January 8, 2009, 10:09 PM CT

When workers try to cheat

In ant society, workers normally give up reproducing themselves to care for their queen's offspring, who are their brothers and sisters. When workers try to cheat and have their own kids in the queen's presence, their peers swiftly attack and physically restrain them from reproducing.

Now, a newly released study published online on January 8th in Current Biology, a Cell Press publication, explains just how the cheaters get caught red-handed. Experimental evidence shows that chemical hydrocarbons produced by those sneaky sorts are a dead giveaway of their fertility status.

The findings represent the first direct evidence that cuticular hydrocarbons are the informational basis for the ants' reproductive policing, said Jrgen Liebig of Arizona State University.

Earlier studies had suggested that other aspects of reproduction in insect societies are regulated through cuticular hydrocarbon signals. Liebig's team and others showed that the chemical profiles are correlated with fertility in queens and workers in a number of species of ants, some wasps, and bees. They also observed that workers use hydrocarbons to discriminate between eggs laid by workers and queens. The chemicals are used in other contexts as well, including nestmate recognition and sexual attraction......... Posted by: Kelly      Read more         Source

January 8, 2009, 10:02 PM CT

Ancient odor-detecting mechanism in insects

The work, led by Leslie B. Vosshall, head of the Laboratory of Neurogenetics and Behavior, revamps traditional ideas regarding the roles of ionotropic glutamate receptors, proteins that reside deep in the brain at the synapses. There, they grab glutamate molecules and quickly relay messages from one nerve cell to the next, helping animals learn, move and remember. But Vosshall's group now shows that insects do not relegate these receptors to the depths of the brain. They also put them to use elsewhere: in the nose.

"On the surface it's a completely absurd idea," says Vosshall, who is also a Howard Hughes Medical Institute investigator. "We know what these proteins do; they sit at the synapse and mediate fast neuronal communication. So the idea that the fly has massively expanded the number of these receptors and positioned them to interact with small molecules in the air seems very strange. But if you think about it, it makes sense. The process is the same, but rather than grabbing small molecules at the synapse, they're grabbing small molecules from the air."

The project began two years ago, when Vosshall and Richard Benton, then a postdoc in her lab, noticed a group of six ionotropic glutamate receptor genes while sifting through the fly genome. Eventhough this group was recognized 10 years ago, ever since the genome was sequenced, the genes did not have a known function, in part because it was assumed they must be similar to any other ionotropic glutamate receptor deep in the fly brain. But to Vosshall and Benton, who is now at the Center for Integrative Genomics in Lausanne, Switzerland, that didn't matter......... Posted by: Kelly      Read more         Source

January 8, 2009, 9:31 PM CT

Hind wings help butterflies make swift turns

New tires allow race cars to take tight turns at high speeds. Hind wings give moths and butterflies similar advantages: They are not necessary for basic flight but help these creatures take tight turns to evade predators.

"To escape a predator, you don't have to be fast, you just have to be more erratic," said Tom Eisner, a world authority on animal behavior, ecology and evolution and the Jacob Gould Schurman Professor Emeritus of Chemical Ecology at Cornell. Eisner is co-author of a study on butterfly wings recently reported in the Proceedings of the National Academy of Sciences (105: 43).

The study proposes that in the course of evolution, the ability of butterflies to evade predators became linked with bright coloring, as an added protection. In evolutionary terms, gaudy colors are commonly a sign to such predators as birds that a prey species has a protective quality, such as a bad taste or great agility, and that chasing them isn't worth the energy. Anyone who has tried to net a colorful butterfly knows they are hard to catch, but this is the first study to show that a butterfly's hind wings are responsible for making them evasive.

