The Mechanics of Stridulation in Bush Crickets (Tettiginioidea, Orthoptera)

Using isolated tegmina of the bush cricket Homorocoryphus nitidulus vicinus (Walker) mounted on the actuator described in a previous paper the parameters controlling tooth-impact rate have been varied. Results have shown that the mirror frame can be thrown into resonant vibration at between 12 and 15 kHz. when the tooth-impact rate approaches these values. The situation in the Homorocoryphus type of stridulation is compared with that of the Conocephalus type where resonance does not occur. The tooth-impact rate in H. n. vicinus is coupled with the frequency of natural vibration of the mirror frame via a plectrum-pivot-frame system which is made to act as a cantilever with the pivot at the mesial end of the vestigial file and the plectrum as the point of excitation. The problem of acoustic coupling involving mechanical and air-column systems is discussed.