Weird Science Discoveries Of All Kind

World's Oldest Fig Wasp Discovered

noreply@blogger.com (Emmanuel n Aruna) — Thu, 17 Jun 2010 07:37:00 +0000

The world's oldest known example of a fig wasp has been identified from the Isle of Wight. Dating back 34 million years, the fossil wasp looks almost identical to the modern species, suggesting the specialized insect has remained virtually unchanged for at least that long.

When discovered in the 1920s on the largest island of England, the fossils had been wrongly identified as belonging to an ant. New analyses of the fig wasp specimens suggest instead they belong to a fig wasp.

"We believe from molecular evidence that fig wasps and fig trees have been evolving together for over 60 million years," said Steve Compton, a fig wasp expert at the University of Leeds in England. "Now we have fossil confirmation that gets us a bit closer to that date. Although we often think of the world as constantly changing, what this fossil gives us is an example of something remaining unchanged for tens of millions of years."

Fig wasps are tiny insects - measuring just 0.06 inches (1.5 millimeters) in length - that breed exclusively within figs. In return for the breeding spot, the wasps each pollinate one of the 800 ore so modern tree specieswhile ignoring the other fig trees. The flowers, where the pollination occurs, are completely concealed within the fig. The wasps have developed a particular body shape and features so they can crawl into figs to reach the flowers.

The larvae of fig wasps fare best if they feed within a pollinated flower, and so the most highly developed species of wasps actively pollinate the figs before laying their eggs, rather than passively spreading pollen as they move between trees. The wasps collect pollen in pockets on the underside of their bodies and then take it to another tree, where they pull it out and spread it on the flowers before laying their eggs.

Compton and his colleagues used high-tech microscopy techniques to compare the ancient wasp fossils with modern fig wasps and with a specimen of a fig wasp encased in Dominican amber dated to 20 million years ago. Both fossil insects showed the same body shape and features as the modern species, they found.

The team also found pollen pockets on the underside of the fossil wasp and the wasp trapped in amber and identified grains of fig pollen within those pockets.

"What makes this fossil fascinating is not just its age, but that it is so similar to the modern species," Compton said. "This means that the complex relationship that exists today between the fig wasps and their host trees developed more than 34 million years ago and has remained unchanged since then."

A cheating tactic used by modern trees today seems to have already been in play years ago as well. The edible figs we eat are produced on specialized female plants that trick the wasps into entering the figs and strip off their wings, but then prevent them from laying any eggs. As a result, the figs produce only seeds and no wasp offspring. The length of the organ the wasp uses to lay its eggs (called the ovipositor) on the Isle of Wight fig wasp suggests its host fig tree had already evolved this method of cheating on its insect partner.

The research will be published online this week in the journal Biology Letters.

Original Story: World's Oldest Fig Wasp Discovered

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Cord Blood Transplants A Viable Option In Leukemia

noreply@blogger.com (Emmanuel n Aruna) — Thu, 17 Jun 2010 07:26:00 +0000

CHICAGO (Reuters) – Adult patients with leukemia fare just as well when they get stem cell transplants taken from a cord blood bank as they do from a well-suited adult donor, U.S. researchers said on Tuesday.

They said umbilical cord transplants are a viable option for adults with leukemia who urgently need a bone marrow transplant to replace cells destroyed by chemotherapy or radiation treatments, but cannot find a donor.

"What we found is when you look at the outcome of leukemia-free survival, which is the likelihood of a patient being alive without disease, it's the same whether you are transplanting using an adult graft which is from an adult donor or a cord blood unit," said Dr. Mary Eapen of the Medical College of Wisconsin, whose study appears in the journal Lancet Oncology.

Cord blood worked even if it was not a great match, Eapen said in a telephone interview.

Only about half of all white adult patients can find a suitable donor, and the odds are much lower if the patient is African American or Asian, Eapen said.

"In general ... if you don't have an acceptable tissue match with a donor, your chances of having a complication are higher and it can result in death," she said.

But that is less so with stem cells from umbilical cord blood. "The body is more tolerant to the cells in the placental blood, even though they are not a perfect match."

