diversity is actually going up, as lower-elevation species react to the warming climate by moving upslope to higher, cooler elevations.
Diversity among high-elevation butterflies is beginning to fall as temperatures become uncomfortably warm for them and, Shapiro says, "There is nowhere to go except heaven."
Using a battery of statistical approaches, Shapiro and his colleagues concluded that climate change alone cannot account in full for the deteriorating low-elevation numbers. Land-use data show that the butterfly losses have been greatest where habitat has been converted from rural to urban and suburban types.
He added that one of the most surprising findings was that ruderal ("weedy") butterfly species that breed on "weedy" plants in disturbed habitats and are highly mobile are actually declining faster than "non-weedy" species -- those that specialize in one habitat type.
This is especially true in the mountains, where such species do not persist over winter but must recolonize every year from lower altitudes. As their numbers drop in the valleys, fewer are available to disperse uphill, and the rate of colonization drops.
"Butterfly folks generally consider these ruderal species to be 'junk species,' sort of the way bird watchers think of pigeons and starlings," said Shapiro. "So it came as a shock to discover that they were being hit even harder than the species that conservationists are used to thinking about.
"Some of the 'weedy' species have been touted as great success stories, in which native butterflies had successfully adapted to the changed conditions created by European colonization of California. That was the case for many decades, but habitat loss has apparently caught up with them now."
The study was funded by the National Science Foundation.
Additional authors are: at UC Davis, research scientist James Thorne in the Department of Environmental Science and Policy, and graduate students Joshua O'Brien in the Graduate Group in Ecology and David Waetjen in the Geography Graduate Group; at Denison University in Ohio, assistant professor Andrew McCall; and at the University of Tennessee at Knoxville, assistant professor Nathan Sanders and associate professor James Fordyce (another former Shapiro student).
The Shapiro database is online at http://butterfly.ucdavis.edu. It includes butterfly observations and study site maps, together with climate data from nearby weather stations, descriptions of study sites and habitats, and numerous photos. The 10 survey sites lie along Interstate 80 and range from low-lying Suisun Marsh on San Francisco Bay to 9,103-foot-high Castle Peak near Donner Summit.
The database was made public in 2007, also with funding from the National Science Foundation.

Story Source:
Adapted from materials provided by University of California - Davis.

Journal Reference:
1.Arthur Shapiro et al. Compounded effects of climate change and habitat alteration shift patterns of butterfly diversity. PNAS, January 11, 2010

New Species of Lichen Discovered in Iberian Peninsula.

2010-01-11T14:06:00.001-08:00

Source: ScienceDaily

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ScienceDaily (Jan. 11, 2010) — Spanish scientists have described the lichen Phylloblastia fortuita, new to the Iberian Peninsula and to science. Another species from the same family, Phylloblastia dispersa, is also a new entry for Europe and is the first time it has been found outside the tropics.

Foliicolous lichens, symbiosis between fungi and algae, are organisms associated with tropical or sub-tropical climates, and their presence in environments such as the Iberian Peninsula, outside of the tropics, is associated with conditions of very stable ecological and environmental conditions
"We have identified three Phylloblastia lichens in the Iberian Peninsula, one of which is new to science (Phylloblastia fortuita), and we present a fourth species new to European flora, Phylloblastia dispersa," says Esteve Llop, main author and research at the Departamento de Biología Vegetal-Botánica [Department of Plant-Botanical Biology] of the University of Barcelona (UB).
Together, the scientists Esteve Llop and Antonio Gómez-Bolea analysed the lichen flora in a protected area near Barcelona. Although some species of lichen have already been recorded on leaves in the North East of the Iberian Peninsula, this is the first time new species have been described.
The study, recently published in The Lichenologist, brings together biological material that had not been identified by researchers in a previous study carried out in 2006, as well as new material related to previous samples. Llop points out that "the literature about the group to which the samples belong had increased because of contributions from intertropical zones with extratropical species."
The field of study where the lichens were found in Catalonia is also important for science. The presence of Phylloblastia fortuita in the Iberian Peninsula and of Phylloblastia dispersa in Europe reveals areas of "great sensitivity" to environmental changes and may serve as indicators of climatic change.
The biologist states that "we have found a new area with Foliicolous lichen flora, rich in important plant life, which, as in other locations, is associated with conditions of ecological and environmental stability," and concludes: "Scientists consider the importance of protecting these locations based on their relevance to ecology and biodervsity."

Story Source:
Adapted from materials provided by FECYT - Spanish Foundation for Science and Technology, via EurekAlert!, a service of AAAS.

Journal Reference:
1.Llop, Esteve; Gómez-Bolea, Antonio. The lichen genus Phylloblastia ( Verrucariaceae) in the Iberian Peninsula, with a new species from Western Europe. The Lichenologist, 2009; 41 (6): 565 DOI: 10.1017/S002428290900872X

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2010-01-11T13:28:00.000-08:00

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New spider species discovered.

2010-01-11T08:28:00.000-08:00

Source: Physorg.com

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The new species is the largest of its type in the Middle East, but its habitat is endangered. "It could be that there are other unknown species that will become extinct before we can discover them," says Dr. Uri Shanas of the University of Haifa, who is heading the research in the area. Credit: Photo by Yael Olek, courtesy of the University of Haifa
A new and previously unknown species of spider has been discovered in the dune of the Sands of Samar in the southern Arava region by a team of scientists from the Department of Biology in the University of Haifa-Oranim. Unfortunately, however, its habitat is endangered.

"The discovery of this new spider illustrates our obligation to preserve the dune," says Dr. Shanas, who headed the team of scientists.
The Sands of Samar are the last remaining sand dune in Israeli territory in the southern Arava region. In the past, the sands stretched across some 7 square kilometers, but due to the rezoning of areas for agriculture and sand quarries, the sands have been reduced to fewer than 3 square kilometers.

During a course of studies that Dr. Shanas's research team has carried out in the region, they discovered this new spider, a member of the Cerbalus genus. Since it has been found in the Arava, it has been given the name Cerbalus aravensis. The researchers say that this spider's leg-span can reach up to 14 cm., which makes it the largest spider of its type in the Middle East. Even though details are still lacking to enable a full analysis of its biology and of its population in the sands, the scientists know that this is a nocturnal spider, mostly active in the hottest months of the year, and that it constructs an underground den which is closed with a "lifting door" made of sand particles that are glued together to camouflage the den.

The scientists' excitement is indeed mixed with apprehension. According to Dr. Shanas, the Israel Land Administration intends to renew mining projects in the Sands of Samar in the near future, which will endanger the existence of the newly discovered spider. He adds that it is possible that there are additional unknown animal species living in the sands, and therefore efforts should be made to preserve this unique region in the Arava. "The new discovery shows how much we still have to investigate, and that there are likely to be many more species that are unknown to us. If we do not preserve the few habitats that remain for these species, they will become extinct before we can even discover them," Dr. Shanas concludes.

Provided by University of Haifa

Warmer Climate Could Stifle Carbon Uptake by Trees, Study Finds.

2010-01-10T01:39:00.001-08:00

Source: ScienceDaily

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ScienceDaily (Jan. 8, 2010) — Contrary to conventional belief, as the climate warms and growing seasons lengthen subalpine forests are likely to soak up less carbon dioxide, according to a new University of Colorado at Boulder study.

As a result, more of the greenhouse gas will be left to concentrate in the atmosphere.
"Our findings contradict studies of other ecosystems that conclude longer growing seasons actually increase plant carbon uptake," said Jia Hu, who conducted the research as a graduate student in CU-Boulder's ecology and evolutionary biology department in conjunction with the university's Cooperative Institute for Research in Environmental Sciences, or CIRES.
The study will be published in the February edition of the journal Global Change Biology.
Working with ecology and evolutionary biology professor and CIRES Fellow Russell Monson, Hu found that while smaller spring snowpack tended to advance the onset of spring and extend the growing season, it also reduced the amount of water available to forests later in the summer and fall. The water-stressed trees were then less effective in converting CO2 into biomass. Summer rains were unable to make up the difference, Hu said.
"Snow is much more effective than rain in delivering water to these forests," said Monson. "If a warmer climate brings more rain, this won't offset the carbon uptake potential being lost due to declining snowpacks."
Drier trees also are more susceptible to beetle infestations and wildfires, Monson said.
The researchers found that even as late in the season as September and October, 60 percent of the water in stems and needles collected from subalpine trees along Colorado's Front Range could be traced back to spring snowmelt. They were able to distinguish between spring snow and summer rain in plant matter by analyzing slight variations in hydrogen and oxygen atoms in the water molecules.
The results suggest subalpine trees like lodgepole pine, subalpine fir and Englemann spruce depend largely on snowmelt, not just at the beginning of the summer, but throughout the growing season, according to the researchers.
"As snowmelt in these high-elevation forests is predicted to decline, the rate of carbon uptake will likely follow suit," said Hu.
Subalpine forests currently make up an estimated 70 percent of the western United States' carbon sink, or storage area. Their geographic range includes much of the Rocky Mountains, Sierra Nevada and high-elevation areas of the Pacific Northwest.
Study co-authors included David Moore of King's College London and Sean Burns of the National Center for Atmospheric Research and CU-Boulder.
CIRES is a joint institute of CU-Boulder and the National Oceanic and Atmospheric Administration. For more information about CIRES visit cires.colorado.edu.

Story Source:
Adapted from materials provided by University of Colorado at Boulder.

Journal Reference:
1.Jia Hu, David J. P. Moore, Sean P. Burns, Russell K. Monson. Longer growing seasons lead to less carbon sequestration by a subalpine forest. Global Change Biology, 2010; 16 (2): 771 DOI: 10.1111/j.1365-2486.2009.01967.x

Echinoderms Contribute to Global Carbon Sink; Impact of Marine Creatures Underestimated.

2010-01-10T01:16:00.000-08:00

Source: ScienceDaily

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ScienceDaily (Jan. 9, 2010) — The impact on levels of carbon dioxide in the Earth's atmosphere by the decaying remains of a group of marine creatures that includes starfish and sea urchin has been significantly underestimated.

"Climate models must take this carbon sink into account," says Mario Lebrato, lead author of the study. The work was done when he was at the National Oceanography Centre, Southampton (NOCS) and affiliated with the University of Southampton's School of Ocean and Earth Science (SOES); he is now at the Leibniz Institute of Marine Science in Germany.
Globally, the seabed habitats occupy more than 300 million million square metres, from the intertidal flats and pools to the mightiest deep-sea trenches at 11,000 meters. The benthos -- the animals living on and in the sediments -- populate this vast ecosystem.
Calcifying organisms incorporate carbon directly from the seawater into their skeletons in the form of inorganic minerals such as calcium carbonate. This means that their bodies contain a substantial amount of inorganic carbon. When they die and sink, some of the inorganic carbon is remineralised, and much of it becomes buried in sediments, where it remains locked up indefinitely.
Lebrato and his colleagues provide the first estimation of the contributions of starfish, sea urchins, brittle stars, sea cucumbers and sea lilies -- all kinds of echinoderm -- to the calcium carbonate budget at the seabed. They estimate that the global production from all echinoderms is over a tenth (0.1) of a gigatonne of carbon per year -- that is, more than a hundred thousand million kilograms.
This is less than the total biological production in the main water column, or pelagic zone, which scientists believe to be between around 0.6 and 1.8 gigatonnes of carbon per year. But echinoderms apparently deliver more carbon to the sediments than do forams, for example. These microscopic animals live in vast numbers in the oceans and are traditionally regarded along with coccolithophores (single-celled marine plants surrounded by calcium carbonate plates) as one of the biggest contributors to the flux of calcium carbonate from the sunlit surface waters to the ocean's interior -- the so-called 'biological carbon pump'.
"Our research highlights the poor understanding of large-scale carbon processes associated with calcifying animals such as echinoderms and tackles some of the uncertainties in the oceanic calcium carbonate budget," says Lebrato: "The realisation that these creatures represent such a significant part of the ocean carbon sink needs to be taken into account in computer models of the biological pump and its effect on global climate."
There is a worry that ocean acidification due to increased carbon dioxide emissions from the burning of fossil fuels could reduce the amount of calcium carbonate incorporated into the skeletons of echinoderms and other calcifying organisms.
However, different echinoderm species respond to ocean acidification in different ways, and the effects of rising temperatures can be as significant as those of rising carbon dioxide. How this will affect the global carbon sink remains to be established.
Lebrato concludes: "The scientific community needs to reconsider the role of benthic processes in the marine calcium carbonate cycle. This is a crucial but understudied compartment of the global marine carbon cycle, which has been of key importance throughout Earth history and it is still at present."
The authors are: Mario Lebrato (NOCS/SOES), Debora Iglesias-Rodríguez (NOCS/SOES), Richard Feely (Pacific Marine Environmental Laboratory/National Oceanic and Atmospheric Administration,, Seattle), Dana Greeley (NOCS/SOES), Daniel Jones (NOCS), Nadia Suarez-Bosche (NOCS/SOES), Richard Lampitt (NOCS), Joan Cartes (Institut de Ciències del Mar de Barcelona), Darryl Green (NOCS) and Belinda Alker (NOCS).

Story Source:
Adapted from materials provided by National Oceanography Centre, Southampton (UK), via EurekAlert!, a service of AAAS.

Ant Has Given Up Sex Completely, Researchers Confirm.

2010-01-10T01:13:00.000-08:00

Source: ScienceDaily

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ScienceDaily (Jan. 9, 2010) — The complete asexuality of a widespread fungus-gardening ant, the only ant species in the world known to have dispensed with males entirely, has been confirmed by a team of Texas and Brazilian researchers.

Most social insects—the wasps, ants and bees—are relatively used to daily life without males. Their colonies are well run by swarms of sterile sisters lorded over by an egg-laying queen. But, eventually, all social insect species have the ability to produce a crop of males who go forth in the world to fertilize new queens and propagate.
Queens of the ant Mycocepurus smithii reproduce without fertilization and males appear to be completely absent, report Christian Rabeling, Ulrich Mueller and their Brazilian colleagues in PLoS ONE this week.
"Animals that are completely asexual are relatively rare, which makes this is a very interesting ant," says Rabeling, an ecology, evolution and behavior graduate student at The University of Texas at Austin. "Asexual species don't mix their genes through recombination, so you expect harmful mutations to accumulate over time and for the species to go extinct more quickly than others. They don't generally persist for very long over evolutionary time."
Previous studies of the ants from Puerto Rico and Panama have pointed toward the ants being completely asexual. One study in particular, by Mueller and former graduate student Anna Himler (now at Arizona State University), showed that the ants reproduced in the lab without males, and that no amount of stress induced the production of males.
Scientists believed that specimens of male ants previously collected in Brazil in the 1960s could be males of M. smithii. If males of the species existed, it would suggest that—at least from time to time—the ants reproduce sexually.
Rabeling analyzed the males in question and discovered that they belonged to another closely related (sexually reproducing) species of fungus-farmer, Mycocepurus obsoletus, thus establishing that no males are known to exist for M. smithii.
He also dissected reproducing M. smithii queens from Brazil and found that their sperm storage organs were empty.
Taken together with the previous studies of the ants, Rabeling and his colleagues have concluded that the species is very likely to be totally asexual across its entire range, from Northern Mexico through Central America to Brazil, including some Caribbean islands.
As for the age of the species, the scientists estimate the ants could have first evolved within the last one to two million years, a very young species given that the fungus-farming ants evolved 50 million years ago.
Rabeling says he is using genetic markers to study the evolution and systematics of the fungus-gardening ants and this will help determine the date of the appearance and genetic mechanism of asexual reproduction more precisely in the near future.

Story Source:
Adapted from materials provided by University of Texas at Austin, via EurekAlert!, a service of AAAS.

In Search Of Wildlife-friendly Biofuels: Are Native Prairie Plants the Answer?

2009-10-01T11:27:00.001-07:00

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ScienceDaily (Oct. 1, 2009) — When society jumps on a bandwagon, even for a good cause, there may be unintended consequences. The unintended consequence of crop-based biofuels may be the loss of wildlife habitat, particularly that of the birds who call this country's grasslands home, say researchers from Michigan Technological University and The Nature Conservancy.

In a paper published in the October 2009 issue of the journal BioScience, David Flaspohler, Joseph Fargione and colleagues analyze the impacts on wildlife of the burgeoning conversion of grasslands to corn. They conclude that the ongoing conversion of grasslands to corn for ethanol production is posing a very real threat to the wildlife whose habitat is being transformed. One potential solution: Use diverse native prairie plants to produce bioenergy instead of a single agricultural crop like corn.
"There are ways to grow biofuel that are more benign," said Flaspohler, an associate professor in the School of Forest Resources and Environmental Science at Michigan Tech. "Our advice would be to think broadly and holistically about the approach you use to solve a problem and to carefully consider its potential long-term impacts."
The rapidly growing demand for corn ethanol, fueled by a government mandate to produce 136 billion liters of biofuel by 2022—more than 740 percent more than was produced in 2006—and federal subsidies to farmers to grow corn, is causing a land-use change on a scale not seen since virgin prairies were plowed and enormous swaths of the country's forests were first cut down to grow food crops, the researchers say.
"Bioenergy is the most land-intensive way to produce energy, so we need to consider the land use implications of our energy policies," said Fargione, lead scientist for The Nature Conservancy's North America Region.
Whether land used to grow corn for ethanol causes a loss of wildlife habitat depends on the type of land use it replaces. Most of the recent expansion in land planted to corn involves land previously used to grow other crops. But there is evidence that more and more land that had been enrolled in the federal Conservation Reserve Program (CRP) is also being converted to crop production.
CRP is a voluntary program that pays rent to landowners to convert their agricultural land to natural grasslands or tree cover, reducing soil erosion, improving water quality and benefiting wildlife. In September 2007, the amount of land enrolled in the CRP peaked at 36.8 million acres.. Just one month later, in October 2007, CRP lands had declined by 2.3 million acres. And the Food, Conservation and Energy Act of 2008 capped CRP land at 32 million acres by 2010.
CRP land has been shown to help native birds survive and thrive. CRP lands have added an estimated 2.1 million ducks annually to the fall flight over North America's prairies. On the other hand, converting CRP land to cropland threatens the grassland birds and mammals there, Flaspohler and Fargione's paper says. A study of the value of CRP land to grassland birds in North and South Dakota indicated that nearly two million birds of five species would be lost without the CRP in those two states.
Conversion of grassland to corn also has a potentially significant negative impact on freshwater ecosystems. Intact grasslands retain soil and nitrogen. Land planted continuously to corn releases significant amounts of nitrates to freshwater systems. When these nitrogen-laden waters real the Gulf of Mexico, they contribute to algal blooms, creating "dead zones" where low oxygen levels make it difficult for fish and other aquatic wildlife to survive. Soil draining off cropland increases sediment in fresh water, raising temperatures and degrading the habitat of fish such as trout.
What's the solution? There are at least two ways to produce bioenergy without destroying wildlife, habitat, the researchers say. One is to use biomass sources that don't require additional land, such as agricultural residues and other wastes from municipal, animal, food and forestry industries.
Another is to grow native perennials such as switchgrass and big bluestem. The natural diversity of prairie plants offers many benefits, including increased carbon storage in the soil, erosion control and the maintenance of insect diversity, which does double duty by providing food for birds and helping to pollinate nearby crops.
"Bioenergy can be produced in ways that provide multiple benefits to society, including energy production, carbon sequestration and wildlife habitat," Fargione said. "The Conservancy is working to implement on-the-ground demonstrations of grass-based energy systems that would increase the economic value of grasslands and provide an incentive for maintaining and extending grassland habitat."
One concern about using native prairie plants as bioenergy crops is a lower yield per acre planted. However, said Flaspohler, he and fellow Michigan Tech associate professor Chris Webster have collected plant productivity data from12 test fields in southern Wisconsin that should shed light on how field level plant species diversity affects the amount of biomass produced per year.
"We are looking at trade-offs between producing a commodity for use as bioenergy and maintaining important ecosystem services such as soil fertility, water quality, and wildlife habitat," Flaspohler noted. "It was by ignoring unintended consequences that we've now found ourselves highly dependent on a non-renewable fuel source (fossil fuels) that is contributing to climate change. With some foresight and with information on key trade-offs, I think we can make wiser decisions in the future."
Journal reference:
Joseph E. Fargione, Thomas R. Cooper, David J. Flaspohler, Jason Hill, Clarence Lehman, Tim McCoy, Scott McLeod, Erik J. Nelson, Karen S. Oberhauser, and David Tilman. Bioenergy and Wildlife: Threats and Opportunities for Grassland Conservation. BioScience, October, 2009
Adapted from materials provided by Michigan Technological University.

Planet's Nitrogen Cycle Overturned By 'Tiny Ammonia Eater Of The Seas'

2009-10-01T10:54:00.001-07:00

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ScienceDaily (Oct. 1, 2009) — It's not every day you find clues to the planet's inner workings in aquarium scum. But that's what happened a few years ago when University of Washington researchers cultured a tiny organism from the bottom of a Seattle Aquarium tank and found it can digest ammonia, a key environmental function. New results show this minute organism and its brethren play a more central role in the planet's ecology than previously suspected. The findings, published online September 30 in the journal Nature, show that these microorganisms, members of ancient lineage called archaea, beat out all other marine life in the race for ammonia. Ecologists now assume that ammonia in the upper ocean will first be gobbled up by phytoplankton to make new cells, leaving very little ammonia for microbes to turn into nitrate.
"Our data suggests that it's the other way around," said co-author Willm Martens-Habbena, a UW postdoctoral researcher. "Archaea are capable of stealing the ammonia from other organisms and turning it into nitrate. Then it's the phytoplankton that take up that nitrate once again."
Ammonia is a waste product that can be toxic to animals. But plants, including phytoplankton, prize ammonia as the most energy-efficient way to build new cells.
The new paper also shows that archaea can scavenge nitrogen-containing ammonia in the most barren environments of the deep sea, solving a long-running mystery of how the microorganisms can survive in that environment. Archaea therefore not only play a role, but are central to the planetary nitrogen cycles on which all life depends.
"Bacterial nitrifiers were discovered in the late 19th century. One century later this other group of nitrifiers is discovered that is not a minor population, it turns out to be the major population," said co-author David Stahl, a UW professor with appointments in the departments of civil and environmental engineering and microbiology. "We have to revise our basic understanding of the nitrogen cycle."
In the tree of life, archaea occupy their own branch. Archaea were discovered only about 30 years ago and were first thought to exist only in extreme environments, such as hot springs or hydrothermal vents. They are now known to be more widespread.
In the early 1990s scientists collecting seawater found strands of genetic material that suggested at least 20 percent of the ocean's microbes are archaea, and circumstantial evidence suggested they might live off ammonia. Stahl's group in 2005 was the first to isolate the organism, which they got from a tropical tank in the Seattle Aquarium, and demonstrate that it can, in fact, grow by oxidizing ammonia. His lab and others have since found the organism in many marine environments, including Puget Sound and the North Sea. The microbe is likely ubiquitous on land and in the seas, they say.
The new experiments show that the organism can survive on a mere whiff of ammonia – 10 nanomolar concentration, equivalent to a teaspoon of ammonia salt in 10 million gallons of water. In the deep ocean there is no light and little carbon, so this trace amount of ammonia is the organism's only source of energy.
"What Willm's work has shown is that these archaea can grow at the vanishingly low concentrations of ammonia found in the ocean," Stahl said. "Until we made the measurements, no one thought it would be possible that an organism could live on these trace amounts of ammonia as a primary energy source."
That finding has two important implications for ocean ecosystems. Scientists knew that something was turning ammonia into nitrate in the deep ocean, but could not fathom what organism might be responsible. Now it appears archaea are those mysterious organisms.
And in the sun-dappled upper ocean waters, it appears that archaea can out-compete phytoplankton for ammonia. The same may be true in soil environments, the researchers say.
The archaea in question are small even by the standards of single-celled organisms. At 0.2 micrometers across, about 8 millionths of an inch, the only life forms smaller are viruses. Martens-Habbena speculates that archaea's size could explain how they are able to survive on such a scant energy supply. The strain used in these experiments is named Nitrosopumilus maritimus, which means "tiny ammonia-oxidizer of the sea."
A better understanding of archaea's lifestyle and role in nitrogen cycles not only would rewrite ecology textbooks. It could also have practical applications, such as devising natural ways to boost a soil's nitrogen content without needing to use chemical fertilizers, or designing sewage treatment plants that employ microbes to remove nitrogenous waste more efficiently, or understanding which microbes produce global-warming gases such as nitrous oxide.
The new findings will also affect the equations used in global climate models, researchers say. Computer models use global cycles of nitrogen and other chemicals to estimate how much carbon dioxide the oceans will absorb and ultimately sink to the bottom of the sea. The new findings suggest that most of the nitrate in the surface water comes from recycling of biomass, and not from the deep water as currently assumed.
"Our data suggest that the carbon pump is weaker than currently assumed, so current climate models may overestimate how much carbon can be absorbed by the oceans," Martens Habbena said.
Other co-authors are the UW's Paul Berube, Hidetoshi Urakawa and Jose de la Torre. The research was funded by the National Science Foundation.
Adapted from materials provided by University of Washington.

