We do not know whether they can hear just because they make a noise, however the moths above in AGARISTINAE and PYRALIDAE certainly can hear the noises as they are used to attract opposite sexes. We also know from experiments which measure nerve responses to sound, that some butterflies and moths can perceive sound. Most research has concerned moths in NOCTUIDAE. Roeder described the ear of these moths. It is a membrane like our ear-drum or tympanum, that forms the outer wall of an air-filled cavity. This cavity is formed from the moths respiratory system by the expansion of a trachea. One ear is located on each side near the "waist" where the thorax and abdomen join. Thus some research has been done indicating that some adult moths and butterflies respond to sounds, so it is likely that Caterpillars also hear sounds. If they do, it is likely that the pair of antennae on the larval head is responsive to sound, but we know of no research investigating this.