Eapen and colleagues analyzed data from 216 transplant centers worldwide. They compared the results of 165 patients 16 or older with acute leukemia who had been received umbilical cord blood to 888 adults given unrelated stem cell transplants, and 472 who had been given unrelated donor bone marrow.

After two years, all the patient groups were equally likely to survive and be free of leukemia regardless of graft source.

"The beauty of umbilical cord blood is you can use that for transplant patients who are not a perfect match and still come up with an acceptable endpoint, which is leukemia-free survival," Eapen said.

She said most transplants being done with cord blood use public cord blood banks, in which parents have donated blood from their infant's umbilical cord.

These have undergone strict testing to ensure the cells are safe and well preserved.

Private cord blood banks, such as those run by Cord Blood America Inc, typically collect and store cord blood for private use for an individual or family member, she said.

In an accompanying comment, Paul Szabolcs of Duke University Medical Center in Durham, North Carolina, said the analysis should bolster efforts to increase donations to public cord blood banks, particularly by minorities, who have the most trouble finding a matched donor.

Public cord blood banks cover the costs to collect, test and store umbilical cord blood. Information on how to donate can be found at http://www.marrow.org.

Marijuana, Alcohol Addiction May Share Genes

noreply@blogger.com (Emmanuel n Aruna) — Sat, 19 Dec 2009 20:09:00 +0000

The genes that make people susceptible to alcoholism also make them prone to becoming addicted to marijuana, a new study suggests.

Researchers interviewed almost 6,300 men and women aged 24 to 36, including almost 2,800 sets of twins who were part of the Australian Twin Registry, about their use of alcohol and marijuana over their lifetime.

Twins are valuable to researchers in determining the role of genetics in various diseases or conditions because identical twins share 100 percent of their genes, while fraternal twins share 50 percent of their genes, the same as other siblings.

About 60 percent of the likelihood of becoming a heavy drinker, a frequent marijuana user or of becoming dependent on marijuana can be attributed to genes, according to the study, while about half of the likelihood of being an alcoholic can be traced to genetics.

"We know there is a high likelihood of alcohol addiction-related problems among people who smoke marijuana heavily and vice versa," said study author Carolyn E. Sartor, a research instructor at Washington University School of Medicine in St. Louis. "What we found is that some of the same genetic influences that impact alcohol use and dependent symptoms also impact marijuana use and dependent symptoms."

Still, that means between 40 percent and 50 percent of the cause of alcohol or marijuana dependence may be due to environmental influences. Despite a genetic tendency, no one is predestined to abuse either substance, Sartor noted.

And even though a common set of genes appear to influence marijuana and alcohol addiction, there are also likely specific genes that influence addiction susceptibility to individual substances, Sartor added.

The study will be published in the upcoming March issue of Alcoholism: Clinical & Experimental Research.

Marijuana is the most commonly used illegal drug, according to the study, citing a 2008 survey that found about 42 percent of high school seniors reported having tried marijuana. About 5 percent said they had used it daily during the previous month.

Though generally believed to be less addictive than nicotine in tobacco products, about 12 percent of marijuana users meet the criteria for dependency, according to the study. Symptoms of marijuana or alcohol dependency include using more heavily or more frequently than intended, giving up important activities to smoke or drink and building a tolerance or needing to use more to get the same effect.

Marijuana's active ingredient, THC, acts on the brain's cannabinoid system, which is involved in learning, memory, appetite and pain perception, explained Dr. Christian Hopfer, an associate professor at the University of Colorado School of Medicine. Medical uses for marijuana including alleviating pain and boosting appetite in people with cancer and other serious illnesses.

But marijuana has its downsides. Other research has shown marijuana use increases the risk of developing mental illnesses, Hopfer added.

Far less research has been done about marijuana than on tobacco or alcohol products, Hopfer said. That needs to change. Not only is marijuana use widespread, but THC levels in pot have increased in recent years, making the drug's effects more potent.

"We are quasi-legalizing it due to medical marijuana, yet we really don't know that much about it except a lot of people are self-administering it," Hopfer said. "Marijuana addiction is a subtler addition than with some other drugs, but it can be a big focus of their life and interfere with their functioning."

