基于亲代投入的两性冲突一直以来都是鸟类繁殖行为研究的热点问题之一，尤其是发现越来越多的社会性单配制物种存在婚外交配现象后，更加引发了人们对两性冲突问题的全新思考。杂色山雀（Sittiparus varius）为雌雄同色同型的社会性单配制鸟类，双亲共同育雏，且存在较高的婚外父权比率，是研究繁殖期两性育雏投入和婚外配代价的理想物种。本项目拟通过实时录像监控和亲本移出等技术手段和方法，研究杂色山雀双亲育雏投入特征和两性突遇变故时的育雏投入调整策略，通过对两性亲本一系列个体质量指标与育雏投入关系的深入分析，阐明决定亲代抚育策略的因素，并研究婚外父权对双亲育雏投入可能带来的影响，以期揭示婚外交配行为是否会加剧繁殖期的两性冲突，为有婚外配现象的社会性单配制鸟类的性选择和性冲突理论提供更多的证据。

The sexual conflict based on the parental investment is one the hot topics in the research area of avian behavior. With more and more monogamous species being found to have the phenomenon of extra-pair copulation, scientists are having new thoughts on the sexual conflict. Varied tit (Sittiparus varius), a social monogamous bird species with biparental care behavior and high extra-pair paternity ratio, is the ideal species for examining biparenta investment at reproductive period and the cost of extra-pair copulation. In this proposed project, we will use a series of technologies and methods, including real-time video monitoring and parent removal, to examine the characters of investments in parental care for both parents and the strategies for the changes of such investment when sudden changes occurred for each side of parents. Based on the analysis of the relationship between the investment of parental care and individual quality index for each parent, we could identity the determining factors for the strategies of parental care. Furthermore, we will examine the potential influences of extra-pair paternity on the investment of parental care, with the aim to find out whether extra-pair mating behavior would intensify sexual conflicts in breeding season. Results from this project would provide more evidence for the development of sexual selection and sexual conflicts theories in monogamous bird species with extra-pair behavior.