Dominant Chemical That Attracts Mosquitoes To Humans Identified

(Dec. 30, 2009) — Scientists at the University of California, Davis, have identified the dominant odor naturally produced in humans and birds that attracts the blood-feeding Culex mosquitoes, which transmit West Nile virus and other life-threatening diseases.

The groundbreaking research, published this week in the early online edition of the Proceedings of the A side view of a Culex mosquito, an important vector in West Nile Virus transmission.

National Academy of Sciences, explains why mosquitoes shifted hosts from birds to humans and paves the way for key developments in mosquito and disease control.

Entomology professor Walter Leal and postdoctoral researcher Zain Syed found that nonanal (sounds like NAWN-uh-nawl) is the powerful semiochemical that triggers the mosquitoes' keen sense of smell, directing them toward a blood meal. A semiochemical is a chemical substance or mixture that carries a message.
"Nonanal is how they find us," Leal said. "The antennae of the Culex quinquefasciatus are highly developed to detect even extremely low concentrations of nonanal." Mosquitoes detect smells with the olfactory receptor neurons of their antennae.
Birds, the main hosts of mosquitoes, serve as the reservoir for the West Nile virus, Leal said. When infected mosquitoes take a blood meal, they transmit the virus to their hosts, which include birds, humans, horses, dogs, cats, bats, chipmunks, skunks, squirrels and domestic rabbits. Since 1999, the U.S. Centers for Disease Control and Prevention have recorded 29,397 human cases and 1,147 fatalities in the United States alone.
The UC Davis researchers tested hundreds of naturally occurring compounds emitted by people and birds. They collected chemical odors from 16 adult human subjects, representing multiple races and ethnic groups.
"We then determined the specificity and sensitivity of the olfactory receptor neurons to the isolated compounds on the antennae of the mosquitoes," Syed said.
Leal and Syed found that nonanal acts synergistically with carbon dioxide, a known mosquito attractant. "We baited mosquito traps with a combination of nonanal and carbon dioxide and we were drawing in as many as 2,000 a night in Yolo County, near Davis," Syed said. "Nonanal, in combination with carbon dioxide, increased trap captures by more than 50 percent, compared to traps baited with carbon dioxide alone."
The UC Davis research was funded in part by the National Institutes of Health; a cooperative research agreement with Bedoukian Research, a supplier of specialty aroma and flavor ingredients headquartered in Connecticut; and the National Science Foundation.

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Cockroaches Offer Inspiration for Running Robots

(Dec. 29, 2009) — The sight of a cockroach scurrying for cover may be nauseating, but the insect is also a biological and engineering marvel, and is providing researchers at Oregon State University with what they call "bioinspiration" in a quest to build the world's first legged robot that is capable of running effortlessly over rough terrain.

Researchers at Oregon State University are using studies of guinea hens and other animals such as cockroaches to learn more about the mechanics of their running ability, with the goal of developing robots that can run easily over rough terrain. (Credit: Image courtesy of Oregon State University)
If the engineers succeed, they may owe their success to what's being learned from these insects and other animals, such as the guinea hen, that have their own remarkable abilities.
The latest findings -- just published in the professional journal Bioinspiration and Biomimetics -- outline how animals use their legs to manage energy storage and expenditure, and why this is so important for running stability. The work is being supported by the National Science Foundation.
"Humans can run, but frankly our capabilities are nothing compared to what insects and some other animals can do," said John Schmitt, an assistant professor in the School of Mechanical, Industrial and Manufacturing Engineering at OSU. "Cockroaches are incredible. They can run fast, turn on a dime, move easily over rough terrain, and react to perturbations faster than a nerve impulse can travel."
Within certain limitations, Schmitt said, cockroaches don't even have to think about running -- they just do it, with muscle action that is instinctive and doesn't require reflex control. That, in fact, is part of what the engineers are trying to achieve. Right now some robots have been built that can walk, but none of them can run as well as their animal counterparts. Even walking robots absorb far too much energy and computing power to be very useful.
"If we ever develop robots that can really run over rough ground, they can't afford to use so much of their computing abilities and energy demand to accomplish it," Schmitt said. "A cockroach doesn't think much about running, it just runs. And it only slows down about 20 percent when going over blocks that are three times higher than its hips. That's just remarkable, and an indication that their stability has to do with how they are built, rather than how they react."
If successful, Schmitt said, running robots could serve valuable roles in difficult jobs, such as military operations, law enforcement or space exploration. Related technology might also be applied to improve the function of prosthetic limbs for amputees, or serve other needs.
The OSU researchers are trying to identify some of the basic biological and mechanical principles that allow certain animals to run so well and effortlessly. A guinea hen, for instance, can change the length and angle of its spring-like legs to almost automatically adjust to an unexpected change in a ground surface as much as 40 percent of its hip height. That would be like a human running at full speed, stepping into a 16-inch-deep hole and never missing a beat.
Researchers are getting closer to their goal.
In a computer model, they've created a concept that would allow a running robot to recover from a change in ground surface almost as well as a guinea hen. They are studying how the interplay of concepts such as energy storage and expenditure, sensor and feedback requirements, and leg angles can produce recovery from such perturbations. Ultimately, a team of OSU engineers hopes to use knowledge such as this to actually build robots that can efficiently run over rough terrain without using significant computing power.
And some day, a robot -- instead of a human -- might be used to run into a dangerous area, check things out and report back for further instructions.

