The Effects of Interspecific Courtship on Mating Success in Drosophila melanogaster

Rebecca Dawson,Scott P Mcrobert

doi:10.5539/ijps.v3n2p14

Abstract

Two sympatric, distantly related Drosophila species, D. melanogaster and D. affinis have been shown to interact sexually. Mature D. melanogaster males perform vigorous courtship in response to both virgin and mated D. affinis females, but perform no courtship in response to virgin females of another sympatric species, D. immigrans. To determine whether inter-specific courtship might interfere with mating success and fitness, D. affinis females were used as ‘interference sex objects’ in tests where D. melanogaster males had access to con-specific females. In these tests the presence of D. affinis females was shown to significantly reduce the mating success of D. melanogaster males. In comparison, the presence of mated D. melanogaster females or virgin D. immigrans females had no impact on the mating success of D. melanogaster males in similar tests.

Highlights

The mating system for Drosophila melanogaster appears to be based on female choice
As reported in earlier studies, the two most common Drosophila species in the Philadelphia area, D. melanogaster and D. affinis (McRobert & Tompkins, 1986a) interact sexually despite their relatively distant taxonomic relationship and the fact that hybrization between these species does not lead to viable offspring (McRobert & Tompkins, 1986b; McRobert & Tompkins, 1988)
In this report we show that the presence of D. affinis females leads to a reduction in their mating success by D. melanogaster males with con-specific females

Summary

Introduction

The mating system for Drosophila melanogaster appears to be based on female choice. Females, the discriminating sex, assess male courtship and control whether or not copulation occurs. If the fly that the male approaches is a con-specific female, the male will pursue her and repeat the courtship display until she slows down and opens vaginal plates to allow copulation to occur (reviewed in Greenspan & Ferveur, 2000). Since courtship subjects flies to an increased predation risk, it would seem likely that mechanisms might evolve that would reduce the amount of courtship males perform toward other species This appears to be true as in many instances Drosophila males either do not initiate courtship of non-con-specific flies, or quickly terminate courtship of these flies (Spieth, 1974; Spieth & Ringo, 1983)

Methods

Results

Conclusion