Cyclical environments drive variation in life-history strategies: a general theory of cyclical phenology
Cyclical environments drive variation in life-history strategies: a general theory of cyclical phenology
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DOI：
10.1098/rspb.2019.0214
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发表时间：
2019-03-06
影响因子：
4.7
通讯作者：
Park, John S.
中科院分区：
文献类型：
--
作者：
Park, John S.
周期，如季节或潮汐，是自然界许多系统的特征。大量证据表明，气候变化导致的环境周期变化——比如季节变长——与世界各地的物候变化有关，这表明环境周期与生命周期之间存在着深刻的联系。然而，周期性环境中生命史进化的一般机制仍然没有得到很好的理解。在这里，我建立了一个人口统计框架，并询问当环境周期性地干扰结构化人口时，生活史策略如何优化适应度，以及策略应如何随着周期性的变化而变化。我指出，周期的周期性改变了经典生命史理论的最优性预测，因为重复的周期会随着时间和世代的推移而产生连锁选择的后果。值得注意的是，与环境周期性和生命史最优性相关的适应度景观会因特定物种的权衡而发生巨大变化。该模型与已知的海洋潮间带桡足动物加利福尼亚虎足的生活史权衡进行了调整，成功地预测了跨越潮汐周期梯度的自然种群的生活史变化形状。这个框架展示了环境循环如何驱动生命史的变化——没有复杂的个体对温度等线索的反应的假设——从而扩大了由理论解释的生命史多样性的范围，并为适应物候学提供了基础。
Cycles, such as seasons or tides, characterize many systems in nature. Overwhelming evidence shows that climate change-driven alterations to environmental cycles-such as longer seasons-are associated with phenological shifts around the world, suggesting a deep link between environmental cycles and life cycles. However, general mechanisms of life-history evolution in cyclical environments are still not well understood. Here, I build a demographic framework and ask how life-history strategies optimize fitness when the environment perturbs a structured population cyclically and how strategies should change as cyclicality changes. I show that cycle periodicity alters optimality predictions of classic life-history theory because repeated cycles have rippling selective consequences over time and generations. Notably, fitness landscapes that relate environmental cyclicality and life-history optimality vary dramatically depending on which trade-offs govern a given species. The model tuned with known life-history trade-offs in a marine intertidal copepod Tigriopus californicus successfully predicted the shape of life-history variation across natural populations spanning a gradient of tidal periodicities. This framework shows how environmental cycles can drive life-history variation-without complex assumptions of individual responses to cues such as temperature-thus expanding the range of life-history diversity explained by theory and providing a basis for adaptive phenology.