Genetic analyses reveal regional structure and demographic expansion of the predominant tea pest Empoasca onukii (Hemiptera: Cicadellidae) in China

Abstract

BACKGROUND: The tea green leafhopper, Empoasca onukii Matsuda, is the most destructive insect pest of tea plantations in East Asia. Despite its economic importance and previous studies on this species, it remains unclear as to how this small-sized pest can have such wide range. RESULTS: By sequencing three mitochondrial genes and 17 microsatellite loci, we revealed the regional structure and demographic expansion of 59 E. onukii populations in China. Bayesian analysis of population genetic structure (BAPS) on microsatellites identified four genetic groups with spatial discontinuities, while analysis on mitochondrial genes inferred five nested and differentiated clusters. Both the Mantel test and the generalized linear model indicated a significant pattern of isolation by geographic distance in E. onukii populations. Based on the approximate Bayesian computation approach, E. onukii was found to have originated from southwestern China and expanded northward and eastward. While MIGRATE-N and Bayesian stochastic search variable selection (BSSVS) procedure in BEAST confirmed the possible eastward and northward dispersal from Yunnan, they also detected more gene flow from the derived populations in central and southeastern China. CONCLUSION: Our results suggest that the current distribution and structure of E. onukii is complicatedly influenced by human activities of cultivation, wide dissemination of tea in ancient China as well as recent transportation of tea seedlings for establishing new tea plantations. Insights into genetic differentiation and demographic expansion patterns from this study provide an important basis for the development of area-wide management of the E. onukii populations.

Population genetics and ecological niche modelling provide insights into management strategies of the herbivorous pest Phytomyza horticola (Diptera: Agromyzidae)

“…These results are supported by the cold‐adaptive biological characteristics of P. horticola and reinforce the inference that the P. horticola population expanded during the LGM. Although many regions may become unsuitable for P. horticola in the future, studies have shown that the expansion of host‐plant cultivation areas and centres of frequent crop trade have contributed to the expansion of pest populations, including those of Empoasca onukii and Frankliniella occidentalis (Cao et al, 2017; Li et al, 2022; Reitz et al, 2020). Therefore, to prevent and control P. horticola in the future, the focus should be on cold areas at high latitudes.…”

Comparative analysis of habitat suitability for a crop and its primary insect herbivore: providing insights for crop planting and pest management strategies

“…The species occurrence records of tea were obtained from a previous study on the global climatic suitability of tea (Zhang et al, 2019b). In contrast, occurrence records for the tea green leafhopper were sourced from three distinct channels: (1) field sampling (Li et al, 2022), (2) published literature (Li et al, 2013;Fu et al, 2014a;Fu et al, 2014b;Zhou et al, 2014;Chen et al, 2015;Zhang et al, 2019a), and (3) the Global Biodiversity Information Facility (GBIF.org). Due to the use of various scientific names for the tea green leafhopper in prior studies, such as E. flavescens, E. pirisuga, Jacobiasca formosana, E. vitis, and E. onukii (Qin et al, 2015), all of these names were employed to compile the occurrence records for the tea green leafhopper.…”

“…Furthermore, considering the field activity characteristics of leafhoppers, the direct impact of precipitation on leafhopper populations can be limited. Female adults of tea green leafhopper lay their eggs in tender tea shoots and leaves, and both the adults and nymphs often seek shelter behind the tender leaves, where they feed on the sap (Li et al, 2022). In this context, tender tea shoots and leaves can help leafhopper populations avoid or alleviate the unfavorable influence of precipitation, resulting in a lesser role for precipitation compared to temperature in driving leafhopper habitat use.…”

“…And apart from these abiotic requirements, insect pests are considered as another important factor restricting the growing of tea plants. Particularly, the tea green leafhopper, Empoasca onukii, poses a significant threat as the primary insect pest in tea plantations, leading to substantial reductions in tea yield and quality as well as annual economic losses ranging from 15% to 50% (Li et al, 2022). Variation of these abiotic and biotic factors above and below tea's thresholds are expected in varied locations, which can initiate different physiological stress levels in tea plants, influence tea's quality and yield, and thus determine how well and where tea plants grow.…”

Altitude as a key environmental factor shaping microbial communities of tea green leafhoppers ( Matsumurasca onukii )

“…Adult females also lay their eggs in these shoots, leading to irreparable damage ( 13 ). Matsumurasca onukii can cause yield losses of between 15% and 50%, and up to 100% in severely damaged plantations ( 14 ). More importantly, M. onukii is well adapted to different tea varieties and geographical variations ( 15 ).…”