Effects of gamma radiation on the pupae of Pieris brassicae L

Pupae of Pieris brassicae L. anchor themselves to a substratum with a silk thread stretched across the thorax. Anchoring pupae detached for irradiation purposes facilitated adult emergence. Pupae were irradiated from a 60Co source with dose rate 1.229 Krad/min. The doses delivered to pupae were 30, 35 and 40 Krad. Irradiation of pupae reduced successful adult emeru.ence. Mortality among the successfully emerged adults was higher at higher doses. But in 30 and 35 Krad treatments the few that survived lived longer than those in the control and 40 Krad treatments. In general, irradiation of males decreased the mating frequency and the oviposition of females mating with them. Fertility was found to decrease with increasing dose and 40 Krad induced sterlity in males. (author)