By CARL ZIMMER The Komodo dragon is already a terrifying beast. Measuring up to 10 feet long, it is the world’s largest lizard. It delivers a devastating bite with its long, serrated teeth, attacking prey as big as water buffaloes. But in a provocative paper to be published this week, an international team of scientists argues that the Komodo dragon is even more impressive. They claim that the lizards use a potent venom to bring down their victims. Other biologists have greeted the notion of giant venomous lizards with mixed reactions. Some think the scientists have made a compelling case, while others say the evidence is thin. Biologists have long been intrigued by the success Komodo dragons have at killing big prey. They use an unusual strategy to hunt, lying in ambush and then suddenly delivering a single deep bite, often to the leg or the belly. Sometimes the victim immediately falls, and the lizards can finish it off. But sometimes a bitten animal escapes. Biologists have noted that the lizard’s victims may collapse later, becoming still and quiet, and even die. For decades, many scientists have speculated that the dragons infected their victims with deadly bacteria that lived in the bits of carrion stuck in their teeth. Yet others have always been skeptical of the bacteria hypothesis. “Your average lion has a much dirtier bite,” said Bryan Fry, a biologist at the University of Melbourne. “It’s complete voodoo.” Copyright 2009 The New York Times Company

Keyword: Neurotoxins
Link ID: 12868 - Posted: 06.24.2010

By Jackie Grom Christine Stracey remembers the first time a mockingbird dive-bombed her head. Since 2005, the graduate student at the University of Florida, Gainesville, has been invading the birds' nests in her neighborhood, counting eggs and banding chicks for a research project. Over time, she noticed that the birds were getting aggressive with her: They would squawk and swoop toward her as soon as they saw her coming. The mockingbirds seemed to have it out for Stracey in particular; they ignored passersby and even gardeners working right beneath their nests. "By the end of the summer, I was absolutely convinced that the birds knew me and did not like me!" she says. The idea that birds can recognize individual humans isn't new. Any parrot owner will tell you that Polly knows the difference between the owner and a stranger. And scientists have shown that crows can identify people by sight: In one unpublished experiment, the birds scolded researchers wearing caveman masks who had caught and banded them months earlier, but they ignored "neutral" figures wearing Dick Cheney masks. Still, no one had actually published work on the ability of birds to recognize people in the wild, and mockingbirds aren't considered to be as intelligent as parrots or crows. So Stracey persuaded her adviser, ecologist Doug Levey, to design an experiment to see if mockingbirds could really recognize individual people. First, Levey, Stracey, and colleagues located a brooding mockingbird on campus. Then they asked one volunteer to stand near the nest for 30 seconds and touch it for half of that time on four consecutive days while the mother mockingbird was present. With each visit, the bird grew more agitated. At first, the mother bird waited until the person came close and then flew to a nearby bush to shout out alarms calls, a behavior called flushing that birds do to distract predators in the wild. But by day four, mom was up and out of her nest when the volunteer was almost 14 meters away--and she or her mate dive-bombed the volunteer's head. © 2009 American Association for the Advancement of Science.

