基于两性获益与代价探讨白眉姬鹟婚外配发生机制

Researchers find that extra-pair mating behavior prevails among socially monogamous bird species. This phenomenon challenges traditional views of sexual selection and mating system, and the occurrence and evolution mechanism of extra-pair mating has become one of the hot-spots in the avian behavior ecology.There have been a lot of theoretical and empirical researches about extra-pair mating of birds,however, no consensus on the basic questions has been received in this area, such as the occurrence of extra-pair mating is primarily controlled by male or female? What is the value for the evolution of extra-pair mating behavior? Which fators leading to intra- and inter-specific variation in the level of extra-pair mating？Therefore, the occurrence and evolution mechanism of extra-pair mating is currently under debate.The Yellow-rumped Flycatcher is selected as target species in the project. By conducting banding, model and song playbacking experiments, we would evoluate the effects of dispersal pattern, behavioural and morphological traits and other factors on the extra-pair mating in the Yellow-rumped Flycatcher.We would integrate the outcome of paternity identification,adult and offspring genetic heterozygosity to reveal the ways that the species gaining benefits and paying costs for extra-pair mating behavior, to analyse the initiative when persuiting extra-pair mating in female and male,and to prove into the occurrence mechanism of extra-pair mating in Yellow-rumped Flycatcher. Results of the project may provide proofs for revealing the occurrence and evolution mechanism of extra-pair mating in birds, and would be helpful in enriching the theroies about sexual selection in animals.

研究发现多数社会单配偶制鸟类存在婚外交配行为，这对传统的动物婚配体制和性选择理论提出了新的挑战。婚外配行为发生与进化机制已成为鸟类行为生态学研究的热点问题之一。虽已开展大量理论和实验研究，但雌性还是雄性主导着婚外配行为的发生?婚外配行为的进化驱动力是什么？影响种内和种间婚外父权分配变化的主要因素是什么？等基本问题未得到一致合理解释，鸟类婚外配行为发生与进化机制仍存在较大争议。本项目选择白眉姬鹟为研究对象，通过环志、模型和声音回放等野外实验，明确白眉姬鹟的扩散模式、行为和形态特征等因素对婚外配行为的影响。结合父权鉴定实验及成鸟和幼鸟杂合度等研究结果进行深入分析，揭示白眉姬鹟雌雄性在婚外配行为中的获益方式与代价付出，分析婚外配发生过程中雌雄个体的主动性，探讨白眉姬鹟婚外配行为发生机制。研究结果可为鸟类婚外配行为的发生和进化机制研究提供相关证据，对丰富动物性选择相关理论具有一定的理论价值。

项目组对白眉姬鹟婚外配行为发生的影响因素和婚外配获益与代价等内容开展了研究。研究发现52.4%监测的繁殖巢存在婚外子代，婚外子代比例为26.8%。雌性白眉姬鹟倾向于选择身体较大、基因杂合度比其社会配偶高的雄性作为婚外配偶；最近邻居间较低的婚外配发生水平可能取决于雌性偏爱高质量雄性；雌性白眉姬鹟可能通过选择携带具最适MHC等位基因数量雄性作为婚外配偶。发生婚外配巢中婚外子代的微卫星基因杂合度显著高于同巢的婚内子代；婚外子代的MHC基因杂合度高于同巢的婚内子代。婚外子代数量对雄性孵化期巢防御和育雏期递食投入无显著影响。雄性可通过婚外交配获得更多的遗传子代而增加繁殖适合度；雄性的配偶监护行为未能有效地防止其父权丧失。社会配偶和婚外配偶的领域鸣唱的句子最高频存在显著差，且句子最高频和句子主频对雄性的婚外父权分配影响显著，但未发现领域鸣唱特征与个体的身体条件相关。未发现雌性对社会配偶的形态特征选择受繁殖经验影响，是否发生婚外配受有无繁殖经验及体长之间的交互作用影响。有无殖经验雌性的孵化日期、出雏日期之间存在显著差异；具有一年和一年以上繁殖经验雌性的首枚卵产期存在显著差异；亲鸟的繁殖经验对婚外配发生概率影响显著，发生概率随繁殖经验增加而增加。白眉姬鹟面对同域与异域捕食者与非捕食者的回应行为存在差异显著，对异域鸟类表现出更多的佯攻行为，更近距离地接近异域鸟类；孵化雌鸟对捕食者与非捕食者的鸣声回应行为存在差异显著。温度与降雨量之间的交互作用对白眉姬鹟的窝卵数存在显著影响。依托项目培养博士后1名、博士研究生1名、硕士研究生7名；发表研究论文5篇，其中SCI 论文4篇；接收论文1篇。