Stunningly Preserved 165-Million-Year-Old Spider Fossil Found

Scientists have unearthed an almost perfectly preserved spider fossil in China dating back to the middle Jurassic era, 165 million years ago. The fossilized spiders, Eoplectreurys gertschi, are older than the only two other specimens known by around 120 million years.

The level of detail preserved in the fossils is amazing, said paleontologist Paul Selden of the University of Kansas and lead author of the study appearing Feb. 6 in Naturwissenschaften. “You go in with a microscope, and bingo! It’s fantastic.”

The fossils were found at a site called Daohugou in Northern China that is filled with fossilized salamanders, small primitive mammals, insects and water crustaceans. During the Jurassic era, the fossil bed was part of a lake in a volcanic region, Selden said.

Spider fossils from this period are rare, because the arachnids’ soft bodies don’t preserve well. The pristine fossil pictured in these photos was probably created when the spider was trapped in volcanic ash. The ultrafine clay particles squashed the spider without breaking up the animals’ delicate cuticle as more coarse sediment would, Selden said.

E. gertschi shows all the features of the modern members of the family, found in North America, suggesting it has evolved very little since the Jurassic period, Selden said. “The scimitar-shaped structure you notice out of the male is so distinctive,” he said. “Looking at modern ones, you think, well, it’s just a dead ringer.”

The findings also suggest this family of spiders, the Plectreuridae, was once much more widespread than it is today. Currently, the family has only been found living in California, Arizona, Mexico and Cuba. Yet 165 million years ago, they lived on a small continent called the North China Block.

“At some point something caused their range to contract to this part of southern North America,” Selden said. He speculates that changes in vegetation during an ice age or other climactic event wiped them out in other areas, “but they were still happy in these arid areas of the Southwest.”

A new high-tech suction device could allow humans to walk on walls like Spider-Man or create adhesive devices that could be turned on and off with the flick of a switch.

The contraption, inspired by a beetle that can hold on to a leaf with a force 100 times its weight, uses the surface tension of water to make an adhesive bond, but it does so with a creative twist. It could be used to create sticky shoes or gloves, researchers said today.

The device consists of a flat top plate riddled with tiny holes, each just a few hundred microns (a millionth of a meter) wide. A bottom plate holds water. In between is a porous layer. A 9-volt battery powers an electric field that forces water to squeeze through the tiny holes in the top layer.

The surface tension of the exposed droplets makes the device grip another surface — much the way two pieces of wet glass stick together. Turn the electricity off, and the bond breaks.

"In our every day experience, these forces are relatively weak," explained Paul Steen, professor of chemical and biomolecular engineering at Cornell University. "But if you make a lot of them and can control them, like the beetle does, you can get strong adhesion forces."

More work is needed to create a version of the device that would hold a human to the side of a building, however. One prototype has 1,000 holes and can hold about 30 grams, or roughly 70 paperclips. But tests showed that with more and smaller holes, a 1-inch square device could hold 15 pounds.

Another possible use would be covering the droplets with thin membranes, making the device exert outward pressure.

"You can think about making a credit card-sized device that you can put in a rock fissure or a door, and break it open with very little voltage," Steen said. "It's a fun thing to think about."

The device is detailed online this week in the Proceedings of the National Academy of Sciences. The research was funded by the Defense Advanced Research Projects Agency (DARPA) and the National Science Foundation.

Sex Life May Hold Key To Honeybee Survival

 (Jan. 11, 2010) — The number and diversity of male partners a queen honeybee has could help to protect her children from disease, say University of Leeds scientists, who are investigating possible causes of the widespread increase in bee deaths seen around the world.
The researchers are working on the theory that the reason some colonies are wiped out while others remain healthy could be down the genetic diversities of the hives.

Dr Bill Hughes, from the Faculty of Biological Sciences at the University of Leeds, says: “By making sure queens mate with enough genetically variable males, we may be able to boost resistance levels and so protect our Bee populations from disease attacks like the ones we have seen hitting the US.”

One possibility is that the loss of honeybees means that the number and variety of potential mates for a queen is becoming too low to maintain genetic diversity and therefore disease resistant populations.

