Analysis of Pheromone-Mediated Behaviors in Male Grapholitha molesta , the Oriental Fruit Moth (Lepidoptera: Tortricidae)

Abstract

In Grapholitha molesta (Busck), the Oriental fruit moth, the behavioral effects of 3 female sex pheromone components, ( Z )-8-dodecenyl acetate (Z8-12:Ac), ( E )-8-dodecenyl acetate (E8-12:Ac), and ( Z )-8-dodecenyl alcohol (Z8-12:OH), are described most precisely only when each component is considered in combination with the other two, rather than individually or in binary blends. In a blend ratio approximating that emitted by G. molesta females, these 3 components elicited increases in both early (long-range) and late (close-range) behaviors in the male response sequence. Hence, these components act as a unit. An added fourth component, dodecanol (12:OH), had significant, but subtle, effects upon the hairpencil display when Z8-12:OH was at suboptimal levels, in contrast to the stronger behavioral effects previously ascribed to 12:OH. Z8-12:OH appears important to the reproductive isolation between G. molesta and G. prunivora (Walsh), because this component strongly reduced trap capture of G. prunivora males when present at a dispenser dosage of only 1% of the acetates, and virtually eliminated capture at 10%. There was a strong correlation between pheromone plume behaviors of pre-flight wing fanning while walking and upwind flight, suggesting that these behaviors may be closely associated, functioning to locate the pheromone source by ground or air, respectively.