Katydids loudest of all insects
Katydids produce the highest-frequency ultrasound of all insects.india Updated: Jan 12, 2007 18:00 IST
Katydids, which belong to the cricket and grasshopper family, have the highest notes.
According to a study carried out by Fernando Montealegre-Z and Glenn Morris from the University of Toronto in Canada, the lonely male Arachnoscelis Katydid makes its presence known with a burst of intense sound. They produce the highest-frequency ultrasound of any known insect, often not heard by humans.
Members of the cricket and grasshopper family are famous for their ability to sing, and most emit chirps at frequencies humans can hear. Some katydids produce ultrasonic chirps by rubbing their forewings together, pushing a scraper on one wing across a series of pegs on the other.
However, according to Montealegre-Z and Morris, the Arachnoscelis species chirps at 130 kilohertz, which is too high a frequency to be generated by merely rubbing the wings together.
Both researchers collected the katydids from the Colombian rainforest to measure their chirps and look at their wings with an electron microscope. They revealed that as the wings rub against each other, the scraper wedges itself behind one of the pegs and distorts, and when released, it springs back into shape, emitting a pulse of ultrasound.