Prevalence and evolutionary history of endosymbiont Wolbachia (Rickettsiales: Anaplasmataceae) in parasitoids (Hymenoptera: Braconidae) associated with Bactrocera fruit flies (Diptera: Tephritidae) infesting carambola

Wolbachia endosymbiont is a maternally inherited bacteria that infects a wide range of hosts, including parasitoids and their respective hosts. In this study, a total of 171 individuals of braconid endoparasitoids, consisting of Fopius arisanus, F.vandenboschi, Diachasmimorpha longicaudata, Psyttalia sp.1, Psyttalia sp.2, P.fletcheri and P.incisi, and their host tephritid fruit flies of Bactrocera dorsalis, B.papayae and B.carambolae infesting carambola were screened molecularly by the Wolbachia surface protein (wsp) gene. Interestingly, 21 (24.14%) wsp gene sequences were successfully isolated from 87 braconid samples tested, showing a low infection rate of Wolbachia. However, despite the close ecological contact between parasitoids and their hosts, none of the tephritid individuals were infected by Wolbachia. A comparison of wsp and host mitochondrial cytochrome c oxidase subunit I (COI) sequences found that braconids did not cluster in connection with Wolbachia infection, suggesting that selective sweep has not yet occurred because Wolbachia may have recently infected the braconid populations in Peninsular Malaysia (approximate to 0.1 MYA). Despite of relatively recent infections of Wolbachia, the history of Wolbachia infection into F. arisanus populations of Peninsular Malaysia is complex, involving at least two independent occasions of infection and two secondary losses.