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Ladder-Walking Locusts Use Vision to Climb, Show Big Brains Aren't Always Best

 (Dec. 28, 2009) — Scientists have shown for the first time that insects, like mammals, use vision rather than touch to find footholds. They made the discovery thanks to high-speed video cameras -- technology the BBC uses to capture its stunning wildlife footage -- that they used to film desert locusts stepping along the rungs of a miniature ladder.

Screen shot of high-speed video of a locust walking on a ladder. (Credit: Copyright 2009 Department of Zoology, University of Cambridge)

The study sheds new light on insects' ability to perform complex tasks, such as visually-guided limb control, usually associated with mammals.
According to lead author Dr Jeremy Niven of the University of Cambridge: "This is another example of insects performing a behaviour we previously thought was restricted to relatively big-brained animals with sophisticated motor control such as humans, monkeys or octopuses."
Because insects such as bees and flies spend a lot of time flying, most research has concentrated on how insects use vision during flight. Many insects that spend a lot of time walking, such as stick insects, crickets and cockroaches have relatively small eyes and use long antennae to 'feel' their way through the environment.
Locusts spend time both walking and flying, and have short antennae and large eyes, which made Niven wonder whether they used vision to find footholds.
To answer this question, the team built a miniature locust-sized ladder and filmed the locusts walking along it. They counted the number of times the locusts missed steps, comparing the number of mistakes they made in different situations.
"By combining all these different experiments, we showed that locusts use vision to place their legs. We showed that when locusts can't see one front leg they stop using that leg to reach to the next ladder rung, favouring the leg they can see," Niven explains.
"Big-brained mammals have more neurons in their visual systems than a locust has in its entire nervous system, so our results show that small brains can perform complex tasks. Insects show us how different animals have evolved totally different strategies for doing similar tasks," he says.
As well as illustrating how insects can achieve similar results to mammals by using simpler mechanisms, the findings deepen our understanding of locusts' neural circuits.
This is important because locusts have been a model organism for studying limb control for the past 40 years. Insects such as the locust have been crucial to many breakthroughs in neuroscience, and insects are often the inspiration for limb control in robotics.

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Spider Mite Predators Serve As Biological Control

(Dec. 28, 2009) — The control of spider mites, which damage tree leaves, reduce fruit quality and cost growers millions of dollars in the use of pesticide and oil spraying, is being biologically controlled in Pennsylvania apple orchards with two tiny insects known to be natural predators, according to Penn State researchers.

"Predator mite attacking a spider mite."

"Spider mites feed on the chlorophyll in the cells of leaves, damaging their ability to use photosynthesis," said David Biddinger, tree fruit entomologist and biocontrol specialist at the Penn State Fruit Research and Extension Center in Biglerville.
 "When the numbers of mites per leaf reaches 25 to 30, the tree becomes stressed and the leaves start to bronze. This affects the quality of its fruit and in two to three seasons can actually kill small trees."

