Lack of Radioresistance in Plodia interpunctella (Lepidoptera: Phycitidae) Exposed to Sublethal Gamma Irradiation for 30 Generations

Populations of Plodia interpunctella receiving sublethal doses of irradiation (0.5, 1, 2, and 4 krad) each generation for 30 generations were checked for reproductive capacity and resistance to an acute dose of irradiation. Reproductive capacity was decreased by an ancestral history of irradiation, and the reduction was generally positively correlated with both the size of the dose per generation and the number of ancestral generations treated. Irradiation of the selected populations with an acute dose revealed no increase in tolerance, even after 30 generations. In general, the greater the amount of ancestral irradiations, the greater the sensitivity.