Abstract Phenotypic flexibility may incur a selective advantage in changing and heterogeneous environments, and is increasingly recognized as an integral aspect of organismal adaptation. Despite the widespread occurrence and potential importance of rapid and reversible background-mediated color change for predator avoidance, knowledge gaps remain regarding its adaptive value, repeatability within individuals, phenotypic correlates, and whether its expression is context dependent. We used manipulative experiments to investigate these issues in two fish species, the three-spined stickleback (Gasterosteus aculeatus) and nine-spined stickleback (Pungitius pungitius). We sequentially exposed individuals to dark and light visual background treatments, quantified color change from video recordings, and examined associations of color change with phenotypic dimensions that can influence the outcome of predator-prey interactions. G. aculeatus expressed a greater degree of color change compared to P. pungitius. In G. aculeatus, the color change response was repeatable within individuals. Moreover, the color change response was independent of body size but affected by sex and boldness, with males and bolder individuals changing less. Infection by the parasite Schistocephalus solidus did not affect the degree of color change, but it did modulate its association with sex and boldness. G. aculeatus adjusted the expression of color change in response to predation risk, with enhanced color change expression in individuals exposed to either simulated attacks, or olfactory cues from a natural predator. These results provide novel evidence on repeatability, correlated traits, and context dependence in the color change response and highlight how a suite of factors can contribute to individual variation in phenotypic flexibility.

中文翻译：

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刺鱼背景介导的颜色变化的表型灵活性


摘要：表型灵活性可能会在不断变化的异质环境中产生选择优势，并且越来越多地被认为是生物体适应的一个组成部分。尽管快速和可逆的背景介导的颜色变化对于躲避捕食者来说广泛存在并且具有潜在的重要性，但关于其适应性价值、个体内的可重复性、表型相关性以及其表达是否依赖于环境的知识仍然存在差距。我们使用操作实验来研究两种鱼类的这些问题，即三刺刺鱼（Gasterosteus aculeatus）和九刺刺鱼（Pungitius pungitius）。我们依次将个体暴露于黑暗和明亮的视觉背景处理中，量化视频记录中的颜色变化，并检查颜色变化与表型尺寸的关联，这些表型尺寸可以影响捕食者与猎物相互作用的结果。与 P. pungitius 相比，G. aculeatus 表现出更大程度的颜色变化。在棘孢G. aculeatus 中，颜色变化反应在个体中是可重复的。此外，颜色变化反应与体型无关，但受性别和胆量的影响，男性和胆量较大的个体变化较小。寄生虫固相裂头虫的感染不会影响颜色变化的程度，但它确实调节了其与性别和胆量的关联。 G. aculeatus 会根据捕食风险调整颜色变化的表达，暴露于模拟攻击或来自自然捕食者的嗅觉线索的个体的颜色变化表达增强。 这些结果为颜色变化反应的可重复性、相关性状和环境依赖性提供了新的证据，并强调了一系列因素如何影响表型灵活性的个体差异。