Success of mutant Drosophila at different sex ratios.

Relative courtship success of mutant Drosophila melanogaster males was found to vary with sex ratio. Males with one of three recessive mutants: White, vermilion, or vestigial, competed with wild type males for females. Female-biased sex ratios were associated with increased success of all three different mutant phenotypes relative to wild-type as compared to an unbiased sex ratio. There was no difference in the success of mutant males in the first or second half of the observation periods, which spanned one hour.