The Effects of Climate-Related Stressors on Social Behaviour in Fish

摘要：动物王国中存在着各种形式的社会行为，有利于捕食者的躲避、觅食和繁殖。然而，到目前为止，我们对人为环境干扰如何影响群居动物几乎一无所知。对水生生态系统最严重的威胁之一是气候变化导致的温度和氧气供应的变化。尽管如此，我们所知道的与气候相关的压力因素如何影响生理和行为，几乎都来自于在没有任何社会背景的情况下对单个动物的观察。考虑到现有的关于环境对单个动物的影响的知识，跟踪动物群体的技术的发展，以及预测种群如何应对气候变化的迫切需要，现在是解决这一知识差距的时候了。气候变化最直接的影响是，到2100年，全球地表温度将升高1.5至5.8摄氏度，局部地区的后果更为严重。在鱼类等变温动物中，变暖通过提高标准代谢率来增加能量需求。基伦的研究表明，本质上高SMR的个体社会性较差，可能是因为他们优先考虑获取食物，从而避免与群体成员竞争。相比之下，能量需求较低的个体优先考虑保护自己免受捕食者的伤害，并与同种生物保持更近的距离。因此，温度升高导致的代谢需求增加可能使个体社会性降低，降低社会群体的凝聚力，可能影响群体觅食、捕食者躲避、社会学习、迁徙和任何依赖于群体凝聚力的现象。变温动物的最大代谢率和耗氧生理功能的有氧范围受温度的影响，通常在热最佳时达到峰值。一般来说，变温动物的自发活动随着温度的升高而增加，但当它们接近临界热最大值时，自发活动就会减少，这是它们经历运动障碍的热敏感性基准。温度对这些变量的影响可能会改变个体成为领导者的方式，因为个体的活动和速度是领导者-追随者动态的决定因素。社会地位或在等级制度中的位置也可以反馈影响诸如大胆等特征，这反过来又与新陈代谢有关，这表明社会互动可能影响对热应激的耐受性。为了研究这些问题，拟议的项目将：(1)研究温度和缺氧如何影响个体动物及其社会群体行为之间的相互作用(2)研究温度和缺氧如何影响群体运动、觅食和捕食者躲避过程中的社会群体功能(3)产生一个强大的群体行为运动模型，该模型可应用于一系列环境条件和生态背景。该项目将使用鱼类作为模型研究系统。鱼类经常被用作研究动物集体行为和环境压力对变温动物的影响的模式分类群。它们遍布全球的水生栖息地，扮演着捕食者和猎物的关键角色，并表现出各种各样的社会行为。通过采用创新的经验和理论方法，结合行为学和生理学，该项目将首次研究气候变化带来的热转移和缺氧如何影响社会行为。

Studentship strategic priority area: BiodiversityKeywords: fish, social behaviour, climate change, metabolism, foragingAbstract: Various forms of social behaviour exist throughout the animal Kingdom, with benefits for predator avoidance, foraging, and reproduction. To date, however, we know almost nothing about how anthropogenic environmental disturbance affects group living in animals. Among the most critical threats to aquatic ecosystems are changes in temperature and oxygen availability due to climate change. Still, nearly everything we know about how climate-related stressors affect physiology and behaviour comes from observations of single animals in the absence of any social context. Now is the time to address this knowledge gap, given existing knowledge of environmental effects on single animals, the development of technologies for tracking of groups of animals and the urgent need to predict how populations will respond to climate change. The most immediate effect of climate change is an increase in global surface temperatures of 1.5 to 5.8oC by 2100, with localised consequences being more severe. In ectotherms such as fish, warming increases energy demand by elevating standard metabolic rate. Supervisor Killen's work has shown individuals with an intrinsically high SMR are less social, likely because they prioritise food acquisition and so avoid competition with groupmates. In contrast, individuals with lower energy demand prioritise protection from predators and stay closer to conspecifics. Accordingly, a greater metabolic demand stemming from temperature increase could make individuals less social and reduce cohesion of social groups, possibly affecting group foraging, predator avoidance, social learning, migration and any phenomena dependent on group cohesiveness. The maximum metabolic rate of ectotherms and aerobic scope for oxygen-consuming physiological functions are influenced by temperature, often peaking at a thermal optimum. In general, spontaneous activity in ectotherms increases with temperature but then decreases as they approach their critical thermal maximum, a benchmark for thermal sensitivity at which they experience locomotor impairment. Effects of temperature on these variables could alter which individuals become leaders because individual activity and speed are determinants of leader-follower dynamics. Social niche or placement within hierarchies can also feedback to affect traits such as boldness, which in turn can be linked to metabolism, suggesting social interactions could affect tolerance to thermal stress. To examine these issues, the proposed project will:(1) examine how temperature and hypoxia affect interplay between behaviour of individualanimals and their social group(2) investigate how temperature and hypoxia influence social group functioning during group movements, foraging, and predator avoidance(3) produce a robust movement model of group behaviour that can be applied to a range of environmental conditions and ecological contexts. The project will use fish as a model study system. Fishes are frequently used as model taxa to study collective behaviour in animals, and the effects of environmental stressors on ectotherms. They occupy aquatic habitats across the globe, play key roles as both predators and prey, and display a variety of social behaviours. By adopting innovative empirical and theoretical approaches and combining behaviour and physiology, this project will be the first to examine how thermal shifts and hypoxia brought on by climate change will affect social behaviour.