Study on sheep shows link between personality, survival, and reproductive success

Washington, September 16 (ANI): Canadian researchers have established a link between personality, survival, and reproductive success by carrying out a study on male bighorn sheep.

Denis Reale, a professor in the Department of Biological Sciences at UQAM and Canada Research Chair in Behavioural Ecology, says that the new study offers insight into personality differences in animals and humans, from an evolutionary perspective.

Since 1969, several teams of researchers have been studying this population of bighorn sheep in Alberta, Canada. They have collected considerable data over the years.

Working in collaboration with researchers from the University of Sherbrooke and the University of Alberta, Reale identified the rams in terms of boldness and docility.

The researchers then conducted paternity tests to determine which rams were reproducing.

They point out that in a system like that of bighorn sheep where there is strong competition among the males for impregnating females, large size and high dominance status are normally key factors in a male’s success.

Males usually attain these conditions in the prime of life, between 6 and 12 years, the researchers say.

However, the paternity tests showed that some young males manage to fertilize females.

The researchers also concentrated on the risk associated with participation in the rut-males can be injured or fall from a cliff in fighting.

Reale and his colleagues hypothesized that the young males that manage to reproduce would be the boldest and most combative, and analysis of the data confirmed it.

However, in exchange for sexual precocity and risk-taking, these rams often die younger than their more docile peers. The latter, instead, invest in the long term, breed later and reach an older age.

Based on their observations, the researchers came to the conclusion that their findings indicate a variation in the personalities and life histories of the population, with two extreme types: one that could be characterised as “live fast and die” and the other as “slow and steady wins the race”.

Depending on their personality, the males managed to breed and to transmit their genes, but in different ways.

The study demonstrates that personality has a direct influence on the lifestyle of individuals.

A research article describing the study has been published in the Journal of Evolutionary Biology. (ANI)

Carrots are better than sticks when it comes to fostering cooperation

Washington, Sept 4 (ANI): Rewards have been found to be much more successful in promoting public cooperation rather than punishment, suggests a new study.

According to researchers, rewards robustly build compliance and cooperation and could help in developing solutions for thorny problems requiring the cooperation of large numbers of people to achieve a greater good.

“All of us engage in public goods games, on both large and small scales,” said David G. Rand, a postdoctoral researcher at Harvard’s Program for Evolutionary Dynamics and lead author of the study.

“Climate change is a huge public goods game: If each person does his or her part to conserve energy and reduce CO2 emissions, it benefits us all.

“On a more local level, public goods games include volunteering on school boards, helping to maintain public facilities in your community, or cleaning up after yourself and doing your share of work at the office.

“In these types of domains, where people interact repeatedly with each other to solve a group social dilemma, our work suggests that rewards result in better outcomes than punishment,” he added.

Rand said that these rewards could change individuals’ behaviour and encourage cooperation without the destructive negative consequences that come with punishment.

During the study headed by Martin A. Nowak of Harvard’s Program for Evolutionary Dynamics, the researchers examined cooperation among 192 participants in a public goods game probing the fundamental tension between the interests of an individual and a group.

Over 50 rounds of interaction, each of four participants in a group would decide how much to contribute toward a common pool that benefited all four equally. Each participant was then able – at a cost to him or herself- to either reward or punish each of the three other subjects for their contributions to the group, or lack thereof.

As in real life, Rand said, study subjects tend to resent “free riders” who fail to contribute to a group yet reap the benefits of membership in it.

“But despite this anger at free riders, rewarding good behaviour is as effective as punishing bad behaviour for maintaining public cooperation and leads to better outcomes for the group. When both options are available, reward leads to increased contributions and payoff for the group, while punishment has no effect on contributions and leads to lower payoff for the group,” Rand added.

The study appears in journal Science. (ANI)

Female fruit flies prefer keeping sex short to get a reproductive boost

Washington, August 22 (ANI): A new study has shown that female fruit flies prefer keeping sex short and sweet because they get a reproductive boost from shorter intercourse.

Since males like sex to last longer, a fight ensues.

