The function of the tympanum is hearing, as tympanum is the grasshopper's hearing organ. Tympanal organs are necessary for sound reception, since they are linked to the grasshopper's brain via the neuropile. As a result, tympanum is adapted to vibrate in response to signals received by the grasshopper.
In a tympanum, the thin, sound-sensing tympanic membrane stretches over an air space and connects to the grasshopper's nervous system. The tympana occur in pairs, appearing in different locations depending on the particular species of Orthoptera, the biological order containing grasshoppers and crickets.
In most species of grasshoppers the tympanum is located on the abdomen's first segment. The tympanic membrane is usually concealed beneath the base of the wing cover. On the inner surface of the membrane is the sensory body from which a bundle of auditory nerve fibers joins nearby nerve fibers to form a large nerve. The large nerve extends to a ganglion in the thorax or the abdomen.
Tympanum is important for the grasshoppers, as they use it to perceive various sounds. For example, male grasshoppers use sounds to call for mates and to claim territory. Females can hear the sound that males make and judge the relative size of the male from the pitch of the call. Other males can hear the sounds and judge the size of a potential rival.