Des Roches Simone, Lambert Max R, Brinkmeyer Michaela S, Howells Jacqueline M, Dettinger Andy, Rosenblum Erica Bree
Science Division, Habitat Program, Washington Department of Fish & Wildlife, Olympia, Washington, United States of America.
School of Aquatic and Fishery Sciences, University of Washington, Seattle Washington, United States of America.
PLoS One. 2025 Aug 4;20(8):e0326443. doi: 10.1371/journal.pone.0326443. eCollection 2025.
Much of our understanding of how natural selection operates comes from studies of highly heritable traits presumed to vary little within individuals. Here we show that intraindividual (within-individual) phenotypic variation is an important source of intraspecific variation, shaping both natural selection and its detection in wild, open populations. We employed a multi-year capture-mark-recapture (CMR) study of two lizard species (Sceloporus cowlesi and Holbrookia maculata) at the ecotone between the white gypsum dunes at White Sands National Park and the surrounding dark Chihuahuan desert soils. Unlike many CMR studies examining selection on morphology, we measured individuals' traits at each capture. We found that our inferences into which traits were under selection depended on which measurement instance we used (first, last, or median measurement of all measurements of a given trait), and, therefore, the degree of intraindividual variation within each trait. We present a contingency analysis to facilitate assessing when traits are under selection, when they are not, and when intraindividual variation complicates these inferences. Beyond these conceptual advances, our work has implications for the White Sands system, a model system for repeated evolution. In particular, both lizard species experience different selection regimes within the same ecotonal habitat, despite both showing convergent evolution in dorsal blanching on White Sands.
我们对自然选择如何运作的许多理解都来自于对高度可遗传性状的研究，这些性状被认为在个体内部变化很小。在这里，我们表明个体内（个体内部）表型变异是种内变异的一个重要来源，它塑造了自然选择及其在野生开放种群中的检测。我们对白沙滩国家公园白色石膏沙丘与周围深色奇瓦瓦沙漠土壤之间的生态交错带的两种蜥蜴物种（考氏强棱蜥和斑纹柔蜥）进行了多年的标记重捕（CMR）研究。与许多研究形态选择的CMR研究不同，我们在每次捕获时测量个体的性状。我们发现，我们对哪些性状受到选择的推断取决于我们使用的测量实例（给定性状所有测量值的首次、末次或中位数测量），因此也取决于每个性状内个体变异的程度。我们提出了一种列联分析，以方便评估性状何时受到选择、何时不受选择，以及个体内变异何时会使这些推断变得复杂。除了这些概念上的进展，我们的工作对白沙系统也有影响，白沙系统是一个重复进化的模型系统。特别是，尽管两种蜥蜴在白沙上背部变白都表现出趋同进化，但它们在同一生态交错带栖息地中经历了不同的选择机制。
