If you've heard a chorus of crickets, you know that orthopterans make sound. Males make nearly all the sounds, to defend territories and attract females. Specialized body parts are rubbed together (stridulation) to produce the sound. Male grasshoppers, for example, rub hard edges (scrapers) of their hind legs against rows of tooth-like bumps (files) on their front wings. Male crickets chafe their front wings together, also causing files to rub scrapers. Females detect the sounds with ears on their front legs or their abdomens. Like car speakers that blast loud music, natural amplifiers have evolved as orthopteran males try to outcompete each other. The amplifier may be a body part, such as a shield-like plate that reflects sound (in katydids), or a part of the environment, such as a burrow used by singing crickets. Older males are at a disadvantage, at least in some species, because their worn-down files do not make as loud a sound.