In the past, researchers have often studied the addictive properties of drugs such as tobacco, cocaine, marijuana, heroin and alcohol separately, Hopfer said. But studies such as this suggest there can be similar genes underlying a propensity toward many types of substance abuse.

"There is a lot of evidence that if you have trouble with one substance you will have trouble with others," Hopfer said. "Twin data shows that the genetic effects may be across substances."

While there are legal drugs available to help treat nicotine and alcohol addiction, there are no drugs to treat marijuana addiction. For marijuana dependency, behavioral modification, family therapy, cognitive behavioral therapy and 12-step programs are among the programs that may help, Hopfer said.

Found: Firm Place To Stand Outside Solar System

noreply@blogger.com (Emmanuel n Aruna) — Thu, 17 Sep 2009 10:11:00 +0000

WASHINGTON – Astronomers have finally found a place outside our solar system where there's a firm place to stand — if only it weren't so broiling hot.

As scientists search the skies for life elsewhere, they have found more than 300 planets outside our solar system. But they all have been gas balls or can't be proven to be solid. Now a team of European astronomers has confirmed the first rocky extrasolar planet.

Scientists have long figured that if life begins on a planet, it needs a solid surface to rest on, so finding one elsewhere is a big deal.

"We basically live on a rock ourselves," said co-discoverer Artie Hartzes, director of the Thuringer observatory in Germany. "It's as close to something like the Earth that we've found so far. It's just a little too close to its sun."

So close that its surface temperature is more than 3,600 degrees Fahrenheit, too toasty to sustain life. It circles its star in just 20 hours, zipping around at 466,000 mph. By comparison, Mercury, the planet nearest our sun, completes its solar orbit in 88 days.

"It's hot, they're calling it the lava planet," Hartzes said.

This is a major discovery in the field of trying to find life elsewhere in the universe, said outside expert Alan Boss of the Carnegie Institution. It was the buzz of a conference on finding an Earth-like planet outside our solar system, held in Barcelona, Spain, where the discovery was presented Wednesday morning. The find is also being published in the journal Astronomy and Astrophysics.

The planet is called Corot-7b. It was first discovered earlier this year. European scientists then watched it dozens of times to measure its density to prove that it is rocky like Earth. It's in our general neighborhood, circling a star in the winter sky about 500 light-years away. Each light-year is about 6 trillion miles.

Four planets in our solar system are rocky: Mercury, Venus, Earth and Mars.

In addition, the planet is about as close to Earth in size as any other planet found outside our solar system. Its radius is only one-and-a-half times bigger than Earth's and it has a mass about five times the Earth's.

Now that another rocky planet has been found so close to its own star, it gives scientists more confidence that they'll find more Earth-like planets farther away, where the conditions could be more favorable to life, Boss said.

"The evidence is becoming overwhelming that we live in a crowded universe," Boss said.

Cosmic Cannibals, A Presidential Alien Abduction And Clowns In Space

noreply@blogger.com (Emmanuel n Aruna) — Wed, 09 Sep 2009 06:12:00 +0000

You gonna eat that? The Andromeda galaxy, our nearest neighbor in space, turns out to have a nasty appetite. Using a telescope scan, astronomers have found evidence of Andromeda's galactic meals. From the AP:

"What we're seeing right now are the signs of cannibalism," said study lead author Alan McConnachie of the Herzberg Institute of Astrophysics in Victoria, British Columbia. "We're finding things that have been destroyed ... partly digested remains."

Earth's galaxy, the Milky Way, is next on Andromeda's snack list. John Dubinksi, co-author of the project, says the two galaxies are headed toward each other at a rate of 75 miles per second. But not to worry: We won't be dinner for another few billion years.

Back on Earth, a U.S.-Australian research team has discovered the coldest, driest, calmest place on the planet. The spot, known only as "Ridge A," is located on the Antarctic Plateau. From LiveScience: "It's so calm that there's almost no wind or weather there at all," said study leader Will Saunders.

