Populations of Bactrocera oleae (Diptera: Tephritidae) and Its Parasitoids in Himalayan Asia

Olive fruit fly, Bactrocera oleae Rossi, is a worldwide pest of olives. To discover new parasitoids for a biological control program in California, olives were collected from various locations in the Himalayan foothills (China, Nepal, India, Pakistan) as part of a comprehensive search for B. oleae throughout its range. Wild olives, Olea europaea ssp. cuspidata, were sparsely distributed and B. oleae-infested olives were scarce. Wild olives were most widespread in Pakistan where fly infestation reached 30%. Infested olives in southwestern China were rare, reaching only 5%. Flies were identified morphologically as B. oleae, the first record from China. No B. oleae were recovered from India or Nepal. Mitochondrial gene sequences from NADH dehydrogenase (ND1), cytochrome oxidase subunit 1 (COX1), and 16S rRNA were obtained from flies and compared with B. oleae sequences in GenBank. A single mitochondrial haplotype was found in Chinese flies. Chinese B. oleae represent a maternal lineage based on ND1 and COX1 that is highly divergent from other B. oleae. Phylogenetic analysis by maximum likelihood and Bayesian inference based on the concatenated dataset of B. oleae sequences with sequences of two close subcongeners, Bactrocera biguttula (Bezzi) and Bactrocera munroi White, and analysis of delineation of species boundaries using the genealogical sorting index, supported the idea that Chinese flies share recent common ancestry with B. oleae. Flies were parasitized by braconid wasps, Psyttalia ponerophaga (Silvestri) in Pakistan, and a Diachasmimorpha species in China. Our survey reinforces the possibility of finding new biocontrol agents of olive fruit fly in the Himalayan region.