Yuan Michael L, Jung Catherine, Frederick Jeffrey H, Fenton Calvin, de Queiroz Kevin, Cassius Jourdan, Williams Rudell, Wang Ian J, Bell Rayna C
Department of Environmental Science, Policy, and Management, College of Natural Resources, University of California, Berkeley, CA, United States.
Museum of Vertebrate Zoology, University of California, Berkeley, CA, United States.
Evolution. 2023 Apr 1;77(4):1031-1042. doi: 10.1093/evolut/qpad018.
Species whose ranges encompass substantial environmental variation should experience heterogeneous selection, potentially resulting in local adaptation. Repeated covariation between phenotype and environment across ecologically similar species inhabiting similar environments provides strong evidence for adaptation. Lesser Antillean anoles present an excellent system in which to study repeated local adaptation because most species are widespread generalists occurring throughout environmentally heterogenous island landscapes. We leveraged this natural replication to test the hypothesis that intraspecific variation in phenotype (coloration and morphology) is consistently associated with environment across 9 species of bimaculatus series anoles. We measured dorsal coloration from 173 individuals from 6 species and 16 morphological traits from 883 individuals from 9 species, spanning their island ranges. We identified striking, but incomplete, parallelism in dorsal coloration associated with annual precipitation in our study species. By contrast, we observed significant patterns of morphological isolation-by-environment in only 2 species and no signal of parallel morphological evolution. Collectively, our results reveal strong divergent natural selection by environment on dorsal coloration but not morphology.
分布范围涵盖大量环境变异的物种应经历异质选择，这可能导致局部适应。在栖息于相似环境的生态相似物种中，表型与环境之间反复出现的协变提供了适应的有力证据。小安的列斯群岛安乐蜥提供了一个绝佳的系统，用于研究反复出现的局部适应，因为大多数物种都是广泛分布的通才，出现在环境异质的岛屿景观中。我们利用这种自然复制来检验以下假设：在9种双斑安乐蜥系列中，表型（颜色和形态）的种内变异始终与环境相关。我们测量了6个物种的173个个体的背部颜色，以及9个物种的883个个体的16个形态特征，涵盖了它们在岛屿上的分布范围。我们在研究物种中发现，与年降水量相关的背部颜色存在显著但不完整的平行现象。相比之下，我们仅在2个物种中观察到显著的形态学环境隔离模式，没有平行形态进化的信号。总体而言，我们的结果揭示了环境对背部颜色而非形态的强烈分歧自然选择。
