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Sunday, February 27th, 2005
10:11 am - Good vibrations rule the termite's world

00:01 22 February 2005
NewScientist.com news service
Emma Young, Sydney

Termites use the vibrations produced when they chew into wood to decide which bits to eat, researchers have discovered.

They also seem to use the acoustic vibration signals to detect the presence of other species of termite on the same piece of wood, and to help control the development of immature workers into sexually-active breeders. These findings might be exploited to protect homes without using pesticides, say the Australian team.

Termites have a reputation as voracious, indiscriminate eaters. But this is not so, says Theodore Evans of CSIRO Entomology in Canberra, Australia. Species that share the same habitat will often each go for only particular sizes of wood, with some eating twigs, and others fallen trees - presumably to avoid competition.

But it has not been clear how the blind insects quickly determine the size of a piece of wood. The new work suggests they use vibration-sensing organs at the base of their antennae and on their legs.

"They detect the resonant frequency of the vibrations made as they chew into the wood," Evans says. "But I assume they also use information from their jaws on the hardness of the wood, and their detection of various chemicals in wood, to identify the wood species. They probably put all these things together to work out how big the piece of wood is."
Burrowing in

The team studied worker drywood termites, Cryptotermes domesticus, which happily munch into wooden buildings.

They exposed the workers to blocks of pine wood of various lengths, and recorded the vibration frequencies made as they walked over and bit into the wood. These workers preferred to burrow into only the shortest, 20-millimetre-long blocks.

But by loudly playing back the 20mm vibration frequencies, the team could trick the termites into burrowing into much longer pieces. Playing frequencies initially produced from long blocks also stopped termites burrowing into their favoured shorter pieces.
King and queen

Evans also noticed an impact on the termites' sexual development. Playing the vibration recordings reduced the number of workers that matured into the reproductive stage by half, on average.

In a natural setting, many vibrations would indicate the presence of lots of other workers in the vicinity. Since workers that develop into breeders must fight with each other until only one king and one queen are left, the signal could have suggested lots of potential competition, and quashed development, Evans says. This is the first time that vibration signals have been linked to reproductive development in insects.

In unpublished work, Evans has also found that drywood workers can use vibration information to detect other species on the same piece of wood. He put one small Cryptotermes termite at one end of a twig, and a large, aggressive species at the other. "And the large species tunnelled straight for the smaller. It's amazing - like guided missiles," he says.

"Now I would love to figure out if we could actually scare termites away from a house if we broadcast the right kind of signals - if we could effectively say that a big, bad, mean termite colony is already here, and you don't want to come in." Such signals could be played at a decibel level audible to termites but not to people, he says.

Journal reference: Proceedings of the National Academy of Sciences (DOI: 10.1073/pnas.0408649102)
Friday, February 11th, 2005
10:17 pm

somebody recommend me some music. pleeeeease.

yay it is friday and i've stayed up late.

the end.
7:19 pm - mildred, bridget, fredericka and ethel

yay, my tank no longer houses my inflatable grasshopper - i have girlies again!

or rather 3 old ladies (slightly disabled with limbs missing) and a teenager. i could feel slightly bad about the condition of them, and the fact i bought them (pound each) but i got them from the tiny pet shop down the road, they weren't advertised or out on display (i rang to ask if they had any) and the man was very nice and seemed a little sad that they weren't thriving, even though he liked them.

it is nice having things to talk to when i get in the house, and something to look after.
Monday, November 29th, 2004
9:47 pm

(i guess i ought to write somewhere on the userinfo that i absolutely will not use lj cut unless i specifically want to but i'm not going to)

from http://www.newswise.com/articles/view/508523/ being a biochemist (oh crap i'm now supposed to be a genetic technologist. damn it i'm a biochemist at heart!) i wish i could learn a little about the chemistry of the pheromone, but hey, i don't have access to such things. :O/ and the nhs doesn't pay me enough.

Newswise — A recent discovery unveils the chemical secret that gives old bees the authority to keep young bees home babysitting instead of going out on the town.

A hard-to-detect pheromone explains a phenomenon Michigan State University entomologist Zachary Huang published 12 years ago – that somehow older forager bees exert influence over the younger nurse bees in a hive, keeping them grounded until they are more mature, and thus more ready to handle the demands of buzzing about.

