The spindly antennae of a common wasp are as sensitive to smells as the wet nose of a drug-sniffing police dog. With this in mind, biological engineer Glen Rains and his colleagues at the University of Georgia at Tifton have devised a contraption called the Wasp Hound: a canister no bigger than a medium-size soda cup filled with insects trained to detect smells. Rains developed a simple regimen to teach the insects to associate a particular odor with food. When the wasps in the canister catch a whiff of that odor—such as a chemical linked to a drug, bomb, toxin, or corpse—they cluster around the source; a minicamera inside the Wasp Hound monitors the insects' movements and transmits the results to a nearby laptop.
"The wasps are small and portable, and the training takes only about 5 or 10 minutes," says Rains, pointing out the advantages of wasps over dogs. The insects die within 48 hours, but when they expire, a cartridge of five freshly trained wasps can be popped into the canister. Rains sees no reason why future versions of the Wasp Hound couldn't be used to detect the chemical signatures of diseases in plants, animals, and humans. "The insects can be trained to recognize most chemicals," he says. "They are sensitive to just about anything."