Artificial selection reveals high genetic variation in phenology at the trailing edge of a species range

Species' responses to climate change depend on the interplay of migration and adaptation, yet we know relatively little about the potential for adaptation. Genetic adaptations to climate change often involve shifts in the timing of phenological events such as flowering. If populations at the edge of a species' range have lower genetic variation in phenological traits than central populations, then their persistence under climate change could be threatened. To test this hypothesis, we performed artificial selection experiments using the scarlet monkeyflower (Mimulus cardinalis) and compared genetic variation in flowering time among populations at the latitudinal center, northern edge, and southern edge of the species' range. We also assessed whether selection on flowering time yielded correlated responses in functional traits, potentially representing a cost associated with early or late flowering. Contrary to prediction, southern populations exhibited greater responses to selection on f...

物种对气候变化的响应取决于迁徙与适应的交互作用，但当前学界对物种适应气候变化的潜力仍了解有限。针对气候变化的遗传适应通常会改变物候事件（phenological events）的发生时间，例如开花进程。若物种分布边缘种群的物候性状（phenological traits）遗传变异（genetic variation）水平低于中心种群，则其在气候变化下的存续可能面临威胁。为验证该假说，我们以红花沟酸浆（*Mimulus cardinalis*）为实验材料开展人工选择实验（artificial selection experiments），比较了该物种分布纬度中心、北部边缘及南部边缘种群的开花时间遗传变异情况。此外，我们还评估了对开花时间的选择是否会引发功能性状（functional traits）的相关响应，这可能代表早花或晚花性状所伴随的适合度代价。与预期相悖的是，南部种群在针对“f……”的选择实验中展现出更强的响应效果。