OVERWINTERING OF THE MEDITERRANEAN FRUIT-FLY (DIPTERA, TEPHRITIDAE) IN NORTHERN GREECE

The overwintering potential of wild Mediterranean fruit fly Ceratitis capitata (Wiedemann), within the northernmost zone of establishment of the fly was studied during 3 winters (1992-1995) in an orchard in nor thern Greece (40.3 degrees north latitude). During late autumn and ear ly winter of these years, larvae within various naturally infested hos t fruits, pupae, and adults were exposed outdoors to natural temperatu re conditions. Mortality rates were 100% for pupae and adults and grea ter than 60% for larvae subjected to the various treatments. The larva e that survived the treatments experienced high mortality in the subse quent pupal stage that was related to the duration of their developmen tal period; the earlier the larvae left the fruits during winter and s pring the lower their survival. Females that emerged from March throug h May laid fertile eggs in late spring and early summer. Average longe vity of adults was approximate to 90 d and average fecundity 246.7 egg s per female. These results suggest that under climatic conditions tha t permit boundary establishment a proportion of C. capitata larvae can overwinter and regenerate a population the following spring. The ecol ogical importance of this finding for temperate, fruit-producing regio ns of the world is discussed.