Says Dr Hughes: “Given the choice, queen honeybees will typically mate with up to 12 different male partners in a matter of minutes and some with over 20. The record is the giant Asian honeybee whose queens normally mate with well over 40 males - and in one case was found to have mated with over a hundred.”

The Leeds scientists will be examining the question of genetic resistance by studying honeybee reactions to a common fungus parasite called Chalkbrood, under carefully controlled laboratory conditions.

The fungus, already found in the majority of UK hives, infects and ‘eats’ larvae, giving them a chalky appearance. Individual larvae die but the parasite rarely kills the whole colony.

In 2008, US average losses of honeybee colonies were 35%, with some beekeepers losing 90% of their colonies. A contributing factor to these high levels of bee may have been a virus. However the same virus has been found in other countries yet does not seem to cause the same problems.

Dr Hughes and his team think infections by hidden parasites in genetically susceptible bees may be combining with other factors to produce a lethal ‘perfect storm’ which overwhelms their defences.

Honeybee survival is vital to the protection of our food supplies because they pollinate up to a third of the food we grow in the UK.

The project, which has received just under £500,000 in funding from the Natural Environment Research Council, is due last for three years. Collaborators include the UK Government’s National Bee Unit based near York and the University of Copenhagen.

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To a Mosquito, Matchmaking Means 'Singing' in Perfect Harmony

 (Jan. 4, 2010) — Researchers have new insight into the sex lives of the much-maligned mosquitoes that are responsible for the vast majority of malaria deaths, according to a report published online on December 31st in Current Biology, a Cell Press publication.
                                                                                 A new study shows that in finding a partner of the right species type, male and female mosquitoes depend on their ability to "sing" in perfect harmony.
In finding a partner of the right species type, male and female mosquitoes depend on their ability to "sing" in perfect harmony. Those tones are produced and varied based on the frequency of their wing beats in flight.
"Everyone must be familiar with the maddening whine a mosquito makes as it hones in for a bite," said Gabriella Gibson of the University of Greenwich at Medway. "There's no doubt many of us have wondered why it makes its presence so obvious -- surely, after all of these centuries of blood-feeding, selection should have favored a more stealthy approach that would leave mosquitoes less vulnerable to the defensive attacks of its unsettled host. Our findings suggest that mosquitoes rely on the sounds they make to attract a mate of the right species, a behavior that is far more vulnerable to selection than avoiding the risk of being squashed by the rare host that is still awake at feeding time."

The Anopheles gambiae mosquitoes in fact include a considerable amount of genetic diversity, representing a complex of seven species and several chromosomal forms. And that diversity comes with real consequences for humans, explained Gibson and Ian Russell of the University of Sussex. The complexity of malaria epidemiology and control is due in part to the mosquito's remarkable genetic plasticity, enabling its adaptation to a widening range of human-influenced habitats.
The new results help to explain how those different mosquito forms manage to reproductively isolate themselves and maintain that genetic diversity, even while some, including the "M" and "S" forms found in Burkina Faso that were the subject of the current study, can be found traveling together in the very same swarms.
Gibson and Russell's team first discovered that male and female mosquitoes harmonize with each other. Gibson said that this is analogous to two partially deaf singers -- one alto and the other soprano -- who can hear low frequencies, but perhaps not their own or each other's songs. Instead, they listen to the terrible dissonance if one or the other goes a bit sharp or flat, which they can get rid of by adjusting their respective tones until the dissonance diminishes to nothing.

"They can do this even if they each sing a different note, say a 'middle C' and a 'G' four tones higher," Russell said. "By listening and subtly altering their pitch to minimize the dissonance, they achieve their goal of 'singing' in a perfect harmony that we, but not they, can hear."
The researchers have now shown that two mosquitoes don't harmonize successfully if they are of the same sex or if they are not the same type of mosquito. They might try for a while, Gibson explained, but they never find that harmony and eventually give up trying.
And that leads Gibson to another take-home of the study. "Even the most 'lowly creatures,' such as mosquitoes, have highly evolved neurosensory systems that can process relatively simple auditory inputs to produce motor outputs enabling them to distinguish between other types of mosquito that are so closely related we need to analyze their DNA to tell them apart."

