Dual-stressor selection alters eco-evolutionary dynamics in experimental communities
Dual-stressor selection alters eco-evolutionary dynamics in experimental communities
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DOI：
10.1038/s41559-018-0701-5
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发表时间：
2018-12-01
影响因子：
16.8
通讯作者：
Becks, Lutz
中科院分区：
文献类型：
--
作者：
Hiltunen, Teppo;Cairns, Johannes;Becks, Lutz
认识到进化何时以及如何快速地推动生态变化，对于我们理解几乎所有的生态和进化过程，如群落聚集、遗传多样化以及群落和生态系统的稳定性，都是至关重要的。一般来说，快速的进化变化是通过对遗传变异的选择驱动的，并受到进化约束的影响，如权衡和多效效应，所有这些都有助于进化变化的总体速度。这些过程中的每一个都可能受到多种环境压力因素的影响，从而降低种群的生殖产量。多应激源选择对快速进化与生态变化之间联系的发生和强度的潜在影响尚不清楚。然而，了解这些对于预测快速进化何时可能导致生态变化是必要的。在这里，我们利用荧光假单胞菌及其捕食者嗜热四膜虫的实验进化来研究两种应激源的存在如何影响这种联系。研究表明，与仅存在两种应激源中的一种相比，捕食者和亚致死抗生素浓度的结合延迟了反捕食者防御和抗生素耐药性的进化。快速的防御进化推动了捕食者-猎物动态的稳定，但在双压力源环境中，进化和生态之间的联系较弱，防御进化较慢，导致种群动态不稳定。随着时间的推移跟踪整个种群的分子进化进一步表明，在多压力源选择下，不同基因的突变更受青睐。总的来说，我们表明多种压力源的选择可以显著改变生态进化动力学及其可预测性。
Recognizing when and how rapid evolution drives ecological change is fundamental for our understanding of almost all ecological and evolutionary processes such as community assembly, genetic diversification and the stability of communities and ecosystems. Generally, rapid evolutionary change is driven through selection on genetic variation and is affected by evolutionary constraints, such as tradeoffs and pleiotropic effects, all contributing to the overall rate of evolutionary change. Each of these processes can be influenced by the presence of multiple environmental stressors reducing a population's reproductive output. Potential consequences of multistressor selection for the occurrence and strength of the link from rapid evolution to ecological change are unclear. However, understanding these is necessary for predicting when rapid evolution might drive ecological change. Here we investigate how the presence of two stressors affects this link using experimental evolution with the bacterium Pseudomonas fluorescens and its predator Tetrahymena thermophila. We show that the combination of predation and sublethal antibiotic concentrations delays the evolution of anti-predator defence and antibiotic resistance compared with the presence of only one of the two stressors. Rapid defence evolution drives stabilization of the predator-prey dynamics but this link between evolution and ecology is weaker in the two-stressor environment, where defence evolution is slower, leading to less stable population dynamics. Tracking the molecular evolution of whole populations over time shows further that mutations in different genes are favoured under multistressor selection. Overall, we show that selection by multiple stressors can significantly alter eco-evolutionary dynamics and their predictability.