Eisner and the paper's main author, Benjamin Jantzen, (M.S. physics '02), a doctoral student in philosophy of science at Carnegie Mellon University, clipped off the hind wings of butterflies and then filmed their flight using two cameras to get three-dimensional views of their flight trajectories; then they analyzed and plotted on a computer the insects' flight velocity, acceleration, how fast they changed direction, the curvature of their path and more......... Posted by: Kelly      Read more         Source

January 8, 2009, 8:58 PM CT

Mosquitoes create harmonic love song

That pesky buzz of a nearby mosquito is the sound of love, researchers have known for some time. But a new Cornell study reports that males and females flap their wings and change their tune to create a harmonic duet just before mating.

Cornell entomologists have discovered that male and female mosquitoes (Aedes aegypti), which can spread such diseases as yellow and dengue fevers, "interact acoustically with each other when the two are within earshot -- a few centimeters of each other," said Ron Hoy, professor of neurobiology and behavior.

The study is available online today (Jan. 8) and will be published in a recent issue of Science, said Cornell associate professor of entomology and mosquito expert Laura Harrington, a co-senior author on the study with Hoy.

"The frequency at which males and females converge is a harmonic or multiple of their wing-beat frequencies, which is approximately 400 hertz [vibrations per second] for the female and 600 hertz for the male," said Hoy.

The mating duet, generated just before the couple mates on the fly, settles at around 1,200 hertz -- roughly an octave and a half above concert A (the pitch to which instruments are tuned -- the A that has a frequency of 440 hertz and is above middle C). "That is significantly higher than what was previously believed to be mosquitoes' upper hearing limit," he added......... Posted by: Kelly      Read more         Source

January 7, 2009, 11:55 PM CT

Spookfish uses mirrors for eyes

A remarkable new discovery shows the four-eyed spookfish to be the first vertebrate ever found to use mirrors, rather than lenses, to focus light in its eyes.

Professor Julian Partridge from the University of Bristol, said: "In nearly 500 million years of vertebrate evolution, and a number of thousands of vertebrate species living and dead, this is the only one known to have solved the fundamental optical problem faced by all eyes - how to make an image - using a mirror".

While the spook fish looks like it has four eyes, in fact it only has two, each of which is split into two connected parts. One half points upwards, giving the spookfish a view of the ocean - and potential food - above. The other half, which looks like a bump on the side of the fish's head, points downwards into the abyss below. These 'diverticular' eyes are unique among all vertebrates in that they use a mirror to make the image.

Very little light penetrates beneath about 1000m of water and like a number of other deep-sea fish the spookfish is adapted to make the most of what little light there is. At these depths it is flashes of bioluminescent light from other animals that the spookfish are largely looking for. The diverticular eyes image these flashes, warning the spookfish of other animals that are active, and otherwise unseen, below its vulnerable belly......... Posted by: Kelly      Read more         Source

January 7, 2009, 11:47 PM CT

Human structures leads creatures into peril

Smooth, dark buildings, vehicles and even roads can be mistaken by insects and other creatures for water, as per a Michigan State University researcher, creating "ecological traps" that jeopardize animal populations and fragile ecosystems.

It's the polarized light reflected from asphalt roads, windows -- even plastic sheets and oil spills -- that to some species mimics the surface of the water they use to breed and feed. The resulting confusion could drastically disrupt mating and feeding routines and lead insects and animals into contact with vehicles and other dangers, Bruce Robertson said.

An ecologist studying at the W.K. Kellogg Biological Station in Hickory Corners, north of Kalamazoo, Robertson said polarized light reflected from man-made structures can overwhelm natural cues to animal behavior. Dragonflies can be prompted to lay eggs on roads or parking lots instead of water, for example, and such aquatic insects are at the center of the food web. Insect population crashes can impact higher levels of the food chain.

"Any kind of shiny, black object -- oil, solar cells, asphalt -- the closer they are to wetlands, the bigger the problem," he said.

