INHERITED STERILITY AND POSTEMBRYONIC SURVIVAL OF TWO GENERATIONS OF TOBACCO BUDWORMS, HELIOTHIS VIRESCEHS (LEPIDOPTERA: NOCTUIDAE), FROM PARTIALLY STERILE MALES

Abstract

Male Heliothis virescens (F.) were irradiated with 7.5, 15.0, or 22.5 krad of 7-rays and crossed with untreated females. Then fertility of these treated males (PJ and of their descendants was studied for two generations. In addition, the postembryonic survival of the Fx and F2 generations was studied. Fertility (percentage egg hatch) of P1 males was greater than that of Ft males or Fj females. There was more postembryonic survival in the F1 than in the F2 generation. When the Px males received 22.5 krad, few F2 larvae hatched, and none survived. When Pt males received 15.0 krad, the fertility of F1 males and females was less than 5, and 10%, respectively, and less than 20% of the F2 larvae survived; however, sterility factors were nearly eliminated by the third generation. When P1 males received 7.5 or 15.0 krad, the average fertility of F2 males was greater than that of F1 or P1 males but less than that of untreated controls, though fertility of some F2 males was normal. The lower the dose received by P1 males, the greater was the frequency of F2 males with normal fertility.