Sexual differences in the flight performance of the oriental fruit moth, Cydia molesta

Cydia molesta Busck (Lepidoptera: Tortricidae), a major pest of stone fruits and an increasingly important late season pest of apple, is predominately monitored by pheromone trapping of male moths. We investigated flight performance in relation to sex, age, and mating status using computer-linked flight mills, and also examined the relationship between female flight and reproduction. The crepuscular flight pattern of the experimental moths in relation to photointensity was very similar to that reported from field studies. Female moths significantly outperformed males in all measured flight parameters including total distance flown, distance of longest single flight, and velocity. The proportion of long-flying females (categorised as those completing an unbroken flight of greater than 1 km) was three to six times greater than that of males. Female flight performance was not related to mating status, but mated males displayed significantly greater flight than unmated males. The maximal flight period of mated females commenced on the third day after eclosion, following 30% egg deposition. Male flight was not significantly related to age. The data suggest that a limited proportion of the population, in particular females, may have the capacity to make inter-orchard flights. The limitations of monitoring C. molesta populations in apple orchards solely by pheromone trapping of males are discussed.