I hear Venus is beautiful this time of year: Reuters is reporting that Miyuki Hatoyama, Japan's next first lady, claims she was abducted by aliens and taken to Venus. The new prime minister's wife wrote a book last year called, "Very Strange Things I've Encountered," in which she describes her close encounter:

"While my body was asleep, I think my soul rode on a triangular-shaped UFO and went to Venus. It was a very beautiful place and it was really green."

Eh, alien abductions are a dime a dozen — but how many people can claim that they knew Tom Cruise in a previous life? When he was Japanese? The Independent reports that Mrs. Hatoyama and Tom Cruise are old pals: "I believe he'd get it if I said to him, 'Long time no see', when we meet," she said in a recent interview.

Bring in the clowns: On September 30, billionaire Cirque du Soleil founder Guy Laliberte is set to launch into space as the world's seventh space tourist. The cost of his ticket to space? A paltry $35 million. During his 11-day trip, Laliberte plans to broadcast the "first ever widely acknowledged artistic performance from space," according to Space.com. OK, so there won't be any clowns, but Laliberte will take part in a reading of a "poetic fairy tale" he wrote to promote clean-water access and water conservation.

Scientists See Rare Turtle for First Time in the Wild

noreply@blogger.com (Emmanuel n Aruna) — Sat, 05 Sep 2009 13:14:00 +0000

Known only by museum specimens and a few captive individuals, one of the world's rarest turtle species - the Arakan forest turtle - has been observed for the first time in the wild.

A Wildlife Conservation Society (WCS) team discovered five of the critically endangered turtles in a wildlife sanctuary in Myanmar (Burma) in Southeast Asia. The sanctuary, originally established to protect elephants, contains thick stands of impenetrable bamboo forests and is rarely visited by people according to the report.

The adult turtles measure less than a foot in length; its shell is light brown with some black mottling. The species was believed extinct until 1994, when conservationists found a few specimens in a food market in China. Before then, the last know record of the species was of a single animal collected by a British Army officer in 1908. Many Asian turtle species have been driven to near extinction due to their demand as food.

The WCS team also found yellow tortoises and Asian leaf turtles in the sanctuary - two other species threatened by the illegal wildlife trade.

"Throughout Asia, turtles are being wiped out by poachers for the illegal wildlife trade," said Colin Poole, WCS Director of Asia programs. "We are delighted and astonished that this extremely rare species is alive and well in Myanmar. Now we must do what we can to protect the remaining population."

A report documenting the turtles' discovery was prepared by Dr. Steven Platt of Sul Ross State University, Alpine, Texas and Khin Myo Myo of WCS. It recommends several steps to ensure that the turtles remain protected in the sanctuary. These include training of local protected area staff, conservation groups and graduate students to collect additional data on the species, and establishing permanent guard posts on roads leading in and out of the park to thwart potential poaching.

The research was supported by Andy Sabin and the Turtle Conservation Fund.

Pups From 1st Cloned Dog To Be Distributed To Public

noreply@blogger.com (Emmanuel n Aruna) — Thu, 03 Sep 2009 09:44:00 +0000

SEOUL (AFP) – Puppies born from the world's first cloned dog will be offered to good homes later this year, South Korean researchers said on Thursday.

The three male and six female pups were fathered by Snuppy, an Afghan hound who was cloned in 2005 by a team led by Professor Lee Byung-Chun of Seoul National University.

Snuppy impregnated two cloned bitches of the same breed through artificial insemination, in an experiment to test the reproductive ability of cloned dogs. The offspring were born in May last year.

"All the puppies are in very good health," Lee told journalists. The university's veterinary college will receive on-line applications through its home page starting on October 31.

"We'll study the applications and distribute the puppies to those who are fond of pets and capable of raising them well," Lee said.

The team also produced the world's first cloned wolves in 2005. But one of the pair died last month, apparently from infection.

Canadian Scientist Aims To Turn Chickens Into Dinosaurs

noreply@blogger.com (Emmanuel n Aruna) — Thu, 03 Sep 2009 09:27:00 +0000

MONTREAL (AFP) – After years spent hunting for the buried remains of prehistoric animals, a Canadian paleontologist now plans to manipulate chicken embryos to show he can create a dinosaur.

