Later research revealed that the wasps' olfactory system was directly linked to their taste receptors and that the insects learn to associate certain smells with food or with corn borers.
Lewis said he soon realized that "you can train them to associate anything with food or their host."
"We knew mammals were doing this, but we had no idea invertebrates were doing this," he added.
Jerry Bromenshenk, a research professor at the University of Montana in Missoula, does similar work with honeybees, training them to detect land mines. He said his team's project and the Georgia team's work are complementary.
Bees are "wide-survey tools. We can search for anything you want to find in a wide area. We can survey areas the size of football fields in a matter of minutes," said Bromenshenk, also the CEO of Bee Alert Technology, Inc.
"The wasps serve functions we can't easily do with honeybees," he said, such as work indoors.
Wasp Miniature Camera
Teaching a small hive of flying insects is one thing. Harnessing their capability is quite another.
Lewis and Rains, the Georgia-based researchers, received funding in 1998 and began actively working on the Wasp Hound. They hope it will make it to market in five to ten years.
The Wasp Hound is a tube made of PVC pipe. At one end is a clear plastic chamber, about two inches (five centimeters) in diameter and an inch (two and a half centimeters) deep, where the wasps are housed.
"It's like a cap that you can take on and off," Rains explained. The chamber has vent holes, a fan, and a miniature camera connected to a computer.
When the wasps aren't working "they just randomly walk around" in their chamber, Rains said. But when the wasps encounter a smell they have been trained to recognize, the hungry insects congregate near the odor source, hoping for food.
The mini-cam tracks their movement, sending pictures to the computer, which analyzes the images and triggers an alarm within 30 seconds.
The insects are so sensitive that they react less or more strongly, depending on the strength of the smell they are exposed to, Rains says.
The wasps can be used for 48 hours. After they complete their shift "we just let them go," Rains explained.
The Wasp Hound has only been tested under laboratory conditions. It needs to be rigorously tested in cold weather, dusty conditions, and other real-world situations before it will be ready for widespread use, Rains said.
Before it appears on the market, the Wasp Hound needs to have infrastructure behind itbreeding laboratories and a system for packing and shipping the devices.
"An idea we're toying with is having one Hound with five cartridges for detecting five different odors," Rains said.
"We're pretty much on the forefront of this type of work," he said.
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