Ephestia Kuehniella Z.: Gamma irradiation effects on the adult stage and mating competitiveness of sterile males

Effects of gamma radiation dosages from 5 to 50 Krad on the adult stage of Ephestia Kuehielia Z. were studied. Irradiated adults paired with untreated adults produced fewer eggs than pairs of unirradiated adults, and these eggs had reduced hatch. This effect was more pronounced with irradiated females or when both parents were irradiated. Radiation greatly reduced life span of treated adults. Adult females were more sensitive to the sterilizing effect of gamma radiation than were males. Males were sterilized when irradiated at 50 Krad, but females at 25 Krad. Previous studies showed that males irradiated as fully grown pupae at 45 Krad were completely sterile. When irradiated (I) males were confined with unirradiated (U) males and females (1:1:1 ratio), infertility of eggs was 48%. Increasing the ratio to 5:1:1, 10:1:1 and 15:1:1 caused 77.9, 84.6 and 94.4 percent infertility of the resulting eggs, respectively. The calculated competitiveness values for the 4 ratios were 0.55, 0.52, 0.42 and 0.88, respectively. Thus I males were only competitive at the highest flooding ration (15:1:1)