Sound Detector (Tympanum) On the Front Leg of a Katydid
Insect hearing organs vary in their ability to discriminate among sounds. Insects that need hearing to do one thing well, such as warning of an approaching bat, can have an auditory system that only responds to sounds made by bats. Some sphingid moths have a single auditory neuron in each tympanum that triggers evasive flight activity.
Using sound to identify, locate and find mates requires more sophisticated auditory processing…
Source: Living With Insects Blog