Adaptive significance of coat colouration and patterns of Sciuromorpha (Rodentia)

An analysis on the adaptive meaning of coat colouration and colour patterns in Sciuromorpha, a successful group within rodents, was carried out. We ran analyses with and without taking into account the phylogeny of Sciuromorpha, by building up a comprehensive phylogenetic tree based on the published literature, as well as by testing a number of hypotheses connecting coat colouration or patterns with eco-behavioural traits of this mammalian group. We found that coat characteristics in these rodents are mostly related to concealment, with associations between colouration/patterns and habitats where each species lives. Communication also seems to play a role in shaping colourations in Sciuromorpha, particularly concerning extremities, with conspicuous ear/face markings and tail patterns being associated with social species; a role for interspecific communication as an antipredatory strategy is also discussed for tail patterns. Thus, concealment seems to be the primary driving force shaping coat colours in Sciuromorpha, with social communication and regulation of physiological processes playing minor roles.

本研究针对啮齿类中一类演化成功的类群——松鼠形亚目（Sciuromorpha）的被毛色彩与色斑模式的适应性意义展开了分析。本研究分别开展了纳入与不纳入松鼠形亚目系统发育关系的分析：一方面基于已发表文献构建了全面的系统发育树，另一方面针对该类哺乳动物的被毛色彩或色斑与生态行为特征之间的关联，检验了多项假说。研究结果显示，这类啮齿动物的被毛特征主要与隐蔽功能相关，其色彩或色斑模式与各物种的栖息环境存在显著关联。此外，通讯作用似乎也参与塑造了松鼠形亚目的被毛色彩，尤其体现在肢体部位：醒目的耳部/面部斑纹与尾部模式，均与社会性物种相关；同时本研究还探讨了种间通讯作为反捕食策略在尾部模式演化中的作用。综上，隐蔽功能应为驱动松鼠形亚目被毛色彩演化的首要动力，而社会通讯与生理过程调控的作用相对次要。