Fitness and fitness components for a two-allele system in Drosophila melanogaster

Abstract

In Drosophila a two-allele system, known to acquire a balanced polymorphism in experimental populations, has been used in various tests undertaken with the aim of estimating total fitness as well as different fitness components and their possible frequency dependence. Two different genetic backgrounds and two different densities have been included. The main fitness component was found to be male mating capacity, which was highest in the genotype with the most intense eye pigmentation. When differences in viability and mating capacity both occurred the result was an apparent frequency-dependent fitness, but deviations from expectations also inferred a real minority advantage. The estimated fitness values could not explain the gene-frequency trends in long-term persistency tests.