Dolphins Get A Lift From Delta Wing Technology

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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

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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

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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

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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

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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

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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

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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

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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

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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

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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

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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'

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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

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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.