By Stephanie Pappas Ever since the second day her son went to kindergarten, Penny Williams has worried about him. That's the day Williams, a real estate broker in Asheville, N.C., got her first call from her child's teacher. Luke wasn't ready for school, the teacher told Williams. He couldn't sit still and didn't want to participate. The insinuation, Williams said, was that she had failed as a parent. Luke, now 8, would later be diagnosed with attention deficit hyperactivity disorder (ADHD), a neurological disorder marked by distraction, disorganization, impulsivity and, as the name suggests, hyperactivity. About 3 percent to 5 percent of school-age children in the U.S. have ADHD. Since the diagnosis, Williams has immersed herself in those children's worlds. She edits a group blog of parents with ADHD kids at adhdmomma.blogspot.comand devours books about ADHD, trying to understand her child's mind. "He has a really high IQ and he's really gifted, and he comes home from school and says how stupid he is," Williams told LiveScience, referring to Luke. "It's hard to watch your kid struggle … It adds stress and anxiety." A new study finds that Williams is far from alone in her sensitivity to her son's moods and needs. Parents of children with ADHD are more in tune to their child's behaviorthan parents with neurotypical children, according to research published in June in the Journal of Family Psychology. All parents' moods ebb and flow based on how their children are behaving, said study researcher Candice Odgers, a psychologist at the University of California, Irvine. But the link between a mother's mood and her child's behavior is stronger when the kid has ADHD. © 2011 LiveScience.com.

Keyword: ADHD; Stress
Link ID: 15592 - Posted: 07.25.2011

by Greg Miller According to some estimates, more than 300,000 United States troops have suffered a traumatic brain injury (TBI) in the current wars in Iraq and Afghanistan. Most of these injuries have resulted from blasts from roadside bombs and other explosives planted by insurgents. The lack of knowledge about how an explosive blast injures the brain has hampered efforts to treat these injuries. Now, two studies offer a potentially important insight, pointing to a mechanism that hadn't been considered before. The lead author of the studies, Harvard University bioengineer Kevin Kit Parker, says he had a vested interest in the research. Parker shifted his focus from cardiac to brain research after two tours in Afghanistan as a U.S. Army infantry officer. "I kept seeing buddies of mine get hit and thought, 'All right, I'll take a look at this and see if I can get an angle on it.' " Back at Harvard, Parker and his lab devised a blast simulator for cells. In one study, published today in PLoS ONE, the researchers grew rat neurons in a culture dish and then attached them to a sheet of stretchy polymer. A high-precision motor gave a carefully calibrated tug to the sheet to subject the neurons to mechanical forces Parker calculated to be comparable to those produced by an explosion. Through a microscope, the researchers saw that the "blast" caused swelling, breakage, and other signs of injuries to the neurons' spindly axons and dendrites, which send and receive signals from other neurons. © 2010 American Association for the Advancement of Science.

Keyword: Brain Injury/Concussion
Link ID: 15591 - Posted: 07.25.2011

By James Gallagher Health reporter, BBC News A 'molecular scalpel' shows promise in patients with a deadly muscle wasting condition, according to researchers. The gene for the protein dystrophin is damaged in people with Duchenne muscular dystrophy. A drug trial on 19 children, published in the Lancet, used the 'scalpel' to removed the damage and restore dystrophin production. The charity Muscular Dystrophy Campaign said there was "real hope for the future". Duchenne muscular dystrophy affects one in every 3,500 newborn boys. Throughout life the muscle wastes away and children can need a wheelchair by the age of 10. The condition can become life-threatening before the age of 30, when it affects the muscles needed to breathe and pump blood around the body. New approach The instructions for making a protein are in the genetic code, but this can be disrupted by mutations or deletions in the code. Stem cell and gene therapy research has tried to find ways of introducing a functional dystrophin gene. This study tried to do the best it could with the damaged code. BBC © 2011