Keyword: Intelligence; Evolution
Link ID: 12867 - Posted: 06.24.2010

by Chris Mooney Vaccines do not cause autism. That was the ruling in each of three critical test cases handed down on February 12 by the U.S. Court of Federal Claims in Washington, D.C. After a decade of speculation, argument, and analysis—often filled with vitriol on both sides—the court specifically denied any link between the combination of the MMR vaccine and vaccines with thimerosal (a mercury-based preservative) and the spectrum of disorders associated with autism. But these rulings, though seemingly definitive, have done little to quell the angry debate, which has severe implications for American public health. The idea that there is something wrong with our vaccines—that they have poisoned a generation of kids, driving an “epidemic” of autism—continues to be everywhere: on cable news, in celebrity magazines, on blogs, and in health news stories. It has had a particularly strong life on the Internet, including the heavily trafficked Huffington Post, and in pop culture, where it is supported by actors including Charlie Sheen and Jim Carrey, former Playboy playmate Jenny McCarthy, and numerous others. Despite repeated rejection by the scientific community, it has spawned a movement, led to thousands of legal claims, and even triggered occasional harassment and threats against scientists whose research appears to discredit it. You can see where the emotion and sentiment come from. Autism can be a terrible condition, devastating to families. It can leave parents not only aggrieved but desperate to find any cure, any salvation. Medical services and behavioral therapy for severely autistic children can cost more than $100,000 a year, and these children often exhibit extremely difficult behavior. Moreover, the incidence of autism is apparently rising rapidly. Today one in every 150 children has been diagnosed on the autism spectrum; 20 years ago that statistic was one in 10,000. “Put yourself in the shoes of these parents,” says journalist David Kirby, whose best-selling 2005 book, Evidence of Harm, dramatized the vaccine-autism movement. “They have perfectly normal kids who are walking and happy and everything—and then they regress.” The irony is that vaccine skepticism—not the vaccines themselves—is now looking like the true public-health threat. (C) Discover

Keyword: Autism
Link ID: 12866 - Posted: 06.24.2010

by Carl Zimmer Four decades ago, an MIT neuroscientist named Jerry Lettvin had a sudden inspiration about how our brains make sense of the world. What if each of us had a special set of neurons in our head whose only job was to recognize a particular person, place, or thing? It was a strange idea, but given what Lettvin knew about the brain, it was plausible. To describe his idea to his students, he made up a story [pdf]. The story was about Alexander Portnoy, the protagonist of Philip Roth’s novel Portnoy’s Complaint, which had just been published. The novel is a long monologue delivered by Portnoy as he lies on the couch of his psychoanalyst. In Lettvin’s version, Portnoy instead decided to go to a neurosurgeon named Akakhi Akakhievitch. Dr. Akakhievitch had discovered 18,000 neurons in the human brain that respond uniquely to a person’s mother. Since much of Portnoy’s misery was caused by thoughts of his overbearing mom, Dr. Akakhievitch opened up his brain and removed all those mother cells. After the operation, Dr. Akakhi­evitch tried a test. “You remember the blintzes you loved to eat every Thursday night?” he asked. “They were wonderful,” Portnoy replied. “So who cooked them?” Portnoy stared at him blankly. Based on this great success, Lettvin told his students, Dr. Akakhi­evitch then extended his search to grandmother cells. (C) Discover

Keyword: Vision
Link ID: 12865 - Posted: 06.24.2010

By ANNIE CORREAL Luke McCarthy said he heard every word. A young man on a noisy street told a story about parking his car next to a construction site, where it was rolled over by a crane. “My car’s been flattened by this 44,000-pound machine,” Mr. McCarthy heard the man say. “It’s been run over like it was, you know, something in a monster truck rally.” Mr. McCarthy, 68, was not outside eavesdropping. He was sitting on Wednesday in a small room at the Center for Hearing and Communication, on the sixth floor of a building in Lower Manhattan, watching a video with an audiologist. “Was that hard?” asked the audiologist, Ellen Lafargue, pausing the video. “No, but I had to pay attention,” Mr. McCarthy said. Mr. McCarthy is deaf in his left ear and uses a hearing aid in his right ear. He was one of the first people to try a new audiovisual hearing test tailor-made for a city that by all accounts never shuts up. Instead of using beeps, tones and word lists — the more typical way to determine how well a new hearing aid works — the test conducted at the center uses sounds that might be heard in New York: cellphone chats, office discussions, the rumble of Midtown traffic. Copyright 2009 The New York Times Company

