Effects of the apterous4 mutation on Drosophila melanogaster males' courtship.

The apterous4 (ap4) mutation has pleiotropic effects on the morphology and lifespan of D. melanogaster adults. The mutation also affects one aspect of male sexual behaviour. Unlike normal, sexually mature males, three day old ap4/ap4 males synthesize courtship-stimulating hydrocarbons that immature males make; as a result they elicit vigorous courtship (Jallon and Hotta, 1979; Jallon et al., 1986). Data presented in this report indicate that expression of the apterous4 mutation does not affect all aspects of sexual maturation in males. Specifically, 24-30 hour old ap4/ap4 males are capable of performing all of the courtship behaviors, including abdominal vibration, a newly described response of mutant and wild-type males to virgin females. However, the mutant males spend less time courting and are less likely to perform some of the courtship behaviours than age-matched controls. These abnormalities are probably indirect effects of the apterous4 allele's previously unreported effects on the flies' motor functions, which include partial paralysis, lack of coordination, and sluggishness.