Effect of infection rate of Wolbachia on the reproduction in Tetranychus kanzawai Kishida (Acari: Tetranychidae) in China

Abstract

The Wolbachia infection in three Chinese Tetranychus kanzawai Kishida (Acari: Tetranychidae) populations (Fuzhou, Nanchang, Pingdong) was investigated and the effect of Wolbachia infection rate on the reproduction of T. kanzawai was checked through crossing experiments. Two populations (Nanchang and Pingdong) were polymorphic for Wolbachia infection with an infection rate between 21-43% and the third one (Fuzhou) was uninfected. The phylogenetic tree of Wolbachia wsp gene sequences indicated that both Chinese Wolbachia strains were in the same Ori subgroup as two Wolbachia from the same host T. kanzawai in Japan. The crosses between natural Nanchang and Fuzhou populations, and natural Pingdong and Fuzhou populations showed no cytoplasmic incompatibility (CI) phenomenon, but the cross between Nanchang and Pingdong showed partial incompatibility. The 100% infected Nanchang population was prepared to cross with the natural Fuzhou population to test the effect on infection rate. Both crosses between artificially infected Nanchang population and Fuzhou population, and the cross between artificially infected Nanchang population and artificially uninfected Nanchangpopulation did not show evidence of cytoplasmic incompatibility. The observed cytoplasmic incompatibility is possibly more related to the Wolbachia strain or density or even host strain, rather than to the Wolbachia infection rate in a certain population or individual host.