Keyword: Hearing
Link ID: 12864 - Posted: 06.24.2010

Keeping the brain active by working later in life may be an effective way to ward off Alzheimer's disease, research suggests. Researchers analysed data from 1,320 dementia patients, including 382 men. They found that for the men, continuing to work late in life helped keep the brain sharp enough to delay dementia taking hold. The study was carried out by the Institute of Psychiatry at King's College London. It features in the International Journal of Geriatric Psychiatry. Around 700,000 people in the UK currently have dementia and experts have estimated that by 2051, the number could stand at 1.7m. It is estimated that the condition already costs the UK economy £17bn a year. Dementia is caused by the mass loss of cells in the brain, and experts believe one way to guard against it is to build up as many connections between cells as possible by being mentally active throughout life. This is known as a "cognitive reserve". There is evidence to suggest a good education is associated with a reduced dementia risk. And the latest study suggests there can also be a positive effect of mental stimulation continued into our later years. Those people who retired late developed Alzheimer's at a later stage than those who opted not to work on. Each additional year of employment was associated with around a six week later age of onset. Researcher Dr John Powell said: "The possibility that a person's cognitive reserve could still be modified later in life adds weight to the "use it or lose it" concept where keeping active later in life has important health benefits, including reducing dementia risk." The researchers also admit that the nature of retirement is changing, and that for some people it may now be as intellectually stimulating as work. (C)BBC

Keyword: Alzheimers
Link ID: 12863 - Posted: 05.19.2009

A common heart disorder has been linked to a raised risk of Alzheimer's disease by US researchers. Atrial fibrillation causes the heart to beat chaotically, increasing the risk of blood clots and, if the condition is left untreated, stroke. It has previously been linked to some types of dementia - but not Alzheimer's, the most common form. The study, by Intermountain Medical Center in Utah, was based on more than 37,000 patients. The study found atrial fibrillation patients under the age of 70 had a 187% greater risk of all types of dementia compared with the general population. But their specific risk of Alzheimer's disease was also up - by 130%. However, the overall risk of Alzheimer's for all patients remained low. Lead researcher Dr Jared Bunch said: "Previous studies have shown that patients with atrial fibrillation are at higher risk for some types of dementia, including vascular dementia. "But to our knowledge, this is the first large-population study to clearly show that having atrial fibrillation puts patients at greater risk for developing Alzheimer's disease." Alzheimer's, which accounts for up to 80% of all dementia cases, is known to be linked to age and genetics. It has long been suspected that poor heart health may also play a role. The researchers said more research was needed to explain why atrial fibrillation may raise the risk of Alzheimer's. They put forward several theories for a possible link. They suspect atrial fibrillation damages the small blood vessels, potentially reducing blood flow to the brain. Alternatively, the condition is linked to tiny micro-strokes, the damage from which may accumulate over time, making Alzheimer's more likely. (C)BBC

Keyword: Alzheimers
Link ID: 12862 - Posted: 05.16.2009

By PETER JARET Like bum knees and crow’s feet, cataracts are the price we pay for getting older. Cataracts form when the normally transparent lens of the eye turns cloudy. At least three out of five people over age 60 will eventually develop them. Today, thanks to a steady march of advances, cataract replacement surgery often gives people better vision than they’ve had in years. Progress in the field has been nothing short of astonishing, experts say, starting with the development of artificial lenses about 30 years ago. “In the early days, all we could do was remove the cataractous lens,” said Dr. Peter R. Egbert, director of the Cataract Service at Stanford University. “Patients ended up with no lens in their eye to focus and had to wear very thick glasses to see. Nobody was happy with the results.” Patients can now choose from a wide range of artificial lenses. The most common are monofocal lenses, which focus vision at a single distance, the way a pair of standard glasses does. Before surgery, ophthalmologists test the eyes to choose the best prescription for the artificial lens, based on whether patients are nearsighted or farsighted or have normal vision. Multifocal lenses, designed to focus both up close and at a distance, are a newer option. They are particularly appealing because by the time people develop cataracts, usually starting in their 60s, most suffer from presbyopia and require reading glasses. Presbyopia occurs when the body’s natural lens stiffens with age and eye muscles can no longer focus it for close vision. Copyright 2009 The New York Times Company

