Population structures of Acaphylla theae and Calacarus carinatus (Acari: Eriophyoidea) from different tea-producing areas of China reveal no host-associated differentiation and recent colonization

摘要

Host plants usually play a crucial role in the first step of speciation, leading to host-associated differentiation (HAD) among populations that use different host plants. Previous studies of eriophyoid mite species have revealed HAD using morphometric and molecular methods. In the present study, we tested the hypothesis that HAD occurred among different populations of the pink tea mite, Acaphylla theae and the purple tea mite, Calacarus carinatus from three tea-producing areas of China. These tea-producing areas grow recently radiated varieties of tea. Therefore, diversification within these phytophagous mites was expected. However, using a K2P comparison, calculation of pairwise F-ST, network analyses and AMOVA based on mitochondrial and nuclear markers, no association between genetic diversity and host plant species was detected. Moreover, a very low level of haplotype and nucleotide diversity and a lack of geographical structure were found. The absence of genetic differentiation among host-associated populations suggests that these two species are real generalists of different varieties of tea. The limited genetic diversity among the populations of these two species can be attributed to their recent colonization of tea, and to their passive spread by frequent human commercial activities