The Physiology of the Tettigoniid Ear

Abstract

The effects of blocking the anterior and posterior tympanal slits suggests that the slits are effectively closed to spiracular sound input, but open to tympanal slit inputs. Removal of both the anterior and posterior cuticular folds significantly lowers the threshold curves for both spiracular and tympanal slit entry. The sensitivity to tympanal slit entry is increased to that of the normal spiracle. Destruction of the anterior membrane eliminates all responses in the frequency range 1–20 kHz; removal of the posterior membrane reduces sensitivity. Point-contact vibration of the three membranes at 16 kHz indicates that the central membrane is non-vibratory and that although the posterior membrane is poorly coupled to sound up to 20 kHz, its mechanical movements are transduced with less loss than those of the anterior membrane.