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

Abstract

ABSTRACT A method has been devised by which the isolated tegmina of bush crickets can be actuated in such a manner as to simulate the insect’s natural song. The actuator was used to make a detailed analysis of the mechanics of sound production, with particular reference to the emission of the more or less pure tone at 15 kHz., characteristic of Homorocoryphus nitidulus. Results involving damping and cautery indicated that the area of the right tegmen responsible for the radiation of this sound was the mirror frame, the vein enclosing the classical mirror membrane. Further experiments involving transduced sound and a probe microphone led to the construction of sound radiation maps of the right tegmen which supported the above view. The cantilever hypothesis, involving the mirror frame with the axis of the vestigial file as the cantilever’s rotational axis, was considered in the light of the Homorocoryphus type. The Homorocoryphus type differed from the Conocephalus type (on which the cantilever hypothesis was based) in that a simpler cantilever is formed in a line direct from the plectrum to the tip of the frame arm.