高寒环境下山噪鹛生活史研究

Reproduction is the most important component in animal life history，reproduction strategy is one kind of abilitieds shaped by natural selection to predict and adapt to various environmental factors so that animals can realize the maximized reproductive success based on current resource. During the process of birds' reproductive, in order to maxmize the fitness each other, the conflict between parental and offspring was called parental-offspring conflict. As the most important component of the theory of parental-offspring conflict, what a kind of parental investment strategy used by parents and sibling rivalry are the research focus in Behavior Ecology and Sociobiology. This proposal will focus on the life history traits especially the two important aspects in avian behavior ecology, parental investment strategy and sibling rivalry pattern of Plain laughing thrushes (Garrulax davidi), a mid-sized babbler endemic to China, under the cold and high altitude environment on the east edge of Tibetan Plateau. It aims to examine:1) parental clutch size strategy, 2) parental incubation behaviors, 3) effects of asynchronous hatching on the within-brood size hierarchy, 4) nestling growth patterns, 5) relationship between parental care and paternity assurement, 6) parental investment strategy and sibling rivalry. Furthermore, we sought to investigate whether nestling development, nestling sex and brood sex ratio determined timimg and order of fledging based on the data above. In addition, we investigated which other characteristics of broods (brood size, hatching date, sex of first fledging and the averages of all individual traits) and individuals (wing length, tarsus length and body mass) were related to timing and order of fledging with this experimental study on the Plain laughing thrushes. New materials will be provided for the study on the behavior and evolution of birds and the social behavior of animals through the project and will enrich the research of the life history study on birds.

繁殖是动物生活史最重要的组成部分，繁殖策略是动物在长期自然选择作用下形成的对环境因子的预判与适应。在繁殖过程中，亲代与子代之间为实现各自最大适合度所产生的矛盾称为亲子冲突。作为亲-子冲突理论的重要组成部分，在育雏期亲本采取的递食策略和后代的同胞竞争一直是行为生态学、社会生物学等研究领域的焦点。本项目将对我国特有鸟种- - 山噪鹛（Garrulax davidi）在高寒环境下的生活史进行研究。围绕鸟类行为生态学中两个重要的方面：亲本的递食策略和雏鸟的同胞竞争进行研究。通过对山噪鹛亲鸟卵大小策略、亲鸟孵卵行为、雏鸟的生长发育规律、亲本递食偏好与亲权的关系、亲本递食模式与同胞竞争的关系和是否性别和巢的性比决定了雏鸟出飞的时间和顺序，以及和雏鸟出飞时间和顺序相关的巢的特征和个体特征的研究，揭示山噪鹛在生活史各阶段采取的对策。项目将为鸟类行为进化及动物社会行为的研究提供新的素材，并将丰富鸟类生活史研究。

项目围绕鸟类行为生态学中两个重要的方面：亲本的递食策略和雏鸟的同胞竞争进行。对山噪鹛亲鸟卵大小策略、亲鸟孵卵行为、雏鸟的生长发育规律、亲本递食偏好、亲本递食模式与同胞竞争的关系和是否性别和巢的性比决定了雏鸟出飞的时间和顺序，以及和雏鸟出飞时间和顺序相关的巢的特征和个体特征进行了研究。项目得到的主要结果有：1）山噪鹛卵长径27.69 ± 1.54 mm，卵短径19.48 ± 0.23 mm。最佳窝卵数为3，平均窝卵数为3.01 ± 0.13。卵初重为5.55 ± 0.46 g。雏鸟初始体重和窝雏数与孵化次序均无显著性关系。雏鸟的出飞体重巢间无显著变异但巢内不同孵化次序间存在显著变异：第一个孵化出的雏鸟具有最重的出飞体重而第四个孵化出的雏鸟出飞时的体重最轻。2）山噪鹛繁殖期在4 月上旬至8月上旬。雌雄均参与孵卵，以雌性为主。孵化期14-16天，育雏期10-14天。雌雄亲鸟共同育雏，以雄鸟为主。育雏初期（幼鸟出壳至4-5d）主要由雄鸟外出觅食，雌鸟坐巢暖雏。育雏后期雌雄亲鸟均外出觅食，共同喂食雏鸟。雄鸟喂食间隔明显小于雌鸟喂食间隔。3）不同窝雏数的山噪鹛雏鸟生长率无显著差异，但不同的孵化次序雏鸟的生长率存在显著差异。第四个孵化出的山噪鹛雏鸟在翅长、嘴峰长和跗蹠长的增长上显著快于早孵化出的雏鸟。4）山噪鹛亲本采取异步孵化策略差异化雏鸟初始竞争力。山噪鹛亲本采取“试探性多分配”与“轮换递食方位”的策略弱化雏鸟间同胞竞争；雏鸟非独立期间，“试探性多分配”起主要作用，但在雏鸟独立期间，“轮换递食方位”起主要作用。5）山噪鹛雏鸟对食物的竞争无攻击行为，在非独立期，雏鸟以展示乞食行为向亲本表达诉求；随日龄增加，雏鸟能动性增加，雏鸟乞食行为由早期以“行为展示”为特点的展示性竞争过度为以“排挤竞争对手为特点”的争胜性竞争。6）山噪鹛雏鸟的出飞时间随雏鸟性比发生显著的变化，性比越偏雌，雏鸟出飞时间越长。本项目的顺利完成，将为鸟类行为进化及动物社会行为的研究提供新的素材，并将丰富鸟类生活史研究。