Keyword: Vision
Link ID: 12861 - Posted: 06.24.2010

Getting a good night’s rest is essential for good health, but people with sleep apnea aren’t able to succumb to slumber. Obstructive sleep apnea causes episodes of stopped breathing during sleep, and the result is a fragmented, restless sleep that leaves sufferers exhausted and drowsy during the day. Sleep apnea is common, affecting more than 12 million Americans. But most people with the problem haven’t been diagnosed. The problem is more common in men, and associated with being overweight and over 40. Untreated sleep apnea has been linked with high blood pressure, memory problems, weight gain, headaches and car crashes. To learn more about life with sleep apnea, listen to the latest installment of the Patient Voices series from New York Times Web producer Karen Barrow. You’ll meet Ursula Forhan, 54, of Chicago, who says constant tiredness is the worst part of having sleep apnea. “It’s a grinding kind of fatigue,” she says. “It’s a fatigue that makes you ration what you’ll do….You don’t have enough energy for everything.” And you’ll meet Eric Ramme, 54, of Manhattan, who thought his sleep problems were linked to his pillow, mattress or even the traffic outside his window. After his diagnosis, he ultimately underwent surgery to correct the problem. “When you have a good night’s sleep you attack your day,” he says. “You’re happier. So many things are related directly to the quality of sleep you have.” Copyright 2009 The New York Times Company

Keyword: Sleep
Link ID: 12860 - Posted: 06.24.2010

By Janet Raloff Testing for lead only in infants and toddlers may be a mistake, a new study suggests. Pediatricians routinely test very young children because this is the age when blood concentrations of the neurotoxic heavy metal tend to be highest. But older children can face significant lead exposures, and lead’s ability to lower IQ, the new study shows, is much greater for exposures in early school-age children than in toddlers. The study, which will appear in an upcoming Environmental Health Perspectives, also finds that the later childhood exposures correlate more strongly than earlier ones with an exaggerated risk of incurring future criminal arrests for violent behavior. The new data “get at a key concept in environmental health: that there may be some windows of vulnerability — stages of development — that are more vulnerable than others,” notes environmental epidemiologist Howard Hu of the University of Michigan in Ann Arbor. If school-age brains are more susceptible to lead toxicity than younger ones, “that’s important to know, from a public health perspective,” he says. Looking for lead in older children would be a first step in identifying families that need counseling on reducing sources of lead in and around the home. Richard Hornung and his colleagues at Cincinnati Children’s Hospital Medical Center analyzed data on lead levels and IQ from 462 children. About half of the data were collected from kids in Cincinnati during the early 1980s, the rest from kids in Rochester, N.Y., during the mid-1990s. © Society for Science & the Public 2000 - 2009

Keyword: Neurotoxins; Intelligence
Link ID: 12859 - Posted: 06.24.2010

by Helen Thomson If I was reading this sentence aloud, your brain would be able to interpret whether I was speaking in anger, joy, relief, or sadness. That's because emotions in speech leave distinct "signatures" in the brain of the listener. Now, for the first time, brain scans have now characterised those patterns. The finding could help determine where in the brain deficits in emotion processing occur in people with psychiatric disorders such as schizophrenia. Thomas Ethofer at the University Medical Center of Geneva, Switzerland, and colleagues identified spatial signatures of emotion in the primary auditory cortex (PAC) – an area of the temporal lobes at the side of the brain, which is responsible for the sensation of sound. This area is known to react more strongly to emotional vocalisations than to neutral speech, but because this increase in activity is similar for all emotions, scientists had been previously unable to separate one mood from another by using scans. To solve this problem, Ethofer scanned the brains of 22 subjects using functional magnetic resonance imaging (fMRI) while they listened to emotional speech, and combined this with a technique called multivariate pattern analysis (MVPA) – used to identify patterns in brain activation. © Copyright Reed Business Information Ltd

