Drug-Sniffing Wasps May Sting Crooks

Adrianne Appel
for National Geographic News
October 27, 2005
Sneaky drug smugglers and terrorists may soon meet their match: a
handheld chemical detector powered by trained wasps.

Dubbed the Wasp Hound, the prototype tool houses five parasitic wasps that react to the smells of explosives, illegal drugs, and plant diseases. In theory, the insects' movements set off an alarm to alert authorities.

"They are an incredibly versatile type of system. We've really just scratched the surface," said Glen Rains, a biological engineer at the University of Georgia, in Tifton, who co-invented the device.

Known for their keen sense of smell, parasitic wasps don't sting humans and are as small as flying ants.

Researchers believe the insects are nearly ideal for the task of sniffing out bombs. Unlike dogs, the wasps can be trained within 30 minutes and bred by the thousands, providing a near limitless supply.

Other scientists are working with honeybees, rats, and fish as chemical detectors.

The Wasp Hound, which is still under development, grew out of decades of study of Microplitis croceipes, a parasitic wasp species native to Georgia.

In the wild the wasps use their antennae to detect corn borer caterpillars, which the parasites use to hatch and grow their young.

The wasps lay single eggs in the caterpillars. As the young mature, they feed on their hosts, which eventually weaken and die.

Surprise Discovery

The Wasp Hound was co-invented by W. Joe Lewis, an expert on parasitic wasps who works as an entomologist with the USDA Agricultural Research Service in Tifton.

In the 1970s Lewis and his colleagues discovered that the wasps locate the caterpillars by detecting a chemical in their feces.

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 it—breeding 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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