Differential allocation of parental investment and the trade-off between size and number of offspring

When parents decide how much to invest in current versus future offspring and how many offspring to divide their current investments between, the optimal decision can be affected by the quality of their partner. This differential allocation (DA) is highly dependent on exactly how partner quality affects reproductive costs and offspring benefits. We present a stochastic dynamic model of DA in which females care for a series of clutches when mated with males of different quality. In each reproductive event, females choose the size and number of offspring. We find that if partner quality affects reproductive costs, then DA in total reproductive investment occurs only via changes in the number of offspring. DA in the optimal size of the offspring occurs only if partner quality affects the offspring benefit function. This is mostly in the form of greater female investment per offspring as male quality decreases. Simultaneously, we find adaptive DA increases in the number of offspring, and th...当双亲权衡对当前后代与未来后代的投资额度，以及如何在多个后代间分配当前投资时，其最优决策会受到配偶质量的影响。这种差异分配（Differential Allocation，DA）的具体模式，高度取决于配偶质量如何影响繁殖成本与后代收益。我们构建了一个关于差异分配的随机动态模型：当雌性与不同质量的雄性交配后，需抚育多窝卵；在每一次繁殖事件中，雌性可自主选择后代的体型与数量。研究结果表明，若配偶质量影响繁殖成本，则总繁殖投资的差异分配仅通过后代数量的变化实现；而后代最优体型的差异分配，仅在配偶质量影响后代收益函数时才会发生，且通常表现为随着雄性质量下降，雌性对单只后代的投资有所增加。同时，我们发现适应性差异分配会随后代数量增加而提升，且...