The two most popular insect specialists used to control
spider mites are a lady bug named Stethorus punctum and a predatory mite named T. pyri. These insects prey on two types of spider mites, the European red mites and the two-spotted spider mites, which are agricultural pests worldwide. Much of Biddinger's work is in Pennsylvania apple orchards, a prime target for both types of pest mites.
Although the lady bug and the predatory mite both hunt spider mites, their ways of tracking them down are different.
"It turns out the predatory mite sort of roams around and bumps into them," said Biddinger. "The lady bug on the other hand is a selective killer, hunting using visual and olfactory cues to prey on spider mites."
The lady bug is tiny, oval, and black and it is a natural killer of pest mites. It is attracted to specific volatile chemical signals given off by the damage the spider mites cause to leaves. It is not just the smell that drives the lady bugs wild; this insect cannot resist the yellowing of the leaves damaged by spider mites. Adult lady bugs can live for over a year and eat up to nine mites an hour or 75 to 100 a day.
The predatory mite is much smaller than the lady bug. It is pear-shaped and is usually creamy-white in color. Young mites develop into adults in a very short time and their voracious appetites make them a formidable enemy to spider mites. Adults have a lifespan of about 75 days and can eat 350 mites during this time.
Reducing pest mite numbers and controlling outbreaks with the aid of mite predators is an important task. The biological control of spider mites reduces the need for mite-controlling chemicals and saves growers millions in integrated pest management costs.

"Biological control is basically using the good bugs to control the bad bugs," said Biddinger.
Growers chose lady bugs as their biological control agent until U.S. Environmental Protection Agency regulations prompted growers to switch to new pesticides that kill lady bugs. The predatory mite, however, was resistant and could live through sprayings. So predatory mites are now the hunter of choice for spider mites.
Biddinger, working with Donald C. Weber, research entomologist, U.S. Department of Agriculture, Agricultural Research Service Invasive Insect Biocontrol and Behavior Laboratory, Maryland, and Larry Hull, professor of entomology, Penn State, published their work in a special issue of Biological Control devoted to ladybugs in agriculture.
"With the pesticides we are using now it is very hard for the lady bug to survive," said Biddinger. "The predatory mite could never exist here before because they could not stand the old pesticides, but they are resistant to the new pesticides. With the predatory mite being more effective than the lady bug, we are probably going to exceed the savings for growers that we had with the lady bug in the past. So far we have reduced miticide use by over 90 percent since we switched. This is saving growers about a million dollars a year and is reducing oil spraying by 45,000 gallons a year."
The State Horticultural Association of Pennsylvania supported this work.

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How the Daisy Got Its Spot: Insect Mimicry

(Dec. 26, 2009) — Dark spots on flower petals are common across many angiosperm plant families and occur on flowers such as some lilies, orchids, and daisies. Much research has been done on the physiological and behavioral mechanisms for how these spots attract pollinators. But have you ever wondered what these spots are composed of, how they develop, or how they only appear on some but not all of the ray florets?

This is the Nieuw morphotype of Gorteria diffusa, which exhibits striking dark petal spots at the bases of some ray florets. Scale bar = 1 cm. (Credit: Courtesy Meredith Murphy Thomas.)


Dr. Meredith Thomas from the University of Cambridge and associates from England and South Africa were interested in exploring these questions and published their findings in the December issue of the American Journal of Botany. They focused on the South African endemic beetle daisy Gorteria diffusa (Asteraceae), which has a unique, raised, dark spot at the base of some of its ray florets.
"I find this plant/pollinator system very exciting to study because of the amazing morphological variation in the flowers between populations," Thomas said. "The spots on the flowers mimic the plant's pollinator, a small fly, which is attracted to the plant because of the spots. The plant is dependent on the pollinator for reproductive success, so it's incredibly important that the plant attracts the flies.
"What we found surprising," Thomas continued, "was how complex the petal spots are in a few populations, when other populations seem to get by with a very simple spot or even no petal spot at all."
By peeling away layers of the tissues that make up the spots on mature ray florets and examining them under a simple dissecting scope, Thomas and associates found that the spots of G. diffusa are more complex than most. These spots are composed of three different types of specialized epidermal cells: the central highlight cells that reflect UV and lack pigment; the interior cells that are shorter, rounder, variously pigmented, and raised above the highlight cells; and, surrounding the spot, a circle of multicellular papillae that are swollen, shiny, and filled with anthocyanin. Moreover, each spot spans four congenitally fused petal lobes, meaning that each lobe contained only part of the spot (and only some cell types) in its genetic makeup.

