Data from: Environmental versus anthropogenic effects on population adaptive divergence in the freshwater snail Lymnaea stagnalis

Repeated pesticide contaminations of lentic freshwater systems located within agricultural landscapes may affect population evolution in non-target organisms, especially in species with a fully aquatic life cycle and low dispersal ability. The issue of evolutionary impact of pollutants is therefore conceptually important for ecotoxicologists. The impact of historical exposure to pesticides on genetic divergence was investigated in the freshwater gastropod Lymnaea stagnalis, using a set of 14 populations from contrasted environments in terms of pesticide and other anthropogenic pressures. The hypothesis of population adaptive divergence was tested on 11 life-history traits, using QST -FST comparisons. Despite strong neutral differentiation (mean FST = 0.291), five adult traits or parameters were found to be under divergent selection. Conversely, two early expressed traits showed a pattern consistent with uniform selection or trait canalization, and four adult traits appeared to evolve neutrally. Divergent selection patterns were mostly consistent with a habitat effect, opposing pond to ditch and channel populations. Comparatively, pesticide and other human pressures had little correspondence with evolutionary patterns, despite hatching rate impairment associated with global anthropogenic pressure. Globally, analyses revealed high genetic variation both at neutral markers and fitness-related traits in a species used as model in ecotoxicology, providing empirical support for the need to account for genetic and evolutionary components of population response in ecological risk assessment.

农业景观内的静淡水生态系统（lentic freshwater systems）反复遭受农药污染，可能会影响非靶标生物的种群演化，尤其是生命周期完全水生且扩散能力较弱的物种。
因此，污染物的演化影响这一议题对生态毒理学家而言具有重要的理论意义。
本研究以淡水腹足类物种静水椎实螺（Lymnaea stagnalis）为研究对象，选取了14个环境条件在农药及其他人为压力方面存在显著差异的种群，探究了历史农药暴露对种群遗传分化的影响。
研究采用QST-FST比较法，针对11个生活史性状检验了种群适应性分化假说。
尽管种群存在显著的中性分化（平均FST=0.291），但有5个成体性状或参数受到歧化选择。
与之相反，2个早期表达的性状表现出与定向选择或性状稳态化（canalization）相符的模式，另有4个成体性状呈现中性演化模式。
歧化选择的模式主要与生境效应一致，表现为池塘种群与沟渠、河道种群间的分化。
相对而言，尽管全球人为压力会导致孵化率受损，但农药及其他人为压力与种群演化模式的相关性较弱。
综合来看，本研究在这一生态毒理学模式物种中，于中性标记及适合度相关性状中均检测到较高的遗传变异，为生态风险评估中需纳入种群响应的遗传与演化维度提供了实证支持。