The distinct coding systems of the pulse song and the sine song emitted by Drosophila melanogaster [abstract]

During courtship, the male Drosophila melanogaster (Diptera, Drosophilidae) produces two kinds of acoustic signals by wing vibration toward the female: the pulse song and the sine song. In order to examine the roles of these two signals, different signals were broadcast to single pairs of flies in which the males were muted by wing cutting). We used a complete song including both the pulse and the sine components, recorded during a successful courtship, to prepare different signals to play back to the flies. Thus, the natural pattern of sound emission was preserved. A preliminary experiment showed that the broadcasting of a natural complete song restored to wingless males a court- ship success comparable to that of normal winged males. A second experiment compared the effects of pulse song and sine song. The pulse song alone was sufficient to stimulate the mating between a wingless male and a virgin female. The sine song had lower effects. In a third experiment, we demonstrated that the intrasine frequency was an important parameter involved in the coding of the information. For the pulse song, the information is carried out by the rhythm of pulse production. Changing the intrapulse frequency had no effects on courtship success.