Extrinsic and intrinsic constraints interact to drive extra-pair paternities in the Alpine marmot

To reproduce, animals have to form pairs and large variations in the degree of mate switching are observed. Extrinsic and intrinsic factors can constrain individual’s mate switching. Among intrinsic factors, genes involved in pair-bonding, such as Avpr-1a, receive increasing attention. The length of microsatellites present in the regulatory region of Avpr-1a determines the neural densities and distributions of the vasopressin receptors known to impact pair-bonding behaviours. For the first time, we investigated if and how the genetic makeup at Avpr-1a, an intrinsic factor, and the social context, an extrinsic factor, experienced by wild Alpine marmot (Marmota marmota) females affect the proportion of extra-pair young. This proportion was positively correlated with the length of their Avpr-1a regulatory region but only when the social constraints were relaxed, i.e. when mature male subordinates were present. When ignoring the interactive effect between the length of their Avpr-1a regulat...为实现繁殖，动物需形成配对关系，且研究观察到配偶更换（mate switching）程度存在显著差异。外在与内在因素均可限制个体的配偶更换行为。在内在因素中，参与配偶纽带（pair-bonding）形成的基因（如Avpr-1a）受到越来越多的关注。Avpr-1a调控区中存在的微卫星序列（microsatellites）长度，决定了已知可影响配偶纽带行为的血管加压素受体（vasopressin receptors）的神经密度与分布模式。本研究首次探讨了野生阿尔卑斯旱獭（Marmota marmota）雌性所携带的内在因素——Avpr-1a基因的遗传组成，以及外在因素——社会环境（social context），如何影响其配偶外子代（extra-pair young）的比例。该比例与Avpr-1a调控区的长度呈正相关，但仅当社会约束得到缓解时，即存在成熟雄性从属个体时，才会出现这一关联。当忽略Avpr-1a调控区长度与