The processes underlying mate choice profoundly influence the dynamics of sexual selection and the evolution of male sexual traits. Consistent preference for certain phenotypes may erode genetic variation in populations through directional selection, whereas divergent preferences (e.g., genetically compatible mates) provide one mechanism to maintain such variation. However, the relative contributions of these processes across episodes of selection remain unknown. Using Drosophila melanogaster, we followed the fate of male genotypes, previously scored for their overall reproductive value and their compatibility with different female genotypes, across pre- and postmating episodes of selection. When pairs of competitor males differed in their intrinsic quality and their compatibility with the female, both factors influenced outcomes from mating success to paternity but to a varying degree between stages. These results add further dimensions to our understanding of how the interactions between genotypes and forms of selection shape reproductive outcomes and ultimately reproductive trait evolution.

We conducted a series of experiments, which involved live observations (e.g. occurrence and timing of copulation between focal individuals or ejection of sperm mass by females) and quantification of offspring or sperm under a fluorescence stereoscope or microscope, respectively. Sperm in storage were counted following dissection of the female reproductive tract.

All analyses were conducted in R using established packages.