The work that identifies the chemical, “Regulation of Behavioral Maturation in Honey Bees by a New Primer Pheromone” is publishing in Proceedings of the National Academy of Science Biological Sciences, Population Biology, Early Edition the week of Nov. 29.
“If the older ones don’t keep them in check, the young ones can mature too quickly,” Huang said. “It’s kind of the same thing as with people, you need the elders to check on the young, even if the young are physically able to go out on their own, it’s not the best situation for anybody and now we know how it works.”

Huang worked with a team that spanned from the United States, France and Canada to explain how the bees kept an exquisitely consistent balance between the ones that go out to collect nectar and pollen and defend the hive, and those that stay home and nurture the larvae. Huang had documented that this balance is controlled by the elder bees, those that typically spend the final one to three weeks of their five-week lifespan out in the field.

Experiments showed that if a significant number of forager bees didn’t come home, the young nurse bees would mature ahead of schedule and head out to become foragers themselves. If the older bees were kept inside more than usual – as in an extended rain shower – fewer young bees would mature, but instead stick to brood care.

But the question was always, why? Pheromones are a chemical signal emitted by animals, insects and humans. Some, called releaser pheromones, are like a quick conversation that changes behavior, such as those that inspire sexual attraction.

Since releasers change behaviors immediately, they historically have been easier to identify. Hundreds of releaser pheromones have been chemically identified, whereas only four (including this new one) have been identified as primer pheromones. Primer pheromones are more difficult to work with because they imparts behavioral changes in a much longer time scale, taking days or sometimes weeks to see an effect.

Huang and his associates spent years futilely searching for a primer pheromone. After many dead ends, the group came upon a crucial difference between forager bees and nurse bees: Forager bees carry a mother load of a chemical called ethyl oleate in the abdominal reservoir in which they store nectar.

That, Huang said, led them to identify ethyl oleate as another kind of pheromone – called primer pheromone.

Forager bees load up on ethyl oleate when they’re buzzing about gathering food, but don’t digest it. The forager bees feed the chemical to the worker bees, and the ethyl oleate keeps them in a teenage state, sort of like being grounded to watch the younger siblings.

As the old bees die off, the chemical no longer is fed to nurse bees. Eliminate ethyl oleate and the bees mature into foragers.

“This provides clear insight into how a bee colony works,” said Gene Robinson, G. William Arends professor of integrative biology and director of the neuroscience program at the University of Illinois at Champaign-Urbana. “What’s most impressive about a honey bee colony is it is able to respond to changing conditions and alter its division of labor. When you think of that type of flexibility and adaptability, you immediately think, ‘who’s in charge’? People from many scientific and engineering endeavors are fascinated by localized decentralized decision making.”

Huang said the system makes sense for the health of the hive. Young bees – those in the first two to three weeks of life – are biologically better suited for brood care, thanks to some boosted blood protein. Bees forced out too early aren’t great navigators, and since foraging is dangerous, they risk dying before their time.

“Our idea has never been disproved, but the lack of mechanism drove me crazy,” said Huang. “Now we know the specific chemical that controls the behavior of honey bees for the good of the whole population.”

In addition to Huang and Robinson, the paper’s authors are Isabelle Leoncini, Yves Le Conte, Didier Crauser, Guy Costagliola and Jean-Marc Bécard, of the National Institute of Agricultural Research in Avignon, France; Mianwei Wang, Erika Plettner and Keith Slessor of Simon Fraser University in Burnaby, Canada; and Amy Toth of the University of Illinois at Urbana-Champaign.

The research was funded by the National Institute of Health. Huang’s research also is supported by the Michigan Agricultural Experiment Station.
Thursday, November 11th, 2004
9:35 pm - and more :)

