There is a significant drop in the courtship index (CI, the fraction of time spent performing any of the steps of courtship) of mutant males. They are capable of all courtship steps, but perform them less frequently. Short-term locomotor activity is unaffected. The male courtship phenotype is still observed if mutants are deprived of visual input or paired with young/mature virgin females. Mutant males do not show increased male-male courtship.