Stridulatory behaviour in a New Zealand weta, Hemideina crassidens



Using a femoral-abdominal stridulatory mechanism, wetas produce the following stridulatory behaviours: aggression, mating, calling, defence and disturbance. Syllable period, rather than number of syllables/echeme or syllable duration, was the most stereotyped temporal parameter for aggression, mating and calling stridulation. Coefficients of variation of the above parameters were large and overlapped considerably for aggression and mating stridulation. We concluded that, for these two behaviours, a basic sound pattern is used to convey different messages to female and male receiver wetas, respectively, but the syllable period of the pattern decreases with increased excitation of males in aggressive encounters. In adult male combat, winners stridulated last in a bout, and produced significantly more aggression sounds than losers.