Monkeys' Grooming Habits Provide New Clues To How We Socialize.

2009-10-01T10:51:00.001-07:00

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ScienceDaily (Oct. 1, 2009) — A study of female monkeys' grooming habits provides new clues about the way we humans socialise. New research, published September 30 in Proceedings of the Royal Society, reveals there is a link between the size of the brain, in particular the neocortex which is responsible for higher-level thinking, and the size and number of grooming clusters that monkeys belong to. The researchers, from the University of Oxford and Roehampton University, have shown that bigger brained female monkeys invest more time grooming a smaller group of monkeys but still manage to maintain contact with other members of their group, even though they have much weaker social bonds with them. In contrast, monkeys of species with smaller neocortices, and therefore less cognitive ability, live in groups with a less complicated social structure.
An analysis of data on the grooming patterns of 11 species of Old World monkeys suggests the relative size of the neocortex is the key factor, rather than overall brain size. The neocortex is connected with cognitive functions, such as learning, memory and more complex thought. In monkeys, species with large neocortices typically live in groups of 25-50 animals, whereas species with small neocortices live in groups of 10-20 individuals.
Species with larger neocortices are able to maintain larger social groups because they can balance a few very intimate friendships against many less close acquaintances. In contrast, species with smaller neocortices cannot manage this, and so have groups that fragment more easily.
The study therefore suggests that, while bigger brained female monkeys concentrate their social effort on core partners in smaller cliques in order to minimize the costs of harassment from other members of the group, their enhanced social skills allow them to exploit weak social links with others in the wider network and maintain good social relations outside their own close-knit groups.
Professor Robin Dunbar, from the Institute of Cognitive and Evolutionary at Oxford University, said: 'These findings give us glimpses into how humans manage the complex business of maintaining coherence in social groups that are much larger than those found in any other primate species. Our neocortex is three times larger than that of other monkeys and apes, and this allows us to manage larger, more dispersed social groups as a result. '
Adapted from materials provided by University Of Oxford.

Rediscovering The Dragon's Paradise Lost: Komodo Dragons Most Likely Evolved In Australia, Dispersed To Indonesia.

2009-10-01T10:46:00.001-07:00

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ScienceDaily (Oct. 1, 2009) — The world's largest living lizard species, the Komodo dragon (Varanus komodoensis), is vulnerable to extinction and yet little is known about its natural history. New research by a team of palaeontologists and archaeologists from Australia, Malaysia and Indonesia, who studied fossil evidence from Australia, Timor, Flores, Java and India, shows that Komodo Dragons most likely evolved in Australia and dispersed westward to Indonesia.

The research, which also details new fossil specimens indicating the presence of a new species of giant varanid found on the island of Timor, is published September 30 in the open-access, peer-reviewed journal PLoS ONE.
Author Scott Hocknull, Senior Curator of Geosciences at the Queensland Museum, said Australia is a hub for lizard evolution.
"The fossil record shows that over the last four million years Australia has been home to the world's largest lizards, including a five metre giant called Megalania (Varanus prisca)," Mr Hocknull said.
"Now we can say Australia was also the birthplace of the three-metre Komodo dragon (Varanus komodoensis), dispelling the long-held scientific hypothesis that it evolved from a smaller ancestor in isolation on the Indonesian islands.
"Over the past three years, we've unearthed numerous fossils from eastern Australia dated from 300,000 years ago to approximately four million years ago that we now know to be the Komodo dragon.
"When we compared these fossils to the bones of present-day Komodo dragons, they were identical," he said.
The varanids are a group of giant monitor lizards, which are the world's largest terrestrial lizards and which were ubiquitous in Australasia for over 3.8 million years, having evolved alongside large-bodied, mammalian carnivores, such as Thylacoleo, the 'marsupial lion'. Growing to 2-3 metres in length and weighing around 70 kilos, the Komodo dragon is the last of the truly giant monitor lizards. New fossil discoveries show that the ancestor of the Komodo dragon evolved on mainland Australia, around 3-4 million years ago and then dispersed west to Indonesia. Historically, Australia was home to many other giant monitor lizards, including Megalania (Varanus prisca)—once the world's largest terrestrial lizard but which died out around 40,000 years ago.
"This research also confirms that both giant lizards, Megalania (Varanus priscus) and the Komodo dragon (Varanus komodoensis) existed in Australia at the same time," Mr Hocknull said.
Scott Hocknull and his international team have compared fossil evidence of Komodo dragons and other giant varanids in order to reconstruct the palaeobiogeography of the world's largest land-based lizards. The researchers hope this will have implications for the conservation of the Komodo dragon, which is now found on just a few isolated islands in eastern Indonesia, between Java and Australia, and vulnerable to extinction, probably due to habitat loss and persecution by modern humans over the last few millennia.
It was previously thought that the Komodo Dragon evolved its large size as a response to insular island processes, lack of carnivore competition, or as a specialist hunter of pygmy elephants called Stegodon. However, Hocknull and colleagues report that the ancestor of the Komodo dragon most likely evolved in Australia and spread westward, reaching the Indonesian island of Flores by 900,000 years ago. Comparisons between fossils and living Komodo dragons on Flores show that the lizard's body size has remained relatively stable since then—a period marked by the extinction of the island's megafauna, the arrival of early hominids by 880,000 years ago, and the arrival of modern humans by 10,000 years ago. Within the last 2,000 years, however, their populations have contracted severely.
Further support for the theory that the giant varanids dispersed to Indonesia from Australia comes from the island of Timor, located between Australia and Flores. Three fossil specimens from Timor represent a new (unnamed) species of giant monitor lizard, which was larger than the Komodo dragon (although smaller than Megalania). More specimens of this new Timor-Australian giant lizard are needed before the species can be formally described.
Journal reference:
Hocknull SA, Piper PJ, van den Bergh GD, Due RA, Morwood MJ, et al. Dragon's Paradise Lost: Palaeobiogeography, Evolution and Extinction of the Largest-Ever Terrestrial Lizards (Varanidae). PLoS ONE, 2009; 4(9): e7241 DOI: 10.1371/journal.pone.0007241
Adapted from materials provided by Public Library of Science, via EurekAlert!, a service of AAAS.

Neon Blue-tailed Tree Lizard Glides Like A Feather, Thanks To Light Bubbly Bones

2009-07-22T08:04:00.000-07:00

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ScienceDaily (July 22, 2009) — Most lacertid lizards are content scurrying in and out of nooks and crannies in walls and between rocks. However, some have opted for an arboreal life style. Neon blue tailed tree lizards (Holaspis guentheri) leap from branch to branch as they scamper through trees in the African forest. There are even anecdotes that the tiny African tree lizards can glide. But without any obvious adaptations to help them to upgrade a leap to a glide, it wasn't clear whether the reptiles really do take to the air and, if they do, how they remain aloft.

Intrigued by all aspects of lacertid locomotion, Bieke Vanhooydonck from the University of Antwerp and her colleagues, Anthony Herrel and Peter Aerts, decided to find out whether neon blue tailed tree lizards really glide. Recruiting undergraduate Greet Meulepas to the team, they began filming dainty neon blue tailed tree lizards, gliding geckos (Ptychozoon kuhli) and the common wall lizard (Podarcis muralis) as the animals leapt from a 2m high platform to see if the neon blue tailed tree lizards really could glide. Vanhooydonck and her colleagues publish their discovery that H. guentheri glide like feathers on 17 July 2009 in the Journal of Experimental Biology.
Unfortunately, filming the lizards was extremely difficult. Having startled the small animals into leaping off the platform, the team had little control over the animal's direction, and couldn't guarantee that it was parallel to their camera. It was also difficult to capture each trajectory with a single camera and tricky to get the lighting conditions right. But after weeks of persistence the team finally collected enough film, as the lizards leapt, to compare their performances.
At first, it didn't look as if the African lizard was gliding any better than the common wall lizard. Both animals were able to cover horizontal distances of 0.5m after leaping from the platform, while the gliding gecko covered distances greater than 1 m, aided by its webbed feet and skin flaps. But when the team compared the lizards' sizes, they noticed that there was a big difference between the common wall lizard and the tree lizard. The tiny tree lizard only weighed 1.5 g, almost 1/3 of the larger common wall lizard's weight and 1/10 the gliding gecko's mass, so Aerts calculated how far each lizard would travel horizontally if they fell like a stone. This time it was clear that the tiny tree lizard was travelling 0.2m further than Aerts would have expected if it were simply jumping off the platform. The tree lizard was definitely delaying its descent and landing more slowly than the common wall lizard; the tree lizard was gliding.
But how was the tiny tree lizard able to remain airborne for so long? Maybe the lizard was squashing itself flat while gliding to increase its surface area and generate more lift. But when the team analysed the lizards' trajectories, the tree lizard's shape did not change. And when Aerts calculated the amount of lift each lizard generated as they descended, it was clear that the tree lizard was unable to produce a lift force. The team realised that instead of increasing its surface area to generate lift, the tree lizard is able to glide because it is so light. The tree lizard's 'wing loading' (mass:surface area ratio) was the same as that of the gliding gecko (assisted by skin flaps and webbed feet) so the tree lizard was able to glide like a feather because it was so light.
Curious to find out why the tree lizard is so light, Herrel contacted Renaud Boistel, Paul Tafforeau and Vincent Fernandez at the European Synchrotron Radiation Facility to scan all three lizards' bodies. Visualising the animals' skeletons with X-rays, it was clear that the tree lizard's bones were packed full of air spaces, making the lizard's skeleton feather light for gliding.
Journal reference:
Vanhooydonck, B., Meulepas, G., Herrel, A., Boistel, R., Tafforeau, P., Fernandez, V. and Aerts, P. Ecomorphological analysis of aerial performance in a non-specialized lacertid lizard, Holaspis guentheri. J. Exp. Biol., 212, 2475-2482
Adapted from materials provided by Journal of Experimental Biology, via EurekAlert!, a service of AAAS. Original article written by Kathryn Knight.

King Crabs Go Deep To Avoid Hot Water

2009-07-19T00:30:00.001-07:00

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ScienceDaily (July 19, 2009) — Researchers from the University of Southampton have drawn together 200 years' worth of oceanographic knowledge to investigate the distribution of a notorious deep-sea giant - the king crab. The results, published this week in the Journal of Biogeography, reveal temperature as a driving force behind the divergence of a major seafloor predator; globally, and over tens of millions of years of Earth's history.

In deep seas all over the world, around 100 species of king crabs live largely undiscovered. The fraction that have been found includes some weird and wonderful examples - Paralomis seagrantii has its eight walking legs and claws entirely covered in long fur-like setae; while related group Lithodes megacanthus grows to lengths of 1.5 metres, and has 15-20-cm long defensive spines covering its body. At temperatures of around 1- 4ºC, these crabs thrive in some of the colder waters on Earth; living and growing very slowly, probably to very old ages. Only in the cooler water towards the poles are king crabs found near the water surface - though temperatures found around some parts of the Antarctic (below 1ºC) are too extreme for their survival.
A paper, published 15 years ago in Nature is thought to show that king crabs evolved from shell-bound hermit crabs - similar to the familiar shoreline animals. Soft-bodied, but shell-free intermediate forms are found only in the shallow waters off Japan, Alaska, and Western Canada.
By looking at 200 years' worth of records from scientific cruises and museum collections, Sally Hall and Dr Sven Thatje from the University of Southampton's School of Ocean and Earth Science at the National Oceanography Centre, Southampton discovered that the soft-bodied forms can live at temperatures about ten degrees higher than the hard-bodied forms, but that both groups can only reproduce when temperature is between 1ºC up to 13-15ºC.
"It seems that most shallow-water representatives of this family are trapped in the coastal regions of the North Pacific because the higher sea surface temperatures further south prevent them from reproducing successfully and spreading," said Dr Thatje.
In order to leave this geographic bottleneck and spread around the world, the shallow water ancestors of current deep-sea groups had to go deep and adapt to the challenges of life in the deep sea. The process of adaptation to constant low temperatures (1-4ºC) prevailing in the deep sea seems to have narrowed the temperature tolerance range of the crabs where they have emerged to the surface waters in the Southern Hemisphere. With differences of only a couple of degrees in temperature affecting the distribution of the king crab, it is difficult to predict the consequences of range expansion in the warming waters around the Antarctic Peninsular region.
King crabs are of great commercial value, and fisheries are established in high latitude regions of both hemispheres. "Understanding their evolutionary history and ecology is key to supporting sustainable fisheries of these creatures," said research student Sally Hall. She adds: "Recent range extensions of king crabs into Antarctica, as well as that of the red king crab Paralithodes camtchaticus in the Barents Sea and along the coast off Norway emphasise the responsiveness of this group to rapid climate change."
This study reveals temperature as a driving force behind the speciation and radiation of a major seafloor predator globally and over tens of millions of years of Earth's history.
The study has been supported by the National Environment Research Council (UK) through a PhD studentship to Sally Hall, and a Research Grant from the Royal Society awarded to Dr Thatje.
Adapted from materials provided by University of Southampton.

Reintroduced Chinese Alligators Now Multiplying In The Wild In China

2009-07-19T00:27:00.000-07:00

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ScienceDaily (July 18, 2009) — The Wildlife Conservation Society announced today that critically endangered alligators in China have a new chance for survival. The WCS's Bronx Zoo, in partnership with two other North American parks and the Department of Wildlife Conservation and Management of the State Forestry Administration of China, has successfully reintroduced alligators into the wild that are now multiplying on their own.

The alligator hatchlings—15 in number—are the offspring of a group of alligators that includes animals from the Wildlife Conservation Society's Bronx Zoo. The baby alligators represent a milestone for the 10-year effort to reintroduce the Chinese alligator on Chongming Island, located at the mouth of China's Yangtze River.
The announcement was made at the International Congress for Conservation Biology, convened by the Society for Conservation Biology in Beijing, China (July 11-16).
"We are grateful to our Chinese partners for their commitment to reintroduce Chinese alligators back into the wild," said Dr. Steven E. Sanderson, President and CEO of the Wildlife Conservation Society. "WCS has championed careful wildlife reintroductions for more than a century. The reintroduction of Chinese alligators is a great example of how WCS partners with governments and local communities around the world to save wildlife and wild places."
"This is fantastic news," said WCS researcher Dr. John Thorbjarnarson, one of the world's foremost experts on crocodilians and a participant in the project. "The success of this small population suggests that there's hope for bringing the Chinese alligator back to some parts of its former distribution."
Plans to reintroduce Chinese alligators started in 1999 with a survey conducted by WCS, the Anhui Forestry Bureau, and the East China Normal University in Anhui Province, the only remaining location where the reptiles are still found in the wild in what is a small fraction of the alligator's former range. The results of the survey were dire, with an estimate of fewer than 130 animals in a declining population.
An international workshop on the species was held in 2001, followed by recommendations for the reintroduction of captive bred alligators. The first three animals released in Hongxing Reserve of Xuancheng County in Anhui in 2003 were from the Anhui Research Center of Chinese Alligator Reproduction (ARCCAR).
To ensure the maximum genetic diversity for the effort, project participants imported 12 more animals to Changxing Yinjiabian Chinese Alligator Nature Reserve from North America, including four from the Bronx Zoo. From this group, three animals from the U.S. were released in 2007 along with three more alligators from Changxing. The alligators were given health examinations by veterinary professionals from WCS's Global Health Program and the Shanghai Wildlife Zoo and fitted with radio transmitters for remote monitoring before being released.
Experts reported that the reintroduced alligators successfully hibernated, and then in 2008, bred in the wild.
With a former range that covered a wide watershed area of East China, the Chinese alligator—or "tu long," which means "muddy dragon"—is now listed as "Critically Endangered" on IUCN's Red List of Threatened Species and is the most threatened of the 23 species of crocodilians in the world today. It is one of only two alligator species in existence (the other is the better known, and much better off, American alligator).
The Yangtze River, where the reintroduction of these alligators took place, is the third longest river in the world (after the Amazon and the Nile) and is China's most economically important waterway. The world's largest hydro-electric dam—the Three Gorges Dam—is also located on the river. The high levels of development along the river have become a challenge for native wildlife; in 2006, a comprehensive search for the Yangtze River dolphin, or baiji, didn't find any, although one isolated sighting of a dolphin was made in 2007.
Other participants in the project include the East China Normal University, Shanghai Forestry Bureau, Changxing Yinjiabian Chinese Alligator Nature Reserve, and Wetland Park of Shanghai Industrial Investment (Holdings) Co. Ltd.
The project is being supported by the Ocean Park Conservation Foundation, Hong Kong.
Adapted from materials provided by Wildlife Conservation Society.

Evolutionary Event Underlying Origin Of Dachshunds, Dogs With Short Legs, Discovered

2009-07-17T02:00:00.001-07:00

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ScienceDaily (July 17, 2009) — A single evolutionary event appears to explain the short, curved legs that characterize all of today's dachshunds, corgis, basset hounds and at least 16 other breeds of dogs, a team led by the National Human Genome Research Institute (NHGRI), part of the National Institutes of Health, reported July 16. In addition to what it reveals about short-legged dogs, the unexpected discovery provides new clues about how physical differences may arise within species and suggests new approaches to understanding a form of human dwarfism.

In a study published in the advance online edition of the journal Science, the researchers led by NHGRI's Elaine Ostrander, Ph.D., examined DNA samples from 835 dogs, including 95 with short legs. Their survey of more than 40,000 markers of DNA variation uncovered a genetic signature exclusive to short-legged breeds. Through follow-up DNA sequencing and computational analyses, the researchers determined the dogs' disproportionately short limbs can be traced to one mutational event in the canine genome — a DNA insertion — that occurred early in the evolution of domestic dogs.
"Every species, including canine and human, carries an amazing record of evolution scripted in its genome that can teach us about the mechanisms at work in biology, as well as about human health and disease," said NHGRI Scientific Director Eric Green, M.D., Ph.D. "This work provides surprising evidence of a new way in which genome evolution may serve to generate diversity within a species."
Specifically, the researchers found that in contrast to other dog breeds, all short-legged dog breeds have an extra copy of the gene that codes for a growth-promoting protein called fibroblast growth factor 4 (FGF4). Although functional, the extra gene lacks certain parts of the DNA code, called introns, found in normal genes. These characteristics led researchers to conclude that the extra gene is a so-called retrogene that was inserted into the dog genome some time after the ancestor of modern dog breeds diverged from wolves.
To understand retrogenes, one first needs to understand how the cell normally makes proteins. To produce a protein, a gene's DNA code is transcribed into a molecule called messenger RNA (mRNA). The mRNA then leaves the cell's nucleus and enters the outer region of the cell, called the cytoplasm. There the mRNA is read by tiny molecular machines, called ribosomes, which use the information to assemble proteins.
Retrogenes are formed when the mRNA encounters something — often a type of virus called a retrovirus — that turns it back into DNA through a process referred to as reverse transcription. This new piece of DNA, which contains the same protein-coding information as the gene that produced the mRNA, may then be inserted back into the genome, usually at a much different place than the original gene. Depending on where it is inserted, this piece of DNA may or may not be capable of producing proteins. If it is functional, it is called a retrogene.
In the case of short-legged dogs, the inserted retrogene results in the overproduction of the FGF4 protein, which researchers hypothesize may turn on key growth receptors at the wrong times during fetal development. Veterinary researchers already know that in certain dog breeds the development of long bones is curtailed due to calcification of growth plates, resulting in short legs with a curved appearance. The trait, called disproportional dwarfism, or chondrodysplasia, is an American Kennel Club standard for more than a dozen domestic dog breeds, including the dachshund, corgi, Pekingese and basset hound. This trait is distinct from the uniformly miniature size of toy breeds, such as the toy poodle.
"Our findings suggest that retrogenes may play a larger role in evolution than has been previously thought, especially as a source of diversity within species," said the study's first author, Heidi G. Parker, Ph.D. of NHGRI. "We were surprised to find that just one retrogene inserted at one point during the evolution of a species could yield such a dramatic physical trait that has been conserved over time."
In the past, retrogenes have been recognized as an important source of changes that have fueled the divergence of species. However, the dog findings are the first example of a retrogene that has spurred significant and long-lasting variation within a single species.
The findings also may have implications for understanding human biology and disease. Researchers note that some people are affected by a similar appearing growth disorder, called hypochondroplasia, which belongs to a group of conditions commonly referred to as dwarfism. While about two-thirds of cases of human hypochondroplasia have been linked to a different gene, the cause of the other one-third remains a mystery.
"This study points to a new gene that should be investigated for its possible role in human hypochondroplasia," said Dr. Ostrander, the study's senior author and a senior investigator in NHGRI's Division of Intramural Research. "Our findings may prove valuable to scientists studying other aspects of human growth and development. The work also underscores the value of canine studies for uncovering new biological mechanisms that are likely relevant to human disease."
In addition to Ostrander and her colleagues at NHGRI, the team included researchers from Cornell University in Ithaca, N.Y.; the University of California, Los Angeles; Oregon Health and Science University, Portland; the Waltham Center for Pet Nutrition in Leicestershire, England; and Affymetrix Corporation, Santa Clara, Calif.
Adapted from materials provided by NIH/National Human Genome Research Institute.

Not Only Dogs, But Deer, Monkeys And Birds Bark To Deal With Conflict

2009-07-15T11:22:00.000-07:00

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ScienceDaily (July 15, 2009) — Biologically speaking, many animals besides dogs bark, according to Kathryn Lord at the University of Massachusetts Amherst, but the evolutionary biologist also says domestic dogs vocalize in this way much more than birds, deer, monkeys and other wild animals that use barks. The reason is related to dogs’ 10,000-year history of hanging around human food refuse dumps, she suggests.

