Diachasmimorpha longicaudata (Ashmead) and Psyttalia fletcheri (Silvestri) are opine 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-produced D. longicaudata and P. fletcheri on a native Hawaiian tephritid, Trupanea dubautiae (Bryan), infesting the flowerheads of the native composite shrub Dubautia raillardioides Hillebrand. Gravid females of D. longicaudata and P. fletcheri were confined with blooming D. raillardioides flowerheads infested with late instar T. dubautiae. Both D. longicaudata and P. fletcheri lacked positive oviposition responses to T. dubautiae larvae 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 parasitoids' normal rearing hosts (B. dorsalis and B. cucurbitae), both D. longicaudata and P. fletcheri readily oviposited in the test larvae. Oviposition by D. longicaudata did not significantly affect the percentage pupation of T. dubautiae, but did reduce the emergence of adult flies. Oviposition by P. fletcheri significantly 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 by D. longicaudata and P. fletcheri have no harmful impact on flower head-infesting T. dubautiae.