Phenotypic plasticity is a prominent mechanism for coping with variable environments, and a key determinant of extinction risk. Evolutionary theory predicts that phenotypic plasticity should evolve to lower levels in environments that fluctuate less predictably, because they induce mismatches between plastic responses and selective pressures. However, this prediction is difficult to test in nature, where environmental predictability is not controlled. Here, we exposed 32 lines of the halotolerant microalga Dunaliella salina to ecologically realistic, randomly fluctuating salinity, with varying levels of predictability, for 500 generations. We found that morphological plasticity evolved to lower degrees in lines that experienced less predictable environments. Evolution of plasticity mostly concerned phases with slow population growth, rather than the exponential phase where microbes are typically phenotyped. This study underlines that long‐term experiments with complex patterns of environmental change are needed to test theories about population responses to altered environmental predictability, as currently observed under climate change.

中文翻译：

---

减少的表型可塑性在难以预测的环境中发展。

表型可塑性是应对各种环境的重要机制，并且是灭绝风险的关键决定因素。进化论预测，表型可塑性应该在波动较小的环境中演化为较低的水平，因为它们会引起塑性响应和选择性压力之间的不匹配。但是，这种预测很难在无法控制环境可预测性的自然环境中进行测试。在这里，我们暴露了32行盐卤微藻杜氏藻达到500代的生态现实性，随机波动的盐度，具有不同的可预测性水平。我们发现，在可预测性较差的环境中，线形可塑性演化程度较低。可塑性的演化主要与种群增长缓慢的阶段有关，而不是与微生物通常被表型化的指数阶段有关。这项研究强调，如气候变化目前所观察到的那样，需要长期进行具有复杂环境变化模式的实验，以测试有关人口对环境可预测性变化的反应的理论。