"Sexually Antagonistic" Bugs Evolve New Weapons

Bijal P. Trivedi
National Geographic Today
February 14, 2002

Forget Valentine's Day. Love is a battlefield. And in the bug world the battle of the sexes has led to an evolutionary arms race—and the weapons to fend off unwanted suitors are getting nasty.
As Locke Rowe, of the University of Toronto in Canada, points out, what is good for one sex is rarely good for the other.
Males want to spread their genes far and wide and mate with as many females as possible. Females would rather keep mating to the minimum.
Water striders—beetle-like creatures with long slender legs that walk on water—have developed biological weaponry to defend their gender-specific interests.
Male water striders have evolved grasping hooks that grip the female in place as he tries to mate with her. To foil the males, females have evolved spines to dislodge unwelcome lovers.
"Mating is a pretty risky thing for any species, but males have a lot to gain," said Rowe. "But females can store sperm and a lifetime's worth of eggs can be fertilized in a single mating session. She doesn't need to waste time on superfluous mating."
Males have everything to gain from mating. A male water strider can dislodge the sperm of the previous male and thus tries to mate with many females. Females, on the other hand, have a lot to lose since mating takes place on the water and leaves them vulnerable to predation.
The Insidious Black Swimmer

An insidious bug called a Back Swimmer swims upside-down just beneath the water and attacks striders from below. It snatches bugs on the water surface and drags them under and devours them. When water striders mate the female floats on the water surface with the male on her back. If a Back Swimmer passes underneath it is usually the female that gets nabbed.

The risk of contracting sexually transmitted diseases is an issue for both sexes.

Hence, the pre-mating "ritual" is a violent struggle between two armed parties.

Locke Rowe and colleague Goran Arnqvist, of the University of Uppsala in Sweden, demonstrated the evolutionary arms race in progress through a study of 15 species of water striders from the United States, Canada, and Europe.

Rowe and Goran found that this arms race—technically known as "sexually antagonistic co-evolution"—is difficult to observe in nature because males and females are continuously evolving weapons and counter weapons, and thus the race always appears at a standstill. Also, in most cases scientists are not aware of the different weaponry used by each species.

Each of the 15 species of water strider the team examined was at different stage of the arms race. Some have developed heavy artillery to keep the other sex at bay, whereas others were barely armed at all. But in most cases the male and female adaptations were balanced.

The researchers found that in the case of water striders, when a female evolves a better weapon and gains the upper hand, the mating rate tends to fall. If the male evolves a better weapon—a stronger grasping hook, for example—the mating rate skyrockets.

Rowe and Arnqvist's study is the first direct evidence for "sexually antagonistic co-evolution," which has long been predicted but never proven.
The study is published in the February 14 issue of the British journal Nature. (2002)
Prior to this study scientists suggested that the female water striders develop weaponry because they want to choose the male with the best genetic traits. But Rowe and Goran's study found that "the females simply do not want to mate," said Rowe.
When a female water strider has mated, she rejects all subsequent males, both high and low quality. "When she hasn't mated, she accepts the duds at the same rate she accepts the studs," said Rowe.
9:32 pm - Robot Helps Show That Water Striders "Row" on H20

more on pond skaters from last year

James Owen
for National Geographic News
August 6, 2003

Many people assumed the insects rode on miniature waves the strider's legs generated on the surface of a pond, river, or lake. However, a U.S.-based research team has learned that what the insects actually do is row. More important, the scientists discovered how they do it.

Scientists used dyed water to examine water strider movements, and found that the striders use a combination of a rowing motion and surface tension to glide across the water with little effort. Water striders can move 100 body lengths in one second, which is equivalent to a six-foot-tall (1.8-meter-tall) human swimming at speeds of over 400 miles per hour (644 kilometers per hour).

Water striders can't pierce the surface of a pond or stream otherwise they'd sink. Instead, the insects press down on the water's surface, creating little dimples around their feet. These dimples act like the blades of an oar, generating swirling underwater currents that propel the insects forward.

The theory was first proposed by a team of applied mathematicians and mechanical engineers from Massachusetts Institute of Technology, in Cambridge, Massachusetts. To confirm their hypothesis, the researchers built a model version of the insect. Christened "Robostrider," its movements closely mimicked those of a living water strider.

Water striders are narrow, light-framed insects often seen in ponds, rivers, and lakes. Belonging to the family Gerridae, they are the world's most advanced surface-dwelling water bugs. One of the few insects to conquer the oceans, some intrepid species venture hundreds of miles across becalmed tropical seas.

The insects rely on surface tension and water-repelling hairs to stay afloat. Their long middle legs drive them in a sculling motion, with the hind legs acting as rudder and brakes. This leaves the front pair free for snaring prey.

While water striders seem to skate effortlessly across water, the surface is like glue to most other insects. Once trapped, the struggling bug is located via telltale ripples. The water strider closes in, snares its meal, and sucks its prey dry.

