Since 1992, the Mexican government has operated a program using the sterile insect technique (SIT) to manage the Mexican fruit fly (Anastrepha ludens). A critical part of any SIT effort is being able to readily discern male and female insects during the rearing process. The program in Mexico uses a strain of A. ludens in which the male pupae are brown (left) and female pupae are black (right). (Photo courtesy of Diana Perez-Staples, Ph.D.)