Detection and Phylogenetic Analysis of Wolbachia wsp in the Chilo suppressalis (Lepidoptera: Crambidae) in China

Wolbachia are a group of intracellular, inherited endosymbiotic bacteria infecting a wide range of insects that are associated with several different reproductive phenotypes in their hosts. We measured the infection status of Wolbachia in the Asiatic rice borer, Chilo suppressalis (Walker) (Lepidoptera: Crambidae), from 23 locations in China by sequencing the wsp gene. Our results showed that C. suppressalis populations differed widely in their Wolbachia infection rate. Wolbachia was not detected in 13 of the geographically separate populations. In the 10 populations for which infections were detected, the highest rates were approximate to 40%, in the Guiyang, Xiangyin, Xuzhou, and Yangzhou populations. Phylogenetic analysis of variation in the wsp gene from the six strains of Wolbachia detected showed they belonged to either supergroup A (two populations) or supergroup B (four populations). The phylogenetic relatedness among the wsp sequences found in C. suppressalis was high, and these sequences were also closely related to wsp sequences in other species. This could be an evidence of horizontal transference.