Keyword: Muscles; Genes & Behavior
Link ID: 15590 - Posted: 07.25.2011

By Julie Steenhuysen PARIS — As a boy, Gary Reiswig would take his grandfather by the hand and guide him on walks around the family farm in western Oklahoma. At 5, Gary knew to avoid the prairie dog town, fearful that his grandfather might stumble over one of the holes that the rodents burrowed into the grassy plain. Occasionally, his grandfather would stop. His eyes took on an eerie stare that spoke of an empty place -- one that once was filled with memories, laughter and toil. In 1945, nobody knew that Gary's grandfather had a rare form of Alzheimer's disease that would strike 10 of Gary's 14 aunts and uncles, his father and his only brother and sister in the prime of their lives. Gary's family has dominantly inherited Alzheimer's disease. It is rare, and it afflicts the young. In his family, symptoms can appear in the early 40s. Story: Predicting Alzheimer's: Would you want to know? This inherited form of Alzheimer's is caused by mutations in one of three genes: amyloid precursor protein, presenilin 1 or presenilin 2. It is the only form of Alzheimer's for which there is a diagnostic test that can predict with certainty whether Alzheimer's will ensue. That may change. Researchers, patient advocates and policy makers are pushing for earlier testing of Alzheimer's, in part because it will help the search for a cure. That means more people could find out if they will succumb to the disease. But without a treatment or a cure, would people want to know? Copyright 2011 Thomson Reuters.

Keyword: Alzheimers; Genes & Behavior
Link ID: 15589 - Posted: 07.21.2011

By KEN BELSON The Ivy League will announce on Wednesday that, in an effort to minimize head injuries among its football players, it will sharply reduce the number of allowable full-contact practices teams can hold. The changes, to be implemented this season, go well beyond the rules set by the N.C.A.A. and are believed to be more stringent than those of any other conference. The league will also review the rules governing men’s and women’s hockey, lacrosse and soccer to determine if there are ways to reduce hits to the head and concussions in those sports. The new rules will be introduced as a growing amount of research suggests that limiting full-contact practices may be among the most practical ways of reducing brain trauma among football players. According to a study of three Division I college teams published last year in the Journal of Athletic Training, college players sustain more total hits to the head in practices than in games. “Because of the seriousness of the potential consequences, the presidents determined the league needed to take proactive steps in protecting the welfare of our student-athletes,” said Robin Harris, the executive director of the Ivy League. According to the new rules, teams will be able to hold only two full-contact practices per week during the season, compared with a maximum of five under N.C.A.A. guidelines. On the other days of the week, practices cannot include contact or live tackles, and no player may be “taken to the ground.” © 2011 The New York Times Company

Keyword: Brain Injury/Concussion
Link ID: 15588 - Posted: 07.21.2011

By Katherine Harmon Just like our animal skin–clad ancestors, we gather food with zeal, lust over the most capable mates, and have an aversion to scammers. And we do still wear plenty of animal skins. But does more separate us from our Stone Age forebears than cartoonists and popular psychologists might have us believe? At first blush, parsing the modern human in terms of behaviors apparently hardwired into the brain over eons of evolution seems like a tidy, straightforward exercise. And 30 years ago, when the field of evolutionary psychology was gaining steam, some facile parallels between ancient and modern behaviors lodged themselves in the popular conceptions of human evolution. "It's very easy to slip into a very simplistic view of human nature," says Robert Kurzban, an associate professor of psychology at the University of Pennsylvania, citing the classic Flintstones stereotype. Advances in neuroscience and genetics now suggest that the human brain has changed more rapidly—and in different ways—than was initially thought, according to a new paper published online July 19 in PLoS Biology. "There's been a lot of recent evolution—far more than anyone envisioned in the 1980s when this idea came to prominence," says Kevin Laland, a professor at the University of Saint Andrew's School of Biology in Scotland and co-author of the new paper. He and his colleagues argue that today's better understanding of the pace of evolution, human adaptability and the way the mind works all suggest that, contrary to cartoon stereotypes, modern humans are not just primitive savages struggling to make psychological sense of an alien contemporary world. © 2011 Scientific American

Keyword: Evolution
Link ID: 15587 - Posted: 07.21.2011

by Virginia Morell In 1991, researchers spotted dolphins doing something unusual in Shark Bay, Western Australia. When the animals got hungry, they ripped a marine basket sponge from the sea floor and fitted it over their beaks like a person would fit a glove over a hand. The scientists suspected that as the dolphins foraged for fish, the sponges protected their beaks, or rostra, from the rocks and broken chunks of coral that litter the sea floor, making this behavior the first example of tool use in this species. But why do dolphins go to all of this trouble when they could simply snag a fish from the open sea? The answer, researchers report online today in PLoS ONE, is that the bottom-dwelling fish are a lot more nutritious. Some species also don't have swim bladders, gas chambers that help other fish control their buoyancy as they travel up and down the water column. In the Bahamas, where dolphins are also known to forage for bottom-dwelling fish, dolphins hunt partly by echolocating these bladders, which give off a strong acoustic signal. That helps the cetaceans find prey even when it's buried in sea sand. But bottom-dwelling fish, such as barred sandperch, which are favored by some Shark Bay dolphins, don't have swim bladders and so are harder to find with echolocation. The sea floor is not nearly as soft here as it is in the Bahamas, so if dolphins want to probe for these fish, they risk injuring their rostra. © 2010 American Association for the Advancement of Science