Keyword: Emotions
Link ID: 12858 - Posted: 06.24.2010

By Elsa Youngsteadt The year was 1970. Simon and Garfunkel topped the charts, floppy disks were brand-new, and California white-crowned sparrows (Zonotrichia leucophrys) sang fast machine-gun trills. Just a few decades later, the sparrows sing noticeably slower songs, and a new study reveals the reason. The birds' habitat has gotten scrubbier, and their melodies have evolved to better penetrate the thickets. Ecologists have argued for decades that habitat influences the evolution of bird song. Slow songs and low-pitched sounds transmit better through dense vegetation, whereas high notes carry farther in open environments. And overall, grassland birds do have faster, shriller songs than those from leafy surroundings have. But researchers discovered this by comparing modern populations or species from different habitats. They didn't know how long it would take a species' song to adapt to a new environment. Now they do, thanks to a collection of historical recordings of white-crowned sparrows. Evolutionary ecologist Elizabeth Derryberry, now of Louisiana State University Museum of Natural Science in Baton Rouge, knew that, beginning in the late 1960s, renowned ornithologist Luis Baptista had spent decades studying the birds' chattery, buzzy songs. But she couldn't find his tapes. Finally, in 2003, 3 years after Baptista's death, Derryberry tracked down the sparrow songs in the professor's old office at the California Academy of Sciences in San Francisco. Among the boxes and reprints, she uncovered the songs of 170 male sparrows from 15 locations on the West Coast. © 2009 American Association for the Advancement of Science

Keyword: Evolution; Language
Link ID: 12857 - Posted: 06.24.2010

-- Monkeys are able to learn from their mistakes and will take risks to potentially win better rewards when playing games, according to a new study. "This is the first evidence that monkeys, like people, have 'would-have, could-have, should-have' thoughts," said Ben Hayden, a researcher at the Duke University Medical Center and lead author of the study published in the journal Science. Hayden and his team trained the monkeys to associate a green square on a computer screen with a "high value" reward and other colors with "low value" treats. The monkeys then played a game similar to the game show "Lets Make a Deal" where they had to choose between eight identical white squares. And to test if they were capable of the abstract thought process that allows humans to consider consequences and potential outcomes, they were shown what prizes they missed after receiving the juice. The researchers monitored the neurons in an area of the monkey's brains called the anterior cingulate cortex, or ACC, which plays an important role in decision-making. © 2009 Discovery Communications, LLC.

Keyword: Learning & Memory
Link ID: 12856 - Posted: 06.24.2010

By Tina Hesman Saey Too much fast food could put people on a fast track to diabetes, a new study suggests. Just one month on a fast food diet was enough to alter the ability of fat cells to respond to insulin, researchers from Linköping University in Sweden reported online April 30 in Molecular Medicine. The inability to respond properly to insulin, called insulin resistance, is a hallmark of type 2 diabetes. Cell biologist Peter Strålfors of Linköping University got the idea to put people on a fast food diet from the 2004 documentary Super Size Me, in which a man eats a steady diet of McDonald’s food and grows heavier and increasingly ill. Strålfors recruited 18 lean young people to go on a fast food binge. At the beginning of the experiment, the volunteers averaged a trim body mass index of 22.4. Body mass index, or BMI, is calculated from a person’s weight and height and indicates the degree of body fat, in most cases. A BMI between 18.5 and 24.9 is considered normal. To follow a high-calorie diet, volunteers ate two fast food meals a day for a month. They also restricted physical activity to 5,000 steps a day — half the recommend amount of daily exercise. Before the experiment began, the researchers extracted fat from under the skin of the volunteers’ bellies. Or tried to — the volunteers were so lean that researchers were able to get enough fat for analysis from only six people. © Society for Science & the Public 2000 - 2009

