Variation in courtship sounds among three geographical strains ofDrosophila mercatorum

Abstract

Sound recordings of courtship in Drosophila mercatorum were analyzed with an oscilloscope. Sounds in this species consist of two kinds of pulses, referred to as the A and B sounds, respectively. These differ from each other in their oscilloscope pattern and in the behavior accompanying them. A comparative study of three strains from widely separated geographical regions (New York, El Salvador, and Hawaii) revealed significant differences among strains in the interpulse interval (ipi) of the A sound. The ipi of the B sound increased as it proceeded for New York and Hawaii males but not for males from El Salvador. These characteristics may influence mating success in interstrain crosses. The present results suggest that the first steps toward divergence in the nature of the sound are quantitative; this may affect the response threshold of the female. Genetic systems responsible for female receptivity may have been independently developed in the two sexes.

Genetics of sexual isolation between two sibling species, Drosophila simulans and Drosophila mauritiana.

“…Although large X chromosome effects have been described in one study of sexual isolation in males (6), they were not found in two other experiments (5,7). In some Drosophila species, characteristics of male courtship "song" may be predominantly located on the X chromosome, while in other species or characters the autosomes are more important (6,(26)(27)(28)(29). The connection between male mating song and sexual isolation is at any rate unclear: in the study of Kawanishi and Watanabe (6), sexual isolation mapped predominantly to the X chromosome but interspecific differences in mating song were predominantly autosomal.…”

Directional selection for pulse repetition rate of the courtship sound and correlated responses occurring in several characters in Drosophila mercatorum.

“…1), and finally attempts to mount. The results obtained so far suggest that the A sound may be essential for the mate recognition and the B sound is more closely associated with copulation itself (Ikeda et al, 1980). In the present study, selection was carried out only with respect to the interpulse interval of the A sound (A11).…”

“…In fact a most remarkable difference is found in the pulse repetition rate between closely related species, subspecies or geographical strains (Bennet-Clark 1978Chang and Miller 1978;Cowling and Burnet 1981;Ewing and Bennet-Clark 1968;Ewing 1979;Ikeda et al 1980 ;Miller et al 1975 ;Waldron 1964). These findings suggest that inter-and intraspecific differentiation in the nature of courtship sounds first occurs in the 1) This paper is dedicated to Emeritus Professor Daigoro Moriwaki on the occasion of his 77th birthday.…”

“…The male of D, mercatorum displays two kinds of courtship behaviors accompanying wing vibration, by which consequently two kinds of courtship sounds are emitted (Ikeda et al 1980). The first (A sound) is produced by wing vibration and wing flicking of the male when positioned behind or by the side of the female.…”

Search for species-specific mating signal in courtship songs of sympatric sibling species, Drosophila ananassae and D. pallidosa.

“…4 of Ewing and Bennet-Clark, 1968). Some Drosophila species sing several different songs (Ewing, 1969;von Schilcher, 1976;Chang and Miller, 1978;Ikeda et al, 1980;Crossley, 1986). Species of the D. bipectinata complex which belong to the ananassae subgroup are known as such species (Crossley, 1986).…”