Predators following misdirected insect prey then also can find themselves in danger......... Posted by: Kelly      Read more         Source

January 6, 2009, 7:57 PM CT

Ladybugs in olive orchards

Present concern for the negative environmental impacts and growing demand for organic olive oil, arise the need to develop useful indicators of agroecosystem health in olive-growing regions. One key indicator of health and sustainability is the abundance and biodiversity of invertebrates, particularly arthropod fauna. Spanish researchers have determined that Coccinellids (ladybugs) can be used to distinguish organic, conventional and integrated farming systems.

Coccinellids were chosen because they are the most abundant family of coleopteran in the olive agroecosystem. They fulfill all the requirements for a useful bioindicator, because thay are a widely distributed and abundant species; are relatively easy to sample and identify; have well-known biologies and life cycles; and are relatively immobile.

The study was carried out over two years, collecting ladybugs from three large olive grove zones, one per management. Results indicate that the richness and abundance of ladybirds were higher in the organic than the non-organic orchards. Conclusions led to identify orchards respectfull with environment......... Posted by: Kelly      Read more         Source

January 6, 2009, 7:20 PM CT

Give Way! Pterosaurs Lift Off

Pterosaurs have long suffered an identity crisis. Pop culture heedlessly - and wrongly - lumps these extinct flying lizards in with dinosaurs. Even paleontologists assumed that because the creatures flew, they were birdlike in a number of ways, such as using only two legs to take flight.

Now comes what is thought to befirst-time evidence that launching some 500 pounds of reptilian heft into flight mandatory pterosaurs to use four limbs: two were ultra-strong wings which, when folded and balanced on a knuckle, served as front "legs" that helped the creature to walk - and leap.

Publishing in Zitteliana, Michael B. Habib, M.S., of the Center for Functional Anatomy and Evolution at the Johns Hopkins University School of Medicine, reports his comparison of bone strength in the limbs of pterosaurs to that of birds and concludes that pterosaurs had much stronger "arms" than legs. The reverse is true of birds.

"We've all seen birds take off, so that's what's most familiar," says Habib. "But with pterosaurs, extinct 65 million years and with a fossil history that goes back 250 million years, what's familiar isn't relevant".

A supersized glitch is inherent in the traditional bipedal launch model, Habib notes: "If a creature takes off like a bird, it should only be able to get as big as the biggest bird"......... Posted by: Kelly      Read more         Source

Thu, 25 Dec 2008 00:20:29 GMT

Weird Animal

Wednesday, December 24, 2008 Siphonophorae or Siphonophora, the siphonophores, are an order of the Hydrozoa, a class of marine invertebrates belonging to the phylum Cnidaria. They are colonial, but the colonies can superficially resemble jellyfish.

Although they appear to be a single organism, each specimen is actually a colony of Siphonophorae. The best known species is the dangerous Portuguese Man o" War.



(via Dark Roasted Blend) Posted by: Gerard      Read more     Source

December 22, 2008, 9:42 PM CT

Protea plants help unlock secrets

New species of flowering plants called proteas are exploding onto the scene three times faster in parts of Australia and South Africa than anywhere else in the world, creating exceptional 'hotspots' of species richness, as per new research published recently in Proceedings of the National Academy of Sciences (PNAS).

Proteas are best known as the national symbol of South Africa. The international team behind today's new study created an evolutionary 'family tree' of all 2,000 protea plant species on Earth the majority of which are found in South Western Australia (SWA) and the Cape Floristic Region (CFR) of South Africa. This 'family tree' enabled the scientists to examine how these and other regions of the planet with Mediterranean-style climates have become so-called 'biodiversity hotspots'.

Until now, researchers have not known exactly why such large numbers of plant and animal species live in these Mediterranean hotspots. They are places of significant conservational importance which, like the rainforests, contain some of the richest and most threatened communities of plant and animal life on Earth.

The research published recently provides the first conclusive proof that plant species in two of these hotspots are evolving approximately three times faster than elsewhere on the planet. The study dates this surge in protea speciation as occurring in the last 10-20 million years, following a period of climate change during which SWA and the CFR became hotter, drier, and more prone to vegetation fires......... Posted by: Kelly      Read more         Source