[en] The effects of second mating on fecundity and fertility of potato tuber moth female mated with 450 Gy - irradiated and normal males or vice versa were studied. Percentage of eggs fertilized by sperm from the 2 nd mate (P2) was 0.99, indicating that sperm transferred during the last mating were predominantly utilized in egg fertilization. Females mated first with irradiated males, remated after 2 days, while those mated first with normal males, remated after 3.3 days. Fecundity of twice-mated females was higher than those mated only once. Females laid their eggs 1.9 days after mating, while unmated females did not lay eggs at all. Duration of mating varied from 102 to 117 minutes for normal and irradiated males, respectively. (author)