To Scare Off Predators, Caterpillar Whistles like a Kettle

It's hard to yell "BACK OFF!" when you have no lungs, but this caterpillar has figured out a way. Under attack, the Nessus sphinx moth caterpillar emits a sort of crackling buzz from its mouth. Scientists compare the unusual mechanism to a whistling teakettle. Or a rocket. Lots of insects make noise, of course, as opening a window on a summer evening will remind you. Conrado Rosi-Denadai, a graduate student at Carleton University, and his coauthors write that sound-making tools in insects "have evolved multiple times and on almost every part of the body wall including legs, wings, mouthparts, head and even genitals." Insects may rub parts of their tough exoskeleton together, vibrate them, or knock them against something to make their distinctive sounds. Rather than relying on percussion, humans and other vertebrates tend to make noise using air, which we force out of convenient, squeezable bags in our bodies. ...