GENETIC VARIATION FOR FEMALE MATE DISCRIMINATION IN DROSOPHILA MELANOGASTER

Abstract

Comparisons between the Canton-S and Tai-Y strains of Drosophila melanogaster (both wild type) revealed variation in female mate discrimination based on chemical courtship signals present as hydrocarbons on the male cuticle. Mating tests indicated that 7-tricosene, which is the primary hydrocarbon on the Canton-S male cuticle but is nearly absent from Tai-Y, was a significant component of the signal. The discrimination was asymmetrical in that Canton-S females clearly distinguished between the two types of males in no-choice tests, but Tai-Y females did not. F₁ females expressed an intermediate ability to discriminate, and female progeny of backcrosses expressed a mating phenotype very similar to that of the parental strain to which the backcross was made. Analysis of independent effects from the X and both major autosomes indicated that the discrimination is controlled by gene(s) on chromosome 3.

Keywords: Drosophila melanogaster; heritable variation; mating discrimination; mating speed; sexual selection.