Hydrophobic Legs

Scientists soon realized that the water strider's hydrophobic legs and undersides, coupled with its small size (typical length is about one centimeter/0.4 inch), are what keep it from drowning. What they couldn't understand is how the insect moves on water without breaking the surface.

"For something to move in a fluid it has to transfer momentum backwards," said research team leader John Bush, an expert in fluid dynamics. "So when you're swimming, for instance, you fling water backwards."

The only visible clue as to how water striders accomplish this are the surface ripples they make when darting about.

It was this observation, and the fact that scientists had not performed more careful experimental studies, which led people to erroneously think that the insects transferred momentum exclusively through surface waves, Bush said.

But Bush and his colleagues were able to disprove this theory by using high-speed video, particle-tracking studies, and dyed water to examine water strider movements more closely.

The results of this research, published this week in the scientific journal Nature, show that with each stroke of their middle legs water striders create hidden, underwater currents. These swirling vortices carry enough momentum to propel the insect at high speed.

Bush said: "This is how rowboats work. The oar goes in the water and scoops fluid backwards. Water striders do the same, except they don't break the surface. The dimples they create act like the blades on an oar."

Michael Dickinson, a professor of bioengineering, added: "It is the rearwards motion of these vortices, and not the surface waves, that propel the animal forwards."

Fast Movers

Water striders can cover 100 body lengths in one second. This is equivalent to a six-foot-tall (1.8-meter-tall) human swimming at speeds of over 400 miles per hour (644 kilometers per hour), a velocity faster than many jet aircraft.

Basing its design on their observations, the researchers built a working replica of the insect. Like its inspiration, Robostrider creates surface ripples and hidden vortices as it moves across the water.

Fashioned from lightweight aluminum, Bush admits this mechanical model doesn't quite match the grace and speed of its natural counterpart, and travels only half a body length per stroke.

He added: "It's fair to say our Robostrider isn't nearly as elegant as the real thing, but it does work."

Having solved the mystery of the water-walking Jesus bug, Bush is turning his attention to locomotion in other waterborne creatures.

He said: "It's a fascinating world, completely dominated by surface tension. People have done a lot of work on birds and fish, but this is in between—neither flying nor swimming."

So take a good look at those other water bugs out there. Their secret could soon be out.
9:27 pm - Hairy Legs Help Bugs Walk on Water

Brian Handwerk
for National Geographic News
November 3, 2004

It's easy to understand why water striders—those six-legged insects that float and glide across the surface of ponds, streams, and lakes—are sometimes called Jesus bugs or pond skaters.

Less clear is how the bugs manage to stay afloat without drowning, especially in turbulent conditions brought by rainstorms or moving water. That is, until now.

Studying the insects under powerful microscopes, researchers in China have found that water strider legs incorporate thousands of microscopic hairs. Measuring about 50 micrometers—or less than two-thousandths of an inch—long, the hairs are scored by miniature groves. These groves trap air, increasing water resistance of the water's striders legs and overall buoyancy of the insect.

"Normal hydrophobicity [or water repellency] may support them resting on water," said Lei Jiang, a researcher with the Chinese Academy of Sciences in Beijing, China, and study co-author.

"Slight touches or disturbances may break that balance. However, the air cushion at the leg-water interface can [enable] them to locomote quickly and stably on the water surface—even in rainstorms or other disturbances."

Jiang noted that other animals developed features, such as the feathers on a duck, that work in similar ways. However, most are far less effective at promoting super water-repellence, he said.

High Water Mark

Common to ponds, rivers, and lakes, water strides (Gerris remigis) are considered the most advanced surface-dwelling water bug found in nature.

The insects, which measure about a centimeter (two-fifths of a inch) long, have two pairs of long, thin legs that they use to float and travel on water surfaces. They also sport an additional pair of smaller frontal legs, which can be used to grab prey.

The water strider's hairy legs work to keep it afloat. The hair-and-trapped-air combination has such water-resistance qualities that the insects legs can create 4-millimeter (0.16-inch) dimples in a water surface without breaking through.

The water-resistant legs displace some 300 times their own volume—the source of the insect's remarkable buoyancy. Jiang and colleague Xuefeng Gao found that the water strider's legs are so buoyant, they can support 15 times the insect's weight without it sinking.