“After about a minute and a half (of mating), the female begins kicking and struggling,” National Geographic News quoted Kirsten Klappert, of the Swiss Federal Institute of Aquatic Science and Technology, as having written in the study report.

The researcher notes that when mating lasts longer, female flies have less time to mate again with a different male, if they do so at all.

Although that is good for males flies, as it means that their sperm have less competition, it can be disastrous for females.

“Many male Drosophila montana are infertile, so if you only mate with one you have a high risk of no offspring at all,” Klappert said.

During the study, Klappert’s team paired live males with dead females to see how much control female flies have over mating length.

The dead insects were propped up to convince the males that they were still alive, and ready for sex, said the researchers.

The team observed that male flies’ sex with the dead insects lasted 1.5 times longer than it did with live females.

This finding does attain significance because scientists at other institutions believe that humans can relate to the female fruit fly’s desires.

Rhonda Snook, a senior lecturer at the University of Sheffield in England who studies sexual selection and reproductive behaviour in fruit flies, said: “I don’t know you could say human females want longer copulation, per se. It’s really the foreplay, not the actual act of copulation. In the insects, prior to that, there’s courtship going on, and that’s like foreplay in humans.”

A research article describing Klappert’s study has been published in the journal BMC Evolutionary Biology. (ANI)

Why male and female lemurs are of same size

Washington, July 15 (ANI): Rice University biologist Amy Dunham has put forward a new theory for one of primatology’s long-standing mysteries-why are male and female lemurs the same size?

In most primate species, males have evolved to be much larger than females, but this has not been found to be true in case of lemurs.

Some theories have suggested that environment played a role or that lemur social development was altered due to the extinction of predatory birds.
“Scientifically, this is quite a big question that researchers have debated for over 20 years. I actually started doing research on lemurs as an undergraduate, working in Ranomafana (National Park in Madgascar), and the question about size monomorphism has bugged me since then,” said Dunham.
In the new study, Dunham has offered one of the first new theories on lemur monomorphism in more than a decade.
After conducting an exhaustive review of the observational work done on lemurs, Dunham concluded that male lemurs do guard their mates, just like other primates.

But unlike gorillas and other primates that fight for mating rights with females, male lemurs have evolved to passively guard their mates.
They do this by depositing a solid plug inside the female’s reproductive tract just as they finish mating. The plug is deposited as a liquid protein but quickly hardens and stays in place for a day or two.

Since many female lemurs are sexually responsive to males for only one day out of the entire year, the plug serves the purpose of preventing other males from mating with the female, while also freeing the male to mate with other females during the brief time they are available.
“If the female has a short receptivity period, as most lemurs do, then we hypothesize that this is likely to be an advantageous strategy,” said Dunham.
To test their hypothesis, the researchers examined 62 primate species and found that copulatory plugs were most likely to occur in species where female sexual receptivity was very brief and where males and females were the same size.

This was true both for lemur species and for a few other species, like South American squirrel monkeys.
The study has been published in the Journal of Evolutionary Biology. (ANI

Global warming may spell demise of key salt marsh constituent

Washington, July 14 (ANI): A new research has shown that global warming may exact a toll on salt marshes in New England, with one key constituent of marshes being especially endangered.

Pannes are waterlogged, low-oxygen zones of salt marshes.

According to Keryn Gedan, a graduate student and salt marsh expert at Brown University, despite the stresses associated with global warming, pannes are “plant diversity hotspots,”

“At least a dozen species of plants known as forbs inhabit these natural depressions,” Gedan said.

The species include the purple flower-tipped plants Limonium nashii (sea lavender), the edible plant Salicornia europaea (pickleweed) and Triglochin maritima, a popular food for Brent and Canada geese as well as ducks and other migratory waterfowl.

Gedan and her adviser, Mark Bertness, chair of the Ecology and Evolutionary Biology Department at Brown, decided to find out how global warming may affect pannes.

In a series of experiments, the pair subjected plots of forb pannes to air as much as 3.3 degrees Celsius (about 6 degrees Fahrenheit) warmer than the surrounding area.

They found that the plants in the test plots responded initially by growing more but then began a rapid die-off. As they died, they were replaced by a salt marsh grass, Spartina patens.