In her recent paper in a special issue of the journal, Behavioural Processes, Lord and co-authors from nearby Hampshire College also provide the scientific literature with its first consistent, functional and acoustically precise definition of this common animal sound.
As Lord, a doctoral candidate in organismic and evolutionary biology at UMass Amherst, explains, “We suggest an alternative hypothesis to one that many biologists seem to accept lately, which seeks to explain dog barking in human-centric terms and define it as an internally motivated vocalization strategy.” In the researchers’ view, however, barking is not a special form of communication between dogs and humans. “What we’re saying is that the domestic dog does not have an intentional message in mind, such as, ‘I want to play’ or ‘the house is on fire,’” explains Lord.
Rather, she and colleagues say barking is the auditory signal associated with an evolved behavior known as mobbing, a cooperative anti-predator response usually initiated by one individual who notices an approaching intruder. A dog barks because she feels an internal conflict―an urge to run plus a strong urge to stand her ground and defend pups, for example. When the group joins in, the barks intimidate the intruder, who often flees.
“We think dogs bark due to this internal conflict and mobbing behavior, but domestic dogs bark more because they are put, and put themselves into, conflicting situations more often,” she says.
The reason traces back to the first dogs that started hanging around human food dumps about 8,000 to 10,000 years ago. They would have experienced a serious disadvantage if they had run a mile away every time a human or other animal approached. As Lord explains, “In evolutionary terms, dogs self-selected the behavior of sticking around, overcoming their fear and being rewarded by getting to eat that meal before some other dog got it. Thus these animals allow people to get unusually close. The scared ones die while those less scared stay, eat, survive and reproduce. So they inherit the tendency.”
She adds, “By contrast, wild animals like wolves have a very long flight distance. They hear something and they run before you’d ever see them. Dogs hang around, but now they have committed to holding their ground and the closer an ‘intruder’ gets, the more likely mobbing is to occur rather than running away.”
An example of the domestic environment (rather than the dog’s own behavior) that increases barking is the animal stuck behind a fence with a person approaching, says Lord. “The dog may either feel anxiety or excitement at seeing a stranger but in either case the dog is prevented from approaching or fleeing. This creates conflict, and thus barking.”
Several technical pages of the researchers’ recent paper identify eight different parameters in three categories which must be met in order to classify a given vocalization as a bark. These include tonality, noise, pitch, volume or amplitude, abrupt onset and pulse duration, for example.
In their view, barking is not self-referential communication to convey a message, but a short, loud sound characterized by combining both noise and tonal sounds, which is unusual in animal calls. This definition widens the bark’s usefulness as a functional behavior seen in many animals, though domesticated dogs display it more often. “Using this definition, even birds bark, and certainly many mammals besides canines, including baboons and monkeys, rodents and deer also bark,” Lord explains. “In a whole bunch of mammals and birds, what they do in such conflicted situations is bark.”
This evolutionary view of barking does not sit well with some pet owners who insist that Buffy communicates with them by barking, the researchers acknowledge. “We understand the objection when people say their dogs bark for supper or to get out and play,” Lord says. “Dogs do quickly learn the simple cause-and-effect relationship between their bark at 10 p.m. and the fact that you’ll get right up and take them outdoors. It’s true, but in our view it’s going too far to suggest the animal is intentionally referring to a specific activity. Rather, it has just learned cues, as it does when it learns to sit or beg for a treat.”
Adapted from materials provided by University of Massachusetts Amherst.

Bee Colony Collapse Disorder: New Bait Lures Varroa Mite To Its Doom

2009-07-15T11:09:00.000-07:00

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ScienceDaily (July 15, 2009) — Varroa mites could literally be walking into a trap—thanks to a new attractant developed by Agricultural Research Service (ARS) scientists in Gainesville, Fla.

The 1/16-inch long parasite, Varroa destructor, is a top pest of honey bees nationwide, hindering the beneficial insects' ability to pollinate almonds, blueberries, apples, zucchini and many other flowering crops.
At the ARS Chemistry Research Unit in Gainesville, research leader Peter Teal and colleagues are testing a bait-and-kill approach using sticky boards and natural chemical attractants called semiochemicals.
In nature, Varroa mites rely on these semiochemicals to locate—and then feed on—the bloodlike hemolymph of both adult honey bees and their brood. Severe infestations can decimate an affected hive within several months—and rob the beekeeper of profits from honey or pollinating services. But in this case, the mites encounter a more heady bouquet of honey bee odors that lure the parasites away from their intended hosts and onto the sticky boards, where they starve.
In preliminary tests, 35 to 50 percent of mites dropped off the bees when exposed to the attractants. Free-roving mites found the semiochemicals even more attractive, according to Teal.
Moreover, the extra dose of semiochemicals wafting through hives didn't appear to significantly interfere with the honey bees' normal behavior or activity, added Teal who, along with postdoctoral associate Adrian Duehl and University of Florida collaborator Mark Carroll, reported the results this past January at the 2009 North American Beekeeping Conference in Reno, Nev.
The team hopes ARS' patenting of the Varroa mite attractants will encourage an industrial partner to develop the technology further.
Adapted from materials provided by USDA/Agricultural Research Service.

Water Snake Startles Fish So They Flee Into Its Jaws

2009-07-14T12:04:00.001-07:00

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ScienceDaily (July 14, 2009) — Forget the old folk tales about snakes hypnotizing their prey. The tentacled snake from South East Asia has developed a more effective technique. The small water snake has found a way to startle its prey so that the fish turn toward the snake's head to flee instead of turning away. In addition, the fish's reaction is so predictable that the snake actually aims its strike at the position where the fish's head will be instead of tracking its actual movement.

"I haven't been able to find reports of any other predators that exhibit a similar ability to influence and predict the future behavior of their prey," says Kenneth Catania, associate professor of biological sciences at Vanderbilt University, who has used high-speed video to deconstruct the snake's unusual hunting technique.
His observations are published the week of June 15 in the online early edition of the Proceedings of the National Academy of Sciences.
Catania, who is the recipient of a MacArthur "genius" award, studies the brains and behavior of species with extreme specializations. He was attracted to the tentacled snake because it is the only snake that comes equipped with a pair of short tentacles on its nose and he was curious about their function.
"Before I begin a study on a new species, it is my practice to spend some time simply observing its basic behavior," Catania explains. The snake forms an unusual "J" shape with its head at the bottom of the "J" when it is fishing. Then it remains completely motionless until a fish swims into the area near the hook of the "J." That is when the snake strikes.
The snakes' motions take only a few hundredths of a second and are too fast for the human eye to follow. However, its prey reacts even faster, in a few thousandths of a second. In fact, fish are famous for the rapidity of their escape response and it has been extensively studied. These studies have found that many fish have a special circuit in their brains that initiates the escape, which biologists call the "C-start." Fish ears sense the sound pressure on each side of their body. When the ear on one side detects a disturbance, it sends a message to the fishes' muscles causing its body to bend into a C-shape facing in the opposite direction so it can begin swimming away from danger as quickly as possible.
Catania is the first scientist to study this particular predator-prey interaction with the aid of a high-speed video camera. When he began examining the movements of the snake and its prey in slow motion, he saw something peculiar. When the fish that the snake targets turn to flee, most of them turn toward the snake's head and many literally swim into its jaws! In 120 trials with four different snakes, in fact, he discovered that an amazing 78 percent of the fish turned toward the snake's head instead of turning away.
Next, the biologist noticed that the first part of its body that the snake moves is not its head. Instead, it flexes a point midway down its body. Using a sensitive hydrophone that he put in the aquarium, he confirmed that this body fake produces sound waves intense enough to trigger the fish's C-start response. Because these sound waves come from the side opposite the snake's head, this reflex action drives the fish to turn and swim directly toward the snake's mouth.
"Once the C-start begins, the fish can't turn back," Catania says. "The snake has found a way to use the fish's escape reflex to its advantage."
As he studied the snake's actions even closer, he made an even more remarkable discovery. When it strikes, the snake doesn't aim for the fish's initial position and then adjust its direction as the fish moves – the way most predators do. Instead it heads directly for the location where it expects the fish's head to be.
"The best evidence for this is the cases when the snake misses," says Catania. "Not all the targeted fish react with a C-start and the snake almost always misses those that don't react reflexively."
Catania's next step will be to determine whether this predictive capability is hard-wired or learned. To do so, he hopes to obtain some baby snakes that have just hatched and videotape their first efforts to catch prey.
The research was supported by a grant from the National Science Foundation.
Adapted from materials provided by Vanderbilt University.

Fire Ant Outcompetes Other Species, Even In Its Native Habitat

2009-07-14T12:01:00.000-07:00

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ScienceDaily (July 14, 2009) — Even in its native Argentina, the fire ant wins in head-to-head competition with other ant species more than three-quarters of the time, according to Agricultural Research Service (ARS) scientists.

ARS scientists at the South American Biological Control Laboratory (SABCL) in Hurlingham, Argentina, have been studying how different ant species fare against the fire ant as part of an effort to learn more about the behavior of this pest—an invasive species in its non-native United States.
Fire ants often attack in swarms--not only causing painful stings to humans, but can even kill small animals. Little has been known, however, about the fire ant's competitive nature or how it interacts with other ants.
SABCL biologist Luis Calcaterra, working closely with lab director Juan Briano, has been studying interactions between the red imported fire ant, Solenopsis invicta, and other aboveground foraging ants in two habitats in northeastern Argentina—using a combination of pitfall traps and baits to study day-to-day activity in ant communities.
The pitfall trap is a 50 milliliter plastic tube buried in the ground and half-filled with soapy water. The bait is one gram of canned tuna placed on a plastic card measuring five centimeters in diameter. The trap and bait gave the scientists a way to determine ant populations at the sites, and showed the dominance of each species.
Some 28 ant species coexisted with S. invicta in an open area of forest growing along a watercourse, whereas only 10 species coexisted with S. invicta in the dry forest grassland. The researchers found that the fire ants had the highest numbers in the open forest area along the watercourse.
Prior to these studies, it was thought that the fire ant—now established throughout the Americas—was not dominant in its native land. But the studies showed that the fire ants were the most ecologically dominant, winning 78 percent of the interactions with other ants, mostly against its most frequent competitor, the South American big-headed ant, Pheidole obscurithorax, an ant of northern Argentina and Paraguay also introduced in the United States. And in battles with the invasive Argentine ant, Linepithema humile, the fire ants were even more dominant, winning out 80 percent of the time.
This study was published in Oecologia, a journal that deals with plant and animal ecology.
Adapted from materials provided by USDA/Agricultural Research Service.

Darwin’s Mystery Of Appearance Of Flowering Plants Explained

2009-07-14T11:58:00.000-07:00

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ScienceDaily (July 14, 2009) — The appearance of many species of flowering plants on Earth, and especially their relatively rapid dissemination during the Cretaceous (approximately 100 million years ago) can be attributed to their capacity to transform the world to their own needs.

In an article in Ecology Letters, Wageningen ecologists Frank Berendse and Marten Scheffer postulate that flowering plants changed the conditions during the Cretaceous period to suit themselves. The researchers have consequently provided an entirely new explanation for what Charles Darwin considered to be one of the greatest mysteries with which he was confronted.
During the Cretaceous, the Earth's surface underwent one of its greatest changes in vegetation composition, a change which also took place with unprecedented speed. Frank Berendse (Professor of Nature Conservation and Plant Ecology), and Marten Scheffer, (Professor of Aquatic Ecology), both at Wageningen University, wanted to understand how this happened. They looked for the explanation in a totally unconventional direction.
Before the early Cretaceous, the vegetation consisted primarily of gymnosperms and ferns. These plants were largely replaced by an entirely new group of plants: the angiosperms (flowering plants). During the early Cretaceous – approximately 125 million years ago – the first flowering plants evolved. Soon thereafter, the gymnosperms in the tropics were replaced almost entirely by the angiosperms. And by the end of the Cretaceous (65 million years ago), the empire of the flowering plants had become definitively established in much of the rest of the world. The gymnosperms continued to exist only in the far north – which is the case even today.
The rapid increase in the fantastic diversity of flowering plants – linked to their rapid conquest of the Earth – was one of the greatest puzzles faced by Charles Darwin. In a letter to Joseph Hooker dated 22 July 1879, he referred to an "abominable mystery". The great diversity of fossil flowering plants from the late Cretaceous, while there were virtually no fossils known from the early Cretaceous, appeared to be completely in conflict with his vision that the emergence of new species could only take place very gradually.
The big question was how this massive change could have taken place with such unprecedented speed. Was it because – just before the Cretaceous – that the big Sauropods were forced out by the much smaller Ornithischian dinosaurs, which then systematically ate all the seedlings of the gymnosperms? Or was it because the flowering plants could evolve simultaneously with many insect species that could pollinate their flowers?
According to Berendse and Scheffer, we must think in a totally different direction. They postulate that the flowering plants were able to change the world to suit their own needs. They grew more rapidly and therefore required more nutrients. In a world that was poor in nutrients and was entirely dominated by the gymnosperms, that kept the soil poor - with their poorly degradable litter - flowering plants had great difficulties to establish. But at some locations where the gymnosperms had temporarily disappeared, for example due to floods, fires or storms, the angiosperms could increase so that they were capable of improving their own conditions with their easily degradable litter.
According to the theory of Berendse and Scheffer, this led to positive feedback; as a result, the flowering plants could increase even more rapidly and were capable of replacing the angiosperms in much of the world. Ultimately, the improved edibility of the leaves and fruits of the flowering plants led to a tremendous increase in the number of plant eaters on the Earth, which opened the way to the rapid evolution of mammals, and finally to the appearance of humans.
Journal reference:
Frank Berendse and Marten Scheffer. The angiosperm radiation revisited, an ecological explanation for Darwin's 'abominable mystery'. Ecology Letters, Published Online: 2 Jul 2009 DOI: 10.1111/j.1461-0248.2009.01342.x
Adapted from materials provided by Wageningen University and Research Centre, via AlphaGalileo.

Scientists Are Learning More About Big Birds From Feathers

2009-07-13T14:24:00.000-07:00

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ScienceDaily (July 13, 2009) — Catching adult eagles for research purposes is no easy task, but a Purdue University researcher has found a way around the problem, and, in the process, gathered even more information about the birds without ever laying a hand on one.

"Many birds are small, easy to catch and abundant," said Andrew DeWoody, associate professor of forestry and natural resources. "With eagles, the effort can be 100 to 1,000 times greater than catching chickadees."
Eagles can be hard to find, they often require live bait to attract and, with sharp talons and beaks capable of snapping off human fingers, they pose a risk to their would-be captors.
Instead of catching eagles, DeWoody collects their feathers and uses the small amount of DNA in them to create a tag that corresponds to a particular bird. Those tags can be used to determine population, parentage, roosting patterns and sex ratio.
"In an afternoon, you can go out and pick up hundreds of feathers," DeWoody said, "As field work goes, it's about as easy as it gets."
DeWoody's method is described in a chapter of the Handbook of Nature Conservation: Global and Economic Issues, which was released this week. The chapter is a compilation of his research on the topic.
Most birds are studied by catching them in nets and attaching tracking devices. Researchers can then follow the birds and use radio technology to triangulate their locations.
Eagles and other large birds present several challenges, however, even beyond catching them.
"Eagles will literally fly hundreds of miles in two days," DeWoody said. "They fly in areas where you can't track them in a pickup truck."
Capturing a bird as large as an eagle can often be traumatic to the animal.
"They're wild animals that don't want to be caught," DeWoody said. "They can get hurt as well. Using feathers, you avoid all that."
And costs can be as high as $5,000 for the tracking technology that researchers must attach to eagles, a prohibitive cost if studying more than a few birds.
DeWoody's studies were done in Kazakhstan with imperial eagles, a top predator of international concern because its population is declining.
The feathers give a good picture of recent eagle habits because they do not survive long in Kazakhstan's winters. Any feathers collected after the winter thaw, then, had to have been recently dropped. In one study, DeWoody's team found that an area thought to have about 40 juvenile eagles living in it based on human observation actually had closer to 300.
The work also helped researchers understand more about the roosting habits of some eagles that use a nest for months at a time versus others who float around from roost to roost. Another study showed that DNA could be used to distinguish eagle species from one another, and that imperial, golden and white-tailed eagles often utilized the same roosts at the same time.
The National Geographic Society and the National Birds of Prey Trust funded DeWoody's research.
Journal reference:
Jamie A. Rudnick, Todd E. Katzner and J. Andrew DeWoody. Genetic Analyses of Noninvasively Collected Feathers Can Provide New Insights Into Avian Demography and Behavior. Handbook of Nature Conservation: Global and Economic Issues, 2009
Adapted from materials provided by Purdue University.

Male Seahorses Like Big Mates

2009-07-12T23:28:00.001-07:00

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ScienceDaily (July 13, 2009) — Male seahorses have a clear agenda when it comes to selecting a mating partner: to increase their reproductive success. By being choosy and preferring large females, they are likely to have more and bigger eggs, as well as bigger offspring, according to Beat Mattle and Tony Wilson from the Zoological Museum at the University of Zurich in Switzerland.

Seahorses have a unique mode of reproduction: male pregnancy. Male seahorses provide all post-fertilization parental care, yet despite the high levels of paternal investment, they have long been thought to have conventional sex roles, with females choosing mating partners and males competing for their attention. However, clutch, egg and offspring size all increase with female body size in seahorses, suggesting that males may obtain fecundity benefits by mating with large-bodied females.
Mattle and Wilson investigated the mating behavior of the pot-bellied seahorse (Hippocampus abdominalis), concentrating on the importance of partner body size in mate selection. A total of 10 female and 16 male sexually mature seahorses, obtained from a captive breeding facility in
Tasmania, took part in the experiment. Individuals of both sexes were presented with potential mating partners of different sizes. Mating preferences were quantified in terms of time spent courting each potential partner.
Mattle and Wilson found striking differences in courtship behavior between male and female seahorses, with choosy males and indiscriminate females.
Male seahorses were highly active and showed a clear preference for larger partners. In contrast, females were significantly less active and showed ambiguous mating preferences.
The authors conclude: "The strong male preferences for large females demonstrated here suggest that sexual selection may act strongly on female body size in wild populations of H. abdominalis, consistent with predictions on the importance of female body size for reproductive output in this species."
Their findings have just been published online in Springer's journal Behavioral Ecology and Sociobiology.
Adapted from materials provided by Springer Science+Business Media, via AlphaGalileo.

Southern Elephant seals responded rapidly to climate and habitat change.

2009-07-11T22:31:00.001-07:00

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ScienceDaily (July 12, 2009) — Southern Elephant seals responded rapidly to climate and habitat change and established a new breeding site thousands of kilometres from existing breeding grounds, according to new research.

An international research team, including post-doctorate Dr Mark de Bruyn and collaborators from the US, South Africa and Italy, led by Professor Rus Hoelzel from the School of Biological and Biomedical Sciences, Durham University, found that when the Antarctic ice sheets of the Ross Sea Embayment retreated in the Holocene period 8,000 years ago, elephant seals, Mirounga leonina, adopted the emergent habitat and established a new population which flourished.
DNA sequences from the ancient remains of seals from the now extinct Antarctic colony showed high levels of genetic diversity, probably due to the very large population size sustained there. The study, published in the academic journal PLoS Genetics, and funded by the US National Science Foundation, shows how environmental change can drive the demographic and evolutionary processes that determine diversity within and among species.
Tracking these processes during periods of change reveals mechanisms for the establishment of populations, and provides predictive data on response to potential future impacts, including those caused by climate change.
Professor Rus Hoelzel said: "In general, this approach of looking to the past to understand what might happen in the future, has good potential for predicting the impact of environmental change in both marine and terrestrial systems.
"We've shown how a highly mobile marine species responded to the gain and loss of new breeding habitat. The new habitat was quickly adopted, probably because seals migrate annually into Antarctic waters to feed. However, when the ice returned and the habitat was lost, only a small proportion returned to the original source population. The Antarctic population crashed and much diversity was lost."
This habitat was released after the retreat of the grounded ice sheet in the Ross Sea Embayment 7,500-8,000 years ago, and is within the range of modern foraging excursions from the Macquarie Island colony. Using ancient mtDNA and evolutionary models, the research team tracked the population dynamics of the now extinct colony and the connectivity between this and modern breeding sites.
The team found clear signs of rapid expansion in the new colony 8,000 years ago. This was followed by directional migration away, coupled with a loss of diversity 1,000 years ago, when the sea ice is thought to have expanded. The data suggest that the new colony seals came initially from Macquarie Island, and that some returned there, but in much smaller numbers, when the new colony habitat was lost 7,000 years later.
In order to understand how biodiversity is generated and maintained over time, the team has set out to understand the process by which the seal populations formed and diverged. They analysed data from ancient DNA to show how elephant seal populations responded when new breeding habitat was gained and then lost over the course of approximately 7,000 years.
Professor Rus Hoelzel said: "Using ancient DNA, we were able to track the dynamics and diversity of a population from its foundation, through to its extinction, in the context of Holocene climate change. We learned that new habitat emerging within the species' migratory range could be quickly taken advantage of, but that the reverse was not true. The movement patterns of seals from this Antarctic breeding site would have been unlikely to take them near other potential breeding sites, and so when their breeding site was lost, their numbers crashed.
"The seals that discovered the new breeding site had things good, because food was abundant and nearby, however when the ice returned, the new colony collapsed and only a few seals made it back to their original home.
"This illustrates the importance of understanding the behaviour and life history of a species, in order to model how it may be able to respond to rapid change."
The key factors in the expansion of the new colony were likely to be the abundant local food resource and extensive physical habitat that allowed rapid expansion after the initial founder event, and a tendency for females to return to annual breeding sites in this species.
When the ice expanded again 1,000 years ago, the seals returned to their origins but in much smaller numbers.
Adapted from materials provided by Durham University, via EurekAlert!, a service of AAAS.

A new way of estimating species richness.

2009-07-11T22:28:00.000-07:00

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ScienceDaily (July 12, 2009) — Ask biologists how many species live in a pond, a grassland, a mountain range or on the entire planet, and the answers get increasingly vague. Hence the wide range of estimates for the planet's biodiversity, predicted to be between 2 million and 50 million species.

A new way of estimating species richness reported this month in the journal Ecology Letters by University of California, Berkeley, ecologist John Harte and colleagues, will make such estimates more precise for habitats of all sizes and types, from deserts to tropical rainforests.
"We know how to census the number of species in a square-meter plot or within an acre, but a major problem in conservation biology and ecology is estimating the diversity of biota at very large spatial scales, such as in the Amazon," said Harte, UC Berkeley professor of energy and resources. "This theory provides a much more accurate means of doing that."
The method, derived from the field of information theory, will affect not only conservation efforts to save species facing habitat loss, but also estimates of the impact of global warming, Harte said.
"Quantifying the magnitude of the extinction crisis involves estimating the richness of life in different habitats," he said. "The new theory is probably going to reduce the direness of the predictions of species loss under either habitat loss or climate change at the largest spatial scales, but it will increase (the direness) of estimates of loss at smaller scales."
Losing half of a small biome, for example, will have a worse impact than people think, while losing half of a large area would turn out better, he said.
Harte, who spends his summers in the Rocky Mountains studying the impact of climate change on plants, has for decades mulled over the problem of extrapolating from small study plots to large areas. Census takers have mastered this art, profiling the U.S. population by sampling small representative subsets. When biologists try to profile specific animals, plants or microbes of the Amazon, however, the estimates based on a small number of meter- or acre-size plots can vary by a factor of 10.
Ecological estimates of the number of species at large scales come from a hypothetical curve based on fractals, which predicts that the number of species will increase with area, but increase more slowly for larger and larger areas - a power-law rise with the number of species proportional to the ¼ power of the area.
"You can sample an area and count the number of species, and then double the area and find more species, but not twice as many, because the species overlap," Harte said.
He and colleague Jessica Green showed in 2003 that the theory of fractals, which posits that physical patterns such as the distribution of plants look similar on small and large scales, does not explain species richness over large areas. In addition, experimental tests of the species-area relationship showed that the curve has to be tweaked for every class of organisms and habitat studied.
Harte and colleagues Adam Smith of UC Berkeley and David Storch of Charles University in Prague, Czech Republic, decided to approach the problem from the perspective of information theory, which has provided key insights into thermodynamics and statistical mechanics.
In their report, they say that maximizing the information entropy - making full use of what is known from small plots without assuming anything about the unknown, larger areas - "provided a formal and robust derivation of the relationship between number of species and area."
The method not only scales up from measurements in small plots to provide more precise estimates of the number of species over large areas, but provides a universal species-area relationship, Harte emphasized.
"People have been finding different curves when looking at different organisms or in different habitats, but in fact, all these curves are the same," he said. "There really is a universal curve people are sampling, they are just sampling along different parts of the curve depending on the habitat or class of organisms."
Harte, Smith and Storch tested their theory with data from one of the few areas on Earth that has been thoroughly studied on both the small and large scale - the Western Ghats mountain range of India overlooking the Arabian Sea. A "biodiversity hotspot" of nearly 60,000 square kilometers, the Western Ghats are partially protected and have been studied extensively by Indian scientists in small sections - 48 quarter-hectare plots - and through large-scale surveys, Harte said.
While earlier species-area theories predict between 400 and 500 species of trees throughout the range of low hills, Harte's theory estimates around 1,070. To date, Indian scientists have documented more than 900 tree species in the preserve. Because a handful of new species is discovered each year, scientists guess that the Western Ghats contain between 1,000 and 1,100 species in all, Harte said.
"Before our publication, there really was no solidly-based theory that provided a means of making such estimates," he said.
The newly derived relationship between number of species and area is mathematically more complicated, but it does predict that as the area increases, the number of new species found approaches zero. This is more realistic than the previous species-area curve, which theoretically predicts an infinite number of species.
Harte has already received several dozen requests for reprints, and he predicts "it will generate a lot of discussion. I think the debate is going to be interesting."
The study was supported by the National Science Foundation, the Czech Ministry of Education and the Academy of Sciences of the Czech Republic, of which Storch is a member.
Adapted from materials provided by University of California - Berkeley.

