The Mechanism of Sperm Precedence in the Spruce Budworm,choristoneura Fumiferana(lepidoptera: Tortricidae)

The mechanism of sperm precedence in the spruce budworm was studied using a genetic marker. When female moths with red-eyes, a recessive trait, are mated twice within a day, first with a red-eyed male followed by a black-eyed male, three types of offspring were observed in the F 1 generation. Some females produced only red-eyed offspring; another group produced only black-eyed progeny; a third group produced a mixture of both types. This indicates that sperms received from either or both matings may be utilized. The time interval between successive sperm transfers appears to be the underlying factor that determines sperm precedence in this insect; a hypothesis to explain this phenomenon is presented.