Keyword: Obesity
Link ID: 12855 - Posted: 06.24.2010

(UPI) -- Older adults with the most difficulty understanding spoken words had less brain tissue in a region important for speech recognition, U.S. researchers found. The findings, published in The Journal of Neuroscience, may help explain why hearing aids do not benefit all people with age-related hearing difficulties. Study leader Kelly Harris of the Medical University of South Carolina said that some hearing loss can be a normal part of aging, but many older adults complain about difficulty understanding speech, especially in challenging listening conditions like crowded restaurants. The researchers scanned the brains of 18 younger adults -- 19-39 years old -- and 18 older adults -- 61-79 years old -- as they tried to identify words in listening conditions that varied in difficulty. During a challenging listening condition, the older adults repeated fewer words correctly than did the younger adults, consistent with previous studies. The older adults who had the most difficulty recognizing words also had the least brain volume in a region of auditory cortex called Herschel's gyrus/superior temporal gyrus, Harris said. © 2009 United Press International, Inc.

Keyword: Hearing
Link ID: 12854 - Posted: 06.24.2010

Is that your work ... or a pill's? By the Monitor's Editorial Board Legal drugs that are designed to treat the mentally ill are now being used widely by people seeking a "brain boost" to enhance their work or studies. In many cases, the pills for this Brave New World are being sold over the Internet. Forget for a second that these neuro-enhancing drugs can be highly addictive or that experts say they may have long-term, adverse side effects. Or that the nonprescribed use of such medicine is illegal and the Food and Drug Administration isn't doing enough to stop it. The bigger danger in this new "mind hacking" is that it furthers the idea that people are material machines that can be altered like robots to perform ever-greater mental feats. The notion of life being more than molecules fades like a beautiful sunset behind a storm cloud. And then there is the unfairness of a student or worker who is "high" on psychostimulants being able to perform better on a test or task than someone who chooses to compete without chemical augmentation. A society that still runs on merit and the integrity and uniqueness of each individual must not be forced to screen people before every exam, job interview, or work presentation to see if they have used memory-boosters, productivity-enhancers, or other such "cosmetic neurology." Just look at how Major League Baseball and many other sports must now screen for steroids as body enhancers. These sports are no longer seen as level playing fields for athletes whose records are often suspect. © 2009 The Christian Science Monitor

Keyword: Learning & Memory; Drug Abuse
Link ID: 12853 - Posted: 06.24.2010

Got a tough problem to solve? Try daydreaming. Contrary to the notion that daydreaming is a sign of laziness, letting the mind wander can actually let the parts of the brain associated with problem-solving become active, a new study finds. Kalina Christoff of the University of British Columbia in Canada and her colleagues placed study participants inside an fMRI scanner, where they performed the simple routine task of pushing a button when numbers appear on a screen. The researchers tracked subjects' attentiveness moment-to-moment through brain scans, subjective reports from subjects and by tracking their performance on the task. Story continues below ↓advertisement | your ad here Until now, scientists had thought that the brain's "default network," which is linked to easy, routine mental activity, was the only part of the brain that remains active when the mind wanders. But in the study subjects, the brain's "executive network" — associated with high-level, complex problem-solving — also lit up. The less subjects were aware that their mind was wandering, the more both networks were activated. "This study shows our brains are very active when we daydream — much more active than when we focus on routine tasks," Christoff said. The findings, detailed in the May 11 issue of the journal Proceedings of the National Academy of Sciences, suggest that daydreaming is an important cognitive state where we may unconsciously turn our attention from immediate tasks to sort through important problems in our lives. © 2009 LiveScience.com.

