Genomic variation in the tea leafhopper reveals the basis of adaptive evolution

The tea green leafhopper (TGL), Empoasca onukii, is of biological and economic interest. Despite numerous studies, the mechanisms underlying its adaptation and evolution remain enigmatic. Here, we used previously untapped genome and population genetics approaches to examine how this pest so rapidly has adapted to different environmental variables and thus has expanded geographically. We complete a chromosome-level assembly and annotation of the E. onukii genome, showing notable expansions of gene families associated with adaptation to chemoreception and detoxification. Genomic signals indicating balancing selection highlight metabolic pathways involved in adaptation to a wide range of tea varieties grown across ecologically diverse regions. Patterns of genetic variation among 54 E. onukii samples unveil the population structure and evolutionary history across different tea-growing regions in China. Our results demonstrate that the genomic change in key pathways, including those linked to metabolism, circadian rhythms and immune system function, may underlie the successful spread and adaptation of E. onukii. This work highlights the genetic and molecular bases underlying the evolutionary success of a species with broad economic impact, and provides insight into insect adaptation to host plants, which will ultimately facilitate more sustainable pest management.