Evolutionary rescue and local adaptation under different rates of temperature increase: a combined analysis of changes in phenotype expression and genotype frequency in Paramecium microcosms

Evolutionary Rescue (ER) occurs when populations, which have declined due to rapid environmental change, recover through genetic adaptation. The success of this process and the evolutionary trajectory of the population strongly depend on the rate of environmental change. Here we investigated how different rates of temperature increase (from 23°C to 32°C) affect population persistence and evolutionary change in experimental microcosms of the protozoan Paramecium caudatum. Consistent with theory on ER, we found that those populations experiencing the slowest rate of temperature increase were the least likely to become extinct and tended to be the best adapted to the new temperature environment. All high-temperature populations were more tolerant to severe heat stress (35°C, 37°C), indicating a common mechanism of heat protection. High-temperature populations also had superior growth rates at optimum temperatures, leading to the absence of a pattern of local adaptation to control (23°C) an...进化拯救（Evolutionary Rescue，ER）指因环境快速变化导致种群数量下降后，种群通过遗传适应实现恢复的过程。该过程的成功与否与种群的演化轨迹在极大程度上取决于环境变化速率。本研究以原生动物尾草履虫（Paramecium caudatum）的实验微宇宙为模型，探究了不同升温速率（从23℃升至32℃）对种群存续与演化变化的影响。与进化拯救理论的预测一致，本研究发现升温速率最慢的种群灭绝概率最低，且往往最适应新的温度环境。所有经高温驯化的种群对极端热胁迫（35℃、37℃）的耐受性均更强，表明其存在共同的耐热保护机制。经高温驯化的种群在最适温度下的生长速率也更为优异，因此未呈现出对对照温度（23℃）的局部适应模式……