Reduction of the response to sex pheromone in the oriental fruit moth, Grapholita molesta (Lepidoptera: Tortricidae) following successive pheromonal exposures

The effects of prior pheromonal experience upon the pheromone- mediated upwind flight response was examined in the oriental fruit moth, Grapholita molesta (Busck) (Lepidoptera: Tortricidae). Adult male G. molesta were subjected to a parallel series of staggered and repeated pheromonal exposures in a sustained-flight wind tunnel. Levels of response to pheromone in male G. molesta significantly decreased in a (a) rectilinear function with increased ages of individuals, (b) logarithmic function of successive trials, and (c) steeper logarithmic function of successive trials with increased dosage of sex pheromone. The baseline levels of responding were not affected by either the (a) dosage of sex pheromone, (b) posteclosion ages of individuals for their initial exposures once the main effect of age itself was estimated, (c) elapsed time in hours between trials, or (d) discrete days of testing as integral intervals, disregarding hours within days.