Station d'Écologie Théorique et Expérimentale, CNRS, 2 route du CNRS, 09200 Moulis, France.
Biological and Marine Sciences, University of Plymouth, Plymouth PL4 8AA, UK.
Philos Trans R Soc Lond B Biol Sci. 2022 Apr 11;377(1848):20210003. doi: 10.1098/rstb.2021.0003. Epub 2022 Feb 21.
Studies in birds and trees show climatic stresses distributed across species' ranges, not only at range limits. Here, new analyses from the butterfly reveal mechanisms generating these stresses: geographic mosaics of natural selection, acting on tradeoffs between climate adaptation and fitness traits, cause some range-central populations to evolve to limits of climatic tolerance, while others remain resilient. In one ecotype, selection for predator avoidance drives evolution to limits of thermal tolerance. In a second ecotype, the endangered Bay Checkerspot, selection on fecundity drives evolution to the climate-sensitive limit of ability to complete development within the lifespans of ephemeral hosts, causing routinely high mortality from insect-host phenological asynchrony. The tradeoff between maternal fecundity and offspring mortality generated similar values of fitness on different dates, partly explaining why fecundity varied by more than an order of magnitude. Evolutionary response to the tradeoff rendered climatic variability the main driver of Bay Checkerspot dynamics, and increases in this variability, associated with climate change, were a key factor behind permanent extinction of a protected metapopulation. Finally, we discuss implications for conservation planning of our finding that adaptive evolution can reduce population-level resilience to climate change and generate geographic mosaics of climatic stress. This article is part of the theme issue 'Species' ranges in the face of changing environments (Part II)'.
鸟类和树木的研究表明，气候压力不仅分布在物种分布范围的边缘，也分布在范围的中心。在这里，蝴蝶的新分析揭示了产生这些压力的机制：自然选择的地理镶嵌作用，作用于气候适应性和适应度特征之间的权衡，导致一些分布范围中心的种群进化到气候耐受极限，而其他种群则保持弹性。在一种生态型中，对捕食者回避的选择驱动了对热耐受极限的进化。在第二种生态型，濒危的湾豹斑蝶，对繁殖力的选择导致了在短暂宿主寿命内完成发育能力的气候敏感极限的进化，导致由于昆虫-宿主物候不同步而经常出现高死亡率。母代繁殖力和后代死亡率之间的权衡产生了不同日期相似的适应度值，部分解释了为什么繁殖力变化超过一个数量级。对这种权衡的进化反应使气候变异性成为湾豹斑蝶动态的主要驱动因素，而与气候变化相关的这种变异性的增加是一个保护区群永久灭绝的关键因素。最后，我们讨论了我们的发现对保护规划的意义，即适应性进化可以降低种群对气候变化的弹性，并产生气候压力的地理镶嵌。这篇文章是主题为“面对不断变化的环境的物种分布范围（第二部分）”的一部分。