Keyword: Attention
Link ID: 12852 - Posted: 06.24.2010

By Amanda Gardner (HealthDay News) -- Any kind of acupuncture, whether it pierced the skin or not, eased chronic lower back pain in a group of adult patients. "All were superior to usual care," said Daniel Cherkin, lead author of a report published in the May 11 issue of the Archives of Internal Medicine. "Acupuncture is an effective treatment for chronic back pain. People receiving acupuncture are more likely to get better." But the unusual finding that non-penetrating acupuncture did as well as acupuncture that used standard needles will raise questions about how this works, added Cherkin, who is a senior investigator with the Group Health Center for Health Studies in Seattle. Chronic back pain is a chronic health issue in the United States, and is the top reason why patients go to acupuncturists, often when traditional therapies disappoint. Although there have been previous studies on whether acupuncture represents a viable treatment option, "the evidence of the value of acupuncture in general is very murky because the quality of the research is not very good," Cherkin said. This trial, the largest randomized one of its kind, was funded by the National Center for complementary and Alternative Medicine, part of the U.S. National Institutes of Health. © 2009 ScoutNews, LLC.

Keyword: Pain & Touch
Link ID: 12851 - Posted: 06.24.2010

By Jesse Bering How does one broach such an indelicate topic as body odor except perhaps to borrow from the immortal words of the Roman playwright, Terence, who famously said that, “nothing human is alien to me.” True, Terence probably wasn’t referring to flatulence, armpit secretions, halitosis, foot odor, and the many and unspeakably loathsome scents associated with various fungal infections in the body’s hinterlands when he wrote this. Still, his axiom covers a lot of territory on the human condition, including our somewhat smelly natures. And as mature science-minded adults, perhaps we shouldn’t be so shy about our stenches, anyway, since it turns out that our social behaviors—particularly human sexual instincts—are driven by our perceptions of each other’s aromas more than we tend to realize. Compared to the brains of other mammals, the primate olfactory cortex (the brain region associated with processing smells) has decreased in size and relative importance over the course of evolution, being outranked in functional priority by the visual system. But we do have noses for a reason. In fact, for many reasons, a sizeable proportion of which involves gathering useful information from the environment in the form of “chemosignals,” more commonly known as pheromones. As recent findings tell us, other people’s apocrine glands—that is to say, their armpits—are routinely piping out a lot of important social information. These armpit odor molecules are sucked up into our sinuses, processed by our brains, and translated into some rather interesting psychological and behavioral reactions. Men’s body odors tend to be more pungent than women’s, and this peculiarly strong punch can communicate a lot of information about the individual’s genetic quality. Women, in turn, have an almost preternatural olfactory sense, one that appears designed for unconsciously sniffing out the mate value of prospective reproductive partners. © 1996-2009 Scientific American Inc

Keyword: Chemical Senses (Smell & Taste); Sexual Behavior
Link ID: 12850 - Posted: 06.24.2010

By Victoria Gill Earwig mothers sniff out their "best" offspring and lavish them with care, according to new research. The insects pick up odours from their clutch of "nymphs" and adjust their maternal behaviour in response. When they pick up a chemical signal from healthy, well-fed youngsters, they spend more time nursing them, at the expense of their hungrier babies. The study, which is the first to show this behaviour in insects, is published in Proceedings of the Royal Society B. Earwig parenting, it seems, is about favouritism; the standard of care drops dramatically when mums pick up the chemical signals from hungry, unhealthy nymphs. In these cases, the adults invest less time and effort in feeding. The researchers, who expected to see the opposite result, suggest that this could be "because the insects look for signals of quality instead of need. These insects have a clutch of 30-60 offspring, and there is lots of mortality," explained lead researcher Flore Mas from the Zoological Institute at the University of Basel, Switzerland. "So there is no point investing (resources) in offspring that are already in bad shape." While communication via chemicals is common in social insects, this study is the first to show exactly how they have evolved to employ it in parenting. The team that carried out the study explained "begging signals" were well recognised in the avian world - hungry chicks opened their mouths widely and made specific sounds that were recognised by their parents to mean "feed me". (C)BBC

Keyword: Sexual Behavior
Link ID: 12849 - Posted: 05.14.2009