Advertisement
WHITE BEETLE DAZZLES SCIENTISTS
Thursday, 18 January 2007
The finger-tip sized Cyphochilus beetle, found in south-east Asia, had a shell whiter than most other materials found in nature, UK researchers said.
Close inspection reveals a unique surface structure covered with scales 10 times thinner than human hair.
A report in Science magazine claims mimicking these scales could provide a range of applications for industry.
"Such pure bright whiteness is uncommon in insects," explained lead scientist Dr Pete Vukusic of Exeter University.
"You do see the odd bit of whiteness here and there, mainly in butterflies, but the whiteness is really incomparable with this little beetle."
In the study of the insect, Vukusic's team used a number of techniques such as optical microscopy, laser analysis and spectrometry.
The researchers found, according to the International Organization for Standardization measurements, the beetle was much brighter and whiter than milk and the average human tooth.
The beetle's shell was covered with ultra-thin scales, measuring just five micrometres (millionths of a metre), with highly random internal 3D structures.
This irregular structure, explained Dr Vukusic, was the cause of the beetle's whiteness.
While colour, he explained, could be created through highly ordered structures, whiteness is achieved through very random features that scatter all colours simultaneously.
"The degree of whiteness given the scales' thinness is the really impressive thing," Dr Vukusic added.
"We can create this quality of white synthetically, but the materials need to be much thicker. This could have many applications."
The researchers believe industry might draw inspiration from the beetle to enhance the whiteness of synthetic objects, such as papers, plastics, paints or white-light displays.
The team thinks the beetle evolved to be so white because the colour provides camouflage in amongst the white fungi common to where it is found.
SOURCE news.bbc.co.uk/2/hi/scien...6272485.stm (good pictures!)
Thursday, 18 January 2007
The finger-tip sized Cyphochilus beetle, found in south-east Asia, had a shell whiter than most other materials found in nature, UK researchers said.
Close inspection reveals a unique surface structure covered with scales 10 times thinner than human hair.
A report in Science magazine claims mimicking these scales could provide a range of applications for industry.
"Such pure bright whiteness is uncommon in insects," explained lead scientist Dr Pete Vukusic of Exeter University.
"You do see the odd bit of whiteness here and there, mainly in butterflies, but the whiteness is really incomparable with this little beetle."
In the study of the insect, Vukusic's team used a number of techniques such as optical microscopy, laser analysis and spectrometry.
The researchers found, according to the International Organization for Standardization measurements, the beetle was much brighter and whiter than milk and the average human tooth.
The beetle's shell was covered with ultra-thin scales, measuring just five micrometres (millionths of a metre), with highly random internal 3D structures.
This irregular structure, explained Dr Vukusic, was the cause of the beetle's whiteness.
While colour, he explained, could be created through highly ordered structures, whiteness is achieved through very random features that scatter all colours simultaneously.
"The degree of whiteness given the scales' thinness is the really impressive thing," Dr Vukusic added.
"We can create this quality of white synthetically, but the materials need to be much thicker. This could have many applications."
The researchers believe industry might draw inspiration from the beetle to enhance the whiteness of synthetic objects, such as papers, plastics, paints or white-light displays.
The team thinks the beetle evolved to be so white because the colour provides camouflage in amongst the white fungi common to where it is found.
SOURCE news.bbc.co.uk/2/hi/scien...6272485.stm (good pictures!)
Advertisement
Advertisement
-
Re: Current Entomology Research
Wed, February 7, 2007 - 10:17 PMMYSTERY KILLER SILENCING HONEYBEES
If the die-off continues, it would be disastrous for U.S. crop yields.
By Sandy Bauers
Inquirer Staff Writer
SOURCE www.philly.com/mld/inquirer/16623837.htm
A bee, laden with pollen. Honeybees pollinate more than $15 billion worth of U.S. crops, including Pennsylvania's apple harvest and New Jersey's cranberries and blueberries.
David M Warren / Inquirer Staff Photographer
A bee, laden with pollen. Honeybees pollinate more than $15 billion worth of U.S. crops, including Pennsylvania's apple harvest and New Jersey's cranberries and blueberries.
