COMPLEX COURTSHIP SONGS IN THE DROSOPHILA-FUNEBRIS SPECIES GROUP - ESCAPE FROM AN EVOLUTIONARY BOTTLENECK

Due to properties of the neuromuscular system involved in courtship song production in Drosophila there is a minimum song inter-pulse interval of approximately 10 ms. Species within the funebris species group all produce songs which contain such pulses. It is suggested that this has tended to produce an evolutionary bottleneck with regard to song pattern and, in order to facilitate species recognition, the following trends have occurred within this group of species. (1) The minimum interpulse interval songs are arranged into bursts with species specific inter-burst intervals (all species except D. subfunebris). (2) Distinct secondary songs which do not contain minimum inter-pulse interval bursts have been added to the song repertoire (all except D. funebris and D. subfunebris). (3) The original minimum inter-pulse interval bursts have been incorporated into the secondary song (D. subfunebris). © 1979.