Keyword: Evolution
Link ID: 15586 - Posted: 07.21.2011

By Nadia Drake Beware the full moon, for as it fades, hungry lions emerge to reclaim the night — and prowl for human flesh. Scientists studying lion attack trends in Tanzania found that predation peaks in the evenings after a full moon. The finding is the first to link lunar cycles with predation on humans, long a source of superstition and lore. The study, led by Craig Packer of the University of Minnesota Twin Cities campus, looked at the relationship between lunar cycles, lion attacks and lion feeding behavior. Researchers used records of more than 1,000 lion attacks on Tanzanian villagers that occurred between 1988 and 2009. Of these, nearly two-thirds were fatal, and most occurred after dark. Researchers were able to pinpoint a precise time of day for 474 attacks, and found that attacks clustered between 6 p.m. and 9:45 p.m. They also found that attack rates were two to four times higher in the 10 days after a full moon. But periods of waxing lunar light were not similarly bloody. That's because lions hunt best in darkness, the researchers report, and are hungry after nights of blazing, brilliant moonlight. Measuring lions' belly sizes — and relative fullness — reveals a dip in food consumption during the full moon. So, as the lunar cycle wanes and nights slip toward inky darkness, lions compensate for their full moon fast by attacking humans. © Society for Science & the Public 2000 - 2011

Keyword: Biological Rhythms
Link ID: 15585 - Posted: 07.21.2011

by Adam Piore On a cold, blustery afternoon the week before Halloween, an assortment of spiritual mediums, animal communicators, and astrologists have set up tables in the concourse beneath the Empire State Plaza in Albany, New York. The cavernous hall of shops that 
connects the buildings in this 98-acre complex is a popular venue for autumnal events: Oktoberfest, the Maple Harvest Festival, and today’s “Mystic Fair.” Traffic is heavy as bureaucrats with ID badges dangling from their necks stroll by during their lunch breaks. Next to the Albany Paranormal Research Society table, a middle-aged woman is solemnly explaining the workings of an electromagnetic sensor that can, she asserts, detect the presence of ghosts. Nearby, a “clairvoyant” ushers a government worker in a suit into her canvas tent. A line has formed at the table of a popular tarot card reader. Amid all the bustle and transparent hustles, few of the dabblers at the Mystic Fair are aware that there is a genuine mind reader in the building, sitting in an office several floors below the concourse. This mind reader is not able to pluck a childhood memory or the name of a loved one out of your head, at least not yet. But give him time. He is applying hard science to an aspiration that was once relegated to clairvoyants, and unlike his predecessors, he can point to some hard results. © 2011, Kalmbach Publishing Co.

Keyword: Robotics
Link ID: 15584 - Posted: 07.21.2011

By DUFF WILSON Warnings for Seroquel will soon recommend that the drug be avoided in combination with 12 drugs linked to arrhythmia. The revised label, posted without fanfare last week on the F.D.A. Web site, says Seroquel and extended-release Seroquel XR “should be avoided” in combination with at least 12 other medicines linked to a heart arrhythmia that can cause sudden cardiac arrest. Sandy Walsh, a spokeswoman for the F.D.A., said the statement was only a precaution for doctors, and should not be considered a complete ban against prescribing Seroquel with the other drugs. Ms. Walsh said the label was changed after the F.D.A. received new information about reports of arrhythmia in 17 people who took more than the recommended doses of Seroquel. Though it should not be a problem at a normal dosage, she said, it may still be good advice to avoid using the drugs together. The arrhythmia, known as prolongation of the QT interval, referring to two waves of the heart’s electrical rhythm, is estimated to cause several thousand deaths a year in the United States. As AstraZeneca prepares to report its second-quarter earnings at the end of this month, it faces additional scrutiny this week. The F.D.A. is considering the London-based company’s dapagliflozin, a proposed diabetes drug with Bristol-Myers Squibb, and is expected to decide soon on Brilinta, an anticoagulant. The company is facing the loss of patents for Seroquel next year and for the heartburn drug Nexium in 2014. © 2011 The New York Times Company