Something is killing the nation's honeybees.
Dave Hackenberg of central Pennsylvania had 3,000 hives and figures he has lost all but about 800 of them.
In labs at Pennsylvania State University, the Pennsylvania Department of Agriculture, and elsewhere in the nation, researchers have been stunned by the number of calls about the mysterious losses.
"Every day, you hear of another operator," said Dennis vanEngelsdorp, acting state apiarist with the Pennsylvania Department of Agriculture. "It's just causing so much death so quickly that it's startling."
At stake is the work the honeybees do, pollinating more than $15 billion worth of U.S. crops, including Pennsylvania's apple harvest, the fourth-largest in the nation, worth $45 million, and New Jersey's cranberries and blueberries.
While a few crops, such as corn and wheat, are pollinated by the wind, most need bees. Without these insects, crop yields would fall dramatically. Agronomists estimate Americans owe one in three bites of food to bees.
The problem caps 20 years of honeybee woes, including two mites that killed the valuable insect and a predatory beetle that attacked the honeycombs of weak or dead colonies.
"This is by far the most alarming," said Maryann Frazier, an apiculture - or beekeeping - expert at Penn State's College of Agricultural Sciences.
One of the first to notice the latest die-off was Hackenberg, who lives in Lewisburg, north of Harrisburg in Union County.
He and his son truck about 3,000 hives up and down the East Coast every year as part of a large but little-known cross-continental migratory bee industry.
Hackenberg's bees pollinate oranges in Florida, apples, cherries and pumpkins in Pennsylvania, and blueberries in Maine. Come summer, they are buzzing along the Canadian border, making honey.
This season, Hackenberg hauled his hives to Florida by Oct. 10, just as he has done for 40 years. By November, some hives were empty; others had just sickly remains.
He made some calls and found out a beekeeper in Georgia had seen the same thing.
Since then, with concern mounting, experts have been investigating. A few months ago, they were referring to the die-off as "fall dwindle disease." Now, they have ratcheted up to "colony collapse disorder."
Last weekend, apiarist vanEngelsdorp and other researchers headed to central California, where hundreds of acres of almond trees - the source of 80 percent of the world's almond harvest - are about to blossom.
Last fall, workers transported managed hives - about 450 per tractor-trailer - to California from colder areas such as the Great Lakes and the Dakotas. Now, hives are coming from Texas, Florida, Maryland and Pennsylvania. In all, about half the country's managed hives are needed for the mass pollination.
As workers openthe hives to check them, "the picture's not so good," said Jeffrey S. Pettis, a leader in bee research at a U.S. Department of Agriculture lab in Beltsville, Md.
Pettis said bees often had some winter loss, but this level of death was unprecedented.
As dead or dying insects are collected, dissected and tested, several possibilities are emerging.
The most recent mite problem - the varroa mite - compromises a bee's immune system, so a virus might be the new culprit, Frazier said. Or it could be a new fungal pathogen.
Frazier said researchers also were looking at a new group of pesticides that might impair the bees' ability to orient to their hives. So maybe they are dying only because they cannot find their way back home.
Honeybees are not natives. The country already had about 3,500 species of pollinating bees before Europeans brought honeybees in the 1600s. But because honeybees produce honey and can be managed so easily, they have become a mainstay of U.S. agriculture.
"Part of the problem is that today we develop these big monocultures of corn or peas or cabbage," Frazier said. "They wipe out the diversity of nectar sources and reduce nesting sites for wild bees. And we use, unfortunately, a lot of pesticides to keep the insects we don't want from eating these crops, which also works to eliminate the pollinators."
So a Pennsylvania orchard manager, say, will bring in bees for the two weeks the apple trees bloom, then take them out so he can apply substances to control other insects.
Neither entomologists nor growers can say what will happen when the 2007 growing season for most of the country's crops starts. "We're coming up onto the season where people are really going to be worried," Frazier said.
Although research suggests the stress of moving bees long distances might be a factor in the die-offs, smaller beekeepers with stationary hives worry the problem will extend to their colonies as well.
