Comparison of sex pheromone composition and pheromone-mediated male behavior of laboratory-reared and wildHeliothis zea (Lepidoptera: Noctuidae).

Analysis of ovipositor extracts of lab-reared (> 120 generations) and wildHeliothis zea indicated small but significant differences in the percent composition of the four aldehyde components of the sex pheromone. (Z)-11-hexadecen-1-ol (Z11-16∶OH) was present in both populations and amounted to only 2.8% of the total pheromone. There was no significant difference in four of the six behavioral categories between lab-reared and wild males exposed to the four-component sex pheromone in the flight tunnel. Ninety and 84% males flew to the pheromone source, respectively. However, with the addition ofZ11-16∶OH to the pheromone blend, none of the wild males flew upwind to the stimulus source, whereas 36% of the lab-reared males completed the flight. It is suggested that prolonged inbreeding in closed quarters rendered these males less discriminating to qualitative differences in a pheromone blend.