Perfumed to be Killed: Interception of Mediterranean Fruit Fly (Diptera: Tephritidae) Sexual Signaling by Predatory Foraging Wasps (Hymenoptera: Vespidae)

Abstract

In a previous field study we demonstrated that predation on pheromone calling Mediterranean fruit fly, Ceratitis capitata (Wiedemann), males by the yellowjacket wasps Vespula gennanica (F.) is mediated through olfactory foraging behavior. The objectives of the current study were to assess wasp predation on sexually immature and mature C. capitata engaged in sexual and nonsexual activites on foliage and fruit and to confirm whether overall wasp attacks and prey capture rates are sexually biased. Our results indicate that capture rate of flies by foraging wasps is highly influenced by fly activity, with mature signaling males being subject to a majority of the attacks and suffering the highest losses on foliage, whereas on fruit it was ovipositing females that suffered the highest mortality. However, mature but virgin females also suffered considerable losses on foliage while visiting leking males. Mating pairs, even though they tended to leave the lek immediately after pair formation, suffered the highest predation losses proportionate to the number of attacks. Possible reasons for this activity- and sex-biased predation are discussed.