SPATIAL DISCRIMINATION BETWEEN SOURCES OF PHEROMONE AND AN INHIBITOR BY THE LIGHT-BROWN APPLE MOTH EPIPHYAS-POSTVITTANA (WALKER) (LEPIDOPTERA, TORTRICIDAE)

Inhibition of the behavioral responses of male Epiphyas postvittana moths by the Z isomer of the major component of the sex pheromone, E11-14:OAc, was studied in a wind tunnel. Inhibition was detectable at a Z isomer concentration of 10% that of the major component and was greatest when it was added to the same source as the pheromone. Inhibition declined rapidly as the inhibitor was moved across-wind away from the pheromone source but was largely maintained when the sources were separated upwind or downwind. The results showed that the insects possess a high degree of temporal resolution for odor plumes of different composition.