Data from: The effects of background risk on behavioural lateralization in a coral reef fish

Behavioural lateralization – the preferential use of one side of the body or either of the bilateral organs or limbs – has been well documented in many species, in a number of contexts. While the benefits reported are numerous, existing latent variability in the degree of lateralization within and across populations, species and taxa indicates that existing costs may modulate its expression. Few studies have reported changes in the degree of lateralization at the individual level, in response to long-term changes in environmental conditions, but not in response to short-term changes in environmental conditions. Predation is highly variable both temporally and spatially and hence is a good candidate for testing lateralization effects based on short-term changes in environmental conditions. Here, we tested the hypothesis that the degree of behavioural lateralization changes following short-term exposure to different levels of risk. We tested whether wild-caught juvenile damselfish exposed to a high or low background level of risk for 4 days would subsequently differ in their turning bias, a trait that has been linked to predator escape behaviour in fishes. We found that 4 days is enough to induce a difference in the absolute lateralization scores of the fish, with high-risk fish being more strongly lateralized than low-risk fish. Practically, this difference stemmed from decreasing lateralization scores for newly recruiting coral reef fishes that were kept in low-risk environments, with the concurrent maintenance of higher lateralization scores for fish maintained under high-risk conditions. Fish from the high-risk background had higher survival than those from the low-risk background upon release into mesocosms containing reef predators. Our study highlights how early exposure to differential predation risk affects the degree of behavioural lateralization. Given the profound effects of lateralization on many aspects of an animal's life from its ability to discriminate conspecifics to how it forages and interacts during agonistic interactions, predation risk may be a key driver of animal development.行为偏侧化（Behavioural lateralization）指偏好使用身体单侧或双侧器官或肢体的现象，目前已在多个物种类群的多种情境中被广泛报道。尽管已有研究揭示了偏侧化的诸多益处，但种群内部、跨种群以及不同物种、类群间的偏侧化程度均存在潜在变异，这表明现存的演化代价可能会调控偏侧化的表达。鲜有研究报道个体层面的偏侧化程度会响应环境条件的长期变化而改变，且目前尚无针对环境短期变化引发偏侧化变化的相关研究。捕食压力在时间与空间维度上均存在高度变异，因此是基于环境短期变化检验偏侧化效应的理想研究对象。本研究旨在验证以下假说：行为偏侧化程度会在短期暴露于不同强度的风险后发生改变。我们将野生捕获的幼雀鲷分别置于高、低背景捕食风险环境中暴露4天，随后检验其转向偏好是否存在差异——鱼类的转向偏好这一性状与逃避捕食者的行为密切相关。研究结果显示，仅4天即可使鱼类的绝对偏侧化评分产生显著差异：高风险组鱼类的偏侧化程度显著高于低风险组。具体而言，该差异源于饲养于低风险环境中的新定居珊瑚礁鱼类的偏侧化评分逐渐降低，而高风险环境组鱼类的偏侧化评分则维持在较高水平。当将两组幼鱼释放至包含礁区捕食者的中型实验生态系中时，高风险组幼鱼的存活率显著高于低风险组。本研究揭示了早期暴露于差异化捕食压力如何影响行为偏侧化程度。鉴于偏侧化对动物生命诸多方面均存在深远影响——从辨别同种个体的能力到觅食行为以及攻击性互动中的社交模式，捕食压力可能是驱动动物发育的关键因素之一。