none Bactrocera dorsalis; HYMENOPTERAN-PARASITES; Biosteres, Diachasmimorpha & Psyttalia; Multiparasitism effect on parasite oviposition & progeny development Biosteres arisanus; DEVELOPMENT-; Progeny, multiparasitism in dipteran host relationships; DIPTERAN-HOSTS; Bactrocera dorsalis; Multiparasitism effect on progeny development Diachasmimorpha longicaudata; Psyttalia incisi; EGG-LAYING; Oviposition behaviour; DEVELOPMENT-; Progeny, multiparasitism in dipteran host relationships; DIPTERAN-HOSTS; Bactrocera dorsalis; Multiparasitism effect on oviposition behaviour & progeny development Multiparasitism (the same fruit fly hosts are parasitized by different parasitoids) of the oriental fruit fly, Bactrocera (=Dacus) dorsalis (Henael), had differential effects on the progeny development of the egg parasitoid Biosteres arisanus (Sonan) and the larval parasitoids Diachasmimorpha longicaudata (Ashmead) and Psyttalia incisi (Silvestri). In addition, contact with previously parasitized hosts had varying effects on oviposition behavior of D. longicaudata and P. incisi. Progeny of each of the 3 species successfully developed in multiparasitized hosts. However, effect of multiparasitism was more costly to survival and emergence of D. longicaudata than to B. arisanus or P. incisi. Competition for the same hosts between D. longicaudata and P. incisi resulted in disproportionately large numbers of progeny by either species depending on which parasitoid the host larvae were exposed to first. Naive females of D. longicaudata and P. incisi oviposited in healthy and parasitized fruit fly larvae. However, oviposition by D. longicaudata was more restrained toward larval hosts that were parasitized initially by B. arisanus, P. incisi, or both. Our results provided a basis for better understanding of the consequences of multispecies releases of fruit fly parasitoids.