大熊猫嗅味标记的功能、配偶选择与MHC变异的关系

Olfactory communication plays an important role in mammal's social life. A wealthy of literature on the chemical compositions and their functions of scent-marking in mammals is available. However, the opinions on the function of scent-marking and its underlying mechanisms are controversial, and whether the sent-marking of mammals is an honest signal about the owner's health and quality , and favored by females remains unknown. Nor information on the relationship between the major histocompatibility complex (MHC) proteins, chemosignals and individual's mate choice can be found. Previous studies show that giant pandas substantially rely on scent markings to communicate with each other and choose their mates. The female uses three and males use five postures to deposit scent-markings. Information concerning about individual's age, sex and genetic relatedness are found to be coded either by digital form or analog form in those scent-markings. The ex situ conservation of the panda has made a big progress in the past two decades with a captive population of 375 individuals till December of 2013. However, the average natural mating rate is less than 12%, and the causes are highly unclear. This project first aims to manipulatively test the current hypotheses on the functions of scent-marking in the giant panda. Second, to test if scent-marking (either deposited by different postures, physical positions or counter marks) is an honest signal indicating the owner's health and quality, and is favored by females in the mating season. Third, to conduct confirmative analyses on the chemical compounds of different scent-marking samples deposited by different postures or from different positions in the counter marks by gas-chromatography-mass spectrometry. Last, try to reveal the relationship between MHC class II protein, odor and female's mate choice. The results will not only be helpful for uncovering the causes for the low natural mating rate in captive pandas, but also useful for ex situ conservation for other endangered species of animal.

嗅觉通讯在哺乳类的社群生活中起重要作用。以往针对哺乳类气味标记的化学成分组成及其功能已开展了很多研究。然而，针对哺乳类气味标记的功能依然存在不同的假说。另外，目前尚不清楚气味标记是否是一种能够表明个体健康状况和遗传品质的第二性征信号，也不了解该信号与主要组织相容性复合体（MHC）是什么关系、对配偶选择有何影响等。本项目拟以圈养大熊猫为研究对象，针对其自然交配成功率较低的现象，采用操控实验手段，将行为观察和MHC分析相结合，首先验证有关气味标记功能的"领地护卫假说"和"繁殖信息交流假说"。然后根据雄性遗留气味标记的频次、不同姿势和标记高度，雌性对这些雄性气味标记的选择偏好，验证"缺陷假说"。最后，综合分析雌雄个体MHC II型分子相似程度和雌性对不同MHC雄性气味的选择结果，从行为学和分子生物学水平揭示其性动机下降、自然交配成功率较低的内在原因，为圈养珍稀濒危野生动物的繁殖和保护提供指导。

嗅觉通讯在哺乳类的社会生活中起着重要的作用，以往有诸多假说解释各种嗅觉通讯行为，然而却缺少足够的证据。嗅觉通讯在大熊猫的社会行为，尤其是交配季节的相互交流与作用中发挥了不可或缺的作用。然而，对嗅觉通讯的功能及其在配偶选择过程中的作用及机制却不甚了解。本项目以圈养大熊猫为研究对象，分别在交配和非交配季节，通过操控实验，分别验证了嗅味标记的“领地护卫假说”、“繁殖信息交流假说”和“缺陷假说”。同时，结合以往的研究基础，自主设计实验装备测定了大熊猫的视力敏锐度。同时，还检验了大熊猫镜像自我识别。然后自主研发并设计制作了基于步态数据特征的大熊猫发情状态监控项圈，并尝试应用于其发情状态监控。.结果发现，非交配季节的嗅味标记行为支持“领地护卫假说”，交配季节的标记行为支持“繁殖信息交流假说”；不同标记高度的标记与反标记实验结果，支持“缺陷假说”，即标记高度表明个体的体型大小——个体遗传质量的优劣。标记高度是一种真实表明个体质量的第二性征信号。针对大熊猫尿液、鼻腔黏液和唾液等分泌物中气味结合蛋白（OBP）的分析结果，发现4种OBP，对照其食物——竹子中的化学成分组成，推测大熊猫性外激素可能来源于竹子，并在鼻腔黏液中被探测到。. 大熊猫的视力敏锐度仅为0.46，相当于人类的高度近视。虽然大熊猫的脑容量较其他熊科动物的大，但是它不具备镜像自我识别能力。此外，针对研究过程中四川华蓥山大熊猫再引入问题的争论，采用入户式问卷调查，发现当地百姓对大熊猫的再引入持积极的态度，受教育程度越高，支持力度越大，支付意愿也高。. 上述结果，在理论上开拓了我们对大熊猫嗅觉通讯行为的认识；在实践上，对于提高圈养大熊猫的自然交配成功率具有指导作用。此外，大熊猫项圈，对于未来普及和应用该技术监测雌性个体的发情状态、适时放对配种，具有重要实践价值。目前，该技术已被应用于警犬训练工作中，未来有望作为装备进行推广和应用。