Keyword: Schizophrenia
Link ID: 15583 - Posted: 07.19.2011

By KATHERINE BOUTON Two ring-tailed lemurs, perhaps a pair, perhaps just two guys out to catch a few rays, sit side by side tilted back as if in beach chairs, their white bellies exposed, knees apart, feet splayed to catch every last drop of the Madagascar sun. All they need are cigars to complete the picture. There’s a perfectly good evolutionary explanation for this posture. Scientists use the term “behavioral thermoregulation” to describe how an animal maintains a core body temperature. But as the animal behaviorist Jonathan Balcombe points out in his exuberant look at animal pleasure, “The Exultant Ark,” they are also clearly enjoying themselves. A scientist through and through, Dr. Balcombe can’t help giving the study of animal pleasure a properly scientific name: hedonic ethology. True to its subtitle — “A Pictorial Tour of Animal Pleasure” — “The Exultant Ark” showcases surprising, funny, touching, sad, heartwarming pictures by photographers all over the world. Dr. Balcombe’s text is a serious examination of the subject of animal pleasure, a study that “remains nascent and largely neglected in scientific discourse.” But it also delights us along the way with Dr. Balcombe’s observations and examples. On the subject of food as pleasure, for instance, he tells us, “Rats will enter a deadly cold room and navigate a maze to retrieve highly palatable food (e.g., shortbread, pâté or Coca-Cola).” If they happen to find rat chow instead, “they quickly return to their cozy nests, where they stay for the remainder of the experiment.” © 2011 The New York Times Company

Keyword: Emotions; Evolution
Link ID: 15582 - Posted: 07.19.2011

By TARA PARKER-POPE Most doctors view pain as a symptom of an underlying problem — treat the disease or the injury, and the pain goes away. But for large numbers of patients, the pain never goes away. In a sweeping review issued last month, the Institute of Medicine — the medical branch of the National Academy of Sciences — estimated that chronic pain afflicts 116 million Americans, far more than previously believed. The toll documented in the report is staggering. Childbirth, for example, is a common source of chronic pain: The institute found that 18 percent of women who have Caesarean deliveries and 10 percent who have vaginal deliveries report still being in pain a year later. Ten percent to 50 percent of surgical patients who have pain after surgery go on to develop chronic pain, depending on the procedure, and for as many as 10 percent of those patients, the chronic postoperative pain is severe. (About 1 in 4 Americans suffer from frequent lower back pain.) The risk of suicide is high among chronic pain patients. Two studies found that about 5 percent of those with musculoskeletal pain had tried to kill themselves; among patients with chronic abdominal pain, the number was 14 percent. “Before, we didn’t have good data on what is the burden of pain in our society,” said Dr. Sean Mackey, chief of pain management at the Stanford School of Medicine and a member of the committee that produced the report. “The number of people is more than diabetes, heart disease and cancer combined.” © 2011 The New York Times Company

Keyword: Pain & Touch
Link ID: 15581 - Posted: 07.19.2011

By SINDYA N. BHANOO Object agnosia is a rare disorder in which an individual cannot visually recognize objects. In the case of a patient known as SM, he mistook a harmonica for a cash register. Researchers from Carnegie Mellon and Princeton University studied SM’s brain and discovered that it was affected not only in the portion of the right hemisphere that had been damaged in a car accident, but also in his structurally intact left hemisphere. They performed functional M.R.I. brain scans on the patient and report their findings in the journal Neuron. The part of the brain where an image is processed, known as the lower visual cortex, was similar in SM and in normal test subjects. But in and around the area where SM had a lesion, he had decreased brain activity. “It’s not that his brain does not respond at all to visual input — it certainly does,” said Marlene Behrmann, a neuroscientist at Carnegie Mellon and one of the study’s authors. Rather, the problem is that his brain is unable to uniquely assign that visual input to a known object, like a harmonica. But the most surprising finding was that there was also abnormal activity in the patient’s intact left hemisphere, in the same small area where the lesion was on the right side. © 2011 The New York Times Company