This excess floatation capacity may allow the insects to bounce on water surfaces, much like a rubber ball on a cement sidewalk, to avoid drowning during a downpour.

The superfloatation also helps the bugs to skate across water surfaces in search of prey with remarkable speed. The insects can dash at speeds of a hundred body lengths per second. To match them, a 6-foot-tall (1.8-meter-tall) person would have to swim at over 400 miles an hour (644 kilometers an hour).

Water striders not only travel quickly, but they venture far afield. Scientists say some bugs have traveled hundreds of miles across calm tropical oceans.
9:21 pm - Why weedy wasps face peril for a clear complexion

Ian Sample, science correspondent
Thursday November 11, 2004
The Guardian

Faking it is a dangerous game if you're a wasp. Try bluffing that you are a big shot and you can expect a good beating, scientists have found.

In the world of wasps status is written all over your face. The puniest, most subordinate wasps have fresh yellow faces, while dominant brutes have faces marked with black spots and specks. Where a wasp is in the pecking order makes a big difference. Wimpy wasps get less food, have to work more and get to reproduce less often.

So bad is life lower down the social ladder that scientists have never been able to discover why weedier wasps do not cheat.

"It's not like they have to grow huge elaborate tails like peacocks do to show off how good they are, it's just a few black spots," said an Arizona University biologist, Elizabeth Tibbetts.

Dr Tibbetts decided to find out what happened if wasps did try to pass themselves off as princes instead of paupers. After chilling wasps in a fridge to slow them down, she donned a pair of rubber gloves and painted the wasps' faces using model aeroplane paint and a toothpick. Weedy wasps were given new black spots, while dominant wasps had their spots hidden.

After their makeovers each wasp was put in a container with another they had not seen before to see how they behaved. The newcomers were not fooled by the charlatans.

"They got beaten up," said Dr Tibbetts. "Whichever was truly dominant would climb on the head of the more subordinate one and start chewing its antennae. The subordinate ones just lay there with their antennae down, looking very miserable."

According to Dr Tibbetts, whose study appears today in the journal Nature, the wasps' smell or behaviour must have given them away. "It shows if there's a social cost, status markings are more likely to be honest."

A similar effect might come into play with people, according to Dr Tibbetts: "Think about karate belts. If you have a really wimpy guy wearing a black belt, the chances are that sooner or later, he's going to get beaten up."
Tuesday, October 5th, 2004
7:54 am

britain is being invaded by the harlequin ladybird, which could threaten butterflies, lacewings and other ladybirds.

its all the american's fault. they introduced it to north america from asia to eat aphids. (although admittedly they do sell it in europe to control the pests)
Monday, September 6th, 2004
8:58 pm

how cute. the natural history museum is employing flesh eating beetles to neatly strip away the meat from animal carcasses in order to reveal the bones underneath.



On a less cute note I'm afraid i committed a terrible sin.

i hoovered up the drosophila.

i know i know, but it was out of hand. i had to throw away a whole punnet of perfectly nice looking nectarines. it was ridiculous- they were everywhere and i couldn't prepare food. this is yorkshire. not florida.
Monday, August 16th, 2004
8:34 pm - Insect Vibrations Tell of Good Times and Bad

John Roach
for National Geographic News
August 12, 2004

Grab a branch of a young acacia tree crawling with appropriately named thornbugs and you just might utter an "ouch" at the sharp prick. The tiny horned insects will not hear your vocalization with ears, but rather as vibrations in the stem.
The thornbug (Umbonia crassicornis) is one of about 3,200 species in the treehopper family that, along with at least 200,000 other insect species, communicate by making the surface they live on vibrate, a method scientifically called substrate vibration.
Thornbugs send signals into the stems of trees by shaking their bodies. Other insects pick up the vibrations via sensors in their legs, explained Rex Cocroft, a biologist at the University of Missouri in Columbia.
Cocroft studies the evolution of communication systems. He is interested in the treehopper family because their communication systems are closely related to the ecology of individual species. For example, treehopers that spend their entire development sucking sap from one stem do not communicate about food, whereas treehoppers that move from branch to branch in search of new leaves to eat do signal about food.