So what attracts the pollinators? Because there is a lot of spot variation in this species, the authors hypothesize that the elements that are found in common among the various populations, such as the presence of anthocyanin pigment or UV reflectivity, might do the trick.
The authors also wanted to know how only a subset of the floral rays develops a spot. Using scanning electron microscopy the authors looked at how the spot developed, or its ontogeny, over time. They found that only the first few ray florets that develop contain the spots, whereas the rest do not. Thomas noted that "the plant has evolved a very clever way of distributing the pollinator-mimicking spots around the inflorescence so that they appear random, as if a few flies had just landed on the inflorescence, when in fact the position of the spots is mathematically pre-determined according to the plant's phyllotaxy [or the order and location in which new floral organs are initiated]." The authors hypothesize that the genes that control the appearance of the spot are turned on initially and then fade with time, such that only the first, and oldest, rays to develop have the spots. Thus, the development of the spots is complex not only at the cellular level, but at the organismal level as well.
"What we now plan to investigate," concludes Thomas, "is whether the development of this adaptive floral trait is regulated by a similarly complex genetic regulatory pathway, or if this plant has simply co-opted and modified a pathway commonly used in plants to produce other types of specialized surface structures, like hairs.$395. Termite Treatments Termite Bonds Pest Control Termite Real Estate Inspections.
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Microscopic Flower Petal Ridges Flash to Attract Pollinating Insects; Scientists Now Know How Ridges Form

 (Dec. 25, 2009) — Microscopic ridges contouring the surface of flower petals might play a role in flashing that come-hither look pollinating insects can't resist. Michigan State University scientists and colleagues now have figured out how those form.

The result could help researchers learn to enhance plants' pollination success and even could lead to high-grip nanomaterials and "green chemical" feedstocks.
"Surprisingly, our work on plant surface biochemistry became a birds and bees and flowers story," said John Ohlrogge, MSU University Distinguished Professor of plant biology. "It's a fundamental property of plant flowers, and we've discovered a basis of how these ridges are made."
Known for 75 years, the exact biological function and nature of the flower nanoridges still eludes scientists. They might help pollinating insects grip petals, and retain glistening water droplets that could attract the visitors. Because the ridges' spacing is approximately that of visible and ultraviolet light wavelengths, moreover, some recent research suggests they produce an iridescent shimmer that attracts pollinators.

To start, visiting professor Mike Pollard and former Ohlrogge post-doctoral research associates Fred Beisson and Yonghua Li tapped new genetic information to find a mutated strain of the standard research plant Arabidopsis thaliana -- mustard weed. The petals have no such nanoridges because the mutation inhibits production of a polymer that forms the plant cuticle, which separates cell walls from plants' waxy surfaces.
Examining the mutant plants' flowers and comparing them to normal mustard plants under scanning electron microscopes, the researchers found that the ridges form from cutin polyester, not from underlying surfaces as some have speculated. How that occurs -- from surface folding or uneven synthesis of cutin polymer across the cell wall, for example, has yet to be learned.
But the research will open doors to further research based on cuticular nanostructures, the researchers noted in a recent edition of the journal Proceedings of the National Academy of Sciences.
"That could include production of polyesters or related basic chemicals by genetically manipulating plants or microbes" said Beisson, now at Aix Marseille Université in Saint-Paul-lez-Durance, France.

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Edge of Nature: Bedbugs are night stalkers

December 15th, 2009, Bedbugs are not as rare as they once were in Orange County; while there are no major outbreaks in the area, the past five years have seen more reports of the blood-sucking creatures than in previous years.

And by all accounts, they are terrible house guests: they bite, they smell bad, and they won’t leave. Experts say getting rid of bedbugs from a building with an entrenched infestation is extremely difficult.