At two sites – Nag Creek (Prudence Island, Rhode Island), and Little River (Maine) – the forbs covered less than 10 percent of the plot, from 50 percent originally, in tests that spanned the summer from 2004 to 2006.

At the third site, Drakes Island (Maine), the forb pannes cover decreased from 50 percent of the plot to 44 percent (a 12-percent decline) in just the summer of 2007.

The researchers believe the forbs disappeared due to changes in the plant-water balance in the zone.

What that means, Gedan explained, is the warmer air causes the forbs to take in more water, thus making the area less waterlogged and more hospitable to an invasion by Spartina patens, which prefers less water-soaked conditions.

“The forbs basically engineer themselves out of their habitat by making it more favorable for their competitor,” said Gedan.

The Brown experiments “demonstrate that New England salt marsh pannes are extremely sensitive to temperature increases and will be driven to local and regional extinction with the temperature increases expected to occur in New England over the next century,” Bertness said. (ANI)

Earliest land vertebrates were more diverse than earlier believed

Washington, July 7 (ANI): A new study of ancient fossils has determined that the earliest land vertebrates, also known as tetrapods, were more diverse than we could possibly imagine.

The study was done by Jennifer Clack, a paleontologist at the University of Cambridge, who has studied the fossils of these extinct creatures for more than two decades.

Long before mammals, birds, and even dinosaurs roamed the Earth, the first four-legged creatures made their first steps onto land, and quickly inhabited a wide range of terrestrial environments.

“These early land vertebrates varied considerably in size and shape,” said Clack.

To understand the anatomical changes that accompanied this diversity, Clack teamed up with two biologists who work on living fishes – Charles Kimmel of the University of Oregon, and Brian Sidlauskas of the National Evolutionary Synthesis Center in North Carolina.

The researchers focused on 35 early tetrapods that lived between 385 and 275 million years ago.

As a proxy for body size and shape, they examined the dimensions of a number of bones in a region of the skull known as the palate.

By tracing changes in the length and width of interlocking bones in this part of the skull, the researchers hoped to get a more fine-grained picture of skeleton evolution as a whole.

“I tend to think the genetic instructions for making a skeleton come from how you make individual bones first, and then how you fit those bones together as a refinement of that,” said developmental biologist Charles Kimmel.

When they mapped the changes in bone length and width onto the tetrapod family tree, the researchers discovered that not all bones changed size at the same rate or in the same direction.

This phenomenon can result in an overall reshaping from one lineage to the next, explained Sidlauskas.

“Sometimes a change in size can have indirect consequences for the shape of the animal. When different parts of an animal’s body change size at different rates over evolutionary time, that can generate changes in body shape from one species to another,” he added.

Moreover, some changes are consistent with an evolutionary quirk known as paedomorphosis, in which species retain in adulthood the youthful dimensions that their ancestors had as juveniles.

“Paedomorphosis is definitely there – the descendents of some groups are retaining the proportions that their juveniles had in the past,” said Clack.

These results not only help explain why early tetrapods were so diverse in size and shape, but also shed light on an important chapter in the evolution of life on land – the transition from fish to amphibians. (ANI)

Climate change causing wild sheep to shrink

Washington, July 3 (ANI): A new study has provided evidence for climate change as the cause of the mysterious decrease in the size of wild sheep on the Scottish island of Hirta.

According to the researchers, 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 the 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 percent over the last 24 years.

The research team analyzed 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.

According to him, “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,” he added.

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. (ANI)

Like humans, birds too avoid inbreeding

Washington, June 30 (ANI): Scientists have found that a strictly monogamous species of bird has the ability to choose partners with a different genetic profile.

The researchers, led by Richard Wagner from the Konrad Lorenz Institute for Ethology of the Austrian Academy of Sciences, said avoidance of inbreeding is evident among humans, and has been demonstrated in some shorebirds, mice and sand lizards. Now the black-legged kittiwake bird has been added to that list.

The scientists said they tracked 10 genetic markers to investigate whether kittiwakes avoid inbreeding by pairing with genetically distant mates, and whether inbreeding reduces the number of chicks they raised.