"Comparison among related species may help reveal how communication systems evolve to meet new challenges," he said.
Peggy Hill, a biologist at the University of Tulsa in Oklahoma, said communication via vibration "appears to be an old option" that has evolved in insects, spiders, crabs, frogs, and even mammals such as kangaroo rats and elephants.
"We are still struggling to learn the breadth and depth of the use of vibration in communication, but it appears to be much more ubiquitous than any of us would have imagined 20 years ago," she said.

Listening In
The communications that thornbugs and other insects send via substrate vibrations are inaudible to human ears without the assistance of technology. To listen in, researchers record the vibrations and play the recordings back though a loudspeaker.
"This doesn't change the frequency or timing of the signals; it just makes them accessible our ears," Cocroft said.
The preferred recording device is known as a laser vibrometer. The tool detects changes in a laser light reflected from a vibrating surface, such as a tree branch, to measure the velocity of the vibrations. Other devices are essentially microphones that scientists clip onto to the branch.
Tiny insects—thornbugs are about a half inch (1.3 centimeters) long—can produce very low frequency sounds more commonly associated with larger animals. "The reason for this has to do with the constraints of broadcasting a signal through air—the signaler must be large enough in relation to the wavelength of the sound to be able to couple the sound to the air efficiently," Cocroft said.
Small animals and insects are thus restricted to making high-frequency airborne sounds. But this constraint does not exist for animals that communicate via substrate vibration. As a result, tiny insects can make very low frequency substrate vibrations.
"Although not all small insects that communicate with vibrations use low frequencies. Many of them do, and this leads to very surprising results for human listeners," Cocroft said.

By listening in on these vibrations and observing treehoppers in the field, Cocroft and his colleagues have learned that the insects use substrate vibrations for many of the same reasons other animals, including humans, use vocal chords—to get each others' attention, find mates, and share the address for a bite to eat.
According to Cocroft young thornbugs—which cluster together on the twigs of trees, where they suck sap for about six weeks as they mature—signal to alert their siblings and mother to the approach of predators.
"Once a few individuals start signaling, the rest of the offspring contribute signals of their own in synchronous waves. When the mother perceives these waves of signals, she responds by walking over to the nymphs and trying to find and drive away the predator," Cocroft said.
After the predator leaves, the mother also signals. Researchers are less certain as to the function of the mother's signal but theorize that it may let her offspring know she is still present and they should stay put.
If the predator wins in the encounter with the mother, the offspring may elect to leave the group and make a go of it on their own, Cocroft said.
Mother or not, thornbugs leave their nest branch about a month and a half after they hatch. Males go in search of female mates, and females go in search of a place to lay their eggs.
Young-adult thornbug vibrations take on a different meaning. "Males produce advertisement signals; if a female is receptive, she answers the male signal with a simpler one of her own," Cocroft said.
Once the male "hears" the female, he begins to locate her position as the pair signals back and forth in a mating duet. If the male encounters another male, "they may exchange a series of rather different signals," Cocroft said.
After mating, the female will lay abut 200 eggs into the tree branch and spend the remaining six weeks of her life caring for and protecting her young.

Peace and Quiet?

With at least 200,000 different insect species communicating via vibrations, there can be several different species communicating—and eavesdropping—on the same surface.
Cocroft said that, in general, insects are able to pick up and respond to the vibrations made by individuals of their own species, telling the signals apart by the pitch or the rhythm of the timing.
"There are also a lot of predators—especially spiders—out there capable of sensing and locating a source of vibrations. So a signaling insect also probably runs a risk of attracting a predator," Cocroft said.
With multiple vibrations on any given surface, Hill said, insects, like humans, find peace and quiet by filtering out all but the most critical incoming messages. For example, when an insect is ready to mate, mating becomes the primary focus.
"If it does not mate within a tiny window of time, it will die without contributing to the gene pool," she said. "In that scenario, motivation is high to process signals linked to mating, while those sent out by any other species are just so much noise."
8:26 pm

this journal is not dead, i have just been busy moving halfway across the country and getting a new job etc. and my computer broke so i've not been online properly.
Saturday, April 17th, 2004
9:22 pm

Mother got these two books for her birthday:

Stumpwork Dragonflies

The Stumpwork, Goldwork and Surface Embroidery Beetle Collection

both by Jane Nicholas

the 3D finished insects really are beautiful, i'd love to have a go at doing them, in fact i i'd like the books myself.

pic of dragonflies from front cover
Tuesday, April 13th, 2004
7:38 pm - Scientists question reports of massive ant supercolonies in California and Europe

April 6, 2004

A team of California scientists made headlines four years ago when it reported finding one of the largest insect colonies in the world -- a 600-mile-long subterranean network of Argentine ants stretching from Northern California to the Mexican border. According to the researchers, this "supercolony" is made up of billions of closely related workers -- all direct descendants of a small group of Argentine ants that were accidentally introduced into California more than a century ago.