That might be because common bedbugs are human specialists, adapted to thrive in our dwellings and batten on our blood. They attack at night, while we sleep, and though some people feel a prick of pain from the bite itself, many don’t realize they have bedbugs until the bites, especially around the face, grow itchy and swollen — or until they see staining on bed sheets from bedbug waste.

Common bedbugs, about the size of a “flattened lady bug,” dine almost entirely on human blood, but will attack other mammals and birds in a pinch, especially chickens and bats.

Meanwhile, other bedbug species sometimes moonlight by attacking humans. Building a bird nest-box on the wall of a house, for instance, might attract purple martins, which could bring along their bedbug specialists. Those bedbugs might then invite themselves inside for a taste of human blood.

Scientific name: Cimex lectularius

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The Buzz on Fruit Flies: New Role in the Search for Addiction Treatments

 (Dec. 21, 2009) — Fruit flies may seem like unlikely heroes in the battle against drug abuse, but new research suggests that these insects -- already used to study dozens of human disease -- could claim that role. Scientists are reporting that fruit flies can be used as a simpler and more convenient animal model for studying the effects of cocaine and other drugs of abuse on the brain.

Andrew Ewing and colleagues note that laboratory mice, rats, and monkeys have been mainstays in research with the ultimate goal of finding effective medicines for treating addiction. Although these mammals have helped establish the behavioral effects of cocaine on the body, they provide relatively complicated models to study the effects of cocaine and other illicit drugs on the brain and nerves. In the hope for a new simpler animal model they turned to fruit flies, which have many biological similarities to mammals, but are easier to study.

A tiny electrode and pipette inserted into the fruit fly brain make it a simple, convenient model for studying drug abuse in humans. (Credit: American Chemical Society)

The scientists confirmed those hopes in research that involved giving cocaine, amphetamine, methamphetamine, and methylphenidate to fruit flies and then studying brain chemistry with a microelectrode one-twentieth the diameter of a human hair. The results demonstrate that fruit flies are a valid model for studying drug addiction in humans, the scientists say.

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New Nasal Vaccine Blocks Parasite Transmission to Mosquitoes

(Dec. 20, 2009) — An experimental nasally administered malaria vaccine prevented parasite transmission from infected mice to mosquitoes and could play an important role in the fight against human malaria.

Researchers from Japan report their findings in the December 2009 issue of the journal Infection and Immunity.
Malaria is one of the most significant infectious diseases affecting developing countries and is often prominent in children. Mortality and morbidity levels are high and although antimalarial drug chemotherapy and insecticide-treated bed nets have somewhat reduced the number of malaria infections, additional prevention and treatment methods such as vaccines are needed for local elimination and ultimately complete eradication. Prior studies show that the ookinete-to-oocyst phase in the malaria life cycle, when the malarial parasite is fertilized in the mosquito's body, is one of the most vulnerable stages making it an ideal target for antitransmission vaccines.
In the study researchers developed a nasal vaccine based on ookinete-surface proteins (OSPs or also known as parasite antigens) and intranasally vaccinated mice infected with malaria. When given in conjunction with the cholera toxin adjuvant vaccinated mice developed a robust antibody response and completely prevented trasmission of the parasite to mosquitoes that were allowed to feed on them after infection.
"To our knowledge, this is the first time that mucosal vaccination has been demonstrated to be efficacious for directly preventing parasite transmission from vaccinated animals to mosquitoes, and the results may provide important insight into rational design of nonparenteral vaccines for use against human malaria," say the researchers.

Why Some Insects Can Survive Freezing: Huge X-Ray Microscope Provides Clues

(Dec. 19, 2009) — Using a microscope the size of a football field, researchers from The University of Western Ontario are studying why some insects can survive freezing, while others cannot. Why is this important? Because the common fruit fly (Drosophila melanogaster) is one of the bugs that cannot survive freezing and the little creature just so happens to share much of the same genetic makeup as humans, therefore finding a way to freeze them for research purposes is a top priority for geneticists the world over (about 75 per cent of known human disease genes have a recognizable match in the genetic code of fruit flies).