Hans Larsson, the Canada Research Chair in Macro Evolution at Montreal's McGill University, said he aims to develop dinosaur traits that disappeared millions of years ago in birds.

Larsson believes by flipping certain genetic levers during a chicken embryo's development, he can reproduce the dinosaur anatomy, he told AFP in an interview.

Though still in its infancy, the research could eventually lead to hatching live prehistoric animals, but Larsson said there are no plans for that now, for ethical and practical reasons -- a dinosaur hatchery is "too large an enterprise."

"It's a demonstration of evolution," said Larsson, who has studied bird evolution for the last 10 years.

"If I can demonstrate clearly that the potential for dinosaur anatomical development exists in birds, then it again proves that birds are direct descendants of dinosaurs."

The research is funded by the Natural Sciences and Engineering Research Council of Canada, the Canada Research Chairs program and National Geographic.

The idea for the project, Larsson said, came about during discussions with renowned American paleontologist Jack Horner, who served as technical advisor for the Jurassic Park films.

Horner recently wrote a book entitled "How to Build A Dinosaur," in which he refers to the embryo experiment as part of a quest to create a "chickenosaurus."

Larsson's team has previously worked to uncover prehistoric animal remains, including eight unknown species of dinosaurs and five new types of crocodile in Niger. He also recently uncovered the remains of a new carnivorous dinosaur in Argentina.

Newfound Planet Orbits Backward

noreply@blogger.com (Emmanuel n Aruna) — Wed, 02 Sep 2009 16:36:00 +0000

Planets orbit stars in the same direction that the stars rotate. They all do. Except one.

A newfound planet orbits the wrong way, backward compared to the rotation of its host star. Its discoverers think a near-collision may have created the retrograde orbit, as it is called.

The star and its planet, WASP-17, are about 1,000 light-years away. The setup was found by the UK's Wide Area Search for Planets (WASP) project in collaboration with Geneva Observatory. The discovery was announced today but has not yet been published in a journal.

"I would have to say this is one of the strangest planets we know about," said Sara Seager, an astrophysicist at MIT who was not involved in the discovery.

What's going on

A star forms when a cloud of gas and dust collapses. Whatever movement the cloud had becomes intensified as it condenses, determining the rotational direction of the star. How planets form is less certain. They are, however, known to develop out of the leftover, typically disk-shaped mass of gas and dust that swirls around a newborn star, so whatever direction that material is moving, which is the direction of the star's rotation, becomes the direction of the planet's orbit.

WASP-17 likely had a close encounter with a larger planet, and the gravitational interaction acted like a slingshot to put WASP-17 on its odd course, the astronomers figure.

"I think it's extremely exciting. It's fascinating that we can study orbits of planets so far away," Seager told SPACE.com. "There's always theory, but there's nothing like an observation to really prove it."

Cosmic collisions are not uncommon. Earth's moon was made when our planet collided with a Mars-sized object, astronomers think. And earlier this week NASA's Spitzer Space Telescope found evidence of two planets colliding around a distant, young star. Some moons in our solar system are on retrograde orbits, perhaps at least in some cases because they were flying through space alone and then captured; that's thought to be the case with Neptune's large moon Triton.

The find was made by graduate students David Anderson at Keele University and Amaury Triaud of the Geneva Observatory.

Bloated world

WASP-17 is about half the mass of Jupiter but bloated to twice its size. "This planet is only as dense as expanded polystyrene, 70 times less dense than the planet we're standing on," said professor Coel Hellier of Keele University.

The bloated planet can be explained by a highly elliptical orbit, which brings it close to the star and then far away. Like exaggerated tides on Earth, the tidal effects on WASP-17 heat and stretch the planet, the researchers suggest.

The tides are not a daily affair, however. "Instead it's creating a huge amount of friction on the inside of the planet and generating a lot of energy, which might be making the planet big and puffy," Seager said.

WASP-17 is the 17th extrasolar planet found by the WASP project, which monitors hundreds of thousands of stars, watching for small dips in their light when a planet transits in front of them. NASA's Kepler space observatory is using the same technique to search for Earth-like worlds.

