Data from: Diversifying selection and color-biased dispersal in the asp viper

Background: The presence of intraspecific color polymorphism can have multiple impacts on the ecology of a species; as a consequence, particular color morphs may be strongly selected for in a given habitat type. For example, the asp viper (Vipera aspis) shows a high level of color polymorphism. A blotched morph (cryptic) is common throughout its range (central and western Europe), while a melanistic morph is frequently found in montane populations, presumably for thermoregulatory reasons. Besides, rare atypical uniformly colored individuals are known here and there. Nevertheless, we found in a restricted treeless area of the French Alps, a population containing a high proportion (>50%) of such specimens. The aim of the study is to bring insight into the presence and function of this color morph by (i) studying the genetic structure of these populations using nine microsatellite markers, and testing for (ii) a potential local diversifying selection and (iii) differences in dispersal capacity between blotched and non-blotched vipers. Results: Our genetic analyses support the occurrence of local diversifying selection for the non-blotched phenotype. In addition, we found significant color-biased dispersal, blotched individuals dispersing more than atypical individuals. Conclusion: We hypothesize that, in this population, the non-blotched phenotype possess an advantage over the typical one, a phenomenon possibly due to a better background matching ability in a more open habitat. In addition, color-biased dispersal might be partly associated with the observed local diversifying selection, as it can affect the genetic structure of populations, and hence the distribution of color morphs.研究背景：种内色彩多态性可对物种的生态学特性产生多重影响；因此，在特定生境类型中，特定色彩形态（color morph）可能会受到强烈选择。例如，阿斯佩蝰（Vipera aspis）存在高水平的色彩多态性：斑纹形态（blotched morph，具隐蔽色）在其分布范围（欧洲中西部）内较为常见，而黑化形态（melanistic morph）则常见于山地种群，推测这与体温调节需求相关。此外，各地偶有罕见的非典型纯色个体被记录。不过，我们在法国阿尔卑斯山一处范围受限的无树区域中，发现了一个该类个体占比超过50%的种群。本研究旨在深入解析这类色彩形态的存在与功能，具体通过以下三方面展开：(i) 利用9个微卫星标记（microsatellite markers）分析这些种群的遗传结构；(ii) 检验是否存在潜在的局部多样化选择（local diversifying selection）；(iii) 比较斑纹与非斑纹蝰蛇的扩散能力差异。 研究结果：遗传分析结果支持非斑纹表型（non-blotched phenotype）存在局部多样化选择的结论。此外，我们还发现了显著的色彩偏向性扩散现象：斑纹个体的扩散能力强于非典型纯色个体。 研究结论：我们提出假说，在该种群中，非斑纹表型相较于典型斑纹表型具有生存优势，这一现象可能源于其在更开阔生境中具备更优异的背景匹配能力。此外，色彩偏向性扩散可能与本次观测到的局部多样化选择存在一定关联，因为该过程可影响种群的遗传结构，进而改变色彩形态的分布格局。