Systematics of the genus Bactrocera (Diptera: Tephritidae) based on mitocondrial and nuclear genes

Tephritid flies in the genus Bactrocera are some of the most economically damaging crop pests in world. Although only three species occur in Hawaii, they can attack over 166 host crops and cost the state millions in the form of crop damage and loss of trade. On the US mainland only Bactrocera oleae occurs but there is constant risk of new invasions from this genus due to active trade and international travel. There are over 500 species within the genus but the most pestiferous group is the Bactrocera dorsalis complex, with 10 of its 75 species of economic importance. Because different species and even populations of Bactrocera may have different host preferences and ecological tolerances, new invasions could result in significantly more damage and challenges for control. The species taxonomy in Bactrocera is not yet fully understood, with many species with unknown hosts. Morphology is of limited use for identifications as many species are separated by subtle morphological differences, hence very hard to distinguish. A robust understanding of Bactrocera species diversity and boundaries is needed to help prevent future invasions, predict the agricultural threat of new invasions and apply the best control strategies for different species. We collected Bactrocera specimens from West Africa, China, French Polynesia, United States, Cambodia, Thailand, Malaysia and Laos. We sequenced five nuclear and two mitochondrial genes for phylogenetic analysis. Data were analyzed using Maximum Likelihood and Bayesian Analysis to understand the evolutionary history and relationships of these species.