Effects of Gamma Radiation on the Tobacco Budworm. II. Irradiation of Moths

Abstract

Observations were made concerning the effects of gamma irradiation of Heliothis virescens (F.) moths on longevity, Opposition, egg viability, mating frequency, competitiveness of sterilized males, and survival of progeny. Males or females exposed to dosages of gamma radioation ranging from 35 to 50 krad produced only a few viable eggs when mated to unexposed moths. Conclusions as to mating frequency and longevity of irradiated males and females could not be made because of insufficient data. However, it appeared that sterilizing dosages did not seriously reduce longevity or mating frequency. Irradiation of females at 35-40 krad resulted in a reduction in oviposition. When both sexes were irradiated and allowed to mate, the egg viability was considerably less than when either sex was irradiated and crossed with unexposed moths. Considerable mortality occurred in the larval and pupal stages of the tobacco bud worms that hatched from eggs oviposited by irradiated parents. Death subsequent to hatching increased as the radiation dose increased and was greater when both parents were irradiated than when only one was exposed. Males exposed to 30 krad appeared to be competitive with normal males for virgin females in laboratory studies. The 72-hr LD50 values for male and female moths exposed to gamma radiation were 192.6 and 190.9 krad, respectively.