Virgin male and femaleLaspeyresia pomonella(L.) (0 to 24-h-old) were exposed to 0, 5, 10, 15, 20, 25, 30, 35, or 40 krad of gamma radiation and each caged individually for life with a single 0 to 24-h-old untreated, virgin moth of the opposite sex. Female mating propensity was increased by exposure to radiation; male propensity was unchanged. Female moths caged with a new 0- to 24-h-old male each day sharply reduced spermatophore passage by the males.