Keyword: Attention; Vision
Link ID: 15580 - Posted: 07.19.2011

By Linda Carroll Two new studies — one in veterans and the other in retired football players — add to the mounting evidence linking head injuries to an increased the risk of dementia Veterans who had been diagnosed with a brain injury, anything from a concussion to a severe head wound, were more than twice as likely to develop dementia compared to those with no injury to the brain, researchers reported today at the Alzheimer’s Association’ International Conference in Paris. The results were even more striking in a study of retired football players: 35 percent of the former National Football League players had signs of dementia, which compares to a 13 percent Alzheimer’s rate in the general population. For the veterans study, researchers reviewed the medical records of 281,540 military personnel age 55 and older who received care at Veterans Administration hospitals from 1997 to 2000 and who had at least one follow-up visit from 2001 to 2007. None of the veterans in the study were diagnosed with dementia at the beginning of the seven year study. Almost 5,000 of the veterans had been diagnosed with a traumatic brain injury (TBI). Their risk of developing dementia by the end of the study was 15.3 percent. That’s compared to 6.8 percent of those with no TBI diagnosis. The football player study is a follow-up of earlier research that included a survey of nearly 4,000 retired NFL players in 2001. In 2008, new surveys were sent to the 905 players who were over 50 years old. © 2011 msnbc.com.

Keyword: Brain Injury/Concussion; Alzheimers
Link ID: 15579 - Posted: 07.19.2011

By Ella Davies Reporter, BBC Nature Stick insects have lived for one million years without sex, genetic research has revealed. Scientists in Canada investigated the DNA of Timema stick insects, which live in shrubland around the west coast of the US. They traced the ancient lineages of two species to reveal the insects' lengthy history of asexual reproduction. The discovery could help researchers understand how life without sex is possible. Scientists from Simon Fraser University, Canada, published their results in the journal Current Biology. Certain species of Timema stick insects were known to reproduce asexually, with females producing young in "virgin births" without the need for egg fertilisation by males. The insects instead produce genetic clones of themselves. Dr Tanja Schwander and her team set out to test how old these species were, and therefore to find out how long they had reproduced in this way. By analysing the DNA of the insects, scientists were able to trace back their lineages to identify when they became a distinct species. BBC © 2011

Keyword: Evolution; Sexual Behavior
Link ID: 15578 - Posted: 07.19.2011

by David Robson Nearly 100 years of linguistics research has been based on the assumption that words are just collections of sounds - an agreed acoustic representation that has little to do with their actual meaning. There should be nothing in nonsense words such as "Humpty Dumpty" that would give away the character's egg-like figure, any more than someone with no knowledge of English could be expected to infer that the word "rose" represents a sweet-smelling flower. Yet a spate of recent studies challenge this idea. They suggest that we seem instinctively to link certain sounds with particular sensory perceptions. Some words really do evoke Humpty's "handsome" rotundity. Others might bring to mind a spiky appearance, a bitter taste, or a sense of swift movement. And when you know where to look, these patterns crop up surprisingly often, allowing a monoglot English speaker to understand more Swahili or Japanese than you might imagine (see "Which sounds bigger?" at the bottom of this article). These cross-sensory connections may even open a window onto the first words ever uttered by our ancestors, giving us a glimpse of the earliest language and how it emerged. More than 2000 years before Carroll suggested words might have some inherent meaning, Plato recorded a dialogue between two of Socrates's friends, Cratylus and Hermogenes. Hermogenes argued that language is arbitrary and the words people use are purely a matter of convention. Cratylus, like Humpty Dumpty, believed words inherently reflect their meaning - although he seems to have found his insights into language disillusioning: Aristotle says Cratylus eventually became so disenchanted that he gave up speaking entirely. © Copyright Reed Business Information Ltd.

Keyword: Language
Link ID: 15577 - Posted: 07.19.2011

By Karen Weintraub Out for a run six years ago, Molly Birnbaum was struck by a car. Recovering from surgeries to repair a broken pelvis and torn tendons, she realized the blow had also left her completely unable to smell. Then a recent college graduate and aspiring chef, Birnbaum said it was as if all the color drained out of life. Without the scent of roses, fresh bread, a spring rain, or even trash, she felt like she was living in a black and white world. Estimates are that 1-2 percent of Americans under 65 have a limited sense of smell; that percentage rises to as high as 50 percent of those over 65. And doctors are just beginning to realize how important smell is to our well-being and our perceptions of the world. “Your nose, sitting there in the middle of your face, is arguably the best chemical detector on the planet, but we usually fail to realize its importance until it goes missing due to illness or injury,’’ said Stuart Firestein, a scientist who studies the sense of smell, and the chairman of the biological sciences department at Columbia University. Research into the olfactory process has increased dramatically in recent years, with the first smell-related Nobel Prize awarded in 2004, to an American team; the discovery that smell plays a role in some brain disorders; and the hope that a better understanding of smell may offer insights into how the brain works. © 2011 NY Times Co.