They found most pairs avoid inbreeding more often than expected by chance, suggesting kittiwakes can somehow tell who their relatives are in a large anonymous population.

The researchers said their study provides the first evidence of inbreeding avoidance in a strictly monogamous species, in which both parents contribute to rearing offspring.

Wagner conducted the study in collaboration with Etienne Danchin from Paul Sabatier University in Toulouse, France, as well as researchers from the Pierre and Marie Curie University in Parks, the Alaska Science Center and the University of Bern.

The study appears in the journal BMC Evolutionary Biology. (ANI)

How ferocious piranhas got their fearful bite

Washington, June 26 (ANI): Researchers from Argentina, the US and Venezuela have uncovered the jawbone of a striking transitional fossil that sheds light on how the ferocious piranhas got their teeth.

Named ‘Megapiranha paranensis’, this previously unknown fossil fish bridges the evolutionary gap between flesh-eating piranhas and their plant-eating cousins.

Present-day piranhas have a single row of triangular teeth, like the blade on a saw, explained the researchers.

But, their closest relatives – a group of fishes commonly known as pacus – have two rows of square teeth, presumably for crushing fruits and seeds.

“In modern piranhas, the teeth are arranged in a single file,” said Wasila Dahdul, a visiting scientist at the National Evolutionary Synthesis Center in North Carolina.
But, in the relatives of piranhas, which tend to be herbivorous fishes, the teeth are in two rows,” said Dahdul.

Megapiranha shows an intermediate pattern: it’s teeth are arranged in a zig-zag row, which suggests that the two rows in pacus were compressed to form a single row in piranhas.

“It almost looks like the teeth are migrating from the second row into the first row,” said John Lundberg, curator at the Academy of Natural Sciences in Philadelphia and a co-author of the study.

If this is so, Megapiranha may be an intermediate step in the long process that produced the piranha’s distinctive bite.

To find out where Megapiranha falls in the evolutionary tree for these fishes, Dahdul examined hundreds of specimens of modern piranhas and their relatives.

“What’s cool about this group of fish is their teeth have really distinctive features. A single tooth can tell you a lot about what species it is and what other fishes they’re related to,” said Dahdul.

Her phylogenetic analysis confirms their hunch that Megapiranha seems to fit between piranhas and pacus in the fish family tree.

Cione’s find suggests that Megapiranha lived between 8-10 million years ago in a South American river system known as the Parana.

By comparing the teeth and jaw to the same bones in present-day species, the researchers estimate that Megapiranha was up to 1 meter (3 feet) in length, which is at least four times as long as modern piranhas.

“Although no one is sure what Megapiranha ate, it probably had a diverse diet,” said Cione. (ANI)

Changing climate make mockingbirds better singers

Washington, May 22 (ANI): Mockingbirds tend to sing fancier tunes with changing climate, say researchers.

The research team from the National Evolutionary Synthesis Centre (NESCent), the Cornell Lab of Ornithology, and McGill University showed that species in more variable climes also sing complex tunes.

“Survival and reproduction become more complicated when weather patterns are unpredictable because you don’t know when food will be available or how long it will be around,” said Carlos Botero, a postdoctoral researcher at NESCent in Durham, NC.

And the consequences of picking a mediocre mate are magnified in harsher climes.

“In really difficult or demanding environments you would expect females to be choosier,” he added.

Botero said that male mockingbirds sing primarily to impress mates and superior singing skills are a cue that a male is a good catch.

“Complexity of song display – how many song types a bird sings, how hard the songs are – is a good predictor of the quality of the individual,” he said.

“Males that sing more complex songs tend to carry fewer parasites, and have offspring that are more likely to survive,” he added.

Moreover, singing skills may be a sign that males are clever enough to cope with iffy environments.

“Individuals that are more intelligent tend to be better able to compensate for the difficulties of unpredictable climates,” said Botero.

“For example, if some individuals are able to invent new foraging techniques, then they are going to be better at surviving harsh winters than the poor guys who only know one way to forage.

