Data from: Genetic diversity of melon aphids Aphis gossypii associated with landscape features

Despite increasing evidence that landscape features strongly influence the abundance and dispersal of insect populations, landscape composition has seldom been explicitly linked to genetic structure. We conducted a genetic study of the melon aphid, Aphis gossypii, in two counties of Beijing, China during spring migration using samples from watermelon. We performed aphid genetic analysis using restriction-site-associated DNA-sequencing (2b-RAD) and investigated the relationship between land cover and the genetic diversity. The percentage area of land cover (cropland, vegetable, orchard, grassland, woodland) was quantified in each particular scale (ranging from 0.5 km to 3 km) and was used as a predictor variable in our generalized linear models. We found a moderate level of genetic differentiation among 9 sampled populations. Geographic distance and genetic distance were not significantly associated, indicating that geographic location was not a barrier to migration. These 9 populations could be clustered depending on their level of genetic diversity (high and low). The genetic diversity (Shannon’s information index) was positively correlated with grassland at the spatial scales of 1 and 2 km and negatively with orchard and vegetable at 0.5 and 1 km. Genetic diversity was best predicted by the grassland + orchard + vegetable model at a spatial scale of 1 km. Based on the method of relative weights, orchard land had the greatest relative importance, followed by grassland and vegetable land, in that order. This study contributes to our understanding of the genetic variation of aphids in agricultural landscapes.

尽管已有越来越多证据表明景观特征可显著影响昆虫种群的丰度与扩散，但景观组成与昆虫种群遗传结构之间的关联却极少被明确探讨。本研究于中国北京的两个区县，以西瓜寄主上的瓜蚜（Aphis gossypii）为研究对象，在春季迁飞期开展了遗传相关研究。本研究采用限制性酶切位点相关DNA测序（restriction-site-associated DNA-sequencing，2b-RAD）技术对瓜蚜进行遗传分析，并探讨了土地覆盖类型与种群遗传多样性之间的关系。本研究在0.5 km至3 km的多个空间尺度下量化了各类土地覆盖类型（耕地、蔬菜地、果园、草地、林地）的面积占比，并将其作为广义线性模型（generalized linear models，GLM）中的预测变量。结果显示，9个采样种群间存在中等程度的遗传分化。地理距离与遗传距离无显著相关性，表明地理阻隔并未对迁飞造成阻碍。可依据遗传多样性水平高低，将这9个采样种群划分为高、低遗传多样性两个类群。以香农信息指数（Shannon’s information index）衡量的遗传多样性，在1km和2km空间尺度下与草地面积占比呈显著正相关，而在0.5km和1km尺度下与果园、蔬菜地面积占比呈显著负相关。在1km空间尺度下，草地+果园+蔬菜地的组合模型对遗传多样性的预测效果最优。基于相对权重法分析，果园土地覆盖类型的相对重要性最高，其次为草地与蔬菜地。本研究有助于加深学界对农业景观中蚜虫遗传变异规律的认知。