From gestation to weaning: combining robust design and multi-event models unveils cost of lactation in a large herbivore

1. The cost of current reproduction on survival or future reproduction is one of the most studied trade-offs governing resource distribution between fitness components. Results have often been clouded, however, by the existence of individual heterogeneity, with high-quality individuals able to allocate energy to several functions simultaneously, at no apparent cost. 2. Surprisingly, it has also rarely been assessed within a breeding season by breaking down the various reproductive efforts of females from gestation to weaning, even though resource availability and energy requirements vary greatly. 3. We filled this gap by using an intensively monitored population of Pyrenean chamois and by expanding a new methodological approach integrating robust design in a multi-event framework. We distinguished females that gave birth or not, and among reproducing females whether they lost their kid or successfully raised it until weaning. We estimated spring and summer juvenile survival, investiga...1. 当前繁殖对自身存活及未来繁殖的成本，是调控适合度组分（fitness components）间资源分配的最受广泛研究的权衡（trade-offs）之一。然而，个体异质性（individual heterogeneity）的存在常常使得相关研究结果模糊不清：优质个体能够同时将能量分配至多项生命功能，且无明显成本代价。 2. 令人意外的是，尽管繁殖季内资源可获得性与能量需求差异极大，却极少有研究通过拆解雌性个体从妊娠（gestation）到断乳（weaning）的各项繁殖投入，在繁殖季内开展此类评估。 3. 本研究借助密集监测的比利牛斯臆羚（Pyrenean chamois）种群，并拓展了一种在多事件框架（multi-event framework）中整合稳健设计（robust design）的全新方法论途径，填补了这一研究空白。我们区分了产仔与未产仔的雌性个体，并在繁殖雌性中进一步区分了幼崽夭折与成功将幼崽抚养至断乳的个体。此外，本研究还估算了春季与夏季的幼体存活率，并对……