“The more intelligent you are, the more resourceful you are, and the more curve balls you’re able to handle,” he added.

During the study, Botero and his colleagues studied nearly 100 tracks from 29 mockingbird species and found that species subject to more variable and unpredictable climates had more elaborate song displays.

The connection between birdsong and climate is new and somewhat surprising, Botero explains. “We’re connecting two dots that were far away before.” (ANI)

Cholesterol-busting bug identified

Washington, May 15 (ANI): Scientists at the Universidad Complutense de Madrid, Spain, have discovered a novel species of bacteria with cholesterol-busting properties.

The new bug, called Gordonia cholesterolivorans, was isolated from sewage sludge.

A steroid found in all body tissues, cholesterol is used in the cosmetics and pharmaceutical industries as stabilizer, emollient and water-binding agent.

As a consequence, steroids – including cholesterol – are a major group of contaminants in urban sewage residues.

Gordonia bacteria have only been classed as a separate group of bacteria since 1997 but they have already proved useful as they are able to degrade a wide range of environmental pollutants including phthalates (used in plastics), rubber and hazardous compounds such as the explosive hexogen (cyclotrimethylenetrinitramine).

Gordonia cholesterolivorans’ ability to break down cholesterol means that it could be used to clean up contamination.

Study author Dr Oliver Drzyzga and colleagues are studying the genetics of this novel bacterium to genetically modify strains that might also be used to synthesise new and industrially useful breakdown products of cholesterol.

“New steroid compounds made by these bacteria may find applications in the pharmaceutical and medical sectors in the future, but as some Gordonia species are pathogenic to humans it is unlikely that they could be used directly to treat high cholesterol-related conditions in humans”, said Drzyzga.

“We are trying to work out exactly how Gordonia cholesterolivorans metabolises cholesterol so that we can identify and construct metabolically engineered strains that are more rapid and effective in breaking down cholesterol,” Drzyzga added.

Their findings are reported in the current issue of the International Journal of Systematic and Evolutionary Microbiology. (ANI)

The way to a lady’s heart is through her stomach – if you’re a chimp

Hamburg – The way to a lady’s heart is through her stomach – if you’re a male chimpanzee seeking a mate. But you have to be patient and feed her lots of meat over a long period of time, according to new findings by German scientists.

Wild female chimpanzees copulate more frequently with males who share meat with them over long periods of time, according to a study led by German researchers from the Max Planck Institute for Evolutionary Anthropology in Munich.

In field studies at Tai National Park, in the Ivory Coast, German scientists Cristina M Gomes and Christophe Boesch found that female chimpanzees copulate more frequently with males, who share meat with them on at least one occasion, compared with males who never share meat with them.

The findings indicated that sharing meat with females improves a male’s mating success, according to the study published in the journal PLoS ONE.

“Our results strongly suggest that wild chimpanzees exchange meat for sex, doing so on a long-term basis. Males who shared meat with females doubled their mating success, whereas females, who had difficulty obtaining meat on their own, increased their caloric intake, without suffering the energetic costs and potential risk of injury related to hunting,” Gomes wrote.

“Previous studies might not have found a relationship between mating success and meat sharing because they focused on short-term exchanges; or perhaps because in those groups access to females was driven by male coercion so females rarely chose their mating partners,” Gomes added.

The findings go a long way toward answering the question of how females choose their mating partners and why males hunt and share meat with them.

Evidence from studies on human hunter-gatherer societies suggest that men, who are more successful hunters, have more wives and a larger number of offspring.

Studies of wild chimpanzees, humans’ closest living relative, have shown that male hunters frequently share meat with females who did not participate in the hunt.

One of the hypotheses proposed to explain these findings is the meat-for-sex hypothesis, whereby males and females exchange meat for mating access. However, there had been little evidence in both humans and chimpanzees to support it – until now.

“Our findings add to the ever-growing evidence suggesting that chimpanzees can think in the past and the future and that this influences their present behaviour,” Boesch concluded.

