Correlated behaviour and stress physiology in fish exposed to different levels of predation pressure
Correlated behaviour and stress physiology in fish exposed to different levels of predation pressure
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DOI：
10.1111/j.1365-2435.2012.01968.x
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发表时间：
2012-06-01
影响因子：
5.2
通讯作者：
Braithwaite, Victoria A.
中科院分区：
文献类型：
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作者：
Archard, Gabrielle A.;Earley, Ryan L.;Braithwaite, Victoria A.
1.自然选择可以通过独立地作用于生理和行为特征或发挥多效性作用的机制来产生相关的表型性状套件。2.目前的理论，人工选择研究的支持下，表明生理和行为的压力反应至少部分地在遗传控制和协变以可预测的方式。事实上，生理机制，如激素应激反应可能是行为变化的基础，包括被描述为气质或个性的一致行为，更大胆，更具探索性和活跃的个体对压力源的反应更少。3.然而，这种关系尚未在自然种群中得到证实。我们调查了激素和行为应激反应之间的关系，在多个自然种群的热带淡水poeciliid鱼，Brachyrhaphis episcopi，经历不同程度的捕食压力，因此遇到不同的压力事件的发生率。捕食可以施加强大的选择压力，并且已知生活在高捕食风险下会选择特定的行为特征。4.我们通过皮质醇释放率（exp. 1)和在旷场试验中的行为，随后是皮质醇释放速率（exp. 2）。与在捕食者较少的地点采样的同类相比，暴露于高水平捕食的种群始终更具探索性和活跃性，并且对压力源的皮质醇释放率较低。5.然而，这种压力反应的差异只有在鱼经历了行为测试的轻度压力后才明显（在实验中）。2），导致皮质醇水平升高。一旦控制了独立因素，激素释放和行为之间的关系在种群内也不明显，突出了个体变异性的大小和性别等因素的重要性。6.这项研究表明，激素和行为应激反应之间的关系可能是由于自然选择的压力，如捕食。
1. Natural selection can generate correlated suites of phenotypic traits by acting independently on physiological and behavioural characters or on mechanisms that exert pleiotropic actions. 2. Current theory, supported by artificial selection studies, suggests that physiological and behavioural stress responses are at least partially under genetic control and covary in a predictable manner. Indeed, physiological mechanisms such as hormonal stress responsiveness may underlie variation in behaviour, including consistent behaviours described as temperament or personality, with bolder, more exploratory and active individuals being less hormonally responsive to stressors. 3. This relationship, however, has yet to be demonstrated in natural populations. We investigated the relationship between hormonal and behavioural stress responsiveness in multiple natural populations of a tropical freshwater poeciliid fish, Brachyrhaphis episcopi, that experience different levels of predation pressure and hence encounter different rates of stressful events. Predation can impose a strong selection pressure, and living with a high risk of predation is known to select for specific behavioural traits. 4. We quantified variation in stress responsiveness via cortisol release rates (exp. 1) and behaviour in an open field test followed by cortisol release rates (exp. 2). Populations exposed to high levels of predation were consistently more exploratory and active and had lower release rates of cortisol in response to a stressor than conspecifics sampled at sites with few predators. 5. However, this difference in stress responsiveness was only apparent after fish had experienced the mild stress of behaviour testing (in exp. 2), which resulted in elevation of cortisol levels. The relationship between hormone release and behaviour was also not apparent within populations once independent factors were controlled for, highlighting the importance of factors such as size and sex on individual variability. 6. This study demonstrates that the relationship between hormonal and behavioural stress responsiveness can result from natural selection pressures, such as that imposed by predation.