A Drosophila male pheromone affects female sexual receptivity

Abstract

Sex pheromones are chemical signals frequently required for mate choice, but their reciprocal role on mate preference has rarely been shown in both sexes. In Drosophila melanogaster flies, the predominant cuticular hydrocarbons (CHs) are sexually dimorphic: only females produce 7,11-dienes, whereas 7-tricosene (7-T) is the principal male CH. Males generally prefer females with 7,11-dienes, but the role of 7-T on female behaviour remains unclear. With perfumed males, control females mated faster and more often with males carrying increased levels of 7-T showing that this CH acts as a chemical stimulant for D. melanogaster females. Control females-but not antenna-less females-could detect small variation of 7-T. Finally, our finding that desat1 mutant female showed altered response towards 7-T provides an additional role for this gene which affects the production and the perception of pheromones involved in mate choice, in both sexes.

Figure 1

Male courtship and female mating response with various males. Individual 5 day old tester males were either paired (a, c) with a single decapitated female and their courtship index (CI) was measured, for 10 min, or (b, d) with an intact female and the frequency of mating, the mean (±s.e.m.) for copulation latency (copulation onset) and for copulation duration (in min) were measured for 60 min. Females were either homozygous for the desat1^1573-N2 allele (N2; white bars), or the desat1^1573-1 allele (desat1; grey bars). Tester males either belonged to the desat1, N2, EP genotypes (a, b) or were desat1 males perfumed by donors of these three genotypes (^*desat1^*, ^*N2^*, ^*EP^*; c, d; see table 1). Statistical differences between different male types (genotype or perfume), measured separately for each female genotype, are shown by the letters inside the histogram bars. Significant differences between the two female genotypes, tested with ANOVA for the three male genotypes or for perfumed males, are indicated above bars as follows: ^***p<0.001; ^**p<0.01; ^*p<0.05. (a) n=22–47; (b) 70–137; (c) 23–32; (d) 47–111.

Figure 2

Effect of antennal ablation on female mating with control and perfumed males. Five day old females homozygous for the desat1^1573-N2 allele (N2) that were either intact ([+]), bilaterally ablated for their aristae ([A⁻]), or for their funiculi ([F⁻]) were either paired with (a) a same age N2 male or (b) with a desat1 male perfumed with the hydrocarbons of desat1 (^*desat1^*), or of EP males (^*EP^*). Data shown represent the frequency of mating, and the mean (±s.e.m.) for copulation latency and duration (in min) measured during a 1 h period. For genotypes, see table 1; for statistics, see figure 1. n=63–82 except for [+] females with N2 males (32).