Video - When Worlds Collide

Mosquito Mystery Explained ~ Finding Smells That Repel

noreply@blogger.com (Emmanuel n Aruna) — Wed, 02 Sep 2009 03:23:00 +0000

If you're one of those people whom mosquitoes tend to favor, maybe it's because you aren't sufficiently stressed-out.

Insects have very keen powers of smell that direct them to their targets. But for researchers trying to figure out what attracts or repels the pests, sorting through the 300 to 400 distinct chemical odors that the human body produces has proved daunting.

Now scientists at Rothamsted Research in the U.K. have been making headway at understanding why some people can end up with dozens of bites after a backyard barbecue, while others remain unscathed. The researchers have identified a handful of the body's chemical odors—some of which may be related to stress—that are present in significantly larger concentrations in people that the bugs are happier to leave alone. If efforts to synthesize these particular chemicals are successful, the result could be an all-natural mosquito repellent that is more effective and safer than products currently available.

"Mosquitoes fly through an aerial soup of chemicals, but can home in on those that draw them to humans," says James Logan, a researcher at Rothamsted, one of the world's oldest agricultural-research institutions. But when the combination of human odors is wrong, he says, "the mosquito fails to recognize this signal as a potential blood meal."

The phenomenon that some people are more prone to mosquito bites than others is well documented. In the 1990s, chemist Ulrich Bernier, now at the U.S. Department of Agriculture's Agricultural Research Service, began looking for what he calls the "magic compounds" that attract mosquitoes. His research helped to show that mosquitoes are attracted to humans by blends of common chemicals such as carbon dioxide, released from the skin and by exhaling, and lactic acid, which is present on the skin, especially when we exercise. But none of the known attractant chemicals explained why mosquitoes preferred some people to others.

Rothamsted's Dr. Logan says the answer isn't to be found in attractant chemicals. He and colleagues observed that everyone produces chemicals that mosquitoes like, but those who are unattractive to mosquitoes produce more of certain chemicals that repel them.

Misguided Mosquitoes

"The repellents were what made the difference," says Dr. Logan, who is interested in the study of how animals communicate using smell. These chemicals may cloud or mask the attractive chemicals, or may disable mosquitoes from being able to detect those attractive odors, he suggests.

Besides delivering annoying bites, mosquitoes cause hundreds of millions of cases of disease each year. As many as 500 million cases of malaria are contracted globally each year, and more than one million people die from it, according to the Centers for Disease Control and Prevention. Mosquitoes can also spread West Nile virus, dengue fever, yellow fever and other illnesses.

Currently the most effective repellents on the market often contain a chemical known as DEET, which has been associated in some studies with potential safety concerns, such as cancer and Gulf War syndrome. It also damages materials made of plastic. The federal Environmental Protection Agency has determined that DEET, when used as directed, is safe.

The Rothamsted team set out to get the mosquitoes' viewpoint. The researchers separated human volunteers into two groups—those who were attractive to mosquitoes and those who weren't. They then put each of the volunteers into body-size foil bags for two hours to collect their body odors. Using a machine known as a chromatograph, the scientists were able to separate the chemicals. They then tested each of them to see how the mosquitoes responded. By attaching microelectrodes to the insects' antennae, the researchers could measure the electrical impulses that are generated when mosquitoes recognize a chemical.

Dr. Logan and his team have found only a small number of body chemicals—seven or eight—that were present in significantly different quantities between those people who were attractive to mosquitoes and those who weren't. They then put their findings to the test. For this they used a so-called Y-tube olfactometer that allows mosquitoes to make a choice and fly toward or away from an individual's hand. After applying the chemicals thought to be repellant on the hands of individuals known to be attractive, Dr. Logan found that the bugs either flew in the opposite direction or weren't motivated by the person's smell to fly at all.

The chemicals were then tested to determine their impact on actual biting behavior. Volunteers put their arms in a box containing mosquitoes, one arm coated with repellent chemicals and the other without, to see if the arm without the coating got bitten more.