Mystery Of Bat With An Extraordinary Nose Solved

2009-07-07T12:35:00.001-07:00

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ScienceDaily (July 7, 2009) — A research paper co-written by a Virginia Tech faculty member explains a 60-year mystery behind a rare bat's nose that is unusually large for its species.

The article, "Acoustic effects accurately predict an extreme case of biological morphology," by Z. Zhang, R. Müller, and S.N. Truong, details the adult Bourret's horseshoe bat (known scientifically as the "Rhinolophus paradoxolophus," meaning paradoxical crest), and it's roughly 9 millimeters in length nose. The typical horseshoe bat's nose is half that long, said Rolf Mueller, an associate professor with the Virginia Tech mechanical engineering department and director for the Bio-inspired Technology (BIT) Laboratory in Danville, Va. "This nose is so much larger than anything else," among other bats of the region, he said.
Mueller's findings show that the bat uses its elongated nose to create a highly focused sonar beam. Bats detect their environment through ultrasonic beams, or sonar, emitted from their mouths -- or noses, as in the case of the paradoxolophus bat. The echoes of the sound wave convey a wealth of information on objects in the bat's environment. This bat from the remote rainforests of South East Asia received its name 58 years ago because of its mysterious trait.
Much like a flashlight with an adjuster that can create an intense but small beam of light, the bat's nose can create a small but intense sonar beam. Mueller and his team used computer animation to compare varying sizes of bat noses, from small noses on other bats to the large nose of the paradoxolophus bat. In what Mueller calls a perfect mark of evolution, he says his computer modeling shows the length of the paradoxolophus bat's nose stops at the exact point the sonar beam's focal point would become ineffective.
"By predicting the width of the ultrasonic beam for each of these nose lengths with a computational method, we found that the natural nose length has a special value: All shortened noses provided less focus of the ultrasonic beam, whereas artificially elongated noses provided only negligible additional benefits," Mueller said. "Hence, this unusual case of a biological shape can be predicted accurately from its physical function alone."
The findings with the paradoxolophus bat are part of a larger study of approximately 120 different bat species and how they use sonar to perceive their environment. Set to finish in February 2010, it is hoped the study's focus on wave-based sensing and communication in bats will help spur groundwork for innovations in cell phone and satellite communications, as well as naval surveillance technology.
Mueller worked on the study with engineers and scientists from China's Shandong University, where he held a professorship when the research project began, and the Vietnamese Academy of Sciences. The article will appear in Physical Review Letters' print edition on July 17 and on the Web site on July 14.
Adapted from materials provided by Virginia Tech, via EurekAlert!, a service of AAAS.

Mangrove-dependent Animals Globally Threatened

2009-07-07T12:32:00.000-07:00

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ScienceDaily (July 7, 2009) — Substantial numbers of terrestrial vertebrates are restricted to mangrove forests. Many of these specialized species are listed as threatened by the International Union for the Conservation of Nature. Prospects for mangrove-restricted animals are bleak, because more than two percent of mangrove forests are lost each year.

More than 40 percent of a sample of amphibians, reptiles, mammals, and birds that are restricted to mangrove ecosystems are globally threatened with extinction, according to an assessment published in the July/August issue of BioScience. The study, by David A. Luther of the University of Maryland and Russell Greenberg of the Smithsonian Migratory Bird Center, was based on an extensive literature search and expert consultations.
The conclusions emphasize the vulnerability of animals that are dependent on a habitat rapidly being lost or degraded through coastal development, overexploitation, pollution, and changes in sea level and salinity.
Mangroves, which are salt-tolerant woody plants concentrated along coastal margins, generally in warm regions, have long been known to support many species of animals. Hundreds of vertebrates are sometimes found in mangroves, but Luther and Greenberg concentrated on the 69 terrestrial vertebrate species and subspecies that seem restricted to mangroves: 48 birds, 14 reptiles, 6 mammals, and 1 amphibian. These include several species with striking adaptations, such as specialized glands to excrete salt. The ground foragers among them feed primarily on crabs, but many of the birds feed on insects. For unclear reasons, mangrove-restricted species and subspecies are concentrated in Asia and Australia.
Between the early 1980s and 2001, between 19 and 35 percent of the world's mangrove forest area was lost. At this rate of loss--about 2 percent each year--mangroves could be extinct in 100 years. Only 27 of the terrestrial vertebrates that are dependent on mangroves have been assessed by the IUCN (International Union for the Conservation of Nature), and 13 of those are classified as threatened on the IUCN Red List, Luther and Greenberg report. They urge research aimed at predicting how continuing changes to mangrove forests are likely to affect the species found there: such information could guide attempts to conserve these specialized ecosystems.
Journal reference:
David A. Luther and Russell Greenberg. Mangroves: A Global Perspective on the Evolution and Conservation of Their Terrestrial Vertebrates. BioScience, July/August
Adapted from materials provided by American Institute of Biological Sciences, via EurekAlert!, a service of AAAS.

New Monkey Discovered In Brazil -- Threatened By Proposed Dams And Other Development In Region

2009-07-07T12:29:00.001-07:00

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ScienceDaily (July 7, 2009) — The Wildlife Conservation Society (WCS) announced on July 7 the discovery of a new monkey in a remote region of the Amazon in Brazil.

The monkey is related to saddleback tamarins, which include several species of monkeys known for their distinctively marked backs. The newly described distinct subspecies was first seen by scientists on a 2007 expedition into the state of Amazonas in northwestern Brazil.
The discovery was published in the June online edition of the International Journal of Primatology. Authors of the study include Fabio Röhe of the Wildlife Conservation Society, José de Sousa e Silva Jr. of Museu Paraense Emílio Goeldi, Ricardo Sampaio of the Instituto Nacional de Parquisas de Amaozônia, and Anthony B. Rylands of Conservation International.
Researchers have dubbed the monkey Mura's saddleback tamarin (Saguinus fuscicollis mura) named after the Mura Indians, the ethnic group of Amerindians of the Purus and Madeira river basins where the monkey occurs. Historically this tribe was spread through the largest territory of any of the Amazonian Indigenous peoples, extending from the Peruvian frontier today (Rio Yavari) east to the Rio Trombetas.
The monkey is mostly gray and dark brown in color, with a distinctly mottled "saddle." It weighs 213 grams (less than ¾ of a pound) and is 240 millimeters (9 inches tall) with a 320 millimeter (12.6 inch) tail.
"The Wildlife Conservation Society is extremely proud to be part of this exciting discovery in the Amazon," said Dr. Avecita Chicchon, Director of WCS's Latin America Programs. "We hope that the discovery will draw attention to conservation in this very fragile but biodiverse region."
According to the study's authors, the monkey is threatened by several planned development projects in the region, particularly a major highway cutting through the Amazon that is currently being paved. Conservationists fear the highway could fuel wider deforestation in the Amazon over the next two decades. Other threats to the region include a proposed gas pipeline and two hydroelectric dams currently in the beginning stages of construction.
"This newly described monkey shows that even today there are still major wildlife discoveries to be made," said the study's lead author, Fabio Röhe of the Wildlife Conservation Society. "This discovery should serve as a wake-up call that there is still so much to learn from the world's wild places, yet humans continue to threaten these areas with destruction."
Journal reference:
Fabio Röhe, José de Sousa e Silva, Ricardo Sampaio and Anthony B. Rylands. A New Subspecies of Saguinus fuscicollis (Primates, Callitrichidae). International Journal of Primatology, 2009; DOI: 10.1007/s10764-009-9358-x
Adapted from materials provided by Wildlife Conservation Society, via EurekAlert!, a service of AAAS.

Battle Of The Sexes Benefits Offspring, Says Research In Birds

2009-07-07T00:47:00.001-07:00

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ScienceDaily (July 6, 2009) — Parents compensate for a lazy partner by working harder to bring up their offspring, but not enough to completely make up for the lack of parenting, says research by bird biologists at the University of Bath.

In nature, it is quite rare for both parents to be involved in raising young, but it is very common in birds, some fish and primates including humans. Researchers therefore wanted to find out why, for some animals, parents stick together.
The study, published in the Journal of Evolutionary Biology, analysed more than 50 previous studies of birds to understand why and how they share their parental duties.
The research was led by Dr Freya Harrison and Professor Tamás Székely at the Biodiversity lab at the University of Bath, in collaboration with researchers from the University of Bristol and the University of Debrecen (Hungary).
Dr Harrison explained: “Caring for offspring is essential for their survival in many species, but it is also very costly in time and effort. Time spent bringing up your young means lost opportunities for remating and having more offspring, so parents face a trade-off between caring for current offspring and creating future offspring.
“This creates a conflict of interest between parents, since each parent would benefit by leaving their partner holding the baby whilst they go off and start a new brood elsewhere.
“This is exactly what happens in most animal species, so we wanted to understand how and why animals like birds and primates have evolved the tendency to share their parental duties.”
The researchers analysed data published over the last 30 years on parenting in birds to see if there was a common pattern in the behaviour of all the species studied.
Dr Harrison said: “In our study we found that if one parent starts slacking off or deserts, its mate works harder to bring up the brood, but not so hard as to completely compensate for their partner’s laziness.
“Some say that marriage is a state of antagonistic cooperation - in this case we found that the secret to a stable pairing was to only partially compensate for your lazy partner’s failings, to make sure that they stick around.”
Professor Innes Cuthill, Professor of Behavioural Ecology at the University of Bristol, added: “Of course, we are not claiming that fish and birds, or even humans, are necessarily making a consciously calculated decision.
“More likely there are innate rules for responding, perhaps modified through learning, that allow successful participation in joint activities without leaving room for being exploited.”
The researchers hope that this work could help scientists better understand how biparental care has evolved in humans.
The study was supported by the European Commission coordination action project: Integrating Cooperation Research Across Europe (INCORE).
Journal reference:
Harrison et al. How is sexual conflict over parental care resolved? A meta-analysis. Journal of Evolutionary Biology, 2009; DOI: 10.1111/j.1420-9101.2009.01792.x
Adapted from materials provided by University of Bath.

Once-a-month Pill For Both Fleas And Ticks In Dogs And Cats

2009-07-05T22:42:00.001-07:00

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ScienceDaily (July 6, 2009) — Scientists in New Jersey are describing discovery and successful tests of the first once-a-month pill for controlling both fleas and ticks in domestic dogs and cats.

Peter Meinke and colleagues at Merck Research Laboratories note the need for better ways of controlling fleas and ticks, driven in part by increases in pet ownership. Estimates suggest that there were 71 million pet dogs and 81 million pet cats in the United States alone in 2007 — up from 61 million and 70 million in 2001.
Although many powders, sprays and other topical agents are on the market, many pet owners prefer the convenience of pills. Products given orally can reach more parts of an animal's body, do not wash off in rain or bath water, and don't transfer from pets to people. At least one existing pill fights fleas in pets, but does not appear effective for ticks.
In tests on fleas and ticks in dogs and cats, a single dose of the new pill was 100 percent effective in protecting against both fleas and ticks for a month. There were no signs of toxic effects on the animals. Scientists obtained the flea and tick fighter from a substance first found in a fungus that "has the potential to usher in a new era in the treatment of ecoparasitic [ticks and fleas, for instance] infestations in companion animals."
Journal reference:
Meinke et al. Discovery of the Development Candidate N-tert-Butyl Nodulisporamide: A Safe and Efficacious Once Monthly Oral Agent for the Control of Fleas and Ticks on Companion Animals. Journal of Medicinal Chemistry, 2009; 52 (11): 3505 DOI: 10.1021/jm801334v
Adapted from materials provided by American Chemical Society.

World's First 'Self-Watering' Plant: Desert Rhubarb

2009-07-05T03:49:00.000-07:00

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ScienceDaily (July 5, 2009) — Researchers from the Department of Science Education-Biology at the University of Haifa-Oranim have managed to make out the "self-irrigating" mechanism of the desert rhubarb, which enables it to harvest 16 times the amount of water than otherwise expected for a plant in this region based on the quantities of rain in the desert. This is the first example of a self-irrigating plant worldwide.

The desert rhubarb grows in the mountains of Israel's Negev desert, where average precipitation is particularly low (75 mm per year). Unlike most of the other desert plant species, which have small leaves so as to minimize moisture loss, this plant is unique in that its leaves are particularly large; each plant's rosette of one to four leaves reaches a total diameter of up to one meter. Prof. Simcha Lev-Yadun, Prof. Gidi Ne'eman and Prof. Gadi Katzir came across this unique plant growing in the desert while studying the field area with students of the Department of Science Education-Biology of the University of Haifa-Oranim, and noticed that its leaves are unusually large and covered with a waxy cuticle. They observed an exceptionally ridged structure on each leaf, forming a leaf structure that resembles the habitat's mountainous topography.
The scientists explained that these deep and wide depressions in the leaves create a "channeling" mountain-like system by which the rain water is channeled toward the ground surrounding the plant's deep root. Other desert plants simply suffice with the rain water that penetrates the ground in its immediate surroundings.
The findings have shown that the natural selection process has resulted in the evolution of this plant's extremely large leaves, which improved its ability to survive in the arid climate of the desert.
The results of experiments and analysis of the plant's growth - in an area with an average annual rainfall of 75 mm - showed that the desert rhubarb is able to harvest quantities of water that are closer to that of Mediterranean plants, reaching up to 426 mm per year. This is 16 times the amount of water harvested by the small-leafed plants of the Negev desert region. When the research team watered the plant artificially, they observed how the water flows along the course of the leave's depressed veins to the ground surrounding the plant's single root and then penetrates the ground to a depth of 10 cm or more. Under the experimental conditions, water penetrated the ground only as deep as 1 cm.
"We know of no other plant in the deserts of the world that functions in this manner," the researchers concluded.
Adapted from materials provided by University of Haifa.

Climate Change And The Mystery Of The Shrinking Sheep

2009-07-04T00:03:00.001-07:00

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ScienceDaily (July 4, 2009) — Milder winters are causing Scotland's wild breed of Soay sheep to get smaller, despite the evolutionary benefits of possessing a large body, according to new research.

The new study provides evidence for climate change as the cause of the mysterious decrease in the size of wild sheep on the Scottish island of Hirta, first reported by scientists in 2007. The researchers believe that, due to climate change, survival conditions on Hirta are becoming less challenging, which means slower-growing, smaller sheep are more likely to survive the winters than they once were. This, together with newly-discovered so-called 'young mum effect' whereby young ewes produce smaller offspring, explains why the average size of sheep on the island is decreasing.
Classical evolutionary theory suggests that over time the average size of wild sheep increases, because larger animals tend to be more likely to survive and reproduce than smaller ones, and offspring tend to resemble their parents. However, among the Soay sheep of Hirta, a remote Scottish island in the St Kilda archipelago, average body size has decreased by approximately 5% over the last 24 years.
The research team analysed body size and life history data, which records the timing of key milestones throughout an individual sheep's life, for Soays on Hirta over this 24 year period. They found that sheep on the island are not growing as quickly as they once did, and that smaller sheep are more likely to survive into adulthood. This is bringing down the average size of sheep in the population over all.
Professor Coulson suggests that this is because shorter, milder winters, caused by global climate change, mean that lambs do not need to put on as much as weight in the first months of life to survive to their first birthday as they did when winters were colder.
He explains: "In the past, only the big, healthy sheep and large lambs that had piled on weight in their first summer could survive the harsh winters on Hirta. But now, due to climate change, grass for food is available for more months of the year, and survival conditions are not so challenging - even the slower growing sheep have a chance of making it, and this means smaller individuals are becoming increasingly prevalent in the population."
Their results suggest that the decrease in average body size seen in Hirta's sheep is primarily an ecological response to environmental changes over the last 25 years; evolutionary change has contributed relatively little.
In addition, the research team also discovered that the age at which a female sheep gives birth affects the size of her offspring. They realised that young Soay ewes are physically unable to produce offspring that are as big as they themselves were at birth. This 'young-mum' effect had not been incorporated into previous analyses of natural selection, which explains in part why the sheep of Hirta are defying biologists' expectations.
"The young mum effect explains why Soay sheep have not been getting bigger, as we expected them to," concludes Professor Coulson, "But it is not enough to explain why they're shrinking. We believe that this is down to climate change. These two factors are combining to override what we would expect through natural selection."
The research was carried out in collaboration with scientists from the Universities of Leeds, Cambridge, Edinburgh and Stanford. It was funded in the UK by the Natural Environment Research Council (NERC).
Journal reference:
Arpat Ozgul et al. The Dynamics of Phenotypic Change and the Shrinking Sheep of St. Kilda. Science, July 3, 2009
Adapted from materials provided by Imperial College London, via EurekAlert!, a service of AAAS.

Small Heat-Shielded Habitats Could Help Threatened Species Survive Climate Change

2009-07-03T13:27:00.001-07:00

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ScienceDaily (July 3, 2009) — Intelligent countryside management could improve the survival chances of animal and plant species threatened by climate change. The creation of small heat-shielded habitats and better links between habitats would counteract a moderate temperature increase and give threatened species more time to adapt better and/or to migrate to cooler regions.

This is the conclusion drawn by scientists at the Helmholtz Centre for Environmental Research (UFZ) from a British study on saving the Large Blue butterfly (Maculinea arion). This butterfly became extinct in Britain in 1979 and was reintroduced there 25 years ago. Since then, the butterfly's reintroduction is seen as a model for the conservation of endangered insects.
A form of countryside management that creates cooler microclimatic conditions, for example through taller grass in today's meadows, should mitigate the effects of global warming in the short and medium term, say the researchers, writing in the current issue of Science. This is, however, not a long-term solution – just a stop-gap for the next few decades.
The Large Blue butterfly (Maculinea arion) is rather rare throughout many European countries. It is found in meadows and pastures where thyme grows because the caterpillars eat only this plant or its close relative, wild marjoram (Origanum vulgare). The butterfly's survival depends on a large number of factors - as it belongs to the genus Maculinea. This means that it is dependent not only on a specific food plant for the caterpillars, but also on a particular species of ant. The caterpillars trick the ants into carrying them into their nest where they feed on the ants' brood through the winter.
However, this trick works only on one very specific type of ant – only Myrmica sabuleti is tricked by the scent of the caterpillars' of the Large Blue. Other ants see through the disguise and remove any caterpillars that have been carried into their nest. During the decline of the Large Blue in Britain, M. sabuleti ants were crowded out by a competing species of ant, M. scabrinoides, which copes better with lower soil temperatures. "A change in the height of the grass by one or two centimetres can result in a two or three degree temperature change in the ants' brood chambers just below the surface," explains Prof. Jeremy A. Thomas of Oxford University. The biologist spent decades studying the complicated interplay and his findings have now been published in the same issue of Science - in a publication to which the Helmholtz scientists refer.
The soil temperature dropped because the meadows on which the butterflies and ants had lived together for so long were grazed less, and because an epidemic among the wild rabbits, which used to keep the grass short, caused their numbers to plummet. A change in land use had thrown the sensitive interplay between the species off balance. By the time this was realised, it was already too late for the Large Blue in Britain. Once the precise reasons for the disappearance of the butterfly populations became known, scientists kept a lookout for suitable donor populations in other European countries so that the butterfly could be reintroduced. Eventually, butterflies were brought in from Sweden and the meadows were kept short in line with the scientific findings.
It was this that turned the reintroduction of the Large Blue into a success story. There are now more butterflies of this highly endangered species living in the UK than there were when records began in the 1950s. "The fact that it was possible to stop and reverse the decline could make this a model for many other insect conservation projects," hopes Jeremy Thomas.
His fellow scientists from the UFZ go a step further in a second article published in Science. The problem with the Large Blue butterfly was that the longer grass made the soil cooler. However, climate change will pose the opposite problem, and many species could simply find it too hot. "We could counter this by simply letting the grass grow longer. Then the microclimate at soil level would remain constant," suggests Dr Josef Settele of the UFZ, one of the two authors of the article. "This may sound trivial, but it is a very simple example of how modified countryside management can cushion against climate changes to give many species a breathing space to adapt or to migrate." Settele coordinates a number of large research projects investigating risks to biodiversity.
In order to recognise environmental changes like these in good time, researchers are now relying on more intensive environmental monitoring. This includes a butterfly monitoring programme in which thousands of volunteers in countries like the UK, the Netherlands and Germany count and record butterflies using the same method. The Europe-wide butterfly-monitoring programme is being coordinated by Butterfly Conservation Europe. In Germany the Helmholtz Centre for Environmental Research (UFZ) has taken on the coordination of the German butterfly-monitoring programme (Tagfalter-Monitoring Deutschland, TMD). "Systematic records, like the ones kept for the Large Blue in England, show the potential offered by data that has been recorded systematically over the long term.
The first four years of the German butterfly-monitoring programme have been very successful. The active participation of around 600 volunteers makes us optimistic that we will be able to make many more statements about a large number of species and large areas in a few years' time," says Elisabeth Kühn, co-author of the UFZ's contribution to Science. In the long term, the TMD data will form an important basis for realistic modelling, e.g. to show the impacts of climate and land use change on butterfly communities. This will provide an opportunity to make forecasts.
The Large Blue butterfly has been included in the European Grassland Butterfly Indicator, which provides information about the ecological status of meadows and pastures by recording typical butterflies. If monitoring can be firmly established as an early-warning system in the long term, there will be a greater chance of preventing species and populations from disappearing entirely, following the British example – ideally before they die out and have to be reintroduced. The UFZ authors therefore highlight the significance of the British study for insect conservation in general: many specialist species, which are frequently endangered, can be conserved only with the help of good ecological data and countryside management which has been derived from it – usually at landscape level.
Journal references:
Josef Settele and Elisabeth Kühn. Insect Conservation. Science, 325, 41-42.
Thomas et al. Successful Conservation of a Threatened Maculinea Butterfly. Science, 2009; 325 (5936): 80 DOI: 10.1126/science.1175726
Dover et al. The influences of landscape structure on butterfly distribution and movement: a review. Journal of Insect Conservation, 2009; 13 (1): 3 DOI: 10.1007/s10841-008-9135-8
Adapted from materials provided by Helmholtz Association of German Research Centres, via EurekAlert!, a service of AAAS.

Salamanders, Regenerative Wonders, Heal Like Mammals, People

2009-07-03T13:24:00.001-07:00

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ScienceDaily (July 2, 2009) — The salamander is a superhero of regeneration, able to replace lost limbs, damaged lungs, sliced spinal cord -- even bits of lopped-off brain.

