for National Geographic News
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.
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.
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