Genetic diversity in the camellia weevil, Curculio chinensis Chevrolat (Coleptera: Curculionidae) and inferences for the impact of host plant and human activity: Genetic variations of Curculio chinensis

The camellia weevil, Curculio chinensis (Coleoptera: Curculionidae), is a host-specific parasite of Camellia seeds that causes huge economic losses in China. Despite its economic impact, little is known about the species' genetic structure and current distribution status, which are important to provide critical insights into establishing a control strategy for this pest. Here, genetic diversity and the phylogenetic structure of C. chinensis were inferred using the sequences of COI and EF1-alpha among different geographical populations. Twenty-two haplotypes for the COI gene and 26 haplotypes for EF1-alpha in 215 individuals from 16 sample regions in China were found. A phylogenetic analysis revealed four distinct clades within C. chinensis. The amova analysis showed significant genetic differentiation among all the populations sampled, however, the genetic differentiation among the residual populations was not significant when JX (Jiangxi) and TC (Tengchong) populations were excluded. The M (M = Nm for haploid data, M = 2 Nm for diploid data) value analysis suggested that JX and TC populations were significantly different from other populations. Thus, these results imply that human activity and host plant could have a significant impact on C. chinensis population diversity and the current geographical population pattern.