Synchrotron x-ray visualisation of ice formation in insects during lethal and non-lethal freezing. (Credit: Image courtesy of University of Western Ontario)

And why the large microscope?
"It's the only one in the world that's set up for this kind of imaging on insects," says lead researcher Brent Sinclair of his team's use of the Advanced Photon Source (APS), located near Chicago, Illinois. The APS generates high-energy x-rays that allow Sinclair and his collaborators to film the formation and spread of ice in real time as the maggots freeze.
An assistant professor in Western's Department of Biology, Sinclair explains that the physical processes of ice formation seem to be consistent among species that do and don't survive freezing. However, it seems that the insects that survive freezing have some control over the process of ice formation. They freeze at consistently higher temperatures than those that don't.

Sinclair says this implies that the main adaptations required to survive freezing are at the cellular or biochemical level, rather than because of fundamental structural differences.
"We're comparing Chymomyza amoena, an insect native to Ontario that survives freezing, with Drosophila melanogaster, because they're very close relatives," says Sinclair. "The idea is to find the magic bullet which allows some bugs to survive freezing and some don't. That's the goal here."
The Western-led research was published in the journal PLoS ONE, an peer-reviewed, open-access resource from the Public Library of Science.

"Rastafarian Grass Snakes"

Killer Catfish? Venomous Species Surprisingly Common, Study Finds

(Dec. 15, 2009) — Name all the venomous animals you can think of and you probably come up with snakes, spiders, bees, wasps and perhaps poisonous frogs. But catfish?

A new study by University of Michigan graduate student Jeremy Wright finds that at least 1,250 and possibly more than 1,600 species of catfish may be venomous -- far more than previously believed. The research is described in a paper published online Dec. 4 in the open access journal BMC Evolutionary Biology.
Lest anyone have concerns about attacks of killer catfish, rest assured that, at least in North America, these finned fatales use their venom mainly to defend themselves against predatory fish, though they can inflict a painful sting that many fishermen have suffered. In other parts of the world, some catfish do have extremely toxic venoms that can be deadly to humans.

Scientists have focused a great deal of attention of venom produced by snakes and spiders, but venomous fish had been largely neglected, said Wright, who used histological and toxicological techniques, as well as previous studies of evolutionary relationships among catfish species, to catalog the presence of venom glands and investigate their biological effects.
Catfish venom glands are found alongside sharp, bony spines on the edges of the dorsal and pectoral fins, and these spines can be locked into place when the catfish is threatened. When a spine jabs a potential predator, the membrane surrounding the venom gland cells is torn, releasing venom into the wound. In his paper, Wright describes how catfish venoms poison nerves and break down red blood cells, producing such effects as severe pain, reduced blood flow, muscle spasms and respiratory distress. However, because none of the species he examined produces more than three distinct toxins in its venom, each species probably displays only a subset of the whole repertoire of effects.
The main dangers to humans who tangle with North American catfish come not from the initial sting and inflammation, but from secondary bacterial and fungal infections that can be introduced through the puncture wound or when pieces of the spine and other tissue break off in the wound, Wright said. "In such cases, complications associated with these infections and foreign bodies can last several months."
On the evolutionary side, Wright's analyses point to at least two independent origins of catfish venom glands. In addition, the toxic proteins show strong similarities with, and might be derived from, previously characterized toxins found in catfish skin secretions.

Those toxins in catfish skin secretions have been shown to accelerate wound healing in humans, so it's possible that the proteins from their venom glands could have similar properties. Probably not very likely, given the known effects of these venoms on humans, but perhaps worth investigating, Wright said.
"I'm currently working to isolate particular toxins and determine their chemical structures and the genes responsible for their production," he said. "It's a very poorly-studied area, with little in the way of scientific literature to draw on, and my studies are just getting off the ground. So at this point it remains to be seen whether they'll have any therapeutic value, though it's worth pointing out that toxins from the venoms of other organisms -- snakes, cone snails and scorpions, for example -- have all been put to pharmaceutical and therapeutic use."
Further examination of the chemical composition of the venoms also will provide valuable insight into the mechanisms and potential selective factors driving venom evolution in fishes, Wright said.

Wright received financial support from the U-M Museum of Zoology and the U-M Rackham Graduate School.

