Fruit fly parasitoids (Hymenoptera: Braconidae) in south‐east Queensland, Australia

Abstract

AbstractOpiine braconids include natural enemies of tephritid fruit flies, and interest in their greater utilisation for fruit fly control is growing. However, there is a lack of basic data on the prevalence and impact of these wasps for most regions of Australia. We sampled fruit fly host fruits from urbanised and peri‐urban locations of south‐east Queensland and reared out parasitoids and their host flies to determine the regional parasitoid community and how parasitism varied across time and habitat type. A total of 4969 fruits were collected from which 21 277 tephritid puparia were obtained. Of 12 601 fruit flies that emerged, the Queensland fruit fly, Bactrocera tryoni, was the dominant species. A total of 5736 parasitoids, representing four species, were recovered from both suburban and peri‐urban sites. For all samples combined, the average parasitism rate was 30%. The exotic, egg–larval–pupal parasitoid Fopius arisanus represented 81% of the parasitoids collected and was recovered from all of the 13 host fruit species sampled. The second most common species, the native larval–pupal parasitoid, Diachasmimorpha kraussii, represented 15% of recovered parasitoids and was collected from a smaller range of host fruit species. The remaining two parasitoids, Diachasmimorpha tryoni and Psyttalia fijiensis, were rare in samples. Parasitoid infestation was highly variable across samples, with higher rates of parasitism observed from October to May. A targeted field experiment to measure differences in parasitism by D. kraussii between urban and peri‐urban habitats detected no variation in the abundance of D. kraussii across habitats, a result consistent with the general survey. The data show that for south‐east Queensland, parasitoids are a significant fruit fly mortality factor in both peri‐urban and urban landscapes. Any manipulation of parasitoids for regional pest management should focus on conservation of F. arisanus.