sound signals of hawkmoths (Lepidoptera, sphingidae)

Temporal and frequency characteristics of the acoustic signals emitted by the pharyngeal sound apparatus were investigated in the hawkmoths, Acherontia atropos (L.), A. lachesis (F.), and Langia zenzeroides Moore. The sound signals of A. atropos consist of sequences of low- and high-amplitude series of clicks with different frequency spectra. In the other two species, the signals are emitted as sequences of uniform series of clicks. The dominant frequencies in the spectra are 7–10 kHz (A. lachesis), 13–20 kHz (A. atropos), and 35–47 kHz (L. zenzeroides). The defensive function of the pharyngeal signals is hypothesized.