Abstract
Synanthropic flies are members of order Diptera and considered as medical and veterinary pests. In this study, parasitoid wasps were determined and their natural host preferences in order to select a suitable agent for biological control of flies. The pupae of three species of flies; Musca domestica, Lucilia sericata and Sarcophaga haemorrhoidalis were used as hosts for natural parasitoids. For this issue, as much as 50 pupae of each fly species put in three separate dishes with covered top by a net. These dishes were placed in the field to attract parasitoid wasps. The most parasitic rate was related to N. vitripennis (%17.2). Host preferences of N. vitripennis on M. domestica pupae were higher than observed parasitism on L. sericata and S. haemorrhoidalis. The emerging rate of two parasitoids; P. vindemmiae and S. nigroaenea were one per host pupae. According to the result, N. vitripennis can be an appropriate candidate for use as natural enemy which expected to be effective in controlling various species of synanthropic flies. Therefore, S. nigroaenea was more suitable to biological control of housefly populations.