Kenkichi Kanmiya

Acoustic studies on the mechanism of sound production in the mating songs of the melon fly,Dacus cucurbitae Coquillett (Diptera: Tephritidae)

The sound production mechanism in the male mating songs for the melon flyDacus cucurbitae Coquillett was acoustically investigated to determine whether sounds resulted from free wing-fanning or stridulation produced by contact between wing and abdominal pecten. Waveforms in the songs of normal (pecten-present) males showed more complex vibrations than those of pecten-removed males. The total harmonic distortion in normal songs was greater than that of the pecten-removed songs. Female (pecten-absent) songs showed different sound signatures on the oscillogram and frequency spectrum from normal male songs. The female songs had more harmonic components than the normal male songs. These results suggest that wing/pecten stridulation of normal male songs produces complicated wing oscillations with a small number of harmonics of near-periodic waveforms and a high harmonic distortion. They also suggest that the free wing-fanning observed during female and pecten-removed male songs produces simple and uniform wing oscillations with many harmonic contents of complex-periodic waveforms and low harmonic distortion. Despite the occurrence of some acoustic differences, pecten-removal did not positively influence the rate of copulation.

Acoustic properties and geographic variation in the vibratory courtship signals of the european chloropid fly,Lipara lucens meigen (Diptera, Chloropidae)

Geographic variation in courtship vibratory signals inLipara lucens from 7 disjunctive European populations were examined. Simple female responding signals showed significant interlocal difference in the pulse-group intervals only in the English population. More differentiated male courtship signals were separated into anterior “preliminary vibration” and posterior “main vibration”. The latter, composed of a train of bursts, showed significant differences among populations in the number of pulses in a burst, burst duration (BD), burst interval (BI) and burst period (BP). Latvian, Hungarian and Bulgarian populations had more pulses in a burst than those of E. Germany, Belgium, Czechoslovakia and England. Latvian and Bulgarian populations showed significantly larger values of BD, whereas that of Belgium showed a significantly smaller value. BI in the English population had the smallest value, and those in the Latvian and Bulgarian populations had the longest values. No significant differences were observed in BD and BI between E. Germany, Czechoslovakia and Hungary. Multivariate statistic analyses on the time-amplitude variables of the male signals showed uniqueness in the Belgian, English, Latvian and Bulgarian populations. Genetic background of the geographic variations in the vibratory signals are discussed in this context.