Mating activity of yellow and sepia Drosophila willistoni mutants

By analyzing the mating activity of newly isolated yellow and sepia mutants of Drosophila willistoni no difference in behavior between sepia and wild-type flies were observed, whereas yellow males were less successful than wild-type males when competing for females. These results are in agreement with those reported for other Drosophila species. D. willistoni was different in the 'females-competing' crosses because wild-type males mated more frequently with wild-type females whereas yellow males mated successfully with both phenotypes. These results indicate the complexity of the courtship behavior in D. willistoni and provide data for comparative and evolutionary research into the genus.