But new studies by Stanford University scientists are raising serious doubts about the existence of a single supercolony running through the Golden State. The Stanford team questions the notion that Los Angeles ants are descended from the same founding population as San Francisco ants, which live 400 miles away. A more likely explanation, they say, is that California has been infested by numerous colonies of genetically distinct Argentine ants during the last 100 years.

Challenging the supercolony paradigm is more than an academic exercise, says Stanford biologist Deborah M. Gordon. Argentine ants have had a major impact in many parts of the world, she says, and understanding how they reproduce and colonize is essential if scientists hope to develop realistic strategies that will keep their populations in check.

"Our data show that it's not the case that the whole California coastline is one genetically homogenous supercolony," says Gordon, a professor of biological sciences. "We find a lot of genetic diversity here, which indicates that there were probably many introductions in the past."

An authority on ant behavior, Gordon has spent more than 20 years studying native and invasive species, including the Argentine ant, or Linepithema humile, which has displaced many of California's indigenous ant species since it was first introduced in the state around 1900.

Read more...Collapse )
Saturday, April 3rd, 2004
8:30 pm - Murder detectives must rethink maggot theory

Exclusive from New Scientist Print Edition.
09:45 05 April 04

An investigation of the way insects colonise corpses left decomposing in the open has cast doubt on one of the key techniques used to estimate when a murder victim died.

Along with assessments of the body's state of decomposition, insect analysis is the most common means for estimating time of death. Many species of flies and beetles may live on a human body as it decomposes. By identifying their stage of development, and comparing them to those on a pig or human body deliberately left to rot in a similar environment, forensic entomologists can work out how long a corpse has been lying dead.

These estimates are often claimed to be accurate to within months or weeks - or even days if the body has been dead for less than a month.

In an experiment to test the accuracy of insect analysis, Melanie Archer of the Victorian Institute of Forensic Medicine in Melbourne, Australia, placed five piglet carcasses in scavenger-proof wire cages in bush land.

At least once a week for four months she identified the insects living on the carcasses and on the ground underneath them. She repeated the experiment each season for two years.

Blowfly maggots

Archer found unexpected variations. For example, blowfly maggots left the carcasses after nine weeks in the first winter, but after only four weeks in the second winter. A beetle species, Creophilus erythrocephalus, arrived after four weeks in the first winter, but after only two in the second (Australian Journal of Zoology, vol 51, p 569).

The differences could be due to several factors, such as varying weather or changes in insect numbers. But until now, Archer says, none of the published studies on reference corpses has been repeated over successive years, so no one takes the variations into account.

Another potential source of error lies in the way temperatures are estimated, Archer found. Insect infestation of a corpse is strongly affected by temperature.

To estimate the temperatures at a site where a body has been found, entomologists usually go back to the site and monitor temperature changes there, and compare them with temperatures at nearby weather stations. They then go back to weather station recordings from the time the body was decomposing to estimate the temperature of its surroundings.

Hypothetical murders
When Archer put this technique to the test at sites of hypothetical murders, the estimates were usually within 1 degree Celsius of actual temperatures.

However, if the weather had changed markedly between the monitoring period and the period the imaginary body was decomposing, the estimates were out by as much as 8 degrees Celsius. That could lead to errors of several days in the estimated time of death (Journal of Forensic Science, DOI: 10.1520/JFS2003258).

"The estimates are not as tight as some forensic scientists imply in court," Archer concludes. "We need to introduce some rigour."

Forensic entomologist Lee Goff at Chaminade University of Honolulu, Hawaii, agrees. He says many lawyers, and even forensic scientists, are unaware of the limitations. "The legal community want things to be precise, but they have to remember that we are dealing with estimates," he says.

