Host species and vegetable fruit suitability and preference by the parasitoid wasp F opius arisanus

Parasitoids that oviposit in a concealed host inside a plant part need to be able to find both the plant and the host. Egg parasitoids of fruit‐infesting T ephritidae need to assess the oviposition site based both on the host egg and the infested fruit. Infestation by T ephritidae fruit flies threatens fruit and vegetable production. Management methods have been implemented including biological control, using F opius arisanus S onan ( H ymenoptera: B raconidae). The parasitism by F . arisanus in three T ephritidae flies in vegetable fruits was investigated. Laboratory assays were conducted to assess the parasitoid's preference and survival. Zucchini, sweet pepper, and tomato were artificially infested with eggs of B actrocera dorsalis H endel, C eratitis capitata W iedemann, and C eratitis cosyra W alker (all D iptera: T ephritidae), then exposed to mated naïve F . arisanus females in a 20:1 egg:parasitoid ratio. Parasitoid behavioral activities (resting, antennating, probing, ovipositing) were observed on the infested fruits. Parasitism rate was determined by dissection of fruit fly eggs under a stereomicroscope. Behavioral activities of F . arisanus differed between all the fruits when infested with B . dorsalis or C . cosyra eggs but differed only between some of the fruits when infested with C . capitata . F opius arisanus preferred B . dorsalis over C . capitata and C . cosyra , with a parasitism rate 2× higher on B . dorsalis compared to the C eratitis species. Preference for fruits was dependent on the infesting fruit fly. The emergence of F . arisanus was higher with B . dorsalis than with C eratitis spp. Although B . dorsalis completed its development earlier than C eratitis spp., host fly species did not affect the developmental time of F . arisanus . We discuss the significance of F . arisanus preference in relation to naturally occurring T ephritidae infestations. We also discuss whether some fruits might constitute a refuge for T ephritidae flies and whether this will affect the current biological control efforts against B . dorsalis .