Already, Janet Katz, a beekeeper in Chester, N.J., thinks three of her 21 hives are failing.
And the bees are stressed already, she said. "The weather last season was not cooperative," she said. "Over the course of the season it was too wet, too dry, too hot and too cold, all at the wrong times."
Bees store honey every autumn - a hive needs 60 pounds to survive the winter - but with this year's warm weather, they ate a lot, and beekeepers had to supplement with sugar syrup.
Now, the bees have sealed themselves inside the hives to stay warm, and the keepers can't open the structures until spring.
"Are we going to see this same thing, this collapsing disorder, in these bees? We don't know," Frazier said. "It's very possible this may extend to our nonmigratory population. We just won't know until spring." -
-
Re: Current Entomology Research
Thu, February 15, 2007 - 8:34 PMAn interesting article with videos too!
source
news.nationalgeographic.com/news....html
Moths Elude Spiders by Mimicking Them, Study Says
John Roach
for National Geographic News
February 14, 2007
The arrival of a jumping spider sends most moths into a flutter trying to escape the predator's lethal pounce.
Not so for metalmark moths in the genus Brenthia. These moths stand their ground with hind wings flared and forewings held above the body at a slight angle.
In that pose the moth looks like a jumping spider, said Jadranka Rota, a graduate biology student at the University of Connecticut.
"That will actually save [the moth's] life," she said.
"The spider needs to act pretty quickly. Deciding whether the moth is potential prey or another jumping spider could take enough time to offer an advantage, in comparison to other moths."
The trickery usually buys the metalmark moth time for a safe escape.
Sometimes the sight triggers territorial postures—raising and waving of the forelegs—from the spider.
Occasionally the spider even backs off.
Rota and her advisor David Wagner described the metalmark moths' behavior last December in the Public Library of Science's interactive online journal PLoS ONE.
Lab Tests
Mimicry is a well-known trick in the animal kingdom. Many creatures are known to adopt the looks and postures of undesirable prey species to evade their predators
But rarely have scientists seen prey mimic their predators to successfully avoid becoming dinner.
Rota said she first noticed the metalmark moths "do something weird" when she was walking through the Costa Rican forest and saw them perched on leaves with their wings flared, seeming to jump around.
Wagner suggested that the moths might be mimicking jumping spiders, which are known to employ their unusually keen eyesight to hunt.
To find out, the biologists pitted the presumed mimic moths and normal moths against jumping spiders in the lab. The pair staged 146 of battles; 77 with the mimics, 69 with controls.
When control moths were used, the test spider captured 62 percent of its potential prey (watch video of jumping spiders attacking control moths in the lab.
When paired with the presumed mimic moths, the spider only took 6 percent of its allotted victims.
In addition, the spider made territorial gestures towards 36 percent of the mimics, but no gestures toward the normal moths.
In 11 of the trials, the spiders even backed away from the mimics.
The moths' "ploy of donning the wolf's clothing proves successful," Rota and Wagner conclude in their paper.
Erick Greene is a biologist at the University of Montana. In 1987 he was part of a team that published research in the journal Science on a fly that also mimics jumping spiders.
"These sorts of mimetic interactions may be more common than anyone had suspected," he said in an email from New Zealand, where he is currently on sabbatical.
"And sometimes the patterns are incredibly specific to one very narrow type of interaction, such as [with jumping spiders]."
Evolution Driver
Spider mimicry may also help the moths avoid predation by birds and other animals through what scientists call evasive prey mimicry, the University of Connecticut's Rota said.
This type of mimicry gives insects protection when they look like prey that is hard to catch.
"Birds don't go after hard-to-catch insects, and since jumping spiders are hard to catch, looking like a jumping spider may be advantageous," Rota said.
She has yet to obtain experimental data to back up this theory, but may do so in future research.
The researchers noted that in addition to metalmark moths and flies, mimicking jumping spiders has been suggested for several planthoppers and other moth species.
"The jumping spider predation seems to be an important selective pressure," Rota said. "They are shaping the evolution of all these insects."
-