Not as silly as it sounds, folks... they've begun field testing bee-based detectors at some airports. Its a box, 3 bees inside stuck to a board, and a high-speed camera.
Two of the bees are one type of breed, the other is another with a better sense of smell. If all three stick out their tounges, the alarm goes off. If the better bee and one of the others stick out their tounges, the warning light goes off.
Just goes to show you... after all, some thought a worthless mold called penecillium couldn't do anything about bacteria...