But it turns out that remarkable ability isn't so mysterious after all -- suggesting that researchers could learn how to replicate it in people.
Scientists had long credited the diminutive amphibious creature's outsized capabilities to "pluripotent" cells that, like human embryonic stem cells, have the uncanny ability to morph into whatever appendage, organ or tissue happens to be needed or due for a replacement.
But in a paper set to appear July 2 in the journal Nature, a team of seven researchers, including a University of Florida zoologist, debunks that notion. Based on experiments on genetically modified axolotl salamanders, the researchers show that cells from the salamander's different tissues retain the "memory" of those tissues when they regenerate, contributing with few exceptions only to the same type of tissue from whence they came.
Standard mammal stem cells operate the same way, albeit with far less dramatic results -- they can heal wounds or knit bone together, but not regenerate a limb or rebuild a spinal cord. What's exciting about the new findings is they suggest that harnessing the salamander's regenerative wonders is at least within the realm of possibility for human medical science.
"I think it's more mammal-like than was ever expected," said Malcolm Maden, a professor of biology, member of the UF Genetics Institute, and author of the paper. "It gives you more hope for being able to someday regenerate individual tissues in people."
Also, the salamanders heal perfectly, without any scars whatsoever, another ability people would like to learn how to mimic, Maden said.
Axolotl salamanders, originally native to only one lake in central Mexico, are evolutionary oddities that become sexually reproducing adults while still in their larval stage. They are useful scientific models for studying regeneration because, unlike other salamanders, they can be bred in captivity and have large embryos that are easy to work on.
When an axolotl loses, for example, a leg, a small bump forms over the injury called a blastema. It takes only about three weeks for this blastema to transform into a new, fully functioning replacement leg -- not long considering the animals can live 12 or more years.
The cells within the blastema appear embryonic-like and originate from all tissues around the injury, including the cartilage, skin and muscle. As a result, scientists had long believed these cells were pluripotential -- meaning they came from a variety of sites and could make a variety of things once functioning in their regenerative mode.
Maden and his colleagues at two German institutions tested that assumption using a tool from the transgenic kit: the GFP protein. When produced by genetically modified cells, GFP proteins have the useful quality of glowing livid green under ultraviolet light. This allows researchers to follow the origin, movement and destination of the genetically modified cells.
The researchers experimented on both adult and embryonic salamanders.
With the embryos, the scientists grafted transgenic tissue onto sites already known to develop into certain body parts, then observed how and where the cells organized themselves as the embryo developed. This approach allowed them to see, literally, what tissues the transgenic tissue made. In perhaps the most vivid result, the researchers grafted GFP-modified nerve cells onto the part of the embryo known to develop into the nervous system. Once the creatures developed, ultraviolet light exams of the adults revealed the GFP cells stretched only along nerve pathways -- like glowing green strings throughout the body
With the adults, they took tissue from specific parts or organs from transgenic GFP-producing axolotls, grafted it onto normal axolotls, then cut away a chunk of the grafted tissue to allow regeneration. They could then determine the fate of the grafted green cells in the emerging blastema and replacement tissue.
The researchers' main conclusion: Only 'old' muscle cells make 'new' muscle cells, only old skin cells make new skin cells, only old nerve cells make new nerve cells, and so on. The only hint that the axolotl cells could revamp their function came with skin and cartilage cells, which in some circumstances seemed to swap roles, Maden said.
Maden said the findings will help researchers zero in on why salamander cells are capable of such remarkable regeneration. "If you can understand how they regenerate, then you ought to be able to understand why mammals don't regenerate," he said.
Maden said UF researchers will soon begin raising and experimenting on transgenic axolotls at UF as part of the The Regeneration Project, an effort to treat human brain and other diseases by examining regeneration in salamanders, newts, starfish and flatworms.
Journal reference:
Martin Kragl et al. Cells keep a memory of their tissue origin during axolotl limb regeneration. Nature, July 2, 2009 DOI: 10.1038/nature08152
Adapted from materials provided by University of Florida, via EurekAlert!, a service of AAAS.

Keeping Fish in Home Aquariums: Two Is Not Company, As Far As Fish Are Concerned

2009-07-02T08:26:00.001-07:00

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ScienceDaily (July 2, 2009) — It might be assumed that aquarium fish don't mind who or what they encounter in their tanks from one minute to the next, if their famously (but incorrectly) short memory is to be believed. Scientists at the Universities of Plymouth and Exeter have carried out research to show this is not the case and are striving to improve conditions for keeping fish in home aquaria.

In line with the aim to establish welfare guidelines for fish, these researchers have been collaborating with the WALTHAM Centre for Pet Nutrition, examining healthy stocking densities and the use of novel objects with fish commonly kept in home aquaria. This current research, to be presented on the 29th of June 2009 at the Society for Experimental Biology Meeting in Glasgow, looked at two common aquaria species, neon tetras and white cloud mountain minnows.
As Dr Katherine Sloman from the University of Plymouth explains 'fish kept alone or in pairs show higher levels of aggression than those kept in groups of ten or more; large groups are also more likely to exhibit natural behaviours such as shoaling'.
Further research is needed to ascertain the criteria for fish welfare in home aquaria; the results of these studies, funded by the WALTHAM Centre for Pet Nutrition, should go some way to improving welfare for these environmentally, economically and socially important and interesting animals.
Adapted from materials provided by Society for Experimental Biology, via EurekAlert!, a service of AAAS.

Study Of Flower Color Shows Evolution In Action

2009-07-01T12:36:00.001-07:00

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ScienceDaily (June 30, 2009) — Scientists at UC Santa Barbara have zeroed in on the genes responsible for changing flower color, an area of research that began with Gregor Mendel's studies of the garden pea in the 1850's.

In an article published recently in the Proceedings of the National Academies of Sciences, two researchers document their studies of the evolution of columbine flowers in North America. They studied red columbines pollinated by hummingbirds, and white or yellow columbines pollinated by hawkmoths. They believe that a color shift from red to white or yellow has happened five times in North America.
"What is important in this research is that hawkmoths mostly visit –– and pollinate –– white or pale flowers," said senior author Scott A. Hodges, professor of ecology, evolution and marine biology at UCSB. "We have shown experimentally that hawkmoths prefer these paler colors."
When a plant population shifts from being predominantly hummingbird-pollinated where flowers are red, to hawkmoth-pollinated, natural selection works to change the flower color to white or yellow, he explained.
"Ultimately we want to know if evolution can be predictable," said Hodges. "In other words, we want to know if each time there is an evolutionary change in flower color, does it happen in the same way? Having identified all the genes that are intimately involved with making red and blue columbines now allows us to determine how these evolutionary transitions have occurred."
In earlier research, Hodges showed that flowers evolve in a predictable fashion to match the mouthparts of pollinating birds and insects. Thus the pollinators of the yellow columbine flower, A. longissima, are predicted to have exceptionally long tongues to reach the nectar at the bottom.
Graduate student Nathan J. Derieg is the second author. This research was entirely funded by the National Science Foundation. It is part of a large multi-university study funded by the NSF through UCSB.
Adapted from materials provided by University of California - Santa Barbara.

Biological 'Fountain Of Youth' Found In New World Bat Caves

2009-07-01T08:20:00.000-07:00

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ScienceDaily (July 1, 2009) — Scientists from Texas are batty over a new discovery which could lead to the single most important medical breakthrough in human history—significantly longer lifespans. The discovery, featured on the cover of the July 2009 print issue of The FASEB Journal, shows that proper protein folding over time in long-lived bats explains why they live significantly longer than other mammals of comparable size, such as mice.

"Ultimately we are trying to discover what underlying mechanisms allow for some animal species to live a very long time with the hope that we might be able to develop therapies that allow people to age more slowly," said Asish Chaudhuri, Professor of Biochemistry, VA Medical Center, San Antonio, Texas and the senior researcher involved in the work.
Asish and colleagues made their discovery by extracting proteins from the livers of two long-lived bat species (Tadarida brasiliensis and Myotis velifer) and young adult mice and exposed them to chemicals known to cause protein misfolding. After examining the proteins, the scientists found that the bat proteins exhibited less damage than those of the mice, indicating that bats have a mechanism for maintaining proper structure under extreme stress.
"Maybe Juan Ponce De León wasn't too far off the mark when he searched Florida for the Fountain of Youth," said Gerald Weissmann, M.D., Editor-in-Chief of The FASEB Journal. "As it turns out, one of these bat species lives out its long life in Florida. Since bats are rodents with wings, this chemical clue as to why bats beat out mice in the aging game should point scientists to the source of this elusive fountain."
Journal reference:
Salmon et al. The long lifespan of two bat species is correlated with resistance to protein oxidation and enhanced protein homeostasis. The FASEB Journal, 2009; 23 (7): 2317 DOI: 10.1096/fj.08-122523
Adapted from materials provided by Federation of American Societies for Experimental Biology, via EurekAlert!, a service of AAAS.

Dolphins Get A Lift From Delta Wing Technology

2009-06-28T04:00:00.000-07:00

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ScienceDaily (June 28, 2009) — We can only marvel at the way that dolphins, whales and porpoises scythe through water. Their finlike flippers seem perfectly adapted for maximum aquatic agility. However, no one had ever analysed how the animals' flippers interact with water; the hydrodynamic lift that they generate, the drag that they experience or their hydrodynamic efficiency. Laurens Howle and Paul Weber from Duke University teamed up with Mark Murray from the United States Naval Academy and Frank Fish from West Chester University, to find out more about the hydrodynamics of whale and dolphin flippers.

They publish their finding that some dolphins' fins generate lift in the same way as delta wing aircraft in The Journal of Experimental Biology.
Using Computer tomography scanning of the fins of seven different species ranging from the slow swimming Amazon River dolphin and pygmy sperm whale to the super-fast striped dolphin, the team made scaled models of the flippers of each species. Then they measured the lift and drag experienced by the flipper at inclinations ranging from -45deg. to +45deg. in a flow tunnel running at a speed that would have been the equivalent of 2m/s for the full scale fin.
Comparing the lift and drag coefficients that the team calculated for each flipper at different inclination angles, they found that the flippers behave like modern engineered aerofoils. Defining the flippers' shapes as triangular, swept pointed or swept rounded, the team used computer simulations of the fluid flows around the flippers and found that sweptback flippers generate lift like modern delta wing aircraft. Calculating the flippers' efficiencies, the team found that the bottle nose dolphin's triangular flippers are the most efficient while the harbour porpoise and Atlantic white-sided dolphin's fins were the least efficient.
Commenting that environmental and performance factors probably play a significant role in the evolution of dolphin and whale flipper shapes and their hydrodynamics, Howle and his colleagues are keen to find out more about the link between the flippers' performances and the environment that whales and dolphins negotiate on a daily basis.
Journal reference:
Weber, P. W., Howle, L. E., Murray, M. M. and Fish, F. E. Lift and drag performance of odontocete cetacean flippers. J. Exp. Biol., 212, 2149-2158
Adapted from materials provided by The Journal of Experimental Biology, via EurekAlert!, a service of AAAS. Original article written by Kathryn Knight.

Can't Compete On Dung? Try Mating On Apple Pomace

2009-06-27T00:33:00.001-07:00

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ScienceDaily (June 27, 2009) — In the mating world of yellow dung flies, large, brawny males almost always get the girl. However, a new study suggests that smaller males rule if presented with an opportunity to woo females when they are not hanging out on cow dung. It is the first time alternative male reproductive strategies have been observed in this species.

In a study published in the June 24 Proceedings of The Royal Society B, a group of Syracuse University (N.Y.) undergraduate students found that small male dung flies, which are traditionally unsuccessful at finding and keeping mates on dung pats, successfully mated with females feeding on composting apple pomace. In fact, large males were generally absent from the pomace mounds.
"This is a new chapter in the story of yellow dung flies," says Scott Pitnick, professor of biology in SU's College of Arts and Sciences. "No one has carefully studied this species off the dung. Small male dung flies can't compete with their larger counterparts on the dung, so in this case, they developed a different tactic to successfully pass their genes to the next generation."
Pitnick co-authored the study with the students. The students were enrolled in an advanced biology course designed to teach them to conduct original scientific research. Pitnick co-teaches the course with J. Albert C. Uy. As part of the course, the students were tasked with designing a study around the size and mating success of yellow dung flies.
"After we made our initial field observations for the class assignment, we could tell from our professors' reactions that our discovery was a piece of important information in the field," says Stephen Maheux '09, a biology major who graduated in May. "The course was designed to teach us how to be biologists; as such, we made a unique observation that ultimately resulted in a publication."
Until now, it was thought that yellow dung flies mated almost exclusively on manure. Females are drawn to the dung only when they are ready to mate. Little is known about the feeding habits of females when they are not at the dung pats, Pitnick says. On the other hand, males were thought to hang out almost exclusively around the manure, awaiting the arrival of the females. Competition on the dung among males is fierce and can result in injury or death to smaller males as well as females caught up in the struggle.
But, on Toad Hollow Farms in Nedrow, N.Y., the students noticed large numbers of females feeding on apple pomace in a field adjacent to the cow pasture where they were observing flies on dung pats. Much to the students' surprise, the females were frequently mating on the pomace, and with males that were significantly smaller in size than those found in the cow pasture. Furthermore, none of the sexually aggressive behaviors normally observed on the dung pats occurred on the pomace.
Owned by Bill Guptill, Toad Hollow Farms produces natural compost made from manure, leaf and yard waste, and fruit and vegetable waste from grocers in and around Central New York. Apple pomace is the pressed pulp that remains after juicing. The students' initial observations suggested that the availability of the pomace seemed to provide male dung flies with alternative mating opportunities.
Maheux and biology major Kali Henn, who will be a senior in the fall, continued working with Pitnick after the class concluded to collect and analyze additional data, re-confirm the initial class results, and help write the manuscript that was submitted for publication to The Royal Society.
"The class focuses on enabling students to experience the research process—from formulating questions and making the observations to designing the experiments, analyzing the data and writing the final manuscript," Pitnick says. "In this case, what started as a class exercise ended up as a significant finding in this field."
Adapted from materials provided by Syracuse University.

Evidence Of Memory Seen In Songbird Brain

2009-06-27T00:30:00.001-07:00

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ScienceDaily (June 27, 2009) — When a zebra finch hears a new song from a member of its own species, the experience changes gene expression in its brain in unexpected ways, researchers report. The sequential switching on and off of thousands of genes after a bird hears a new tune offers a new picture of memory in the songbird brain.

The finding, detailed this month in the Proceedings of the National Academy of Sciences, was a surprise, said principal investigator David Clayton, a professor of cell and developmental biology at the University of Illinois. He and his colleagues had not expected to see so many genes involved, and thought that any changes in gene activity after a bird heard a new song would quickly dissipate.
The new experiments uncovered three distinct profiles of gene expression in the brain. One is typical of a bird sitting alone in silence. A second profile appears quickly just after a bird hears a recorded song – but only if the song is new to the bird. A third profile then emerges 24 hours later, after the song has become familiar.
"I can tell you whether the bird has heard a particular song before or not just by looking at the molecular assay," Clayton said.
In the study, each bird was kept in quiet isolation overnight before it heard a recording of a new song. The recording was then repeated every 10 seconds for up to three hours.
"The most important thing in its whole life is the sound of another bird of its species singing," Clayton said.
"And what we found is that 24 hours after the experience its brain is still trying to make sense of what it heard."
The new study took a broad snapshot of gene activity in the brain. Using DNA microarray analysis, the researchers measured changes in levels of messenger RNAs in the auditory forebrain of finches exposed to a new song. These mRNAs are templates that allow the cell to translate individual genes into the proteins that do the work of the cells. Any surge or drop in the number of mRNAs in brain cells after a stimulus offers clues to how the brain is responding.
Some genes were upregulated within 30 minutes of exposure to a new song, the researchers found, and these included a lot of transcription factors that modulate the activity of other genes. Many other genes were downregulated, including those that code for ion channel proteins, which allow ions to flow into the cell. This could be one way that the brain dampens its response to a powerful stimulus, protecting itself from too much disturbance, Clayton said.
"Whenever something unexpected and different comes along, such as the song of a new bird in the neighborhood, it's going to deform the listening bird's neural network," Clayton said. "And so the system has to basically absorb some of that, make some changes and not be overwhelmed by it. If you push the system around too much, cells die."
On the other hand, if the system were completely resistant to disturbance, no memory would form, he said.
Twenty-four hours after the initial stimulus, the pattern of activated genes was entirely different from that of the initial response, regardless of whether the bird heard the song again on day two or not, Clayton said. Those genes that were originally upregulated or downregulated had returned to baseline, and a new network of genes was engaged. A major focus of this new network appears to be the regulation of energy metabolism. This suggests a lot is still going on in the brain, Clayton said.
"It's like we've lifted the hood and we're seeing that these things are just chugging away," Clayton said. "The bird had this one day of experience and a day later the brain is in a different state. It's still in high gear. It's still processing stuff. It's still reverberating and echoing.
Journal reference:
Shu Dong, Kirstin L. Replogle, Linda Hasadsri, Brian S. Imai, Peter M. Yau, Sandra Rodriguez-Zas, Bruce R. Southey, Jonathan V. Sweedler, and David F. Clayton. Discrete molecular states in the brain accompany changing responses to a vocal signal. PNAS, published 18 June 2009, DOI: 10.1073/pnas.0812998106
Adapted from materials provided by University of Illinois at Urbana-Champaign.

Boy Or Girl? In Lizards, Egg Size Matters

2009-06-22T06:34:00.001-07:00

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ScienceDaily (June 22, 2009) — Whether baby lizards will turn out to be male or female is a more complicated question than scientists would have ever guessed, according to a new report published online on June 4th in Current Biology. The study shows that for at least one lizard species, egg size matters.

"We were astonished," said Richard Shine of the University of Sydney. "Our studies on small alpine lizards have revealed another influence on lizard sex: the size of the egg. Big eggs tend to give girls, and small eggs tend to give boys. And if you remove some of the yolk just after the egg is laid, it's likely to switch to being a boy, even if it has female sex chromosomes; and if you inject a bit of extra yolk, the egg will produce a girl, even if it has male sex chromosomes."
In many animals, the sex of offspring depends on specialized sex chromosomes. In mammals and many reptiles, for instance, males carry one X and one Y chromosome, while females have a pair of X chromosomes. In contrast, animals such as alligators depend on environmental cues like temperature to set the sex of future generations.
The new findings add to evidence that when it comes to genetic versus environmental factors influencing sex determination, it doesn't have to be an either/or proposition. In fact, Shine and his colleagues earlier found in hatchlings of the alpine-dwelling Bassiana duperreyi that extreme nest temperatures can override the genetically determined sex, in some cases producing XX boys and XY girls. His group had also noticed something else: large lizard eggs were more likely to produce daughters and small eggs to produce sons.
Despite the correlation, Shine said he had assumed that the association was indirect. In fact, his colleague Rajkumar Radder conducted studies in which he removed some yolk from larger eggs, more likely to produce daughters, to confirm that assumption.
"We were confident that there would be no effect on hatchling sex whatsoever," Shine said. "When those baby boy lizards started hatching out, we were gob-smacked."
Shine thinks there will be much more to discover when it comes to lizard sex determination.
"I suspect that the ecology of a species will determine how it makes boys versus girls, and that our yolk-allocation effect is just the tip of a very large iceberg," he said.
The authors include Rajkumar S. Radder, University of Sydney, Australia; David A. Pike, University of Sydney, Australia; Alexander E. Quinn, University of Canberra, Australia; and Richard Shine, University of Sydney, Australia.
Journal reference:
Rajkumar S. Radder, David A. Pike, Alexander E. Quinn, and Richard Shine. Offspring Sex in a Lizard Depends on Egg Size. Current Biology, 2009; DOI: 10.1016/j.cub.2009.05.027
Adapted from materials provided by Cell Press, via EurekAlert!, a service of AAAS.

Mate Selection: Honesty In Advertising Pays Off

2009-06-19T12:09:00.000-07:00

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ScienceDaily (June 19, 2009) — Throughout the animal kingdom brilliant colors or elaborate behavioral displays serve as "advertisements" for attracting mates. But, what do the ads promise, and is there truth in advertizing? Researchers at Yale theorize that when males must provide care for the survival of their offspring, the males' signals will consistently be honest — and they may devote more of their energy to caring for their offspring than to being attractive.

The idea that males showcase their best qualities to attract females for mating isn't a new one, nor is the idea that they might be deceptive in what they are promoting. Instead, the new findings better predict the requirement for honesty in advertising as a function of the male's suitability for parenting, according to Natasha Kelly, a graduate student in ecology and evolutionary biology at Yale and lead author of the study.
The peacock's ornate fanned tail — or the primping and posturing of a guy in a bar — are "advertisements" or mating displays that take substantial energy to maintain. When a male's energy is heavily focused on keeping up his appearance, he may have little energy to devote to caring for offspring. But that may be okay, say the researchers — in species where he does not really need to tend to the kids.
Previous research suggested that, under certain circumstances, males could be dishonest about their parenting skills and still have high reproductive success. This new model, now appearing in the online version of the Proceedings of the Royal Society B, examines the reliability of males' mating signals when they must care for offspring — an aspect that was missing in earlier studies.
There are many species in which males could, but do not have to, provide parental care — because females will pick up the slack. The Yale researchers focused on those species, like stickleback fish, where females cannot pick up the slack and males who do not provide care risk the survival of their offspring.
"This new work shows that when males can not escape the cost of failing to provide care, their advertisements will tend to tend to reliably indicate how much care they will provide," said senior author Suzanne Alonzo, assistant professor of ecology and evolutionary biology at Yale.
"The qualifier in this case is where males are obligated to provide care," said Kelly. "In that case, the quiet guy in the corner might be giving the more reliable advertisement for fatherhood."
The National Science Foundation and Yale University funded this research.
Journal reference:
Kelly et al. Will male advertisement be a reliable indicator of paternal care, if offspring survival depends on male care? Proceedings of The Royal Society B Biological Sciences, 2009; DOI: 10.1098/rspb.2009.0599
Adapted from materials provided by Yale University, via EurekAlert!, a service of AAAS.

Not One, But Two Kinds Of Males Found In Invasive Round Goby Fish

2009-06-19T02:37:00.000-07:00

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ScienceDaily (June 18, 2009) — Scientists have found the existence of two types of males of a fiercely invasive fish spreading through the Great Lakes, which may provide answers as to how they rapidly reproduce.

The research, published in the Journal of Great Lakes Research, looks at the aggressive round goby, a bottom-dwelling fish which infested the Great Lakes watersheds around 1990. Presently, they are working their way inland through rivers and canal systems and can lead to the decline of native species through competition and predation.
Researchers at McMaster University discovered evidence that in addition to round goby males which guard the nest from predators and look after their offspring, there exists what scientists call "sneaker" males – little males that look like females and sneak into the nests of the larger males.
"The existence of these two kinds of males will help scientists understand how round gobies reproduce, how quickly their populations grow, and track how these populations change over the course of invasion," says Julie Marentette, lead author and a Ph.D. student in the department of Psychology, Neuroscience & Behaviour at McMaster University. "This has the potential to have a significant impact on how researchers tackle what has become a very difficult problem in the Great Lakes."
Because males expend lots of energy or eat less while guarding their nests, and attracting females while providing care can be difficult, males in some species have found a sneakier way to mate, Marentette explains. Instead of courting females and protecting the young, some males will parasitize the courtship –and sometimes the parenting duties –of conventional males. They do this by sneaking into the nests of big males or pretending to be females.
"Prior to our findings, only one type of male reproductive behaviour would have been incorporated into projections and modeling analyses of the population dynamics of round goby invasive capacities", says Sigal Balshine, associate professor in the department of Psychology, Neuroscience & Behaviour and academic advisor on the study. "Our results will shed light on how populations of this invasive species are likely to grow and spread through time and space."
The McMaster scientists compared the physical, hormonal and sperm traits of hundreds of males, and found that the nest-guarding, parental males were big, black and had wide heads. The small female-like sneaker males were tiny, mottled brown and had narrow heads. Both types of males produced sperm, but sneakers produced more sperm than the parental males, and had bigger testes. By contrast, parental males have bigger glands used to produce pheromones that attract females.
Funding for the research was provided by the Natural Sciences and Engineering Research Council of Canada (NSERC), Canada Fund for Innovation, the Ministry of Research and Innovation and the Department of Fisheries and Oceans (DFO).
Adapted from materials provided by McMaster University.

Humans More Related To Orangutans Than Chimps, Study Suggests

2009-06-19T02:12:00.000-07:00

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ScienceDaily (June 18, 2009) — New evidence underscores the theory of human origin that suggests humans most likely share a common ancestor with orangutans, according to research from the University of Pittsburgh and the Buffalo Museum of Science. Reporting in the June 18 edition of the Journal of Biogeography, the researchers reject as "problematic" the popular suggestion, based on DNA analysis, that humans are most closely related to chimpanzees, which they maintain is not supported by fossil evidence.

