Recent warming reduces the reproductive advantage of large size and contributes to evolutionary downsizing in nature
Recent warming reduces the reproductive advantage of large size and contributes to evolutionary downsizing in nature
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DOI：
10.1098/rspb.2020.0608
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发表时间：
2020-06-10
影响因子：
4.7
通讯作者：
Palkovacs, Eric P.
中科院分区：
文献类型：
--
作者：
Fryxell, David C.;Hoover, Alexander N.;Palkovacs, Eric P.
体型是一个关键的功能特征，预计在变暖情况下会下降。众所周知，变暖会通过表型可塑性导致体型减小，但人们对体型对变暖的进化反应知之甚少。为了测试变暖引起的体型和生长速度的进化反应，我们使用了最近（不到 100 年）从共同来源跨越地热泉产生的强温度梯度（19-33 摄氏度）建立的蚊鱼（Gambusia affinis）种群。每个泉水的温度都非常稳定，并且几乎不受来自其他热环境的基因流的影响。现场调查表明，随着场地温度的升高，体型分布变小，体型较大的繁殖优势下降。经过共同饲养以揭示最近进化的性状差异后，较温暖的来源种群表现出幼体生长速度减慢和小体型繁殖努力增加。这些结果与塑性温度尺寸规则的适应性基础一致，并且它们表明温度本身可以驱动增长率反梯度变化的演变。幼体生长速度降低和小体型繁殖增加的快速演变应该会导致种群体型大幅缩小，从而对变暖世界中的种群动态和生态系统产生影响。
Body size is a key functional trait that is predicted to decline under warming. Warming is known to cause size declines via phenotypic plasticity, but evolutionary responses of body size to warming are poorly understood. To test for warming-induced evolutionary responses of body size and growth rates, we used populations of mosquitofish (Gambusia affinis) recently established (less than 100 years) from a common source across a strong thermal gradient (19-33 degrees C) created by geothermal springs. Each spring is remarkably stable in temperature and is virtually closed to gene flow from other thermal environments. Field surveys show that with increasing site temperature, body size distributions become smaller and the reproductive advantage of larger body size decreases. After common rearing to reveal recently evolved trait differences, warmer-source populations expressed slowed juvenile growth rates and increased reproductive effort at small sizes. These results are consistent with an adaptive basis of the plastic temperature-size rule, and they suggest that temperature itself can drive the evolution of countergradient variation in growth rates. The rapid evolution of reduced juvenile growth rates and greater reproduction at a small size should contribute to substantial body downsizing in populations, with implications for population dynamics and for ecosystems in a warming world.