Natasha Mhatre and Daniel Robert* studied sound detection in the tree cricket, Oecanthus henryi. They found that the cricket will actively oscillate its tympanum in a manner that enhances receptor output at the frequency of its mating song. Playing tones near to the frequency of the mating song suppressed the oscillations. In this way, a sound that is the exact frequency of the mating song will be enhanced and the noise is suppressed. This active amplificateion “tunes” the cricket ear and makes it less sensive to “noise”. This is not an artifact of environmental stimulation as dead crickets exhibited no such oscillation. Active amplification makes it easier for crickets to find mates in a noisy environment.
*Mhatre N, Robert D. 2013. A tympanal insect ear exploits a criti- cal oscillator for active amplification and tuning. Curr Biol 23:1952–1957.