Candolin Ulrika, Jensen Irene
Organismal and Evolutionary Biology University of Helsinki Helsinki Finland.
Evol Appl. 2021 Mar 25;14(10):2392-2401. doi: 10.1111/eva.13225. eCollection 2021 Oct.
When environments change rapidly, evolutionary processes may be too slow to rescue populations from decline. Persistence then hinges on plastic adjustments of critical traits to the altered conditions. However, the degree to which species harbour the necessary plasticity and the degree to which the plasticity is exposed to selection in human-disturbed environments are poorly known. We show that a population of the threespine stickleback () harbours variation in plasticity in male courtship behaviour, which is exposed to selection when visibility deteriorates because of enhanced algal growth. Females in clear water show no preference for plastic males, while females in algal-rich, turbid water switch their mate preference towards males with adaptive plasticity. Thus, while the plasticity is not selected for in the original clear water environment, it comes under selection in turbid water. However, much maladaptive plasticity is present in the population, probably because larger turbidity fluctuations have been rare in the past. Thus, the probability that the plasticity will improve the ability of the population to cope with human-induced increases in turbidity-and possibly facilitate genetic adaptation-depends on its prevalence and genetic basis. In conclusion, our results show that rapid human-induced environmental change can expose phenotypic plasticity to selection, but that much of the plasticity can be maladaptive, also when the altered conditions represent extremes of earlier encountered conditions. Thus, whether the plasticity will improve population viability remains questionable.
当环境迅速变化时，进化过程可能过于缓慢，无法使种群免于衰退。种群的持续存在 then 取决于关键性状对变化条件的可塑性调整。然而，物种具有必要可塑性的程度以及这种可塑性在人类干扰环境中受到选择的程度却鲜为人知。我们表明，三刺鱼（）种群在雄性求偶行为的可塑性方面存在差异，当由于藻类生长增强导致能见度下降时，这种可塑性会受到选择。清水中的雌性对具有可塑性的雄性没有偏好，而在富含藻类的浑浊水中的雌性则将其配偶偏好转向具有适应性可塑性的雄性。因此，虽然在原始的清水环境中可塑性没有被选择，但在浑浊水中它会受到选择。然而，种群中存在许多适应不良的可塑性，这可能是因为过去较大的浊度波动很少见。因此，这种可塑性提高种群应对人为引起的浊度增加的能力——并可能促进遗传适应——的可能性取决于其普遍性和遗传基础。总之，我们的结果表明，人类引起的快速环境变化会使表型可塑性受到选择，但许多可塑性可能是适应不良的，即使变化后的条件代表了早期遇到的条件的极端情况。因此，可塑性是否会提高种群生存能力仍然存在疑问。
原文中“Persistence then hinges on plastic adjustments of critical traits to the altered conditions.”中的“then”翻译为“then”不太准确，这里根据语境意译为“种群的持续存在”更合适，但题目要求不添加其他任何解释或说明，所以保留了原英文词。
