Animal Ecology/Department of Ecology and Genetics, Evolutionary Biology Centre, Uppsala University, Norbyvägen 18D, 75236, Uppsala, Sweden.
Department of Ecology, Swedish University of Agricultural Sciences, Almas Alé 8, 75007, Uppsala, Sweden.
J Comp Physiol B. 2022 Sep;192(5):669-682. doi: 10.1007/s00360-022-01449-2. Epub 2022 Jul 20.
Environmental stress is a major driver of ecological and evolutionary processes in nature. To cope with stress, organisms can adjust through phenotypic plasticity and/or adapt through genetic change. Here, we compared short-term behavioural (activity) and physiological (corticosterone levels, CORT) responses of Rana arvalis tadpoles from two divergent populations (acid origin, AOP, versus neutral origin, NOP) to acid and predator stress. Tadpoles were initially reared in benign conditions at pH 7 and then exposed to a combination of two pH (acid versus neutral) and two predator cue (predator cue versus no predator cue) treatments. We assessed behavioural activity within the first 15 min, and tissue CORT within 8 and 24 h of stress exposure. Both AOP and NOP tadpoles reduced their activity in acidic pH, but the response to the predator cue differed between the populations: AOP tadpoles increased whereas NOP tadpoles decreased their activity. The AOP and NOP tadpoles differed also in their CORT responses, with AOP being more responsive (CORT levels of NOP tadpoles did not differ statistically across treatments). After 8 h exposure, AOP tadpoles had elevated CORT levels in the acid-predator cue treatment and after 24 h exposure they had elevated CORT levels in all three stress treatments (relative to the benign neutral-no-cue treatment). These results suggest that adaptation to environmental acidification in R. arvalis is mediated, in part, via behavioural and hormonal plasticity.
环境压力是自然中生态和进化过程的主要驱动因素。为了应对压力，生物体可以通过表型可塑性进行调节，或者通过遗传变化进行适应。在这里，我们比较了来自两个不同种群（酸起源，AOP，与中性起源，NOP）的红腹滨鹬蝌蚪在短期行为（活动）和生理（皮质酮水平，CORT）对酸和捕食者压力的反应。蝌蚪最初在 pH 值为 7 的良性条件下饲养，然后暴露于两种 pH（酸与中性）和两种捕食者线索（捕食者线索与无捕食者线索）的组合中。我们在应激暴露后的前 15 分钟内评估了行为活动，在 8 小时和 24 小时内评估了组织 CORT。AOP 和 NOP 蝌蚪在酸性 pH 下均降低了活动量，但对捕食者线索的反应在两个种群之间存在差异：AOP 蝌蚪增加，而 NOP 蝌蚪减少了活动量。AOP 和 NOP 蝌蚪在 CORT 反应上也存在差异，AOP 更敏感（NOP 蝌蚪的 CORT 水平在不同处理之间没有统计学差异）。在 8 小时暴露后，AOP 蝌蚪在酸-捕食者线索处理中 CORT 水平升高，在 24 小时暴露后，它们在所有三种应激处理中 CORT 水平升高（相对于良性中性-无线索处理）。这些结果表明，红腹滨鹬对环境酸化的适应部分是通过行为和激素可塑性介导的。