Jeffrey H. Schwartz, professor of anthropology in Pitt's School of Arts and Sciences and president of the World Academy of Art and Science, and John Grehan, director of science at the Buffalo Museum, conducted a detailed analysis of the physical features of living and fossil apes that suggested humans, orangutans, and early apes belong to a group separate from chimpanzees and gorillas. They then constructed a scenario for how the human-orangutan common ancestor migrated between Southeast Asia—where modern orangutans are from—and other parts of the world and evolved into now-extinct apes and early humans.
The study provides further evidence of the human-orangutan connection that Schwartz first proposed in his book "The Red Ape: Orangutans and Human Origins, Revised and Updated" (Westview Press, 2005).
Schwartz and Grehan scrutinized the hundreds of physical characteristics often cited as evidence of evolutionary relationships among humans and other great apes—chimps, gorillas, and orangutans—and selected 63 that could be verified as unique within this group (i.e., they do not appear in other primates). Of these features, the analysis found that humans shared 28 unique physical characteristics with orangutans, compared to only two features with chimpanzees, seven with gorillas, and seven with all three apes (chimpanzees, gorillas, and orangutans). Gorillas and chimpanzees shared 11 unique characteristics.
Schwartz and Grehan then examined 56 features uniquely shared among modern humans, fossil hominids—ancestral humans such as Australopithecus—and fossil apes. They found that orangutans shared eight features with early humans and Australopithecus and seven with Australopithecus alone. The occurrence of orangutan features in Australopithecus contradicts the expectation generated by DNA analysis that ancestral humans should have chimpanzee similarities, Schwartz and Grehan write. Chimpanzees and gorillas were found to share only those features found in all great apes.
Schwartz and Grehan pooled humans, orangutans, and the fossil apes into a new group called "dental hominoids," named for their similarly thick-enameled teeth. They labeled chimpanzees and gorillas as African apes and wrote in Biogeography that although they are a sister group of dental hominoids, "the African apes are not only less closely related to humans than are orangutans, but also less closely related to humans than are many" fossil apes.
The researchers acknowledge, however, that early human and ape fossils are largely found in Africa, whereas modern orangutans are found in Southeast Asia. To account for the separation, they propose that the last common human-orangutan ancestor migrated between Africa, Europe, and Asia at some point that ended at least 12 million to 13 million years ago. Plant fossils suggest that forests once extended from southern Europe, through Central Asia, and into China prior to the formation of the Himalayas, Schwartz and Grehan write, proposing that the ancestral dental hominoid lived and roamed throughout this vast area; as the Earth's surface and local ecosystems changed, descendant dental hominoids became geographically isolated from one another.
Schwartz and Grehan compare this theory of ancestral distribution with one designed to accommodate a presumed human-chimpanzee relationship. They write that in the absence of African ape fossils more than 500,000 years old, a series of "complicated and convoluted" scenarios were invented to suggest that African apes had descended from earlier apes that migrated from Africa to Europe. According to these scenarios, European apes then diverged into apes that moved on to Asia and into apes that returned to Africa to later become humans and modern apes. Schwartz and Grehan challenge these theories as incompatible with the morphological and biogeographic evidence.
Paleoanthropologist Peter Andrews, a past head of Human Origins at the London Natural History Museum and coauthor of "The Complete World of Human Evolution" (Thames & Hudson, 2005), said that Schwartz and Grehan provide good evidence to support their theory. Andrews had no part in the research, but is familiar with it.
"They have good morphological evidence in support of their interpretation, so that it must be taken seriously, and if it reopens the debate between molecular biologists and morphologists, so much the better," Andrews said. "They are going against accepted interpretations of human and ape relationships, and there's no doubt their conclusions will be challenged. But I hope it will be done in a constructive way, for science progresses by asking questions and testing results."
Schwartz and Grehan contend in the Journal of Biogeography that the clear physical similarities between humans and orangutans have long been overshadowed by molecular analyses that link humans to chimpanzees, but that those molecular comparisons are often flawed: There is no theory holding that molecular similarity necessarily implies an evolutionary relationship; molecular studies often exclude orangutans and focus on a limited selection of primates without an adequate "outgroup" for comparison; and molecular data that contradict the idea that genetic similarity denotes relation are often dismissed.
"They criticize molecular data where criticism is due," said Malte Ebach, a researcher at Arizona State University's International Institute for Species Exploration who also was not involved in the project but is familiar with it.
"Palaeoanthropology is based solely on morphology, and there is no scientific justification to favor DNA over morphological data. Yet the human-chimp relationship, generated by molecular data, has been accepted without any scrutiny. Grehan and Schwartz are not just suggesting an orangutan–human relationship—they're reaffirming an established scientific practice of questioning data."
Journal reference:
John R. Grehan1 and Jeffrey H. Schwartz. Evolution of the second orangutan: phylogeny and biogeography of hominid origins. Journal of Biogeography, 2009 DOI: 10.1111/j.1365-2699.2009.02141.x
Adapted from materials provided by University of Pittsburgh.

Hunters Are Depleting Lion And Cougar Populations, Study Finds

2009-06-19T02:04:00.000-07:00

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ScienceDaily (June 18, 2009) — Sport hunters are depleting lion and cougar populations as managers respond to demands to control predators that threaten livestock and humans, according to a study published in the June 17 issue of PLoS One. The study was led by Craig Packer, a University of Minnesota professor and authority on lion behavior, who worked with an international team of conservationists.

The study looked at numbers of lions and cougars killed by hunters over the past 15 to 25 years in Africa and the western United States. The analysis suggested that management agencies often adjusted quotas to control rather than conserve the big cats in areas where humans or livestock were threatened.
Sport hunting takes a significant toll on these large feline species because replacement males routinely kill their predecessors' cubs to improve their mating opportunities. (Killing cubs forces female lions into estrus or "heat.") The team of scientists confirmed this effect by comparing the impact of hunting on populations of lions, cougars and leopards with its impact on black bear populations because male black bears do not routinely kill infants of other males.
Lion and cougar populations have suffered the greatest decline in African countries and U.S. states where sport hunting has been most intense over the past 25 years, the researchers found. Leopards were not as affected as lions and cougars, most likely because they benefited from reduced numbers of lions. Black bears, by contrast, appear to be thriving despite the thousands of bears killed by hunters.
The study results point to the need for new approaches to protect humans and livestock and to manage sport hunting without endangering these vulnerable species. One possibility would be to restrict sport hunting to older males whose offspring have matured.
"We need to develop scientifically-based strategies that benefit hunters, livestock owners and conservationists," Packer says. "It's important to educate the public about the risks these large predators pose to rural communities and to help hunters and wildlife managers develop methods to sustain healthy populations."
"Packer's colleagues included co-authors Luke Hunter, Executive Director of Panthera and Kristin Nowell from the International Union for the Conservation of Nature Species Survival Commission (IUCN/SSC) Cat Specialist Group, as well as Dave Garshelis, Chair of the IUCN/SSC Bear Specialist Group."
Journal reference:
Packer C, Kosmala M, Cooley HS, Brink H, Pintea L, et al. Sport Hunting, Predator Control and Conservation of Large Carnivores. PLoS ONE, 4(6): e5941 DOI: 10.1371/journal.pone.0005941
Adapted from materials provided by University of Minnesota, via EurekAlert!, a service of AAAS.

Polar Bear And Walrus Populations In Trouble, Stock Assessment Report Suggests

2009-06-19T02:01:00.001-07:00

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ScienceDaily (June 19, 2009) — The U.S. Fish and Wildlife Service has released reports documenting the status of polar bears and Pacific walrus in Alaska. The reports confirm that polar bears in Alaska are declining and that Pacific walrus are under threat. Both species are imperiled due to the loss of their sea-ice habitat due to global warming, oil and gas development, and unsustainable harvest.

“Polar bears and walrus are under severe threat, and unless we act rapidly to reduce greenhouse pollution and protect their habitat from oil development, we stand to lose both of these icons of the Arctic,” said Brendan Cumming, oceans program director at the Center for Biological Diversity.
The reports, issued pursuant to the Marine Mammal Protection Act, summarize information on population abundance and trends of polar bears and walrus, threats to the species, and include calculations of human-caused mortality and whether that mortality is sustainable.
There are two polar bear populations in Alaska: a Southern Beaufort Sea stock, which is shared with Canada, and a Chukchi/Bering Sea stock which is shared with Russia. The Pacific walrus occurs in the Bering and Chukchi seas and is shared with Russia.
For the Southern Beaufort Sea polar bear stock, the Fish and Wildlife Service estimated a minimum population of 1,397 bears and an annual human-caused mortality of 54 animals, well above the calculated sustainable rate of 22 animals per year. The stock assessment states that “the Southern Beaufort Sea population is now declining.”
For the Chukchi/Bering Sea polar bear stock, the Service estimated a minimum population of 2,000 bears and an annual human-caused mortality of 37 animals from Alaska and between 150-250 bears killed per year in Russia. The calculated sustainable rate of harvest is 30 animals per year. The stock assessment states that “the population is believed to be declining” and is “reduced based on harvest levels that were demonstrated to be unsustainable.”
For the Pacific walrus, the Service estimated a minimum population of 15,164 animals and an annual human-caused mortality of between 4,963 and 5,460 animals. The calculated sustainable rate of harvest is 607 animals per year.
Of the three population estimates, only the estimate for the well-studied Beaufort Sea polar bears is considered reliable. The Chukchi/Bering Sea polar bear population is based on incomplete data and could be an overestimate, while the walrus estimate is an underestimate as it only represents surveys in about half of the walrus habitat and does not account for walrus not counted because they were in the water rather than hauled out on ice.
“These reports publicly confirm what scientists have known for several years: Polar bear and walrus populations in Alaska are in trouble,” added Cummings. “And even if the population numbers are not precise, we know that without their sea-ice habitat they are likely doomed.”
The Marine Mammal Protection Act requires that the secretary of the interior and the secretary of commerce prepare stock assessments for marine mammals. The assessments are meant to be used as the basis for management decisions such as permitting the killing or harassment of the animals from commercial fisheries, oil and gas exploration, boating and shipping, and military exercises.
To ensure that decision-makers have the most accurate information, stock assessments are supposed to be revised every year for endangered marine mammals and every three years for other species. While the National Marine Fisheries Service – the agency responsible for whales, dolphins, and seals – has largely complied with this requirement, the Fish and Wildlife Service, responsible for polar bears, walrus, sea otters, and manatees, had completely ignored it.
In 2007 the Center sued the Wildlife Service and obtained a court order requiring the release of updated reports. Stock assessments for the Florida manatee were released last week, while sea otter reports were issued last year.
The polar bear is currently listed as threatened under the Endangered Species Act as a result of a petition and litigation by the Center for Biological Diversity. The Fish and Wildlife Service is under court order to make a finding on the Center’s petition to protect the Pacific walrus under the Endangered Species Act by September 10, 2009.
A copy of the stock assessments released June 18 can be found at http://alaska.fws.gov/fisheries/mmm/reports.htm
Adapted from materials provided by Center for Biological Diversity.

Biologist Discovers Pink-winged Moth In Chiracahua Mountains

2009-06-12T11:47:00.001-07:00

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ScienceDaily (June 12, 2009) — University of Arizona biologist Bruce Walsh has identified a new species of moth in southern Arizona. Normally, this is not a big deal. The region is one of the most biologically rich areas in the country and collectors have been finding hundreds of new species for decades. This one, however, is different.

Walsh is a professor of ecology and evolutionary biology and a member of the UA's BIO5 Institute. He is best known in the science community as an authority on plant and animal breeding, having written one of the leading textbooks on the subject.
His work also spans several departments and programs, including statistics, applied math, insect science and genetics. He also teaching biostatistics in the UA Zuckerman College of Public Health and has worked with trial attorneys on interpreting DNA evidence. Collecting moths is a hobby.
His new discovery is Lithophane leeae. Walsh found it in the Chiracahua mountains east of Tucson, and reported it in the journal Zoo Keys.
Lithophane moths are members of the noctuid family, which often are dull colored. Walsh's moth, in contrast, is bright pink. He also named it after his wife, Lee, who has an affinity for the color.
Walsh discovered L. leeae while collecting one evening at Onion Saddle, at about 7,700 feet in the Chiracahuas. Collecting involves illuminating a sheet with mercury vapor lamps. Moths are attracted by the lights and will land on the sheet.
"This large moth flew in and we didn't think much of it because there is a silk moth very much like it, a Doris silk moth that feeds on pines that has dark wings with pink on the hind wings. It's fairly common there."
On closer inspection, though, the moth, a female, appeared to be an entirely different species from an entirely different family. Walsh said it currently is the only known individual.
Scientists are generally reluctant to identify a new species based on one individual, but L. leeae appears so distinct from others that Walsh said it is highly unlikely that it is an aberration of an existing species. A DNA barcode later confirmed it as a distinct species.
Walsh said he is confident there are bound to be more. "If this thing is flying at the top of the Chiracahuas, it's probably pretty common," he said.
Finding it is another matter because moths like Lithophane tend to over-winter at higher elevations, hibernating when there is snow on the ground and flying off at the first signs of spring. Walsh said bats are the primary predators of moths, and so if the insects can make it through the winter, when bats hibernate, they will likely do well as the weather gets warmer.
As to why L. leeae hasn't been found before, Walsh theorized that his specimen simply emerged late from hibernation when it was caught. Another theory is that it could be a stray from another mountain range in the region. He said there are a number of species that fly early in the summer and are rare in collections and not often seen in most years.
"We can now add L. leeae to this group of large, but quite elusive, species," he said.
Adapted from materials provided by University of Arizona.

Close Social Ties Make Baboons Better Mothers, Study Finds

2009-06-12T10:35:00.000-07:00

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ScienceDaily (June 11, 2009) — Baboons whose mothers have strong relationships with other females are much more likely to survive to adulthood than baboons reared by less social mothers, according to a new study by researchers at UCLA, the University of Pennsylvania and other institutions.

"If you're a baboon, the strength of your mother's relationship with other females is the best predictor of whether you'll live to have children yourself," said Joan Silk, the study's lead author and a UCLA professor of anthropology. "The study adds to mounting evidence of the biological benefits of close relationships among females."
The findings are significant because "survivorship to reproduction is the gold standard in evolutionary biology," said co-author Dorothy Cheney, a professor of biology at the University of Pennsylvania. "Females who raise offspring to a reproductive age are more likely see their genes pass along, so these findings demonstrate an evolutionary advantage to strong relationships with other females. In evolutionary terms, social moms are the fittest moms — at least when it comes to baboons."
The study appears online in the Proceedings of the Royal Society B, a peer-reviewed journal published by the national academy of science of the United Kingdom and the Commonwealth.
Silk, Cheney and seven other researchers from the University of Pennsylvania, the University of Michigan and the University of St. Andrews in Kenya analyzed 17 years worth of records on more than 66 adult female baboons in the Moremi Game Reserve, a 2,000-square-mile national park in Botswana that teems with wildlife.
Collected on the ground by primatologists who tracked the baboons six days a week, 12 months a year, the records reflected the sex and survival rates of baboon offspring, as well as telling details of the mothers' social lives, including their ranking within the group, as measured by the direction of approach/retreat interactions, and the amount of social interactions they had with each of the group's other females.
In addition to showing how often one animal approached another, the records of social interactions included details of grooming, which is known to be the primary form of social interaction in Old World monkeys. The researchers noted how much time — frequency and duration — the females spent grooming each other and how often they solicited grooming from other females.
Of all the factors studied, the strength of a mother's social bonds with another female had the most significant effect on the survival rates of offspring. A mother's dominance rank proved to have no affect on the survival rate of her offspring.
"We really expected dominance status to be more influential than it proved to be," Silk said.
Offspring from the most social mothers turned out to be about one-and-a-half times more likely to survive to adulthood than offspring from the least social mothers.
The strongest social bonds were measured between mothers and adult daughters, followed by sisters and all other potential relationships, including aunts, nieces, cousins and baboons with no familial ties. Bonds between mothers and adult daughters proved to be three times stronger than those between sisters and 10 times stronger than relationships with other females.
"What really matter to these girls are mother-daughter bonds," Silk said. "They're really strong, and they last forever. If your mom is alive, she's one of your top partners, always. But more importantly, it's the strength of these bonds, because females whose bonds with their mothers and daughters were strong had higher offspring survival than females whose bonds with these relatives were weak."
Silk's past research with Jeanne Altmann, the Eugene Higgins Professor of Ecology and Evolutionary Biology at Princeton University, and Susan C. Alberts, a professor of biology at Duke University, on baboons in the Amboseli Basin of Kenya had found a higher survival rate for baboons with social mothers, but the research only tracked offspring through the first year of life.
For the new study, researchers followed offspring from 1 year of age through sexual maturity — roughly 5 years of age. The new study also differs from past baboon research by focusing on the strength and duration of relationships between pairs of females rather than on the amount of social interactions in general.
"The benefit comes not from being wildly social — it's about having close social bonds," said Cheney, who runs the Moremi baboon-tracking project with University of Pennsylvania psychology professor Robert M. Seyfarth.
"These females form strong relationships with particular partners," Silk said. "They don't treat everyone the same. They spend a lot more time with — and a lot more time grooming — some females than others, and these relationships tend to be very long-lasting."
Additional research is needed to determine how the female bonds improve infant survival, but it may have to do with such stress hormones as cortisol, Silk said. Research has shown that prolonged elevations of stress hormones in primates can lead to cardiovascular disease and other serious health problems. Research has also shown that grooming tends to lower these stress hormones in baboons.
"Our research suggests that somehow there is a link between the kind of social relationships you form and the natural, normal stresses that occur in everyday life, and that seems to have — at least in baboons — a long-term effect on reproductive success," Silk said.
Said to share 92 percent of their DNA with humans, baboons are close relatives of humans. Baboons and humans last shared a common ancestor about 18 million years ago. The new findings on social interactions among mothers parallel recent research that has shown health benefits for humans who enjoy particularly close social networks.
"Our findings suggest benefits from forming close relationships are built into us from a long way back," Silk said.
The research received funding from the National Geographic Foundation, the Research Foundation of the University of Pennsylvania, the Institute for Research in Cognitive Science at the University of Pennsylvania, the National Institute of Health and the National Science Foundation.
Adapted from materials provided by University of California - Los Angeles.

Female Water Striders Expose Their Genitalia Only After Males 'Sing'

2009-06-12T10:21:00.000-07:00

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ScienceDaily (June 11, 2009) — Chang Seok Han and Piotr Jablonski at Seoul National University, Korea have found that by evolving a morphological shield to protect their genitalia from males' forceful copulatory attempts, females of an Asian species of water strider seem to "win" the evolutionary arms race between the sexes. Instead, females only expose their genitalia for copulation after males produce a courtship "song" by tapping the water surface.

150 years after the publication of Charles Darwin's On the Origin of Species, Han and Jablonski used common insects, water striders, to study the intricacies of evolutionary conflict between males and females. The mechanisms for the way Darwinian natural selection, acting separately on males and females, result in different traits in males than in females (for example, different body sizes to guarantee the highest number of offspring during an individual's lifetime) are already quite well understood.
Sometimes, however, a behavioral trait, such as mating frequency, depends on both the male and the female characteristics. Natural selection favors higher mating frequency in males than in females in many animals, including humans. This leads to an evolutionary "arms race" where males evolve adaptations that force females to mate, while females evolve defenses against males' attempts.
As in the arms races between countries and political powers, it is rare for one sex to "win" in this evolutionary race.
However, in the study by Han and Jablonski, carried out at the Laboratory of Behavioral Ecology and Evolution at Seoul National University, females of an Asian species of water striders, Gerris gracilicornis, do seem to win this race as they have evolved a morphological shield behind which their genitalia are hidden from males, protecting them against the males' forceful attempts to mate.
In an apparent response to the female adaptation, after the violent mounting onto the female's back (typical in water striders), males of this species produce courtship signals by tapping the water surface with their middle legs. It is only after receiving the male's "song" that females expose their genitalia for copulation
Journal reference:
Han et al. Female Genitalia Concealment Promotes Intimate Male Courtship in a Water Strider. PLoS ONE, 2009; 4 (6): e5793 DOI: 10.1371/journal.pone.0005793
Adapted from materials provided by Public Library of Science, via EurekAlert!, a service of AAAS.

Temporary Infidelity May Contribute To Stability Of Ancient Relationships

2009-06-05T07:19:00.001-07:00

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ScienceDaily (June 1, 2009) — Fungus-farming ants have cultivated the same fungal crops for 50 million years. Each young ant queen carries a bit of fungus garden with her when she flies away to mate and establish a new nest. Short breaks in the ants' relationship with the fungus during nest establishment may contribute to the stability of this long-term mutualism, according to a study at the Smithsonian Tropical Research Institute in Gamboa, Panama.

"We were struck by the paradox that even though the ants transfer a single fungal strain from generation to generation, nests of different ant species, and even genera, throughout Central America share genetically very similar fungi, indicating that there are exchanges going on between fungi from different nests," said Michael Poulsen, who held a Smithsonian short term fellowship while a doctoral student at the University of Copenhagen. "In these experiments, we found that there is a very short window of time--as the young queen establishes a new nest--when partner switching can occur."
Ants in the genus Acromyrmex cultivate a single fungal species in their nests: Leucoagaricus gonglyophorus. Mature ant colonies contain one fungal clone--a single genotype, which uses several strategies to make sure that other fungi do not invade.
Researchers noticed that several queens from different colonies sometimes start nests very close together and wondered if young queens were given fungi from a nest other than their natal nest—would they treat it as their own fungal crop?
"That's exactly what happens," said Poulsen, now research associate at the University of Wisconsin. "Young queens adopt a fungus from another nest and cultivate it in their new nest. This sort of temporary partner switching probably acts as an evolutionary safety net in the ant-fungus mutualism by preventing the accumulation of deleterious mutations."
The study, published in the journal Evolution, was supported by The Smithsonian Tropical Research Institute, the Lundbeck Foundation, the U.S. National Science Foundation and the Danish National Research Foundation. Panama's National Environmental Authority (ANAM) issued permits.
Journal reference:
Michael Poulsen, Hermógenes Fernández-Marín, Cameron R. Currie, Jacobus J. Boomsma. Ephemeral Windows Of Opportunity For Horizontal Transmission Of Fungal Symbionts In Leaf-cutting Ants. Evolution, 2009; DOI: 10.1111/j.1558-5646.2009.00704.x
Adapted from materials provided by Smithsonian Tropical Research Institute, via EurekAlert!, a service of AAAS.

Basking Sharks: Disappearing Act Of World's Second Largest Fish Explained

2009-05-14T13:23:00.000-07:00

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ScienceDaily (May 14, 2009) — Researchers have discovered where basking sharks – the world's second largest fish – hide out for half of every year, according to a report published online on May 7th in Current Biology. The discovery revises scientists' understanding of the iconic species and highlights just how little we still know about even the largest of marine animals, the researchers said.

