Rainforest katydids’ hearing mechanism resembles that of mammals

Science News : The auditory mechanisms of a South American rainforest katydid have been found to be remarkably similar to those of mammals, according to Daniel Robert of the UK’s University of Bristol and colleagues, whose x-ray microtomography study appeared online today in Science. A katydid’s ears sit below its knees, with a drum on each side of the leg. Similar to mammals’ three-stage processing system, katydids “hear” because their eardrums sense sound waves, which cause a small plate on each drum to vibrate. The vibration sends ripples through a liquid-filled chamber inside the leg, where detector cells sense the frequencies. The researchers found, however, that not only does the katydid ear do much the same job as a mammal’s ear, it is much smaller and simpler. An understanding of its design could help researchers develop miniature hearing aids for humans.