Data from: Adaptive phenotypic plasticity in a clonal invader

Organisms featuring wide trait variability and occurring in a wide range of habitats, such as the ovoviviparous freshwater New Zealand snail Potamopyrgus antipodarum, are ideal models to study adaptation. Since the mid-19th century, P. antipodarum, characterized by extremely variable shell morphology, has successfully invaded aquatic areas on four continents. Because these obligately and wholy asexual invasive populations harbor low genetic diversity compared to mixed sexual/asexual populations in the native range, we hypothesized that 1) this phenotypic variation in the invasive range might be adaptive with respect to colonization of novel habitats, and 2) that at least some of the variation might be caused by phenotypic plasticity. We surveyed 425 snails from 21 localities across northwest Europe to attempt to disentangle genetic and environmental effects on shell morphology. We analysed brood size as proxy for fitness and shell geometric morphometrics, while controlling for genetic background. Our survey revealed 10 SNP genotypes nested into two mtDNA haplotypes and indicated that mainly lineage drove variation in shell shape but not size. Physicochemical parameters affected both shell shape and size and the interaction of these traits with brood size. In particular, stronger stream flow rates were associated with larger shells. Our measurements of brood size suggested that relatively larger slender snails with relatively large apertures were better adapted to strong flow than counterparts with broader shells and relatively small apertures. In conclusion, the apparent potential to modify shell morphology plays likely a key role in the invasive success of <i>P.antipodarum</i>; the two main components of shell morphology, namely shape and size, being differentially controlled, the former mainly genetically and the latter predominantely by phenotypic plasticity.具有广泛性状变异且栖息于多种生境的生物，如卵胎生淡水新西兰蜗牛<i>Potamopyrgus antipodarum</i>（后简称P. antipodarum），是研究适应性演化的理想模型。自19世纪中期以来，以壳形极度多变为特征的P. antipodarum已成功入侵四大洲的水生区域。相较于原生分布区中兼具有性与无性繁殖的混合种群，这些专性完全无性的入侵种群遗传多样性较低。据此我们提出两项假说：其一，入侵区域内的表型变异或许可适配新生境的定殖需求；其二，该变异中至少部分由表型可塑性所致。我们对欧洲西北部21个采样点的425只蜗牛开展了调查，旨在厘清遗传与环境因素对壳形形态的影响。我们以幼体数量作为适合度的替代指标，同时控制遗传背景变量，对壳形几何形态测量学特征与幼体数量展开了分析。本次调查共检出10个单核苷酸多态性（Single Nucleotide Polymorphism, SNP）基因型，它们隶属于2个线粒体DNA（Mitochondrial DNA, mtDNA）单倍型；结果显示，谱系差异主要影响壳形变异，但对壳大小无显著作用。理化参数同时影响壳形与壳大小，以及这两类性状与幼体数量的交互作用。具体而言，水流流速越快，蜗牛的壳体型越大。我们对幼体数量的测定结果显示，相较于壳更宽、壳口相对较小的个体，体型更大、壳形更修长且壳口相对较大的蜗牛更能适应强水流环境。综上，改造壳形形态的潜在能力或许是P. antipodarum入侵成功的关键驱动因素；壳形形态的两大核心组分——壳形与壳大小——受到差异化调控：前者主要受遗传因素控制，后者则主要由表型可塑性决定。