Abstract: 【Aim】 This study aims to analyze the patterns of genetic differentiation and gene flow among different populations of the tea green leafhopper, Empoasca onukii, in different tea plantations, and to investigate the genetic structure difference and dispersion characteristics of E. onukii populations and their relationship with the landscape pattern around tea plantation. 【Methods】 A total of 530 E. onukii samples were collected from 18 tea plantations in Anxi County, Fujian Province, southeastern China. ArcMap 10.5 and raster of R package were used to analyze the landscape composition and configuration around each studied tea plantation. E. onukii samples were then individually amplified and individually genotyped at 23 microsatellite loci. The genetic diversity and genetic differentiation of E. onukii populations were measured using ARLEQUIN 3.5.2, FSTAT 2.9.3 and R package adegenet 2.0.0. Population genetic differentiation was analyzed using both STRUCTURE 2.3.4 and DAPC in R package adegenet 2.0.0. BAYESASS 3.0.4 was used to estimate the dispersal rates over the last few generations among populations. Meanwhile the correlation between the genetic differentiation of E. onukii populations and the spatial data of landscape composition and landscape configuration was analyzed by using Mantel tests, multiple regression on distance matrices (MRM) and generalized linear mixed models (GLMM). 【Results】 All the 23 microsatellite loci in 18 E. onukii populations were polymorphic, with alleles varying from 9 to 52, the allelic richness (A_R) from 3.686 to 4.397, the gene diversity (D_IV) from 0.676 to 0.734, and the expected heterozygosity (He) from 0.659 to 0.729. Cluster analysis showed that the populations of five sampling sites from the tea plantations surrounded by woodland habitats in the northwestern Anxi clustered into one distinct cluster, the populations of five sampling sites from the tea plantations surrounded by residential areas and croplands in the northeastern Anxi formed two separate clusters, and the populations of sampling sites from the intensified tea plantations in the southern Anxi formed two clusters. The Nei’s distance between two populations ranged from 0.042 to 0.984, Provesti’s genetic distance from 0.207 to 0.650, and the pairwise F_ST value from 0.002 to 0.222. BAYESASS analysis showed fairly low gene flow (Nm)(0.007-0.180) among populations, and the gene flow within population ranged from 0.674 to 0.854. The Mantel tests and MRM model demonstrated that geographical distance and the area percentage of grassland in the circular sector of 1 000 m radius around sampling site were two key factors in shaping genetic patterns of E. onukii populations. GLMM further confirmed a significant linear relationship between the genetic differentiation of E. onukii populations and these two key factors, and also between genetic diversity of E. onukii populations and the area percentage of grassland in the circular sector of 1 000 m radius around sampling site.【Conclusion】 The results provide direct evidence for significant population genetic differentiation and isolation by distance in E. onukii, and suggest that limited recent gene flow has occurred among populations sampled from different sites. These findings support the idea that E. onukii may have limited dispersal capacity and is unlikely to naturally undergo long-distance migration. The grassland habitat adjacent to tea plantation at the spatial scale of 1 000 m has positive effects on the genetic diversity of E. onukii populations. The landscape composition and scale around tea plantations may be related to the genetic structure of E. onukii by affecting the dispersal and colonization of E. onukii populations.

Key words: Empoasca onukii, tea plantation, landscape pattern, genetic structure, gene flow, sustainable pest management