Effect of Two Opiine Parasitoids (Hymenoptera: Braconidae) Introduced for Fruit Fly Control on a Native Hawaiian Tephritid,Trupanea dubautiae(Diptera: Tephritidae)

Diachasmimorpha longicaudata(Ashmead) andPsyttalia fletcheri(Silvestri) are opiine parasitoids introduced into Hawaii for control of the Oriental fruit fly,Bactrocera dorsalis(Hendel) and the melon fly,Bactrocera cucurbitae(Coquillett), respectively. Both species have recently been mass-reared and released for research in augmentative biocontrol programs. Laboratory and field sleeve cage experiments were conducted to investigate the potential impact of mass-producedD. longicaudataandP. fletcherion a native Hawaiian tephritid,Trupanea dubautiae(Bryan), infesting the flowerheads of the native composite shrubDubautia raillardioidesHillebrand. Gravid females ofD. longicaudataandP. fletcheriwere confined with bloomingD. raillardioidesflowerheads infested with late instarT. dubautiae.BothD. longicaudataandP. fletcherilacked positive oviposition responses toT. dubautiaelarvae in infested flowerheads and caused neither parasitism nor mortality to the flies. However, when larvae were removed from the flowerheads and presented in screened dishes containing artificial diet of the parasitoidsʹ normal rearing hosts (B. dorsalisandB. cucurbitae), bothD. longicaudataandP. fletcherireadily oviposited in the test larvae. Oviposition byD. longicaudatadid not significantly affect the percentage pupation ofT. dubautiae,but did reduce the emergence of adult flies. Oviposition byP. fletcherisignificantly reduced both pupation and adult fly emergence. All progeny of both parasitoid species died as eggs or first-instar larvae. Results from our experiments demonstrate that biological control programs targeted against frugivorous tephritid pests byD. longicaudataandP. fletcherihave no harmful impact on flowerhead-infestingT. dubautiae.