Normal courtship in the fruit fly Drosophila consists of an ordered set of behaviors. The behavior of males is most obvious. Upon noticing a female the male orients toward her, then follows her and taps her abdomen with his forelegs. After some period of singing, the male extends his proboscis and touches the female's genital structures. Wild type males do not normally direct these behaviors at mature males.
Females play an equally important, if more subtle, role in courtship.
After a period of time in which the male demonstrates both his ability to follow the female and to perform the courtship rituals, the female slows or stops moving and positions herself for copulation. Flies containing mutations in genes required for normal courtship exhibit abnormal sexual behavior. Males mutant for dsf are bisexual, courting mature males as well as females. A tape of a normal male courting a female, including following and singing A tape showing mature dsf males. Note the chains of courting males, with each male singing at the male in front of him.