Cerqueira Marco, Rey Sonia, Silva Tome, Featherstone Zoe, Crumlish Margaret, MacKenzie Simon
Centro de Ciências do Mar (CCMAR), Universidade do Algarve, Campus de Gambelas 8005-139, Faro, Portugal.
Institute of Aquaculture, School of Natural Sciences, University of Stirling, Pathfoot Building, Stirling, FK9 4LA, UK.
J Anim Ecol. 2016 Sep;85(5):1389-400. doi: 10.1111/1365-2656.12555. Epub 2016 Aug 3.
Environmental temperature gradients provide habitat structure in which fish orientate and individual thermal choice may reflect an essential integrated response to the environment. The use of subtle thermal gradients likely impacts upon specific physiological and behavioural processes reflected as a suite of traits described by animal personality. In this study, we examine the relationship between thermal choice, animal personality and the impact of infection upon this interaction. We predicted that thermal choice in Nile tilapia Oreochromis niloticus reflects distinct personality traits and that under a challenge individuals exhibit differential thermal distribution. Nile tilapia were screened following two different protocols: 1) a suite of individual behavioural tests to screen for personality and 2) thermal choice in a custom-built tank with a thermal gradient (TCH tank) ranging from 21 to 33 °C. A first set of fish were screened for behaviour and then thermal preference, and a second set were tested in the opposite fashion: thermal then behaviour. The final thermal distribution of the fish after 48 h was assessed reflecting final thermal preferendum. Additionally, fish were then challenged using a bacterial Streptococcus iniae model infection to assess the behavioural fever response of proactive and reactive fish. Results showed that individuals with preference for higher temperatures were also classified as proactive with behavioural tests and reactive contemporaries chose significantly lower water temperatures. All groups exhibited behavioural fever recovering personality-specific thermal preferences after 5 days. Our results show that thermal preference can be used as a proxy to assess personality traits in Nile tilapia and it is a central factor to understand the adaptive meaning of animal personality within a population. Importantly, response to infection by expressing behavioural fever overrides personality-related thermal choice.
环境温度梯度提供了鱼类定向的栖息地结构，个体的热选择可能反映了对环境的一种基本综合反应。利用微妙的热梯度可能会影响特定的生理和行为过程，这些过程表现为一系列由动物个性所描述的特征。在本研究中，我们研究了热选择、动物个性以及感染对这种相互作用的影响之间的关系。我们预测尼罗罗非鱼（Oreochromis niloticus）的热选择反映了不同的个性特征，并且在受到挑战时，个体表现出不同的热分布。尼罗罗非鱼按照两种不同的方案进行筛选：1）一系列个体行为测试以筛选个性；2）在一个定制的水箱中进行热选择，该水箱具有从21到33°C的热梯度（TCH水箱）。第一组鱼先进行行为筛选，然后进行热偏好测试，第二组鱼则以相反的方式进行测试：先进行热测试，然后进行行为测试。评估48小时后鱼的最终热分布，以反映最终的热偏好。此外，然后使用海豚链球菌模型感染对鱼进行挑战，以评估主动型和反应型鱼的行为发热反应。结果表明，偏好较高温度的个体在行为测试中也被归类为主动型，而反应型的同代个体选择的水温明显较低。所有组在5天后都表现出行为发热，并恢复了个性特定的热偏好。我们的结果表明，热偏好可以用作评估尼罗罗非鱼个性特征的指标，并且它是理解种群中动物个性的适应性意义的核心因素。重要的是，通过表现出行为发热对感染的反应会超越与个性相关的热选择。