“These findings are bound to have an impact on our current knowledge about relationships between men and women; and similar studies will determine if the direct nutritional benefits that women receive from hunters in human hunter-gatherer societies could also be driving the relationship between reproductive success and good hunting skills,” Gomes concluded. (dpa)

Butterflies use wings to send both ‘sexy’ and ‘repulsive’ signals

Washington, April 2 (ANI): The eyespots of some butterflies serve to both attract mates and ward off predators, according to new research by Yale University biologists.

The researchers say that butterflies seem able to both attract mates and ward off predators by using different sides of their wings.

“You want to be noticeable and desirable for mates, but other onlookers, including predators, are paying attention to those signals as well,” says Jeffrey Oliver, a postdoctoral associate in Yale’s Department of Ecology and Evolutionary Biology.

Oliver joined forces with Yale biologist Antonia Monteiro to study whether the eyespots on the upperside of butterflies’ wings – specifically, those of bush brown butterflies – serve a different purpose than the ones on the underside.

The researchers used different evolutionary models for their study.

They found that the eyespots on the upperside of the butterflies’ wings appeared to evolve much more quickly than those on the underside, meaning they appear and disappear frequently through the course of evolution.

According to them, the finding is consistent with the theory that these are used to attract mates, as signals used for sexual selection tend to evolve faster than others.

Oliver claims that his group’s study is the first to employ evolutionary history models to show that a species can use the same signal on different areas of its body to communicate different messages.

He says that butterflies can flash hidden eyespot on their forewings to confuse predators and give themselves time to escape.

While the researchers have yet to find out how the upperside eyespots communicate with potential mates, it is thought that they might help butterflies identify each other and thus would help keep different species from cross-mating.

Oliver has revealed that his team next plans to use longer evolutionary timescales to study where and how eyespots evolved, as well as whether they developed all at once, or independently over time.

The study appears in the journal Proceedings of the Royal Society B: Biological Sciences. (ANI)

Opposites don’t really attract, says study

Washington, Mar 29 (ANI): They say people with opposite traits make for loving couples, but a new study is not obliging with the belief.

The research, published in the journal Evolutionary Psychology, says when it comes to personality, people seek partners with their same qualities – but say they want someone who is different.

To reach the conclusion, researchers quizzed 760 members of an online dating site to answer questionnaires regarding their personality traits, as well as the traits they would want in an ideal long-term partner.

They then were asked if they most wanted a partner that complemented them, or resembled them.

The answers showed a preference for someone with the same sort of personality; the traits, which included neuroticism, extraversion, openness, agreeableness, and conscientiousness, all had positive participant-to-partner correlations, ranging from .51 to .62.

“When asked about their preferences for a mate, people may partially draw upon lay theories of romantic attraction rather than their true desires for a mate,” Live Science quoted Pieternel Dijkstra, a professor at the University of Groningen in the Netherlands and the study’s lead researcher, as saying.

“Although many individuals occasionally feel attracted to ‘opposites,’ attractions between opposites often do not develop into serious intimate relationships and, when they do, these relationships often end prematurely,” she said.

The study also found that in addition to looking for a similar partner, women wanted men who were conscientious, outgoing, and emotionally stable, all traits that indicate an investment in the relationship and in any potential children.

However, “there were no particular traits that men seemed to prefer more than women,” Dijkstra said. (ANI)

Evolution of fins and limbs linked with that of gills

Washington, March 24 (ANI): A new research has suggested the genetic toolkit that animals use to build fins and limbs is the same genetic toolkit that controls the development of part of the gill skeleton in sharks.

The research was conducted by Andrew Gillis and Neil Shubin of the University of Chicago, and Randall Dahn of Mount Desert Island Biological Laboratory.

“In fact, the skeleton of any appendage off the body of an animal is probably patterned by the developmental genetic program that we have traced back to formation of gills in sharks,” said Andrew Gillis.

“We have pushed back the evolutionary origin of the developmental genetic program that patterns fins and limbs,” he added.

This new finding is consistent with an old theory, often discounted in science textbooks, that fins and (later) limbs evolved from the gills of an extinct vertebrate.

