Data from: Faithful or not: direct and indirect effects of climate on extra-pair paternities in a population of Alpine marmots

Despite being identified an area that is poorly understood regarding the effects of climate change, behavioural responses to climatic variability are seldom explored. Climatic variability is likely to cause large inter-annual variation in the frequency of extra-pair litters produced, a widespread alternative mating tactic to help prevent, correct or minimize the negative consequences of sub-optimal mate choice. In this study, we investigated how climatic variability affects the inter-annual variation in the proportion of extra-pair litters in a wild population of Alpine marmots. During 22 years of monitoring, the annual proportion of extra-pair litters directly increased with the onset of earlier springs and indirectly with increased snow in winters. Snowier winters resulted in a higher proportion of families with sexually mature male subordinates and thus, created a social context within which extra-pair paternity was favoured. Earlier spring snowmelt could create this pattern by relaxing energetic, movement and time constraints. Further, deeper snow in winter could also contribute by increasing litter size and juvenile survival. Optimal mate choice is particularly relevant to generate adaptive genetic diversity. Understanding the influence of environmental conditions and the capacity of the individuals to cope with them is crucial within the context of rapid climate change.

尽管气候变化影响相关领域仍存在诸多未被阐明的问题，但针对气候变异性的行为响应研究却极为匮乏。气候变异性或会导致额外配对幼崽（extra-pair litters）出现频率产生显著年际波动，而额外配对是一种广泛存在的替代性交配策略，用于规避、修正或最小化次优配偶选择带来的负面影响。本研究以野生阿尔卑斯旱獭（Alpine marmots）种群为研究对象，探究了气候变异性如何影响额外配对幼崽占比的年际变化。在长达22年的监测过程中，额外配对幼崽的年度占比随春季提前到来呈直接上升趋势，同时随冬季降雪量增加呈间接上升趋势。降雪量更大的冬季会使携带性成熟雄性从属个体的家庭占比升高，进而形成有利于额外配对父权（extra-pair paternity）的社会环境。春季融雪提前可通过缓解个体在能量、活动与时间上的限制，形成上述趋势。此外，冬季积雪更厚还可通过增加窝仔数与幼体存活率，间接推动额外配对幼崽占比上升。最优配偶选择对于产生适应性遗传多样性（adaptive genetic diversity）至关重要。在气候变化速率不断加快的背景下，厘清环境条件的影响以及个体应对环境变化的能力，具有极为重要的研究意义。