EFFECT OF INTERSPECIFIC HYBRIDIZATION BETWEEN HELIOTHIS-VIRESCENS AND HELIOTHIS-SUBFLEXA (LEPIDOPTERA, NOCTUIDAE) ON SEX-PHEROMONE PRODUCTION BY FEMALES

The effect of interspecific hybridization between Heliothis virescens and H. subflexa on the production of sex pheromone by females was studied. The F-1 hybrid females from crosses between H. virescens male and H. subflexa female did not produce sex pheromone during a distinct period in the scotophase. The mean amounts of pheromone present in extracts obtained from insects sampled at 1 h intervals remained relatively constant from the second to ninth hours of the scotophase. Hybrid females from the reciprocal cross (H. subflexa male x H. virescens female) had peak pheromone production at the sixth hour of the scotophase. Homogenates of cephalic ganglia obtained from either of the hybrid lines stimulated pheromone production when injected into either of the parent species or either of the F-1 hybrid lines during the photophase. Thus, F-1 females had the capacity to produce pheromone and pheromonotropic substances were present in the cephalic ganglia. We conclude that hybridization between H. virescens male and H. subflexa female affected the endogenous release of pheromonotropic substances from the cephalic ganglia.