Rachel Nowak, Melbourne
Friday, March 19th, 2004
3:48 pm



fab arthropod sculptures made with wire and blades

there are 29 in total in her gallery, most not for sale, but she does do custom commissions.
Thursday, March 18th, 2004
7:49 pm

Been making a new amazon wish list* discovered this book: Origami Insects and their Kin by Robert Lang

i want it!

gallery of some of the completed insects here

and here

*amazon@paper-flies.org and this time i won't forget it!
Sunday, March 14th, 2004
9:22 am - Periodical Cicadas to Emerge in May


Friday March 12, 2004 6:31 PM


Associated Press Writer

STATE COLLEGE, Pa. (AP) - After 17 years of relative quiet, Mother Nature is bringing the noise. Periodical cicadas, a species of the grasshopper-like insects best known for the scratching, screeching ``singing'' of the males, will emerge this May, filling forests in more than a dozen states. Almost as abruptly as they arrive, they'll disappear underground for another 17 years.
``Why do certain insects take only one year to develop, and others take two or three? It's just part of their genetic programming,'' said Greg Hoover, senior extension entomologist for Penn State University.
There are at least 13 broods of 17-year cicadas, plus another five broods that emerge every 13 years. The last to emerge, Brood IX, was seen last spring in parts of West Virginia, Virginia and North Carolina.
This year, it's time for Brood X, the so-called ``Big Brood,'' to surface. Its range stretches from Georgia, west through Tennessee and to isolated pockets of Missouri, north along the Ohio Valley and into Michigan, and east into New Jersey and New York.
``This is one of those years we kind of dread,'' said Paris Lambdin, professor of entomology and plant pathology at the University of Tennessee. ``We had an emergence a couple years ago around Nashville, but nothing like what we expect this one will be.''
No other periodical cicada covers so much ground. And with hundreds of them per acre in infested areas, the noise will be hard to miss.
``In 1987, coming back from the University of Maryland on Interstate 95, when you drove through a wooded area you could hear the insects,'' Hoover said. ``This would have been mid to late June, with the windows down, and then it would shut down when you got to a field or a non-wooded area.''
In rare years, a 13-year brood can emerge to add its collective voice to that of a 17-year brood.
``Out in the Midwest is where things get really hairy,'' Hoover said. ``Missouri, Illinois, Indiana have combinations of 17-year-brooded individuals and 13-year-brooded individuals, and they can have overlap.''
There's no question that the class of 2004 will be a nuisance. The cicadas will make plenty of noise, and adults are poor fliers that tend to bump into things. But as swarms go, these cicadas aren't that bad. Adults don't feed on leaves, so they won't strip the trees, but they do lay their eggs in twigs.
``The females, once mated, will lay pockets of eggs along twigs that will cause structural weakening of those twigs,'' Hoover said. ``Eventually they may drop off and fall to the ground, the nymphs will drop off and fall to the soil, and that's where this species is for the next 17 years.''
Wednesday, March 10th, 2004
6:56 pm


i need these for my house!!!! they're fantastic (and big :)

Friday, March 5th, 2004
9:48 pm - Ants, Like Humans, Avoid Traffic Congestion

Wed 3 March, 2004 18:10

LONDON (Reuters) - Ants, just like motorists, hate congestion and use alternative routes to avoid it, scientists said Wednesday.

The industrious insects push and shove each other out of the way when it gets too crowded, forcing some to find another route from a food source back to the nest.
"Ants are able to find a solution when they are faced with congestion on trails," said Vincent Fourcassle, a biologist at the Center for Cognitive Animal Research in Toulouse, France.
In a study published in the science journal Nature, Fourcassle and a team of researchers analyzed videotapes of thousands of ants in an experiment on collective movement.
Using a mathematical model, they explained how the individual behavior of the ants affected their collective movement and group behavior.
Foraging ants prefer to carry food along a favorite trail that is marked with scent clues. In the experiment, the insects had to cross a diamond-shaped bridge between the location of the food and their nest.
Fourcassle said that if the two branches of the bridge were quite wide, traffic on the preferred route was much heavier. But when the branches were narrowed and the ants encountered a bottleneck getting to the favorite route, congestion on both branches was more equal because ants chose the alternative route.
Pushing seemed to be the favorite way to maintain a steady flow of food back to the nest.
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