FIGURE 1.

Motor programs used in fruit fly aggression. The Venn diagram shows the different motor programs used in male and female aggression. Some of the motor programs are sexually dimorphic. The motor programs encircled in blue are specific for male aggression. The motor programs encircled in red are specific to female aggression. The intersection enlists the motor programs common to both male and female aggression (A). The most consistent motor program in male aggression is a lunge (B). In a lunge, a male fly stands on its hind legs and snaps down on its opponent. The most consistent motor program in female aggression is a head butt. In a head butt, the female fly extends her torso and strikes the opponent with her head (C).