Oldham Richard C, Pintor Lauren M, Gray Suzanne M
School of Environment and Natural Resources, The Ohio State University, Columbus, OH, USA.
Curr Zool. 2019 Feb;65(1):33-42. doi: 10.1093/cz/zoy027. Epub 2018 Apr 12.
Animals are increasingly faced with human-induced stressors that vary in space and time, thus we can expect population-level divergence in behaviors that help animals to cope with environmental change. However, empirical evidence of behavioral trait divergence across environmental extremes is lacking. We tested for variation in behavioral traits among 2 populations of an African cichlid fish ( Seegers, 1990) that experience extremes of dissolved oxygen (DO) and turbidity and are known to vary in a number of physiological and life history traits associated with these stressors. Using a common garden rearing experiment, F1 progeny from wild-caught parents originating from a swamp (low DO, clear) and a river (high DO, turbid) were reared in high DO, clear water. Predator simulation assays were conducted to test for (1) variation in boldness, general activity, and foraging activity between populations, (2) differences in correlations between behaviors within and across populations, and (3) repeatability of behaviors. There was strong evidence for divergence between populations, with swamp fish being more bold (i.e., leaving refuge sooner after a simulated predator attack) and active (i.e., spent more time out of refuge) than river fish. Across populations there were positive correlations between foraging activity and both boldness and general activity; however, within populations, there was only a strong positive relationship between foraging activity and boldness in the river population. Here, we have demonstrated that populations that originate from drastically different environments can produce progeny that exhibit measurable differences in behaviors and their correlated relationships even when reared under common conditions.
动物越来越多地面临着人为造成的、在空间和时间上各不相同的应激源，因此我们可以预期，在有助于动物应对环境变化的行为方面，种群水平会出现差异。然而，目前缺乏关于行为特征在极端环境中出现差异的实证证据。我们测试了一种非洲丽鱼科鱼类（Seegers，1990）的两个种群在行为特征上的差异，这两个种群经历了溶解氧（DO）和浊度的极端情况，并且已知在与这些应激源相关的许多生理和生活史特征方面存在差异。通过一项共同环境饲养实验，将来自沼泽（低溶解氧，清澈）和河流（高溶解氧，浑浊）的野生亲本的F1后代饲养在高溶解氧、清澈的水中。进行捕食者模拟试验，以测试（1）种群之间在胆量、一般活动和觅食活动方面的差异，（2）种群内部和种群之间行为相关性的差异，以及（3）行为的重复性。有强有力的证据表明种群之间存在差异，沼泽鱼比河流鱼更大胆（即在模拟捕食者攻击后更快离开避难所）且更活跃（即在避难所外花费更多时间）。在不同种群中，觅食活动与胆量和一般活动之间存在正相关；然而，在种群内部，只有河流种群中觅食活动与胆量之间存在强正相关。在这里，我们已经证明，即使在共同条件下饲养，来自截然不同环境的种群也能产生在行为及其相关关系上表现出可测量差异的后代。