Keyword: Chemical Senses (Smell & Taste)
Link ID: 15576 - Posted: 07.19.2011

By Dave Mosher The brain is an exceedingly complex machine that harbors about 100 trillion neural connections. So it comes as no surprise that neuroscientists make great efforts to reduce or represent that complexity in their research with innovative imaging techniques. For all the time and creativity poured into publication-worthy imagery, however, most of it never leaves the pages of academic journals. Daniel Margulies of the Max Planck Institute for Human Cognitive and Brain Sciences and other neuroscientists thought it was time for a change. "We wanted to create a forum where neuroscientists could be credited for their innovations and engage in dialogue about the aesthetic possibilities of our fields," Margulies says. Along with several colleagues from The Neuro Bureau—an "open neuroscience" forum on the Web—he helped found the inaugural Brain-Art Competition this year. The event's aims were not simply focused on bragging rights and artistic merit. The organizers wanted to bring new imaging techniques and ideas to the fore and help colleagues think about brain research in new ways. "This whole thing started out as a joke in a bar. We knew of other neuroimaging data competitions in our respective fields, and we wondered, 'What could we do that would bring everyone to the table, even artists?'" Margulies says. The competition accepted 55 entries sprinkled across four categories: 3-D brain renderings, representations of the human "connectome" (the brain's connections), abstract illustrations and a humor category. Twenty judges then picked the best entry in each group. © 2011 Scientific American

Keyword: Vision; Miscellaneous
Link ID: 15575 - Posted: 07.19.2011

by Rebecca Kessler Elephant seals are renowned for their rather brutish breeding system, in which one big, pumped-up male jealously defends a harem of females from would-be usurpers in thunderous, bloody battles. The so-called beachmaster wins exclusive mating rights to the comparatively tiny females in his domain, who can get roughed up or killed in his throes of passion. The system is often touted as a textbook example of polygyny in the animal kingdom, but a new study shows that reality is more complex. Female elephant seals often steer clear of the appointed beach during breeding season, sticking to the high seas where they mate on the sly. Southern elephant seals haul out on sub-Antarctic beaches only twice a year, once to molt and once to mate. During the spring breeding season, the males arrive early to stake out their territories. Females, returning to the beaches where they were born, show up a few weeks later and give birth. After the pups are weaned, the males mate with dozens or even hundreds of females in their domain, duking it out with any challengers. The females depart soon after, followed by the males. For the few beachmasters, the system's evolutionary advantage is clear: each one gets to mate with plenty of females. As for the females, researchers have presumed that the opportunity to mate with primo males keeps them returning faithfully to the breeding colony each year. But there was one little problem with the idea. When adult females make their breeding-colony debut, at age 3 or 4, they give birth to a pup—one obviously conceived outside the harem system. © 2010 American Association for the Advancement of Science.

Keyword: Sexual Behavior; Evolution
Link ID: 15574 - Posted: 07.19.2011

by Daniel Strain Even ants can't completely swear off sex. A new survey of a Latin American species famed for being one of the world's few asexual ants has uncovered a surprising find: secret nooky. And that could explain why the insect has managed to survive for so long. The species in question, Mycocepurus smithii, is a fungus-harvesting ant that, like a farmer, sows fungi for food. Researchers didn't suspect anything unusual about it until a 2005 study reported that colonies of M. smithii in Puerto Rico seemed to be missing something important: males. Two 2009 studies discovered similar societies made up entirely of female workers and one or more queens. These matriarchs were reproductively mature, but their spermatheca, chambers that store sperm postmating, remained bone dry, says Christian Rabeling, an evolutionary biologist at Harvard University and a co-author of one of the 2009 studies. "When I did the first dissections, ... I suspected that I made a mistake," he says. Rabeling's surprise was understandable. With males a no-show, queens would have to reproduce asexually, somehow turning eggs into larvae without fertilization from sperm. Of the more than 10,000 known species of ants, researchers have identified only a handful that could boast similar skills. And most of those seemed to mix sexual and asexual reproduction. Celibate animal species are rare for a reason, Rabeling says. Because asexual populations can't mix and match genes through mating, they often lack the genetic diversity to respond to unexpected challenges like disease. © 2010 American Association for the Advancement of Science

Keyword: Sexual Behavior; Evolution
Link ID: 15573 - Posted: 07.19.2011