Conserved infections and reproductive phenotypes of Wolbachia symbionts in Asian tortrix moths

Abstract

AbstractWolbachia is a ubiquitous endosymbiotic bacterium that manipulates insect reproduction. A notable feature of Wolbachia is male killing (MK), whereby sons of infected females are killed during development; however, the evolutionary processes by which Wolbachia acquired the MK ability remain unclear. The tea tortrix moth Homona magnanima (Tortricidae) harbours three non‐MK Wolbachia strains (wHm‐a, wHm‐b and wHm‐c) and an MK strain wHm‐t. Although wHm‐t and wHm‐c are closely related, only wHm‐t has an MK‐associated prophage region. To understand the evolutionary processes underlying the emergence of MK wHm‐t, we examined Wolbachia infections and phenotypes in 62 tortricid species collected from 39 localities across Japan, Taiwan, Vietnam and Indonesia. PCR assays detected wHm‐c relatives in 51 species and triple infection of wHm‐a, wHm‐b and wHm‐c in 31 species. Apart from Taiwanese H. magnanima, no species exhibited the MK phenotype and were positive for the wHm‐t‐specific prophage. While wHm‐t infection was dominant in Taiwanese H. magnanima, wHm‐a, wHm‐b and wHm‐c were dominant in Japanese H. magnanima populations. These results suggest that wHm‐a, wHm‐b and wHm‐c strains descended from a common ancestor with repeated infection loss and that wHm‐t evolved from the wHm‐c acquiring MK ability in allopatric populations of H. magnanima.