Brelin Daniel, Petersson Erik, Dannewitz Johan, Dahl Jonas, Winberg Svante
Comparative Physiology/Department of Physiology and Developmental Biology, Evolutionary Biology Centre, Uppsala University, SE-752 36 Uppsala, Sweden.
Horm Behav. 2008 Apr;53(4):546-56. doi: 10.1016/j.yhbeh.2007.12.011. Epub 2008 Jan 5.
In a challenging situation some animals respond by active avoidance, aggression and an activation of the sympathetic nervous system whereas others respond by immobility, low levels of aggression and a predominant adrenocortical stress response. When consistent over time and across situations such inter-individual differences in behavioural and physiological stress responses are referred to as stress coping strategies. In a previous study we reported the existence of two distinct stress coping strategies in a sea-ranched brown trout (Salmo trutta) population. Using the same method, we here show that four brown trout populations with different origin, but reared under identical conditions, differ in their endocrine stress response, behaviour during hypoxia and aggression. Further more, if individuals are classified as high- and low responsive based on post-stress blood plasma noradrenalin levels (indicator of sympathetic reactivity) the frequency distribution shows that populations with hatchery origin are biased towards having higher frequencies of high responsive individuals. However, the number of high responsive trout ranges from 14-48% in the different populations which shows that generally the frequency is biased towards lower levels of high responsive individuals. We discuss different frequency-dependent mechanisms that maintain multiple phenotypes in populations and speculate about differences in selection regime among the studied populations.
在具有挑战性的情况下，一些动物通过主动回避、攻击和激活交感神经系统做出反应，而另一些动物则通过不动、低水平攻击和主要的肾上腺皮质应激反应做出反应。当行为和生理应激反应中的这种个体间差异在一段时间内和不同情况下保持一致时，就被称为应激应对策略。在之前的一项研究中，我们报告了在一个海养褐鳟（Salmo trutta）种群中存在两种不同的应激应对策略。使用相同的方法，我们在此表明，四个来源不同但在相同条件下饲养的褐鳟种群，其内分泌应激反应、缺氧时的行为和攻击性存在差异。此外，如果根据应激后血浆去甲肾上腺素水平（交感反应性指标）将个体分为高反应性和低反应性，频率分布表明，具有孵化场来源的种群中高反应性个体的频率较高。然而，不同种群中高反应性鳟鱼的数量在14%至48%之间，这表明总体上频率偏向于高反应性个体的较低水平。我们讨论了维持种群中多种表型的不同频率依赖机制，并推测了所研究种群之间选择模式的差异。