The researchers include C. Pennetier, University of Sussex, U.K., University of Greenwich at Medway, Kent, U.K., B. Warren, University of Sussex, U.K.; R. Dabire, Institut de Recherche en Science de la Sante/Centre Muraz, Burkina Faso; I.J. Russell, University of Sussex, U.K.; and G. Gibson, University of Sussex, U.K., University of Greenwich at Medway, Kent, U.K.

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Final Moments of Bee Landing Tactics Revealed

(Jan. 2, 2010) — Landing is tricky: hit the ground too fast and you will crash and burn; too slow and you may stall and fall. Bees manage their approach by monitoring the speed of images moving across their eyes. By slowing so that the speed of the looming landing pad's image on the retina remains constant, bees manage to control their approach. But what happens in the final few moments before touch down? And how do bees adapt to landing on surfaces ranging from the horizontal to upside-down ceilings?

Bees manage their approach by monitoring the speed of images moving across their eyes. By slowing so that the speed of the looming landing pad's image on the retina remains constant, bees manage to control their approach. (Credit: iStockphoto/Amit Erez)

Flies land on a ceiling by simply grabbing hold with their front legs and somersaulting up as they zip along, but a bee's approach is more sedate. Mandyam Srinivasan, an electrical engineer from the Queensland Brain Institute, The University of Queensland and the Australian Research Council's Vision Centre, knew that bees must be doing something different from daredevil flies. Curious to know more about bee landing strategies Srinivasan teamed up with Carla Evangelista, Peter Kraft, and Judith Reinhard from the University of Queensland, and Marie Dacke, visiting from Lund University.

The team used a high-speed camera to film the instant of touch down on surfaces at various inclinations and publish their discoveries about bee landing tactics in The Journal of Experimental Biology on December 28 2009 at http://jeb.biologists.org/.
First the scientists built a bee-landing platform that could be inclined at any angle from horizontal to inverted (like a ceiling), then they trained bees to land on it and began filming. Having collected movies of the bees landing on surfaces ranging from 0deg. to 180deg., and every 10deg. inclination between, Evangelista began the painstaking task of manually analysing the bees landing strategies, and saw that the bees' approach could be broken down into 3 phases.
Initially the bees approached from almost any direction and at any speed, however, as they got closer to the platforms, they slowed dramatically, almost hovering, until they were 16mm from the platform when they ground to a complete halt, hovering for anything ranging from 50ms to over 140ms. When the surface was horizontal or inclined slightly, the bees' hind legs were almost within touching distance of the surface, so it was simply a matter of the bee gently lowering itself and grabbing hold with its rear feet before lowering the rest of the body.

However, when the insects were landing on surfaces ranging from vertical to 'ceilings', their antennae were closest to the surface during the hover phase. The team saw that the antennae grazed the surface and this contact triggered the bees to reach up with the front legs, grasp hold of the surface and then slowly heave their middle and hind legs up too. 'We had not expected the antennae to play a role and the fact that there is a mechanical aspect of this is something that we hadn't thought about,' admits Srinivasan.

Looking at the antennae's positions, the team realised that in the final stages as the insects approached inverted surfaces, they held their antennae roughly perpendicular to the surface. 'The bee is able to estimate the slope of the surface to orient correctly the antennae, so it is using its visual system,' explains Srinivasan. But this is surprising, because the insects are almost completely stationary while hovering and unable to use image movement across the eye to estimate distances. Srinivasan suspects that the bees could be using stereovision over such a short distance, and is keen to test the idea.
Finally the team realised that bees are almost tailor made to land on surfaces inclined at angles of 60deg. to the horizontal. 'When bees are flying fast their bodies are horizontal, but when they are flying slowly or hovering their abdomen tilts down so that the tips of the legs and antennae lie in a plane that makes an angle of 60deg.' explains Srinivasan: so the legs and antennae all touch down simultaneously on surfaces inclined at 60deg. 'It seems like they are adapted to land on surfaces tilted to 60deg. and we are keen to find out whether many flowers have this natural tilt,' says Srinivasan.
Srinivasan is optimistic that he will eventually be able to use his discoveries in the design of novel flight control systems.

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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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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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