Le Coeur Christie, Pisanu Benoît, Chapuis Jean-Louis, Robert Alexandre
Centre d'Ecologie et des Sciences de la Conservation (CESCO), Muséum national d'Histoire naturelle, Centre National de la Recherche Scientifique, Sorbonne-Université, 61 rue Buffon, 75005, Paris, France.
Oecologia. 2018 Nov;188(3):765-776. doi: 10.1007/s00442-018-4259-3. Epub 2018 Sep 15.
Reproduction costs depend on the general life-history strategies employed by organisms for resource acquisition, the decision rules on resource allocation, and the resource availability. Although the predictability of resource availability is expected to influence the breeding strategy, the relationship between predictability and strategy has rarely been investigated at the population level. One reason is that, while the resource availability is commonly variable in space and time, their predictability is generally assumed constant. Here, we addressed the temporal variation of the breeding strategy and its associated survival cost in a hibernating population of Tamias sibiricus, in which food resources vary in their availability between years and in their predictability within years. Based on 11 years of mark-recapture data, we used multi-event modelling to investigate seasonal variations in reproduction costs of female chipmunks that breed twice a year (spring and summer). In summer, during which a large variety and quantity of resources is available (income breeding strategy), the proportion of breeding females was consistent across years and reproduction yielded no mortality cost. In contrast, in spring, the proportion of breeding females was positively correlated with the amount of resources available for hibernation (partial capital breeding strategy). Spring reproduction yielded no immediate cost, but induced a delayed mortality cost over the next winter if future unknown conditions were unfavorable. Our findings highlight complex temporal reproductive patterns in a short-lived species: not only does the modality of resource acquisition vary among seasons, but also the decision rule to breed and its associated cost.
繁殖成本取决于生物体用于获取资源的一般生活史策略、资源分配的决策规则以及资源的可利用性。尽管资源可利用性的可预测性预计会影响繁殖策略，但在种群水平上，可预测性与策略之间的关系很少被研究。一个原因是，虽然资源的可利用性通常在空间和时间上是可变的，但它们的可预测性通常被假定为恒定的。在此，我们研究了西伯利亚花鼠冬眠种群中繁殖策略及其相关生存成本的时间变化，在该种群中，食物资源的可利用性在年份之间有所不同，且在同一年份内其可预测性也存在差异。基于11年的标记重捕数据，我们使用多事件建模来研究每年繁殖两次（春季和夏季）的雌性花鼠繁殖成本的季节性变化。在夏季，此时有大量多样的资源可供利用（收入繁殖策略），繁殖雌性的比例在各年份间保持一致，且繁殖不会产生死亡成本。相比之下，在春季，繁殖雌性的比例与可供冬眠的资源量呈正相关（部分资本繁殖策略）。春季繁殖不会立即产生成本，但如果未来未知条件不利，会在次年冬季引发延迟的死亡成本。我们的研究结果凸显了一个短命物种复杂的时间繁殖模式：不仅资源获取方式在不同季节有所不同，而且繁殖的决策规则及其相关成本也存在差异。