“A dearth of fossils prevents us from definitely concluding that fins evolved from gills. Nevertheless, this research shows that the genetic architecture of gills, fins and limbs is the same,” said Gillis.

The research builds on the breakthrough discovery of the fossil Tiktaalik, a “fish with legs,” by Neil Shubin and his colleagues in 2006.

“This is another example of how evolution uses common developmental programs to pattern different anatomical structures,” said Shubin, who is the Associate Dean of Organismal and Evolutionary Biology at the University of Chicago.

“In this case, shared developmental mechanisms pattern the skeletons of vertebrate gill arches and paired fins,” he added.

The research also showed for the first time that the gill arch skeleton of embryonic skates (a living relative of sharks that has gill rays) responds to treatment with the vitamin A derivative retinoic acid in the same way a limb or fin skeleton does, by making a mirror image duplicate of the structure as the embryo develops.

According to the researchers, the genetic circuitry that patterns paired appendages (arms, legs and fins) has a deep evolutionary origin that actually predates the origin of paired appendages themselves.

“These findings suggest that when paired appendages appeared, the mechanism used to pattern the skeleton was co-opted from the gills,” Gillis said.

“Perhaps we should think of shark gills as another type of vertebrate appendage-one that’s patterned in essentially the same way as fins and limbs,” he added. (ANI)

Animal families with most diversity also have largest range of body sizes

Washington, March 18 (ANI): A new research has found that families of animals grouped together by a similar body plan, with the greatest diversity of species, were also those with the largest range of body sizes.

The research was carried out by the National Evolutionary Synthesis Center (NESCent) researchers in the US, as part of an analysis of body sizes across all orders of animal life.

Researchers Craig McClain and Alison Boyer created a giant database on body sizes across all orders of animal life and found that phyla – families of animals grouped together by a similar body plan – with the greatest diversity of species were also those with the largest range of body sizes.

The sponges, Poriferans, were found to have some of the greatest diversity of both body size and species, ranging from microscopic to the size of an automobile.

Molluscs (snails, squid, clams, chitons), and Arthropods (crabs, insects, lobsters, copepods) also showed great diversity.

So did our family, the Chordates, which ranges from a half-inch fish in the swamps of Borneo to the truly leviathan 100-ton Blue Whale, with all the fishes, birds and mammals in between.

“On the one hand, it may seem obvious that diversity in size and diversity in species go together,” acknowledged marine biologist McClain, assistant director of science at NESCent.

“But, it also says something a little more subtle about how new species arise and adapt to all the available niches in the environment. This really comes down to understanding the diversity of life on Earth,” he added.

There are apparently physical limits to the range of sizes that can work for some body plans. n worms, for example, it is impossible to slither along if the girth and weight become too large. (The largest worm, Riftia pachyptila, from deep-sea vents, doesn’t move.)

“Within the range of sizes that works for a given body plan, evolution creates new species and new sizes,” McClain said.

The finding also points to areas where more species might be waiting to be discovered.

For example, the little-studied priapulid worms have only 16 species on the books, but with a very large range in size.

McClain’s guess is that there may be more undiscovered species within that range of sizes.

“There are groups that definitely don’t have a lot of people studying them,” he said. “Knowing something about a body plan’s size constraints also might allow for a ballpark estimate of its number of species,” he added. (ANI)

A good night”s sleep protects against parasite infestation

Washington, Jan 9 (ANI): Researchers from Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany have found that animals that sleep longer do not suffer from parasite infestation.

They hope that the research may have implications for human health.

“Sleep is a biological enigma. Despite occupying much of an animal”s life, and having been scrutinized by numerous experimental studies, there is still no consensus on its function,” lead researcher Brian Preston said.

“Similarly, nobody has yet explained why species have evolved such marked variation in their sleep requirements (from 3 to 20 hours a day in mammals).

“Our research provides new evidence that sleep plays an important role in protecting animals from parasitic infection,” he added.

During the study, the researchers showed that evolutionary increases in mammalian sleep durations are strongly associated with the number of circulating immune cells.

And mammalian species that sleep for longer periods also have substantially reduced levels of parasitic infection.

