SYMMETRY IN THE SONGS OF CRICKETS

Acoustic signals produced by males are often subject to sexual selecti on. The mechanism of song production in crickets is well documented. C ricket songs are said to be characterised by almost pure tones of cons tant frequency. However, contrary to previous work, we show that crick et songs exhibit frequency modulation to varying degrees, dependent on the degree of asymmetry in the sound resonators or harps. Recent stud ies of sexually selected traits suggest that size and symmetry may ref lect male quality. The harps of crickets exhibit directional asymmetry to a degree that is directly related to the degree of fluctuating asy mmetry in a measure of body size. We show that females prefer pure ton es of low carrier frequency, characteristic of large symmetrical harps . Directional asymmetry may thus convey reliable information regarding male quality encoded in the male's song.