HOST-MARKING PHEROMONE AND USE OF PREVIOUSLY ESTABLISHED OVIPOSITION SITES BY THE MEDITERRANEAN FRUIT-FLY (DIPTERA, TEPHRITIDAE)

Under controlled conditions, the Mediterranean fruit fly, Ceratitis capitata (Wiedemann) preferred to initiate oviposition into preexisting, naturally formed oviposition punctures in a host fruit, kumquat (Fortunella japonica), over establishing new sites on the fruit. This preference was expressed despite the presence of naturally deposited host-marking pheromone (HMP) shown previously to deter oviposition. An almost-identical preference for existing punctures was expressed when females were presented with fruit bearing artificially made punctures on which HMP had been naturally deposited. Using artificial punctures and HMP extracts, the occurrence of punctures was manipulated independently of the presence of HMP. Under field-cage conditions, we found that (1) punctures stimulated egg-laying on kumquats, regardless of HMP treatment; (2) HMP extract inhibited egg-laying, regardless of the occurrence of punctures; and (3) the extent to which HMP inhibited egg-laying was greater on fruit free of punctures than on fruit bearing them. The physiological, evolutionary, and pest management implications of these results are discussed.