Significant Repellency

The group's latest paper, published in March in the Journal of Medical Entomology, identified two compounds with "significant repellency." One of the compounds, 6-methyl-5-hepten-2-one, is a skin-derived compound that has the odor of toned-down nail-polish remover, according to George Preti, an organic chemist at the Monell Chemical Senses Center in Philadelphia, who is involved in a separate line of research into insect-biting behavior. The other, identified in the paper as geranylacetone, has a pleasant odor, though there is some question about whether the chemical is formed by the human biochemical process or is picked up in the environment, Dr. Preti says.

Dr. Logan declined to comment about the specific chemicals because of proprietary concerns. He says the findings have been patented and the group is working with a commercial company to develop the compounds into a usable insect repellent. One issue that still needs to be resolved: how to develop a formulation of the repellent chemicals that will stay on the skin, rather than quickly evaporating as they do naturally. The hope is to get a product to market within a year or two, he says.

Some of the chemicals researchers identified are believed to be related to stress, Dr. Logan says. Previous research has shown that these particular chemicals could be converted from certain other molecules and this could be as a result of oxidation in the body at times of stress, he says. However, it's not clear if the chemicals observed by the Rothamsted researchers were created in this way, and research is continuing to answer this and other questions.

Dr. Logan suggests that mosquitoes may deem hosts that emit more of these chemicals to be diseased or injured and "not a good quality blood meal." Proteins in the blood are necessary for female mosquitoes to produce fertile eggs, and Dr. Logan says it might be evolutionarily advantageous for mosquitoes to detect and avoid such people.

Other Research

Other research includes an effort by scientists at the University of California, Riverside, who published a paper in the journal Nature last week identifying a recently discovered class of molecules that inhibit fruit flies' and mosquitoes' ability to detect carbon dioxide. Mosquitoes can detect carbon dioxide emissions from long ranges, so turning off the ability to detect the gas, perhaps by releasing the inhibiting molecules into the environment, may be a way of keeping the bugs at bay, the researchers suggest. Another team, at the Monell Chemical Senses Center, is launching a study into whether the taste of human skin and blood are related to the insects' interest in biting certain individuals.

Zombie Ants Controlled by Fungus

noreply@blogger.com (Emmanuel n Aruna) — Mon, 31 Aug 2009 10:37:00 +0000

In a bizarre parasitic death sentence, a fungus turns carpenter ants into the walking dead and gets them to die in a spot that's perfect for the fungus to grow and reproduce.

Scientists have no clue how the fungus takes control of the brains of ants so effectively. But a new study in the September issue of the American Naturalist reveals an incredible set of strategies that ensue.

The carpenter ants nest high in the canopy of a forest in Thailand, and they trek to the forest floor to forage. The fungus, Ophiocordyceps unilateralis, prefers to end up on the undersides leaves sprouting from the northwest side of plants that grow on the forest floor, the new study showed. That's where temperature, humidity and sunlight are ideal for the fungus to grow and reproduce and infect more ants.

Once infected by the fungus, an ant is compelled to climb down from the canopy to the low leaves, where it clamps down with its mandibles just before it dies.

"The fungus accurately manipulates the infected ants into dying where the parasite prefers to be, by making the ants travel a long way during the last hours of their lives," said study leader David P. Hughes of Harvard University.

After the ant dies, the fungus continues to grow inside it. By dissecting victims, Hughes and colleagues found that the parasite converts the ant's innards into sugars that help the fungus grow. But it leaves the muscles controlling the mandibles intact to make sure the ant keeps its death grip on the leaf.

The fungus also preserves the ant's outer shell, growing into cracks and crevices to reinforce weak spots, thereby fashioning a protective coating that keeps microbes and other fungi out.
"The fungus has evolved a suite of novel strategies to retain possession of its precious resource," Hughes said.

After a week or two, spores from the fungus fall to the forest floor, where other ants can be infected.

Making nests in the forest canopy might be an evolved ant strategy to avoid infection, Hughes figures. The ants also seem to avoid foraging under infected areas. This too might be an adaptive strategy to avoid infection, but more study is needed to confirm it, he said.

How the fungus controls ant behavior remains unknown. "That is another research area we are actively pursuing right now," Hughes said.