RELATIVE EFFECTS OF FEMALE FECUNDITY AND MALE MATING SUCCESS ON FERTILITY SELECTION IN DROSOPHILA-PSEUDOOBSCURA

The fertility component of natural selection acting on chromosomal inv ersions In two experimental populations of Drosophila pseudoobscura wa s subdivided into the effects of female fecundity and male mating succ ess. The offspring of the three female genotypes could be distinguishe d by their mitochondrial DNA haplotypes, thus permitting a direct meas urement of the relative fecundities of the female genotype. The effect s of male mating success on inversion frequency were measured by compa ring inversion frequencies in parents and their offspring, Selection b y fertility caused significant changes in inversion frequency in both populations, In one population, the changes in inversion frequency due to female fecundity and to male mating success were comparable, In th e other population, however, the changes in Inversion frequency due to male mating success were considerably larger than those due to female fecundity, The difference between the two populations underscores the intrinsic variability of the fertility component of fitness.