SOUND PRODUCTION IN CICADAS: TIMBAL MUSCLE ACTIVITY DURING CALLING SONG AND PROTEST SONG

Abstract

ABSTRACT Electromyograms (EMGs) of the timbal muscles were recorded during the calling songs and ‘protest songs’ (also referred to as alarm signals) in five species of cicadas: Cicada barbara lusitanica, Tettigetta josei, Tettigetta argentata, Tibicina quadrisignata and Tympanistalna gastrica. The timbal muscle contraction rates of all species ranged from 50 to 250 Hz. The basic timbal cycle generating sound during the inward and outward buckling of the timbal was maintained in calling song and protest song for all five species. Comparison of the temporal parameters and the corresponding timbal muscle activity in both sound signals revealed that the timbal muscle period as well as the intertimbal delay showed the same mean values. Major differences between calling song and protest song are apparent in the pattern determining echemes and phrases as well as in the sound amplitude modulation. The amplitude of the sound pulse during the inward movement of the timbal was positively correlated with the time lag...