Data from: The influence of weather conditions during gestation on life histories in a wild Arctic ungulate

The internal predictive adaptive response (internal PAR) hypothesis predicts that individuals born in poor conditions should start to reproduce earlier if they are likely to have reduced performance in later life. However whether this is the case remains unexplored in wild populations. Here, we use longitudinal data from a long-term study of Svalbard reindeer to examine age-related changes in adult female life-history responses to environmental conditions experienced in utero as indexed by rain-on-snow (ROSutero). We show that females experiencing high ROSutero had reduced reproductive success only from 7 years of age, independent of early reproduction. These individuals were able to maintain the same annual reproductive success between 2 and 6 years as phenotypically superior conspecifics that experienced low ROSutero. Young females born after high ROSutero engage in reproductive events at lower body mass (about 2.5 kg less) than those born after low ROSutero. The mean fitness of females that experienced poor environmental conditions in early life was comparable to that of females exposed to good environmental conditions in early life. These results are consistent with the idea of internal PAR and suggest that the life-history responses to early-life conditions can buffer the delayed effects of weather on population dynamics.

内源性预测适应性反应（internal predictive adaptive response，以下简称PAR）假说提出，若个体在晚年的生存性能会降低，则出生于恶劣环境条件下的个体应当更早开始繁殖。然而，这一假说在野生种群中尚未得到实证检验。本研究依托针对斯瓦尔巴群岛驯鹿（Svalbard reindeer）的长期纵向研究数据，以雪面降雨（rain-on-snow, ROSutero）作为子宫内环境暴露的量化指标，探究成年雌性个体对子宫内环境条件的生活史响应随年龄的变化规律。研究结果显示，经历高ROSutero暴露的雌性个体，仅在7岁及以后才会出现繁殖成功率下降的情况，且该效应不受早期繁殖行为的影响。此类个体在2至6岁年龄段的年繁殖成功率，与表型更优异、经历低ROSutero暴露的同类雌性个体无显著差异。相较于出生于低ROSutero环境的雌性个体，出生于高ROSutero环境的年轻雌性会在更低的体重（约低2.5千克）时开展繁殖活动。早年暴露于恶劣环境的雌性个体的平均进化适合度，与早年暴露于良好环境的雌性个体相近。上述研究结果与内源性PAR假说的预测相符，表明针对早年环境条件的生活史响应，能够缓冲天气因素对种群动态产生的延迟效应。