“We suggest that sleep fuels the immune system. While awake, animals must be ready to meet multiple demands on a limited energy supply, including the need to search for food, acquire mates, and provide parental care,” he said.

“When asleep, animals largely avoid these costly activities, and can thus allocate resources to the body”s natural defenses.”

“Given the declines in human sleep durations that have occurred over the past few decades, there is a clear need for studies that further clarify the immunological significance of sleep,” he added.

The study has been published in the open-access journal BMC Evolutionary Biology. (ANI)

Hind wings help butterflies make swift turns to evade predators

Washington, Jan 9 (ANI): A new study has proposed that a butterfly’s hind wings help it to make swift turns to evade predators, just like new tires allow race cars to take tight turns at high speeds.

According to a report in Cornell Chronicle Online, the study was undertaken by Tom Eisner, a world authority on animal behavior, ecology and evolution and the Jacob Gould Schurman Professor Emeritus of Chemical Ecology at Cornell University.

“To escape a predator, you don’t have to be fast, you just have to be more erratic,” said Eisner.

The study proposes that in the course of evolution, the ability of butterflies to evade predators became linked with bright coloring, as an added protection.

In evolutionary terms, gaudy colors are usually a sign to such predators as birds that a prey species has a protective quality, such as a bad taste or great agility, and that chasing them isn”t worth the energy.

Anyone who has tried to net a colorful butterfly knows they are hard to catch, but this is the first study to show that a butterfly’s hind wings are responsible for making them evasive.

Eisner and the research paper’s lead author, Benjamin Jantzen, a doctoral student in philosophy of science at Carnegie Mellon University, clipped off the hind wings of butterflies and then filmed their flight using two cameras to get three-dimensional views of their flight trajectories.

Then, they analyzed and plotted on a computer the insects’ flight velocity, acceleration, how fast they changed direction, the curvature of their path and more.

They found that clipping the back wings did not affect basic flight, but “we were able to show that removing the hind wings cut their turning acceleration in half,” said Jantzen.

It was found that the butterfly’s hind wings scoop air and provide extra force to quickly turn when chased.

“The wings are also colorful advertising for the whole group,” said Jantzen. “The colors say, we are butterflies, don’t bother to chase us, because you won’t catch us,” he added. (ANI)

Bacteria that add flavour to world’s most exclusive cheeses identified

Washington, Jan 7 (ANI): Researchers at Newcastle University have identified a new line of bacteria which they believe add flavour to some of the world’s most exclusive cheeses.

The team used DNA fingerprinting techniques to identify eight previously undiscovered microbes on the French cheese Reblochon.

One of France’s great mountain cheeses, Reblochon is a ‘smear-ripened’ cheese where the surface of the cheese is washed with a salt solution containing bacteria.

This process helps to spread the bacteria across the surface of the cheese, ripening it from the outside in.

Other popular smear-ripened cheeses on the Christmas cheeseboard include Port de Salut, Livarot, Taleggio, Limburger and the Irish cheese Gubbeen.

The team has named the microbes Mycetocola reblochoni after the cheese they were first discovered in.

Project lead Professor Michael Goodfellow of Newcastle University said: “It has always been thought the bacteria cheese makers were putting in at the start of the process gave Reblochon its distinctive flavour.

“What our research actually showed was this new group of bacteria – the reblochoni –were responsible for the ripening process, influencing the taste, texture and smell of the cheese.”

Reblochon – a soft, creamy, brie-like cheese – is made in the Savoy mountain region of France.

Using samples from three different farmhouses, the team carried out a series of modern molecular techniques to classify the bacteria.

Traditionally, smear-ripened cheeses such as Reblochon are exposed to a starter culture, a live mixture containing the microbe Brevibacterium linens, to ripen the cheese.

Now the research has shown that a new group of bacterial strains are involved in the later stage of ripening, out-competing the Brevibacterium and providing the flavour.

The reblochoni microbes are part of a large group of bacteria known as the Actinomycetes, many of which are already used in the production of antibiotics to treat diseases such as tuberculosis and diphtheria.

The study has been published in International Journal of Systematic and Evolutionary Microbiology. (ANI)