"While commonly sighted in surface waters during summer and autumn months, the disappearance of basking sharks during winter has been a great source of debate ever since an article in 1954 suggested that they hibernate on the ocean floor during this time," said Gregory Skomal of Massachusetts Marine Fisheries. "Some 50 years later, we have helped to solve the mystery while completely re-defining the known distribution of this species."
Using new satellite-based tagging technology and a novel geolocation technique, the researchers found that basking sharks make ocean-scale migrations through tropical waters of the Atlantic Ocean during the winter, traveling at depths of 200 to 1,000 meters. Their data show that the sharks sometimes stay at those depths for weeks or even months at a time. "In doing so, they have completely avoided detection by humans for millennia," Skomal said, emphasizing that as one of the very largest of marine animals, the sharks grow to over 10 meters and weigh as much as seven metric tons.
Skomal said they were "absolutely surprised" when they first received a signal from the tagged sharks coming from the tropical waters of the western Atlantic, in the vicinity of the Caribbean and Bahamas. After all, basking sharks were always believed to be cool-water sharks, restricted to temperate regions.
Several factors had made basking sharks a challenge to study. On top of the fact that they disappear for long periods of time, they also feed exclusively on plankton. That means they can't readily be captured with traditional rod-and-reel methods. And even when the sharks are found closer to the ocean surface, they spend their time in the cool-temperature, plankton-rich waters that limit underwater visibility and make diving difficult.
The findings could have important implications for the conservation of basking sharks, which have shown some signs of dramatic decline in the last half century and are listed as threatened by the International Union for Conservation of Nature.
"Coupled with recent genetic data, our finding indicates that the Atlantic population – and perhaps the world population – are connected and may constitute a single population," Skomal said. "Hence, the global population of basking sharks may be even smaller than previously thought." Efforts to boost basking sharks' numbers will therefore need to be coordinated at a global scale.
The authors include Gregory B. Skomal, Massachusetts Division of Marine Fisheries, Oak Bluffs, MA; Stephen I. Zeeman, University of New England, Biddeford, ME; John H. Chisholm, Massachusetts Division of Marine Fisheries, New Bedford, MA; Erin L. Summers, Maine Department of Marine Resources, Boothbay Harbor, ME; Harvey J. Walsh, Woods Hole Oceanographic Institution, Woods Hole, MA; Kelton W. McMahon, Woods Hole Oceanographic Institution, Woods Hole, MA; and Simon R. Thorrold, Woods Hole Oceanographic Institution, Woods Hole, MA.
Journal reference:
Gregory B. Skomal, Stephen I. Zeeman, John H. Chisholm, Erin L. Summers, Harvey J. Walsh, Kelton W. McMahon, and Simon R. Thorrold. Transequatorial Migrations by Basking Sharks in the Western Atlantic Ocean. Current Biology, 2009; DOI: 10.1016/j.cub.2009.04.019
Adapted from materials provided by Cell Press, via EurekAlert!, a service of AAAS.

Communal Stomach Of An Ant Colony

2009-05-10T23:10:00.001-07:00

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ScienceDaily (May 11, 2009) — How do ant colonies manage the nutrients in their food? Audrey Dussutour from the Centre de recherche sur la cognition animale (CNRS/Université Paul Sabatier) and Steve Simpson from Sydney University have shown that an ant colony functions like a “collective mouth and gut”. The members of a colony are capable of dealing with the nutritional needs of their social structure by sharing tasks (foraging, digestion and excretion).

In an ants' nest, food is brought home by only 10% of the colony members - the foragers. This food is then regurgitated and shared among all the ants in the colony. Nutritional needs differ, however, between the young (larvae) and adults of the colony.
Audrey Dussutour and Steve Simpson have recently shown that the larvae, which cannot move or leave the nest, are capable of communicating their nutritional needs to forager ants, who adapt their gathering strategy accordingly. These researchers provided sugar- or protein-rich foods for ant colonies with and without larvae, and observed that ant behaviour differed. When a colony had larvae, high protein foods were preferentially gathered that could sustain larval growth. Inversely, when there were no larvae, the ants preferentially gathered sugar-rich foods.
In a second experiment, the researchers showed that sugar is the key nutrient regulating gathering in ants. Provided with a range of food containing varying proportions of protein and sugar, foragers are capable of harvesting the same quantity of sugar. These researchers also observed that when the food was rich in protein and poor in sugar, the excess of proteins was ejected from the nest. Ants are therefore capable of extracting sugar from food and regurgitating protein in the form of waste pellets.
However, despite this food manipulation, the colonies reared with protein-rich food had extremely high mortality due to protein toxicity and suffered losses of up to 75%. In comparison, the ant colonies reared on food of lower protein content lost less than 5% of their numbers.
The scientists noticed that the mortality was lower in colonies with larvae. They demonstrated that the ants in these colonies managed to partially escape the toxic effects of proteins by giving the work of nutrient processing to the larvae, which are better equipped for protein digestion. The researchers also confirmed the highly toxic effect of protein-rich food on ants, as they had previously demonstrated in fruit flies.
Journal reference:
Dussutour et al. Communal Nutrition in Ants. Current Biology, May 12, 2009; DOI: 10.1016/j.cub.2009.03.015
Adapted from materials provided by CNRS.

Flight Of The Bumble Bee Is Based More On Brute Force Than Aerodynamic Efficiency

2009-05-09T23:55:00.001-07:00

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ScienceDaily (May 10, 2009) — Brute force rather than aerodynamic efficiency is the key to bumblebee flight, Oxford University scientists have discovered.

In recent years scientists have modelled how insect wings interact with the air around them to generate lift by using computational models that are relatively simple, often simplifying the motion or shape of the wings.
"We decided to go back to the insect itself and use smoke, a wind tunnel and high-speed cameras to observe in detail how real bumblebee wings work in free flight," said Dr Richard Bomphrey of the Department of Zoology, co-author of a report of the research published this month in Experiments in Fluids. ‘We found that bumblebee flight is surprisingly inefficient – aerodynamically-speaking it’s as if the insect is ‘split in half’ as not only do its left and right wings flap independently but the airflow around them never joins up to help it slip through the air more easily.’
Such an extreme aerodynamic separation between left and right sets the bumblebee [Bombus terrestris] apart from most other flying animals.
"Our observations show that, instead of the aerodynamic finesse found in most other insects, bumblebees have a adopted a brute force approach powered by a huge thorax and fuelled by energy-rich nectar," said Dr Bomphrey. "This approach may be due to its particularly wide body shape, or it could have evolved to make bumblebees more manoeuvrable in the air at the cost of a less efficient flying style."
Professor Adrian Thomas of Oxford’s Department of Zoology, co-author of the report, said: "a bumblebee is a tanker-truck, its job is to transport nectar and pollen back to the hive. Efficiency is unlikely to be important for that way of life."
Observing insects in free – as opposed to tethered – flight is a considerable challenge. The Oxford team trained bumblebees to commute from their hive to harvest pollen from cut flowers at one end of a wind tunnel. They then used the wind tunnel to blow streams of smoke passed the flying bees, to reveal vortices in the air, and recorded the results with high-speed cameras taking up to 2000 images per second. From these images the team were able to visualise the airflow over flapping bumblebee wings.
The old myth that "bumblebees shouldn’t be able to fly" was based on calculations using the aerodynamic theory of 1918-19, just 15 years after the Wright brothers made the first powered flight. These early theories suggested that bumblebee wings were too small to create sufficient lift but since then scientists have made huge advances in understanding aerodynamics and how different kinds of airflow can generate lift.
Journal reference:
Richard James Bomphrey, Graham K. Taylor and Adrian L. R. Thomas. Smoke visualization of free-flying bumblebees indicates independent leading-edge vortices on each wing pair. Experiments in Fluids, 2009; 46 (5): 811 DOI: 10.1007/s00348-009-0631-8
Adapted from materials provided by University of Oxford.

Baboons Benefit From Strong Social Networks, Expert Says

2009-05-09T09:00:00.001-07:00

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ScienceDaily (May 9, 2009) — Monkey communication expert Robert Seyfarth began his lecture on May 5, the kick-off of the University of Delaware's Year of Darwin celebration, with a true story, documented in 1961, about a female baboon that herded goats in an African village.

The baboon knew all of the relationships between the goats so well that at night she would carry a bleating kid from one barn directly to its mother in another barn.
“For all the centuries we've bred dogs, no dog has exhibited this knowledge of kids and mothers,” said Seyfarth, who is a psychology professor at the University of Pennsylvania. “The question is where does this mind come from?”
Seyfarth transported an audience of about 200 people into the fascinating world of the baboons of Botswana's Okavanga Delta, which he and Dorothy Cheney, his research partner, fellow Penn professor, and spouse, studied from 1992 to 2008.
Based on their research, Seyfarth said, he and Cheney argue that the baboon's ability to recognize social relationships is due to natural selection. This is the process in nature, according to Darwin's theory of evolution, in which only the organisms best adapted to their environment tend to survive and reproduce.
The baboons that Seyfarth and Cheney studied live in groups of 80-90 individuals. Males leave the group in which they are born, while females stay in the group for their entire lives, with close bonds to female relatives.
The females are arranged in a matrilineal hierarchy of families, with ranks maintained for years. Although once in a while a coup is attempted, such moves are not often successful.
“Families stick together,” Seyfarth said. “The rules are, like in a Jane Austen novel, be nice to your relatives and get in with the high-ranking relatives.”
In their experiments, Seyfarth and Cheney observed baboons with names such as Sylvia, Champagne, and Helen, and recorded their language, which consists of no more than 18 sounds, and the interactions of their families.
They found that baboons use certain calls only in certain contexts. Screams and fear barks are only given from a lower-ranking to a higher-ranking baboon, while threat grunts are given only from a higher-ranking to a lower-ranking baboon.
By recording the various calls and then playing them in situations that “break the rules,” the scientists determined from the animals' behavior that baboons are able to put together the discrete elements of identity, kinship, and rank.
“The animals somehow see this world in all of its complexity,” Seyfarth said.
“It's an innate property of the baboon mind -- done instantly and unconsciously,” he noted.
What social factors stress baboons? Seyfarth and Cheney were able to measure the animals' stress levels by analyzing fecal samples for gluccocorticoid stress hormones.
They found that pregnancy and incidences of predation are major stressors. Ninety-five percent of baboon deaths are caused by predators, mostly lions, Seyfarth said.
Also, some high-ranking males practice infanticide, targeting infants by rank. Mothers may form relationships with lower-ranking males who will help look after their babies.
And just as in humans, the loss of a close relative is high on the list, Seyfarth said.
“Females respond to stress by associating with their closest grooming relationships,” Seyfarth said. “They turn to their support network if they lose someone. They broaden and extend to replace old relationships with new ones. Female baboons with strong social bonds survive better,” he said.
This work is highlighted in the award-winning book Baboon Metaphysics: The Evolution of a Social Mind, published by the University of Chicago Press in 2007.
Additional support for the series is being provided by the Provost's Office, the College of Agriculture and Natural Resources, the Science Ethics and Public Policy Program, and the following departments: Biological Sciences, English, Geography, Geological Sciences, Linguistics and Cognitive Science, and Philosophy.
Adapted from materials provided by University of Delaware.

Ultrasonic Communication Among Frogs

2009-05-09T08:58:00.001-07:00

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ScienceDaily (May 9, 2009) — UCLA scientists report on the only known frog species that can communicate using purely ultrasonic calls, whose frequencies are too high to be heard by humans. Known as Huia cavitympanum, the frog lives only on the Southeast Asian island of Borneo.

Ultrasounds are high-pitched sounds more than 20 kilohertz (kHz) in frequency, which exceeds the upper limit of sounds detectable by humans and is far higher than the 5 to 8 kHz frequencies most amphibians, reptiles and birds are capable of hearing or producing. Key parts of the ear must be specially adapted to detect ultrasounds.
The frogs can hear sounds up to 38 kilohertz, the highest frequency any amphibian species has been known to hear, the scientists report. Humans can hear up to about 20 kHz and typically talk at 2 or 3 kHz.
While most of the more than 5,000 frog species worldwide have eardrums that are flat on the side of the head, Huia cavitympanum has eardrums recessed in the side of the skull, similar to mammals.
Peter Narins, UCLA distinguished professor of physiological science and of ecology and evolutionary biology, and Victoria Arch, a UCLA graduate student in ecology and evolutionary biology, spent several nights in the remote area where the frogs live.
"We had very little information suggesting that they would be in this location," said Arch, lead author of the study. "We found them our first night out."
Huia cavitympanum produces some audible calls and others that are entirely ultrasonic.
"You look at the frog and can see it is vocalizing — you can tell because their vocal pouches pulsate — but you don't hear any sound. It's amazing," Arch said. "Then you look down at the recording equipment and see the lights flashing, indicating sound. I have never seen that before. In a frog, it's unprecedented to have purely ultrasonic vocalizations."
Narins and Arch have an idea about why the frogs, which live along a noisy stream, use both ultrasonic communication and calls that are audible to humans.
"Our hypothesis is that these frogs have shifted to use higher frequencies in their communication to avoid the interference of sound produced by rushing water in the lower-frequency range," Arch said. "However, high-frequency sounds do not transmit as far. By producing some lower-frequency calls, they can transmit calls over a greater distance, so they can communicate with frogs that are farther away. But by also producing some calls that are high-frequency — all ultrasonic — they may be able to communicate better over that background noise.
"Producing both types of calls might be a bet-hedging strategy to be heard," Arch said. "This is how males attract females, communicate with one another and establish territorial boundaries."
The research may have implications for improving human hearing aids and addressing hearing loss. Most hearing aids, Narins said, simply amplify sound, including unnecessary background noise. Better hearing aids that are directional, for example, could result from the research.
In 1998, Kraig Adler, a professor of neurobiology and behavior who had been Narins' professor at Cornell University, told Narins he should go to China to see "a frog with an ear canal like a human," Narins recalled.
Narins took the advice. Along with colleagues, including Albert Feng from the University of Illinois, Urbana-Champaign, he discovered a frog species that lives in rushing streams and waterfalls in east-central China called Odorrana tormota (formerly known as Amolops tormotus). Odorrana tormota, Narins found, could detect and produce ultrasounds due to the highly unusual presence of an ear canal. That research was published March 16, 2006, in the journal Nature.
The frogs in China produce very loud calls that are, at the same time, both audible and ultrasonic. In Borneo, however, Huia cavitympanum produces some sounds that are purely ultrasonic.
"That was unique — and the first time that has been found in any frog species," said Narins, who has studied dozens of frog species. "We are reporting this for the first time."
"With the Chinese frog species, every time you see the vocal sac pulsate, you will hear a sound," Arch said. "With the Bornean frog, sometimes you will see it is calling and you don't hear anything; it's all outside of our hearing range."
The frogs in China and Borneo's Huia cavitympanum are the only two frog species known to have recessed ear drums, Narins said.
In China, the scientists had set up a loudspeaker in the frogs' natural habitat near a river, then played frog calls and recorded the frogs' vocal responses with a microphone and very high-frequency equipment.
Later, they learned of this second species in Borneo with similar ear morphology. Narins and Arch went to Borneo in 2007, and Arch went back last summer.
In Borneo, they lived in a camp with a roof and three walls, with one side open. They slept on a wood floor, protected by mosquito nets. Narins was bitten by leeches and woke up several mornings soaked in blood. They ate noodles and peanut butter.
"It was a huge adventure, and so exciting to study the animals in their habitat," Arch said. "You feel like you're eavesdropping on them."
"There are not many places on the planet left that are so pristine and untouched by humans," Narins said. "It's exciting to go there and wonderful to have a sense of discovering something brand-new. We were there a week and saw only two other people."
Arch and Narins studied male frogs. In the majority of frog species, the females do not vocalize, and when they do, they do so less frequently than males, Arch said.
The research was funded by the National Geographic Society's Committee for Research and Exploration, the Paul S. Veneklasen Research Foundation, the National Institute on Deafness and Other Communication Disorders (NIDCD) of the National Institutes of Health, and the National Science Foundation (through a doctoral dissertation improvement grant to Arch).
Co-authors are T. Ulmar Grafe, a faculty member in the biology department at Borneo's University Brunei Darussalam, and Marcos Gridi-Papp, a UCLA postdoctoral scholar in Narins' laboratory.
Journal reference:
Arch et al. Pure Ultrasonic Communication in an Endemic Bornean Frog. PLoS ONE, 2009; 4 (4): e5413 DOI: 10.1371/journal.pone.0005413
Adapted from materials provided by University of California, Los Angeles.

'Gecko Vision': Key To Future Multifocal Contact Lens?

2009-05-08T00:30:00.001-07:00

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ScienceDaily (May 8, 2009) — Nocturnal geckos are among the very few living creatures able to see colors at night, and scientists' discovery of series of distinct concentric zones may lead to insight into better cameras and contact lenses.

The key to the exceptional night vision of the nocturnal helmet gecko is a series of distinct concentric zones of different refractive powers, according to a new study.
This multifocal optical system is comprised of large cones, which the researchers calculated to be more than 350 times more sensitive than human cone vision at the human color vision threshold.
"We were interested in the geckos because they – and other lizards – differ from most other vertebrates in having only cones in their retina," said project leader Lina Roth, PhD, from the Department of Cell and Organism Biology at Lund University in Sweden. "With the knowledge from the gecko eyes we might be able to develop more effective cameras and maybe even useful multifocal contact lenses."
The nocturnal geckos' multifocal optical system gives them an advantage because light of different ranges of wavelengths can focus simultaneously on the retina. Another possible advantage of their optical structure is that their eyes allow them to focus on objects at different distances. Therefore the multifocal eye would generate a sharp image for at least two different depths. Geckos that are active during the day do not possess the distinct concentric zones and are considered monofocal, Roth said.
The scientists also developed a new method to gather optical data from live animals without harm with their modifications to the Hartmann-Shack wavefront sensor.
"Studies of animals with relatively large eyes, such as owls and cats, have included surgery and fixation of the head," the article states. "In this study, we demonstrate that it is possible to obtain high-resolution wavefront measurements of small, unharmed gecko eyes without completely controlling the gaze or the accommodation of the animal eyes."
Journal reference:
Lina S. V. Roth et al. The pupils and optical systems of gecko eyes. Journal of Vision, Volume 9, Number 3, Article 27, Pages 1-11 DOI: 10.1167/9.3.27
Adapted from materials provided by Association for Research in Vision and Ophthalmology, via EurekAlert!, a service of AAAS.

Ants In Southern Hemisphere Richer And More Diversified Than Northern Hemisphere Ants

2009-05-06T09:16:00.001-07:00

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ScienceDaily (May 6, 2009) — There are fewer species of ants in the northern hemisphere than in the southern hemisphere. This is the conclusion drawn by an international team of scientists that have studied 1,003 local ant assemblages on five different continents. According to the study, ant communities in the northern hemisphere may have suffered more extinctions as a result of the climate changes that occurred between 53 and 54 million years ago.

An international team of more than 26 researchers - including scientists from the Autonomous University of Barcelona (AUB) and the Doñana Biological Station - has studied the global patterns that govern the biological diversity of ant communities. They conclude that latitudinal asymmetry is due to climatic and historical differences between hemispheres, which have led to there being a larger number of species of ants in the southern hemisphere than in the northern hemisphere.
"There is a latitudinal gradient in local ant species richness. However, there is latitudinal asymmetry around the equator and, therefore, sites in the southern hemisphere are more diverse than sites in the northern hemisphere", co-author of the study and a researcher at the Ecology Unit and Centre of Ecological Research and Forestry Applications (CREAF) at the AUB, Xavier Arnan explained to SINC.
The study, which was published recently in Ecology Letters, examines species richness in 1,003 local ant assemblages on five different continents. Researchers attribute the differences between hemispheres to climate-related and historical variables such as regional history, disturbance history and the history of climate change itself.
Results suggest that contemporary climatic conditions explain this difference, along with the Eocene climate changes (between 53 and 54 million years ago). "It appears that a greater change in climate since the Eocene (when temperatures were 10ºC warmer than today) in the northern hemisphere than in the southern hemisphere led to a larger number of extinctions in the north with the subsequent effect on ant species richness on a local scale", Arnan indicated.
Australia has more ants than the entire northern hemisphere
Ant species richness ranges from 0 to 184 different species, variations being caused by temperature and rainfall, the levels of which are higher in the southern hemisphere for one same latitude. Almost half (49%) of the variation in the number of species between the different locations studied is due to climate differences.
In 1845, English naturalist Charles Darwin explained that the greater diversity of life forms in the southern hemisphere was related to a more equable climate, a theory this international study supports.
There is such a large difference between the two hemispheres that Australia alone has greater ant species richness than the entire northern hemisphere. Unlike birds, amphibians or plants, ant species richness is greater in dry habitats, particularly in the warmest regions of the planet. "In warm and dry environments, ants are diverse", the ecologists clarify.
The researchers, from eight different countries, contributed to the study with regional data and their own field work. This information was used to create the Global Ant Community Database, "a database that contains information on the diversity and abundance of ant communities in more than 3,000 sites around the world", Arnan informed SINC Arnan.
This is the second study using this database that has been published and one of the first large-scale studies of local communities, in this case between hemispheres, which jointly considers the impact of both historical and contemporary factors on hemispheric diversity asymmetries," the scientist concludes.
Journal reference:
Dunn et al. Climatic drivers of hemispheric asymmetry in global patterns of ant species richness. Ecology Letters, 2009; 12 (4): 324 DOI: 10.1111/j.1461-0248.2009.01291.x
Adapted from materials provided by Plataforma SINC, via AlphaGalileo.

Two Brown Bear Populations In Spain In Danger of Extinction Have Been Isolated For Past 50 Years

2009-05-06T09:13:00.000-07:00

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ScienceDaily (May 6, 2009) — The situation of bears in the Iberian Peninsula is critical. Researchers from the University of Oviedo (UO) and the Superior Council of Scientific Research (SCSR) have performed a genetic identification based on the analysis of stools and hair of brown bears (Ursus arctos) from the Cantabrian mountain range, gathered between 2004 and 2006.

The non-invasive analysis of 146 samples has allowed for the identification of 39 bears in the western sub-population, and 9 in the eastern one, so as to show the genetic structure of the population. In order to obtain the individual genotypes of the bears, scientists have employed 18 micro-satellite markers in a joint fashion, and a sex marker with high-class genetic technology.
"The level of genetic diversity was 45% in the western sub-population, and 25% in the eastern population¨, explain Trinidad Pérez and Ana Domínguez Sanjurjo to SINC, authors of the study and researchers at the Department of Functional Biology (Genetics) at the UO.
According to Pérez, these levels of gene variation (which allow for adaptation, survival and evolution of the species) are ¨among the lowest of those described in scientific literature for this species¨.
The study, which appears in the latest edition of the magazine Conservation Genetics, points out that the difference between the two Cantabrian sub-populations is ¨extreme¨, around 41%. This value is comparable, for example, to that of the chamois (Rupicapra), which are considered a different species.
For Domínguez Sanjurjo, this phenomenon ¨can only be explained by an absolute isolation between both sub-populations, joined with an extremely reduced size in the eastern¨. From this differentiation data between sub-populations, ¨it can be inferred that there has been no genetic flow between them for at least 50 years¨, affirm the scientists.
In this fashion, we know that in the eastern population, the endogamy rate (reproduction of individuals from the same lineage) per generation is approximately 10%, ¨a value with amply exceeds the maximum tolerable rate given for domestic animals, which is 1%¨, asserts Pérez to SINC.
The sub-population has a number of around 20 individuals, a number which ¨is very far from the size considered as a viable minimum, which means its short-term conservation is seriously compromised¨, adds the biologist.
On the other hand, the western sub-population presents moderated levels of diversity, ¨probably due to an important reduction in the number of bears which would have begun 300 years ago¨, highlights Pérez. Although at the end of the 90s, the estimated size of this sub-population was between 50 and 60 members, ¨this number should be situated around 200 individuals for the bear population to be viable short-term¨, declare the scientists.
Connecting populations, a solution
In spite of the fact that the eastern population has less individuals, the western one possesses ¨a great risk of extinction in the near future¨, points out Domínguez. To this end, the researchers explain that ¨the connectivity between the two sub-populations is priority if we want to maintain the eastern nucleus, which would be at risk of immediate extinction¨.
The genetic analysis has allowed for the identification of a macho individual in Palencia belonging to the western sub-population. ¨In theory, if one migrant from one sub-population managed to reproduce with another every 10 years, it would reduce the differentiation between the two bear populations by 20%¨, confirm Pérez and Domínguez. The genetic difference would diminish by 11% if they were two bears. ¨This migration would increase diversity in the eastern sub-population, considerably increasing their possibilities of survival¨, points out Pérez.
In order for the brown bears to be out of danger long-term, ¨it would be necessary to control the population as a whole, estimate size and tendency, procure connectivity between the two sub-populations and avoid losses of habitat¨, conclude the researchers.
Journal reference:
Pérez et al. Non-invasive genetic study of the endangered Cantabrian brown bear (Ursus arctos). Conservation Genetics, 2009; 10 (2): 291 DOI: 10.1007/s10592-008-9578-1
Adapted from materials provided by Plataforma SINC.

