Fitness measuresData on the fitness of different lines, following mutation accumulation, for either juveniles, males, or females of that genotype. Group: the trait measured, either juvenile egg-to-adult viability, male reproductive success, or female reproductive success. MA_generation: the number of generations since lines were initiated; juvenile fitness was assessed at 16, 30, and 46, adult traits at 52. Treatment: whether the replicate is of a line that underwent mutation accumulation (mutant), or is from one of three control populations (controlX, controlY, controlZ). Line: an arbitrary replicate number, i.e. a mutant or control genotype. Note that mutant lines are consistent across generations, whereas control genotypes in a given generation are independent of those in another generation. Offspring: a measure of fitness. For juveniles, the number of focal individuals emerging as adults, in the presence of standard competitors. For adults (males, females), the number of offspring sired/produced in the presence of standard competitors.SharpAgrawalEvolutionData.xlsx

In populations with males and females, sexual selection may often represent a major component of overall selection. Sexual selection could act to eliminate deleterious alleles in concert with other forms of selection, thereby improving the fitness of sexual populations. Alternatively, the divergent reproductive strategies of the sexes could promote the maintenance of sexually-antagonistic variation, causing sexual populations to be less fit. The net impact of sexual selection on fitness is not well understood, due in part to limited data on the sex-specific effects of spontaneous mutations on total fitness. Using a set of mutation accumulation lines of Drosophila melanogaster, we found that mutations were deleterious in both sexes and had larger effects on fitness in males than in females. This pattern is expected to reduce the mutation load of sexual females and promote the maintenance of sexual reproduction.