Population genetic structure of the pumpkin fruit fly, Bactrocera tau (Walker) (Diptera: Tephritidae) in Himachal Pradesh, India

Abstract

The population genetic structure of the pumpkin fruit fly, Bactrocera tau, a fruit fly pest that causes significant losses to cucurbit cultivations, has been studied in Himachal Pradesh (India) using mitochondrial cytochrome oxidase I (mtCOI) gene sequences. Levels of differentiation (genetic distances and FST values) among samples from different locations are minimal, suggesting the local occurrence of a large and geographically undifferentiated population, with the possible exception of population Solan. Nevertheless, overall genetic variability is substantial, with 10 different haplotypes detected in 16 individuals and only one of these – likely the original one as it occupies a central position in the network and is found at a relatively high frequency –shared between multiple populations. The phylogenetic analysis of local B. tau samples in the context of the different sibling species that constitute the B. tau complex in its South-East Asia region of origin revealed that local B. tau is closely related to B. tau species A from Thailand. This should be taken into account in any intervention aimed at the control of this pest, e.g. area wide integrated pest management (AW IPM). The marked local genetic uniformity and predominance of one single species of the species complex further suggest that the sterile insect technique (SIT) may be a viable option.