Entomologists have long known the bombardier beetle hoses down its enemies with a searing, blister-raising spray, emitted from a nozzle located at its rump, which swivels around like a turret.
Thomas Eisner of Cornell University and his colleagues report in the current issue of the journal Science that instead of just spraying its foes, the beetle produces a rapid-fire series of tiny explosions.
Basically, Eisner said, the bombardier beetle is like a binary weapon.
It takes hydrogen peroxide and an irritant and mixes them together with special enzymes in a reaction chamber located in the insect's abdomen, where "for all intents and purposes, you get a series of chemical explosions."
Eisner knew the beetle probably issued a series of micro-explosions, but researchers could not prove it until they visited the lab of inventor Harold "Doc" Edgerton of the Massachusetts Institute of Technology, whose superfast strobe lights were capable of firing several thousand times a second.
By rigging up the cameras and strobes and pinching the beetle's leg, the scientists captured the bombardier firing at more than 500 pulses a second.
"There are great advantages to firing in pulses," Eisner said. "Just like it's better to have a machine gun spitting out bullets than blowing up a barrel of nails."