How Social Insects Recognize Dead Nestmates

2009-05-06T09:08:00.000-07:00

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ScienceDaily (May 6, 2009) — When an ant dies in an ant nest or near one, its body is quickly picked up by living ants and removed from the colony, thus limiting the risk of colony infection by pathogens from the corpse.

The predominant understanding among entomologists – scientists who study insects – was that dead ants release chemicals created by decomposition (such as fatty acids) that signal their death to the colony's living ants.
But now UC Riverside entomologists working on Argentine ants provide evidence for a different mechanism for how necrophoresis – the removal of dead nestmates from colonies – works.
In a research paper recently published online in the early edition of the Proceedings of the National Academy of Sciences, the researchers report that all ants, both living and dead, have the "death chemicals" continually, but live ants have them along with other chemicals associated with life – the "life chemicals." When an ant dies, its life chemicals dissipate or are degraded, and only the death chemicals remain.
"It's because the dead ant no longer smells like a living ant that it gets carried to the graveyard, not because its body releases new, unique chemicals after death," said Dong-Hwan Choe, the lead author of the research paper and a graduate student working towards his doctoral degree with Michael Rust, a professor of entomology at UCR.
Choe explained that the research paper's results resolve a conundrum of long-standing in animal behavior and correct a misinterpretation of previous results that has become both popular and widespread in literature.
"There is no mistaking that it is the dissipation of chemical signals associated with life rather than the increase of a decomposition product 'death cue' that triggers necrophoric behavior by Argentine ants," he said.
Along with Rust and UCR's Jocelyn Millar, a professor of entomology, Choe used analytical chemistry techniques to identify the "signals of life" in the Argentine ant: the chemicals dolichodial and iridomyrmecin.
"These chemicals, or compounds similar to them, are found in numerous ant species that display necrophoresis," Choe said. "Therefore, these ant species also are likely to have necrophoric behavior triggered by the decrease or absence of chemical signs of life, rather than by cues associated with death. We plan to research this next."
He added that dolichodal, iridomyrmecin, or similar compounds are found also in other insects, such as thrips, stick insects, aphids and rove beetles.
"Understanding the exact mechanism of ant necrophoresis will help researchers develop a more environmentally friendly pest management strategy by which we can achieve results with smaller amounts of insecticide," Choe said. "A recent study on Argentine ants that we did in the lab indicated that nestmates can efficiently distribute slow-acting and non-repellent insecticides among themselves via necrophoresis. When an ant exposed to an insecticide dies in the nest, other ants carry its body around, with the insecticide transferring easily from the corpse to healthy ants."
Choe's coauthors on the research paper are Millar and Rust. The Carl Strom/Western Exterminator Scholarship, a Pi Chi Omega Scholarship and a Bayer Young Scientist of the Year 2008 Scholarship to Choe funded the three-year study.
Choe, who expects to graduate this summer, received his bachelor of science degree in agriculture from Korea University, Seoul (2002), and his master's degree in entomology from UCR (2005).
Journal reference:
Dong-Hwan Choe, Jocelyn G. Millar, and Michael K. Rust. Chemical signals associated with life inhibit necrophoresis in Argentine ants. Proceedings of the National Academy of Sciences, 2009; DOI: 10.1073/pnas.0901270106
Adapted from materials provided by University of California - Riverside.

'Sobering' Decline Of Caribbean's Big Fish, Fisheries: Overfishing Deemed Most Likely Cause

2009-05-06T09:05:00.000-07:00

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ScienceDaily (May 6, 2009) — Sharks, barracuda and other large predatory fishes disappear on Caribbean coral reefs as human populations rise, endangering the region's marine food web and ultimately its reefs and fisheries, according to a sweeping study by researcher Chris Stallings of The Florida State University Coastal and Marine Laboratory.

While other scientists working in the Caribbean have observed the declines of large predators for decades, the comprehensive work by Stallings documents the ominous patterns in far more detail at a much greater geographic scale than any other research to date.
"Seeing evidence of this ecological and economic travesty played out across the entire Caribbean is truly sobering," said Associate Professor John Bruno of the University of North Carolina at Chapel Hill, who served as the PLoS One academic editor for Stallings' new paper.
"I examined 20 species of predators, including sharks, groupers, snappers, jacks, trumpetfish and barracuda, from 22 Caribbean nations," said Stallings, a postdoctoral associate at the FSU Coastal and Marine Laboratory. "I found that nations with more people have reefs with far fewer large fish because as the number of people increases, so does demand for seafood. Fishermen typically go after the biggest fish first, but shift to smaller species once the bigger ones become depleted. In some areas with large human populations, my study revealed that only a few small predatory fish remain."
Stallings said that although several factors -- including loss of coral reef habitats -- contributed to the general patterns, careful examination of the data suggests overfishing as the most likely reason for the disappearance of large predatory fishes across the region. He pointed to the Nassau grouper as a prime example. Once abundant throughout the Caribbean, Nassau grouper have virtually disappeared from many Caribbean nearshore areas and are endangered throughout their range.
"Large predatory fish such as groupers and sharks are vitally important in marine food webs," Stallings said. "However, predicting the consequence of their loss is difficult because of the complexity of predator-prey interactions. You can't replace a 10-foot shark with a one-foot grouper and expect there to be no effect on reef communities. Shifts in abundance to smaller predators could therefore have surprising and unanticipated effects. One such effect may be the ability of non-native species to invade Caribbean reefs."
A case in point, said Stallings, is the ongoing invasion by Pacific lionfish, which were introduced by aquarium releases.
"Lionfish are minor players on their native Pacific reefs, yet they are undergoing a population explosion and overeating small fishes in the greater Caribbean region," said Professor Mark Hixon of Oregon State University, Stallings' doctoral advisor at OSU. "Preliminary evidence suggests that lionfish are less invasive where large predatory native fishes are abundant, such as in marine reserves," Hixon said.
The study also demonstrates the power of volunteer and community research efforts by non-scientists. Stallings used data from the Reef Environmental Education Foundation's (REEF) online database, which contains fish sightings documented by trained volunteer SCUBA divers, including more than 38,000 surveys spanning a 15-year period.
"Chris was completely undaunted by the lack of fisheries data and essentially adopted the 'Audubon Christmas Bird Count' approach in a marine system to find strong evidence for a native fisheries effect," said Felicia Coleman, director of the FSU Coastal and Marine Laboratory and Stallings' postdoctoral advisor.
Given that about half the world's populations live near coastlines and that the world population is growing, demands for ocean-derived protein will continue to increase, Stallings warned. He said meeting such demands while retaining healthy coral reefs may require multiple strategies, including implementation of marine reserves, finding alternative sources of protein, and increased efforts to implement family-planning strategies in densely populated areas.
Journal reference:
Stallings et al. Fishery-Independent Data Reveal Negative Effect of Human Population Density on Caribbean Predatory Fish Communities. PLoS ONE, 2009; 4 (5): e5333 DOI: 10.1371/journal.pone.0005333
Adapted from materials provided by Florida State University, via EurekAlert!, a service of AAAS.

Evolution's Impact On Ecosystems Shown Directly For First Time

2009-04-12T23:49:00.000-07:00

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ScienceDaily (Apr. 12, 2009) — Scientists have come to agree that different environments impact the evolution of new species. Now experiments conducted at the University of British Columbia are showing for the first time that the reverse is also true.

Researchers from the UBC Biodiversity Research Centre created mini-ecosystems in large aquatic tanks using different species of three-spine stickleback fish and saw substantial differences in the ecosystems in as little as 11 weeks.
Their findings are published in the April 1 Advanced Online Publication of the journal Nature.
Stickleback fish originated in the ocean but began populating freshwater lakes and streams following the last ice age. Over the past 10,000 years – a relatively short time span in evolutionary terms – different species with distinct physical traits have emerged in some fresh water lakes.
The UBC study involved new species found in British Columbia lakes that have evolved distinct physical traits: limnetic sticklebacks (smaller open water dwellers with narrow mouths), benthic sticklebacks (larger bottom dwellers with a wide gape) and a generalist species to represent the probable ancestor of the two species.
“Simply by what they eat and how they live, even young species that have ‘recently’ diversified can have a major impact on their food web,” says study lead author Luke Harmon, who conducted the study while a post-doctoral fellow at UBC. He is now an assistant professor at the University of Idaho. “This study adds to a broader body of literature showing that species diversity matters in important ways.”
Further analysis showed the tanks with the two newest species had larger molecules of dissolved organic carbon, or bits of decaying plants and animals. This prevented sunlight from penetrating the water and inhibited plant growth. “Our study shows that through evolution, sticklebacks can engineer the light environment of their own ecosystems,” says co-author Blake Matthews, a UBC post-doctoral fellow who is now a researcher at Eawag, the Swiss Federal Institute of Aquatic Science and Technology. “It also demonstrates how speciation of a predator might alter the evolutionary course of other organisms in the food web.”
“As new species arise from a common ancestor and evolve new ways of exploiting the environment, each inadvertently reshapes the dynamics of the ecosystem around it,” says co-author UBC Prof. Dolph Schluter. “We are just beginning to understand how.”
Journal reference:
Luke J. Harmon, Blake Matthews, Simone Des Roches, Jonathan M. Chase, Jonathan B. Shurin, Dolph Schluter. Evolutionary diversification in stickleback affects ecosystem functioning. Nature, 2009; DOI: 10.1038/nature07974
Adapted from materials provided by University of British Columbia.

Public Trust Doctrine Could Aid Management Of U.S. Ocean Waters

2009-04-12T23:14:00.001-07:00

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ScienceDaily (Apr. 13, 2009) — Since Congress lifted a moratorium on offshore drilling last year, federal lawmakers have grappled with the issue of how best to regulate U.S. ocean waters to allow oil, wave and wind energy development, while sustainably managing critical fisheries and marine animal habitats.

A new policy paper, published April 10 in Science by a team of Duke University experts, argues that establishing a public trust doctrine for federal waters could be an effective and ethical solution to this and similar conflicts.
"The public trust doctrine could provide a practical legal framework for restructuring the way we regulate and manage our oceans. It would support ocean-based commerce while protecting marine species and habitats," says lead author Mary Turnipseed, a PhD student at Duke's Nicholas School of the Environment.
The public trust doctrine is "a simple but powerful legal concept," Turnipseed says, that obliges governments to manage certain natural resources in the best interests of their citizens, without sacrificing the needs of future generations.
The doctrine already is well established in the United States at the state level, where natural resource agencies are legally bound to seek legal action against private parties who are infringing on the public trust.
Extending the public trust doctrine to U.S. ocean waters would help federal agencies better manage conflicting demands such as conservation, offshore energy development, fisheries and shipping in the 3.6 million nautical square miles of water included in the nation's territorial sea and Exclusive Economic Zone (EEZ), Turnipseed says. Currently, more than 20 different federal agencies, operating under dozens of laws, regulate species and activities in these waters, without any mandated, systematic effort to coordinate their actions for the public good.
"In the Gulf of Maine, as an example, a wide range of different activities -- including shipping lanes, ferry routes, U.S. Navy operations, fisheries and proposed wind farms -- overlap critical habitat of the endangered right whale," she says. "Most of these are regulated by separate agencies, with only piecemeal coordination. A public trust doctrine would identify these agencies as trustees of the U.S. ocean public trust, unifying them for the first time under a common mandate to manage the gulf's resources sustainably."
Many analysts, including the presidentially appointed U.S. Commission on Ocean Policy, have simply assumed that the public trust doctrine already extends to these federal waters, notes co-author Stephen Roady, senior lecturing fellow at Duke's School of Law and an environmental lawyer at Earthjustice. "Though the public trust doctrine is well suited to serve as a critical legal foundation for a coordinated, ecosystem-based federal ocean policy, it has not yet been formally articulated by the executive branch, nor has it been recognized by federal courts or expressly established in statutory law," Roady says.
The Duke researchers identify three possible avenues for establishing a public trust doctrine for federal waters.
"Each of the three branches of government has the authority to take action," says Larry B. Crowder, Stephen Toth Professor of Marine Biology at the Nicholas School and director of Duke's Center for Marine Conservation. "The doctrine could be established by a Presidential executive order; federal courts could extend it to the U.S. territorial sea and EEZ by invoking the same precedents and statutes relied upon by state courts; or Congress could mandate it by unambiguously writing the doctrine into a federal oceans law."
Regardless of which approach is used, the need to establish the doctrine is pressing, says Raphael Sagarin, associate director for coastal and ocean policy at Duke's Nicholas Institute for Environmental Policy Solutions.
"We need to move past the failing status quo of current U.S. ocean management policies and build a vigorous mandate that provides both the authority and the responsibility for federal agencies to work jointly to manage our oceans as whole ecosystems," Sagarin says. "As we contemplate managing our ocean resources, not only for today but for future generations, we need to ask ourselves two critical questions: For whom should the country's oceans be managed? And for what purpose? The public trust doctrine answers both of these questions."
Journal reference:
Mary Turnipseed, Larry B. Crowder, Raphael D. Sagarin, and Stephen E. Roady. OCEANS: Legal Bedrock for Rebuilding America's Ocean Ecosystems. Science, 2009; 324 (5924): 183 DOI: 10.1126/science.1170889
Adapted from materials provided by Duke University, via EurekAlert!, a service of AAAS.

Amphibians May Develop Immunity To Fatal Fungus

2009-04-10T11:20:00.001-07:00

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ScienceDaily (Apr. 10, 2009) — Amphibian populations are declining worldwide, principally because of the spread of the fungal disease chytridiomycosis. Researchers know that some amphibian populations and species are innately more susceptible to the disease than others.

Recent preliminary evidence, described in the April issue of BioScience, suggests also that individual amphibians can sometimes develop resistance to chytridiomycosis, which is caused by the fungus Batrachochytrium dendrobatidis (Bd). Jonathan Q. Richmond, of the US Geological Survey, and three coauthors argue that researchers should broaden their studies of chytridiomycosis to include so-called acquired immunity, because this might improve predictive models of Bd's spread and so suggest ways to protect threatened frog and toad populations.
Richmond and colleagues discuss experimental studies indicating that two species of New Zealand frogs infected with Bd but treated with the antimicrobial drug chloramphenicol were later resistant to reinfection with the fungus. Other studies indicate that North American toads that survived after being first exposed to Bd in dry conditions survived longer when reinfected in wet conditions than did toads that were exposed to Bd in wet conditions.
Richmond and colleagues emphasize that innate immunity has to be activated in an animal before acquired immunity can develop. They point to several key immune-system components—notably, toll-like receptors and major histocompatibility complex molecules—that most likely play a role in bridging the innate and the acquired immune systems, and urge researchers to undertake collaborative studies of the genetics of how these systems interact as Bd spreads.
Adapted from materials provided by American Institute of Biological Sciences.

Deep-sea Corals May Be Oldest Living Marine Organism

2009-03-26T01:55:00.000-07:00

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ScienceDaily (Mar. 25, 2009) — Deep-sea corals from about 400 meters off the coast of the Hawaiian Islands are much older than once believed and some may be the oldest living marine organisms known to man.

Researchers from Lawrence Livermore, Stanford University and the University of California at Santa Cruz have determined that two groups of Hawaiian deep-sea corals are far older than previously recorded.
Using the Lab's Center for Accelerator Mass Spectrometry, LLNL researchers Tom Guilderson and Stewart Fallon used radiocarbon dating to determine the ages of Geradia sp., or gold coral, and specimens of the deep-water black coral, Leiopathes sp. The longest lived in both species was 2,740 years and 4,270 years, respectively. At more than 4,000 years old, the deep-water black coral is the oldest living skeletal-accreting marine organism known.
“And to the best of our knowledge, the oldest colonial organism yet found,” Guilderson said. “Based on the carbon 14, the living polyps are only a few years old, or at least their carbon is, but they have been continuously replaced for centuries to millennia while accreting their underlying skeleton.”
The research appears in the March 23 early online edition of the Proceedings of the National Academy of Sciences.
Using a manned deep-sea research submersible, the team used samples that were individually collected from the Makapuu and Lanikai deep-sea coral beds off the coast of Oahu, Keahole Point deep-sea coral bed off the coast of the Big Island and Cross Seamount about 100 miles south of Oahu.
Carbon dating uses radiocarbon (carbon 14) to date the age of an object. Radiocarbon is the most widely used geochronological tool in the earth sciences for the late Quaternary (the last 50,000 years).
Earlier radiocarbon studies showed that individual gold coral colonies from the Atlantic and Pacific oceans have life spans of 1,800 to 2,740 years, but the results remain contentious with some biologists. In particular, some have questioned whether the corals feed on re-suspended sediment (which could be old) and not on recently photosynthesized carbon that falls through the water column, or that they grew faster and then stopped growing when they reached a certain size.
To answer these questions, the group analyzed not only polyps (the living animals that make up corals) but a branch of one specimen.
The living animals had the same carbon 14 concentration as the overlying surface water. This shows that the carbon in the polyps was recently photosynthesized in the surface prior to being “eaten” by the polyps. The skeleton's carbon 14 concentration mimicked that of the overlying surface water's 'post-bomb' time series: the time since the late 1950s when the testing of nuclear weapons augmented the natural abundance of carbon 14 in the atmosphere.
The radial growth rate during the last 50 years is similar to the long-term growth rate of the 300-year branch. The radial growth rate also is consistent with that derived from larger fossil samples. The radial growth rate is similar within a rather small range of tens of microns per year for all specimens analyzed.
In the recent research, the Geradia coral was assumed to be much younger when amino acid and growth band methods were used. With radiocarbon dating, the average life span of the analyzed specimens is 970 years and ranges from about 300 years for a small branch (with a radius of 11 millimeters) to about 2,700 years (with a radius of 38 mm).
“These ages indicate a longevity that far exceeds previous estimates,” Guilderson said. “Many of the Geradia samples that we have analyzed are branches, not the largest portions of the colony and so the ages may not indicate how old the entire individual is.”
Hawaiian deep sea corals face direct threats from harvesting for jewelry and from commercial fisheries that trawl the ocean bottoms. In addition, the close relationship between deep sea corals (and the mid-water ecosystems) and ocean's surface means that they can be affected by natural and manmade changes in surface ocean conditions including ocean acidification, warming and altered stratification.
The antiquity of the coral is an additional call for action, Guilderson said.
“The extremely long life spans reinforce the need for further protection of deep-sea habitat” he said. “The research has already had an impact for activities in Hawaiian waters where a harvesting and fishing moratorium has been enacted to protect certain areas. There are similar habitats in international waters and it is hoped that the results will provide the scientific basis for agreements under the Law of the Sea, and United Nations Environment Programme.”
Journal reference:
E. Brendan Roark, Thomas P. Guilderson, Robert B. Dunbar, Stewart J. Fallon, and David A. Mucciarone. Extreme longevity in proteinaceous deep-sea corals. Proceedings of the National Academy of Sciences, 2009; DOI: 10.1073/pnas.0810875106
Adapted from materials provided by DOE/Lawrence Livermore National Laboratory.

Earliest Evidence Of Domesticated Maize Discovered: Dates Back 8,700 Years

2009-03-26T01:51:00.001-07:00

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ScienceDaily (Mar. 25, 2009) — Maize was domesticated from its wild ancestor more than 8700 years according to biological evidence uncovered by researchers in the Mexico's Central Balsas River Valley. This is the earliest dated evidence -- by 1200 years -- for the presence and use of domesticated maize.

According to Ranere, recent studies have confirmed that maize derived from teosinte, a large wild grass that has five species growing in Mexico, Guatemala and Nicaragua. The teosinte species that is closest to maize is Balsas teosinte, which is native to Mexico's Central Balsas River Valley.
"We went to the area where the closest relative to maize grows, looked for the earliest maize and found it," said Ranere. "That wasn't surprising since molecular biologists had determined that Balsas teosinte was the ancestral species to maize. So it made sense that this was where we would find the earliest domestication of maize."
The study began with Piperno, a Temple University anthropology alumna, finding evidence in the form of pollen and charcoal in lake sediments that forests were being cut down and burned in the Central Balsas River Valley to create agricultural plots by 7000 years ago. She also found maize and squash phytoliths -- rigid microscopic bodies found in many plants -- in lakeside sediments.
Ranere, an archaeologist, joined in the study to find rock shelters or caves where people lived in that region thousands of years ago. His team carried out excavations in four of the 15 caves and rock shelters visited in the region, but only one of them yielded evidence for the early domestication of maize and squash.
Ranere excavated the site and recovered numerous grinding tools. Radiocarbon dating showed that the tools dated back at least 8700 years. Although grinding tools were found beneath the 8700 year level, the researchers were not able to obtain a radiocarbon date for the earliest deposits. Previously, the earliest evidence for the cultivation of maize came from Ranere and Piperno's earlier research in Panama where maize starch and phytoliths dated back 7600 years.
Ranere said that maize starch, which is different from teosinte starch, was found in crevices of many of the tools that were unearthed.
"We found maize starch in almost every tool that we analyzed, all the way down to the bottom of our site excavations," Ranere said. "We also found phytoliths that comes from maize or corn cobs, and since teosinte doesn't have cobs, we knew we had something that had changed from its wild form."
Ranere said that their findings also supported the premise that maize was domesticated in a lowland seasonal forest context, as opposed to being domesticated in the arid highlands as many researchers had once believed.
"For a long time, I though it strange that researchers argued about the location and age of maize domestication yet never looked in the Central Balsas River Valley, the homeland for the wild ancestor," said Ranere. "Dolores was the first one to do it.'
In addition to Ranere and Piperno, other researchers in the study included Irene Holst of the Smithsonian Tropical Research Institute, Ruth Dickau of Temple, and Jose Iriarte of the University of Exeter. The study was funded by the National Science Foundation, National Geographic Society, Wenner-Gren Foundation, Smithsonian National Museum of Natural History, Smithsonian Tropical Research Institute and the Temple University College of Liberal Arts.
Journal references:
Anthony Ranere, Dolores Piperno et al. The Cultural and chronological context of early Holocene maize and squash domestication in the Central Balsas River Valley, Mexcio. PNAS, March 24, 2009
Anthony Ranere, Dolores Piperno et al. Starch grain and phytolith evidence for early ninth millennium B.P. maize from the Central Balsas River Valley, Mexico. PNAS, March 24, 2009
Adapted from materials provided by Temple University.

Mount Redoubt Volcano In Alaska Erupts Explosively

2009-03-23T11:53:00.001-07:00

SOURCE

ScienceDaily (Mar. 23, 2009) — Alaska's Mount Redoubt Volcano has erupted, spewing ash thousands of feet into the air.

The volcano, 106 miles southwest of Anchorage, erupted explosively on March 22, 2009, at approximately 10:38 PM AKDT, sending a cloud of volcanic ash to an estimated 50,000 feet above sea level. Scientists from the Alaska Volcano Observatory (AVO) are monitoring the volcano closely as the eruption continues.
Ash plumes generated by the explosive bursts are drifting north-northeast. Ash fall has been reported in Skwentna and the Chuitna area.
The eruption follows an increase March 15 of seismic activity at Mount Redoubt, when approximately four hours of continuous volcanic tremor ensued. The onset of the tremor was associated with a small explosion that produced a plume of gas and ash that rose to about 15,000 feet above sea level and deposited a trace amount of ash over the summit-crater floor and down the south flank of the volcano to about 3,000 feet.
AVO's dynamic website (http://www.avo.alaska.edu/) contains extensive information about present and past volcanic activity in Alaska and is increasingly popular as a destination for real-time data about Alaska's restless volcanoes.
The Alaska Volcano Observatory is a cooperative program of the U.S. Geological Survey, the University of Alaska Fairbanks Geophysical Institute, and the Alaska Division of Geological and Geophysical Surveys.
Adapted from materials provided by U.S. Geological Survey.