Sexual conflict over sperm quality in Drosophila simulans

TOURMENTE, MAXIMILIANO; ARCHER, C. RUTH; HOSKEN, DAVID J.

Marsella

Congreso; 22nd Evolutionary Biology Meeting; 2018

Association pour l´Etude de l´Evolution Biologique

Sperm viability is a major determinant of male fertility, with higher viability often associated with enhanced sperm competitiveness. While many studies have focussed on sperm viability from the male fitness standpoint, its impact on female fitness are less clear. Here we used a panel of 32 isogenic Drosophila simulans lines to test for genetic variation in sperm viability (percentage of viable cells), and to test how variability affected female fitness by mating females to either low viability or high viability lines. We found significant variation in sperm viability among isolines, with viability values ranging from 71 to 91%. Moreover, females mated to males from high sperm-viability isolines laid more eggs, but also had more eggs failing to hatch. It therefore appears that mating with high sperm-viability genotypes leads to egg wastage for females. These results suggest that high sperm quality, a trait beneficial in male-male (sperm) competition, negatively impacts female fitness, generating sexual conflict over optimal sperm quality.