Social flexibility and social evolution in mammals: a case study of the African striped mouse (Rhabdomys pumilio)
Social flexibility and social evolution in mammals: a case study of the African striped mouse (Rhabdomys pumilio)
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哺乳动物的社会灵活性和社会进化：非洲条纹小鼠（Rhabdomys pumilio）的案例研究
作者：
C. Schradin;A. Lindholm;J. Johannesen;I. Schoepf;C. Yuen;B. König;N. Pillay
环境变化给许多生物带来了挑战。一个物种对这种变化的适应力取决于它适应性反应的能力。社会灵活性是这样一种适应性反应，即两性个体根据环境条件的波动而改变其生殖策略，从而导致社会系统的变化。社会灵活性侧重于个体灵活性，并提供了一个独特的机会，通过比较同一种群中独居和群居的个体来研究社会性的最终和近因：为什么动物会形成群体，群体生活如何受到环境和神经内分泌系统的调节？在过去的十年里，这些关键问题已经在条纹小鼠Rhabdomys pumilio中进行了研究。高人口密度有利于亲合和群体生活，而生殖竞争有利于分散和独居。遗传亲子关系的研究表明，相对适合的替代生殖策略取决于当时的环境。当竞争能力重要时，策略在受限生态条件下具有不同的适应性。在放松生态约束的条件下，替代策略可以产生相等的适应度。雄性和雌性条纹小鼠都显示出基于单一策略的替代生殖策略，即所有个体都遵循相同的决策规则。这些变化是由内分泌机制调节的。社会灵活性被认为是对不可预测的环境变化的适应，基于广泛的反应规范选择高表型灵活性，而不是特定策略的遗传多态性。
Environmental change poses challenges to many organisms. The resilience of a species to such change depends on its ability to respond adaptively. Social flexibility is such an adaptive response, whereby individuals of both sexes change their reproductive tactics facultatively in response to fluctuating environmental conditions, leading to changes in the social system. Social flexibility focuses on individual flexibility, and provides a unique opportunity to study both the ultimate and proximate causes of sociality by comparing between solitary and group‐living individuals of the same population: why do animals form groups and how is group‐living regulated by the environment and the neuro‐endocrine system? These key questions have been studied for the past ten years in the striped mouse Rhabdomys pumilio. High population density favours philopatry and group‐living, while reproductive competition favours dispersal and solitary‐living. Studies of genetic parentage reveal that relative fitness of alternative reproductive tactics depends on the prevailing environment. Tactics have different fitness under constrained ecological conditions, when competitive ability is important. Under conditions with relaxed ecological constraints, alternative tactics can yield equal fitness. Both male and female striped mice display alternative reproductive tactics based on a single strategy, i.e. all individuals follow the same decision rules. These changes are regulated by endocrine mechanisms. Social flexibility is regarded as an adaptation to unpredictably changing environments, selecting for high phenotypic flexibility based on a broad reaction norm, not on genetic polymorphism for specific tactics.