Monday, October 24, 2005

Wasps Used as Scent Detectors

A team in Georgia has built a tiny device that uses trained wasps to detect specific odors -- a prototype "biological sensor" capable of sniffing out anything from chemical warfare agents to corpses.

Five fly-size parasitic wasps -- which don't sting -- are placed in a disk-shaped chamber about the size of two stacked checkers, with a hole in the bottom and a tiny fan that sucks air into the disk. If the wasps detect the suspect odor, they gather around the hole, creating a cluster of pixels for a tiny webcam that sends an alarm signal.

Entomologist W. Joe Lewis of the Agriculture Department's Agricultural Research Service said he and colleagues have known for nearly 20 years that, with a reward of sugar water, wasps can be trained in as little as five minutes to respond to almost any odor.

"But this is the first packaged system," Lewis said from his lab in Tifton, Ga. Ultimately, the "Wasp Hound" will be "like a small BlackBerry" that can be operated robotically or by hand, he added. The disk would be swapped out after a few passes. Lewis and Glen C. Rains, a biological engineer at the University of Georgia, are publishing their latest research in the January-February issue of the journal Biotechnology Progress.

"The wasps are cheap and reliable, and you can breed thousands of them," Lewis said. Other researchers are showing that insects besides wasps can also be trained.

"What we once thought of as instinct is, in fact, learning," Lewis said. "And once you know that, you have a whole new emerging technology."

-- Guy Gugliotta

A New Natural Antifreeze

Canadian scientists studying tiny insects known as snow fleas have discovered two new frost-busting compounds that apparently keep the bugs from becoming six-legged ice cubes in subfreezing temperatures.

The natural antifreeze molecules are distinct from those previously found in other animals, suggesting that antifreeze compounds arose independently on many occasions through evolution, the team reported in Friday's issue of the journal Science.

Snow fleas, also known as springtails, are not really fleas. Just a millimeter or so in length, each sports a pair of stiff tail bristles that fold forward beneath the body, where they are held in place with a tiny hook. When the bristles are suddenly released, the insect flips through the air in a flealike acrobatic jump.

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