亲缘选择在准社会性寄生蜂合作抚育行为中的作用

Cooperation is a defining attribute of sociality. Social behaviours are rich in diversity in insects, from simple egg-guarding to cooperation between classes in reproductive divisions of labor. However, evolutionary mechanisms for this diversity are far beyond clarity. In ecto-parasitic Sclerodermus wasps, foundresses cooperate in brood care, an unique quasi-social behaviour in parasitoids, can be an ideal model system for evolutionary study of insect society. Our preliminary study shows that foundresses gained higher fitness from cooperatively subduing larger hosts. The cooperative brood care can be explained by “Allee effects”, without invoking or precluding kin selection effects. However, we hypothesize that kin selection have effects on the cooperative brood care by foundresses in Sclerodermus. To test this hypothesis, we, use S. guani as the model system, examine effects of kin relationship between foundresses on host selection, subduing, oviposition, and developmental performances, using molecular markers, biochemical methods, and behavioural methodology. This research program would reveal kin selection effects on the cooperative brood care in Sclerodermus parasitoids, providing data for developing theoretical models to explain quasi-social behaviour evolution, with an eventual aim to understand the evolution of insect society.

物种内个体间的合作行为是社会行为的重要属性。昆虫中存在复杂多样的社会类型，从最简单的护卵到复杂精致的生殖分工与合作，但对其进化机理仍不清楚。肿腿蜂是表现雌蜂合作抚育的准社会行为的唯一寄生蜂类群，是研究昆虫社会行为进化的难得材料。前期研究发现，多头雌蜂寄生同一寄主有助于制服大体型寄主的反抗，从而提高各自的适合度，该行为可用“Allee效应”解释，但不排除亲缘选择。本项目提出假说：亲缘选择影响肿腿蜂的合作抚育行为。为检验该假说，以管氏肿腿蜂为模式生物，采用分子标记技术、生化和行为学试验方法，观察母亲蜂间的亲缘关系对搜寻和选择寄主、克服寄主防卫、产卵决策以及子代发育适合度等重要行为和适合度特征的影响。本研究将阐明亲缘关系在肿腿蜂合作抚育社会行为中的地位和作用，为下一步构建肿腿蜂准社会行为进化的理论模型提供依据，并为最终阐释昆虫社会行为的进化提出新的认识。

围绕计划的六项研究内容开展室内研究和野外调查。已基本完成项目计划研究任务。项目研究获得的重要进展：硬皮肿腿蜂合作繁育社会行为的进化无需借助经典的亲缘选择理论进行阐释，合作母蜂不对称的资源持有潜力也与实现适合度利益无关，但占有寄主顺序的不对称可影响适合度利益。研究结论是：硬皮肿腿蜂母蜂在合作利用寄主中的贡献大小，是硬皮肿腿蜂准社会行为进化的主要动力；母蜂间的亲缘关系对合作繁殖没有影响。本研究的发现为认识膜翅目昆虫复杂的真社会的演化路径提供了重要依据：寄生蜂可能是真社会演化路径的节点之一。完成了项目的总体目标。