Sucker-Footed Bats Don't Use Suction After All

 (Dec. 16, 2009) — In first-time experiments in the wild, a researcher at Brown University has discovered that a species of bat in Madagascar, Myzopoda aurita, uses wet adhesion to attach itself to surfaces. The finding explains why the bat -- unlike almost all others -- roosts head-up. It also helps to explain how it differs from a similar head-up roosting species. Results appear in the Biological Journal of the Linnean Society.
There are approximately 1,200 species of bats worldwide. Of that total, only six are known to roost with their heads pointed upward. Investigators did not know why, because they knew next to nothing about one key group.
The sucker-footed bats of Madagascar, Myzopoda aurita, had rarely been seen in the wild and were listed as vulnerable to extinction by the International Union for Conservation of Nature. But several years ago, biologists stumbled upon some colonies in a new-growth forest on the southeastern section of the island, opening the door to studies.
Daniel Riskin, a postdoctoral research associate in ecology and evolutionary biology at Brown University, traveled last summer to Madagascar to study one of the two species of sucker-footed bats with biologist Paul Racey. In first-time experiments in the wild, the pair made a surprising discovery: The bats don't use suction after all. Instead, they use wet adhesion, secreting a fluid, possibly sweat, that enables the pads on the bats' wrists and ankles to attach to surfaces. The pair's findings are published in the Biological Journal of the Linnean Society.
While the finding settles the question of how the bats roost, it means science has misnamed the bat. "Myzopoda literally means 'sucker foot,'" Riskin, the paper's lead author, said. "You can't change Latin names, so it's stuck with it."
Riskin used a force plate he had built to determine how Myzopoda clung to surfaces. He placed the sucker-footed bats on the plates, first with evenly spaced holes and then with the holes covered by tape underneath the plate. In both instances, Myzopoda had no problem adhering to the plate, effectively ruling out suction as the adhesive technique. (Had suction been used, the holes would have prevented the bats from establishing a seal on the surface.)

Next, Riskin sought to understand how the bats roost head-up by testing how they detach their limbs from a surface. Holding the bat so it was head up-and in a vertical position, Riskin discovered that he could easily "unpeel" the bats' pads from the surface. He also encountered little resistance when pushing the bat in an upward direction. But when Riskin tried to drag the bat downward, the animal clung doggedly to the vertical surface. Through further investigation, Riskin figured out the bats detach themselves from their roosting position by using tendons in their wrists and ankles to decrease the pads' surface area of attachment. This explains why video footage shows the bats' pads peeling off the surface when they begin walking. It also explains why the bats would come unlatched if they tried to roost head down.

The finding helps scientists understand how Myzopoda lives in the wild. The bat, a small creature about two inches long and weighing one-third of an ounce, roosts on the slick surface of broad, fan-like leaves located high off the ground in an indigenous tree called Travelers' Palm (Ravenala madagascariensis).

The researchers' finding also settles speculation that Myzopoda differs from its head-up roosting alter ego, Thyroptera, which is a suction-footed species that lives in tropical climes in Central and South America. The question is, with two species living in similar tropical environments under similar competitive pressures, which adhesive technique came first?

Riskin believes that Thyroptera is a later stage of evolution of the two bats. Why? While Myzopoda, through wet adhesion, can only roost head-up, Thyroptera, using suction, can roost either head-up or head-down. In terms of evolution, Riskin noted, "It doesn't make sense to go through suction to get to wet adhesion, but it does make sense to go through wet adhesion to get to suction."

The research was funded by the National Geographic Society and a private family donation.

From Fruit Fly Wings to Heart Failure: Notch Is Key Signalling Pathway for Heart Development and Healing

(Dec. 15, 2009) — Almost a century after it was discovered in fruit flies with notches in their wings, the Notch signalling pathway may come to play an important role in the recovery from heart attacks. In a study published today in Circulation Research, scientists at the European Molecular Biology Laboratory (EMBL) in Monterotondo, Italy, are the first to prove that this signalling pathway targets heart muscle cells and thus reveal its crucial role in heart development and repair.

The Notch pathway is a molecular mechanism through which cells communicate with each other. Scientists in Nadia Rosenthal's group at EMBL used sophisticated genetic mouse models to uncover critical roles for this pathway in heart muscle cells. When they inactivated Notch specifically in the heart muscle precursor cells of early mouse embryos, the scientists discovered that the mice developed heart defects. Curiously, increasing Notch signalling in the heart muscle cells of older embryos had the same detrimental effect, uncovering different requirements for Notch as development proceeds.

