How cicadas make so much noise

Science : Scientists have long puzzled over how such a small animal as a cicada can produce such a deafening drone. Now Derke Hughes of the US Naval Undersea Warfare Center and colleagues have used microcomputed tomography to image the tiny noise-making structures, called tymbals, that are on either side of a cicada’s abdomen. Each of a cicada’s two tymbals consists of a series of microscopic ribs connected by a membrane. Unlike many insects, which make noise by rubbing body parts together, cicadas cause the tymbals to vibrate. They pull the tymbals’ ribs together and then allow them to snap apart some 300â400 times per second, and the sound is amplified by the creatures’ hollow abdomen. Some cicadas can produce sounds up to 120 decibelsâmdash;loud enough to cause hearing loss in humans. The investigators hope to use their study of cicadas to improve current sonar systems for underwater exploration.