Electrophysiological and behavioral activities of sex pheromone and structurally related compounds in lightbrown apple moth, Epiphyas postvittana

Species-specific pheromone communication in moths is often achieved by the precise control of the production of a multi-component sex pheromone blend in females and selective perception of pheromone compounds in males. Reproductive isolation mediated by sex pheromone can be enhanced by the sensitive detection of structurally related non-pheromone components that are not used as pheromone in the same species but used as pheromone components in similar species. Here, we identified several unsaturated aliphatic acetates inhibiting the attraction of male moths to conspecific female sex pheromone in the lightbrown apple moth, Epiphyas postvittana (Walker) (Lepidoptera: Tortricidae), through electroantennogram (EAG) and field trapping studies. In EAG screening with 46 pheromone and structurally related compounds, eleven compounds exhibited significant male-specific EAG responses at 1 µg dose. The EAG-active compounds were mainly mono- or di-unsaturated 14-carbon acetates. In subsequent field trapping tests to evaluate the behavioral activities of the EAG-active compounds on male attraction to the binary blend (E11-14:Ac + E9E11-14:Ac) of female sex pheromone of E. postvittana, each of nine compounds (E9-12:Ac, Z9-12:Ac, E9-14:Ac, Z9-14:Ac, Z10-14:Ac, Z11-14:Ac, Z12-14:Ac, Z9E11-14:Ac and Z9E12-14:Ac) displayed clear inhibition of male moths to the sex pheromone blend in a dose-dependent manner. Our findings provide useful information in understanding the pheromone communication system of E. postvittana and related species.