"The cardiac malformations we observed are characteristic of Alagille syndrome, a human congenital disorder," said first author Paschalis Kratsios,. "Therefore, our findings could help to explain the cardiac symptoms associated with Alagille syndrome and related forms of congenital heart disease."

Intriguingly, the scientists were able to improve the cardiac function and survival rate of adult mice that had suffered heart attacks by re-activating Notch, suggesting new therapeutic approaches to help the heart recover from damage.

"Overall, these results highlight the importance of timing and context in biological communication mechanisms" Nadia Rosenthal concludes: "Our findings also lend support to the notion that, in certain situations, redeployment of embryonic signalling pathways could prove beneficial for tissue regeneration in the adult."

Ok, this is way too much fruit Fly info..I think I have squeezed out all the stories that I can out of those little guys...seeya

Female Fruit Flies Can Be 'Too Attractive' to Males, Scientists Show

 (Dec. 14, 2009) — Females can be too attractive to the opposite sex -- too attractive for their own good -- say biologists at UC Santa Barbara. They found that, among fruit flies, too much male attention directed toward attractive females leads to smaller families and, ultimately, to a reduced rate of population-wide adaptive evolution.
In an article published in the December 8 issue of Public Library of Science Biology, the authors described their experiments on the sex lives of fruit flies.

"Can females be too good looking?" asks William Rice, biology professor at UCSB. "Can there be disadvantages to being attractive? The answer is yes: If you are too attractive, you get too much male attention, and that interferes with your ability to function biologically."
The authors explain that the term "good looking," among fruit flies, refers to something, like a large body. From the perspective of a male fly, a desirable mate is a female that is larger and can therefore produce more offspring.
"These larger females are disproportionately courted and harassed by males attempting to obtain matings," said Tristan A. F. Long, the study's first author. "When these males are 'choosy' with their courtship, there may be negative consequences to the species' ability to adaptively evolve."
According to the scientists, too much mating is harmful to the females because seminal fluid from the male has toxic side effects. Too much courtship can also hinder the female's ability to forage effectively.

"When they court the females, the males sing to them; they do this by vibrating their wings," said Rice. "They dance and sing at the same time. This might sound romantic, and it would be if it only happened once. But males are doing it all the time. This courtship is unrelenting -- like mosquitoes on a warm summer night -- as the male fruit flies try to persuade females to mate. The males are so persistent that they get them to mate almost every day."
In many species, females are frequently subject to intense courtship "harassment" from males attempting to obtain additional matings, according to the researchers. These coercive activities can result in attractive females becoming less fit to reproduce -- a factor that has a major effect on the entire population.

"We found that when harmful courtship behaviors were directed predominantly toward larger females of greater fecundity potential -- and away from smaller females, of lesser fecundity potential -- this resulted in an overall reduction in the variation of lifetime reproductive success of females in the population," said Long.

The male-mediated, persistent courtship bias can have important consequences for the ability of a population to adaptively change over time. If, for example, a female acquires a mutation that increases metabolic efficiency, allowing her to grow larger, and produce more offspring over her lifetime, this mutation should rapidly spread through the population. However, if the males get in the way of the biological success of these more attractive females, the mutation won't spread through the population as well as it might if males courted females indiscriminately.
The experiments clearly showed that the evolutionary adaptation of fruit flies is hindered by this mating situation. "This change in the distribution of fitness represents a previously unappreciated aspect of sexual selection -- one with important implications for the ability of beneficial genetic variation to spread through the gene pool, and ultimately for a species' capacity to adaptively evolve," Long explained.

Long was a Natural Sciences and Engineering Research Council of Canada (NSERC) postdoctoral fellow at UCSB at the time that he carried out the experiments designed with Rice. Long is currently a postdoctoral fellow with the University of Toronto in the Department of Ecology and Evolutionary Biology. The other authors are Alison Pischedda, a graduate student, and Andrew D. Stewart, a postdoctoral fellow, both of UCSB.