Sperm transfer by gypsy moths (Lepidoptera: Lymantriidae) from irradiated males: implication for control by inherited sterility

When gypsy moths, Lymantria dispar (L.), whose male parent received 6, 8, or 10 krad of gamma irradiation were mated with untreated females, fewer transferred sperm than progeny of untreated males. Further, the quantity of eupyrene sperm transferred by offspring of irradiated males was less than that of progeny of untreated males. The effect was dependent upon dose. In untreated insects, fecundity as determined by weight of the egg mass was dependent upon quantity of eupyrene sperm in the spermatheca. But when the male parent was irradiated, fecundity of his daughters or of untreated females mated with his sons was less than that of untreated adults regardless of the quantity of eupyrene sperm. Females from 10-krad-treated males took longer than untreated females to begin copulating. These results suggest that insects from irradiated males released for suppression of a population may not be sufficiently competitive with feral insects