How Moths Fool Bats
Bats enjoy a meal of moths and use their sonar equipment to catch them. But a moth’s detection system is a highly sophisticated warning device that gives moths time to fly for cover. Bats locate moths by sending out ultrasonic chirps and the echoes tell them whether a moth is in reach or not. This device works well up to about ten feet, but beyond that, the echo grows too faint for the bat to make good use of it. On the other hand, the moth can hear the bat’s chirp about 75 feet away. So whenever the moth picks up the bat’s signal, it flies away from the sound’s source and out of the bat’s reach. But within ten feet the moth has to do some quick maneuvering. Sometimes it dives for the ground. At times it simply folds its wings and drops. At other times it may use dive power, or it may spiral down. Some moths taste bad to bats. These bad-tasting moths let out a strong clicking sound in flight. Hearing this “click,” the bat stops its pursuit at once. The good-tasting moths, however, will disguise themselves by sending an ultrasonic “click” to confuse the bat. The frustrated bat will not give chase. But what the bat does not know is that among the loudest “clickers” are the tastiest moths.