标题： 将繁殖力-存活力权衡加入具有成熟延迟的离散种群模型 显示英文标题

标题： Adding a fecundity-survival trade-off to a discrete population model with maturation delay

摘要： 尽管在种群模型中经常加入新个体的成熟延迟，研究人员很少考虑出生到成熟之间的个体死亡率。 先前的研究在离散种群模型中加入了未成熟个体的死亡率，发现增加延迟会导致平衡状态下的种群水平下降。 此外，当成熟延迟超过临界阈值时，最终会导致所建模物种的灭绝。 由于在自然界中经常发现超过一个繁殖周期的成熟延迟，显然，成熟延迟也必须具有正向的好处，从而形成权衡。 我们通过推导一类具有成熟延迟和现实繁殖权衡假设的离散单种群模型来探索这种权衡。 在这种繁殖权衡中，虽然延长的成熟延迟会降低总的存活概率，但延迟会导致更大的体型，我们基于一些鱼类物种假设这会导致更高的繁殖力。 我们考察了两种情况：非密度依赖的存活和同批个体密度依赖的存活。 对于成熟和未成熟的个体，我们考虑了两种不同但流行的存活函数：Beverton-Holt模型和Ricker模型。 总体而言，我们确定了一个使种群规模最大化的正向成熟延迟，我们将其称为“最优成熟延迟”。 显示英文摘要

摘要： Although maturation delays of new individuals are frequently added in population models, researchers rarely account for the mortality of individuals between birth and maturity. Previous studies have added mortality of immature individuals to the maturation delay in discrete population models, finding that increasing the delay results in a decreased population level at equilibrium. Furthermore, increasing the maturation delay beyond a critical threshold ultimately leads to the extinction of the modeled species. Because maturation delays beyond one breeding cycle are often found in nature, clearly, maturation delays must also have a positive benefit leading to a trade-off. We explore such a trade-off by deriving a class of discrete single species models with a maturation delay and the realistic assumption of a reproductive trade-off. In this reproductive trade-off, although a prolonged maturation delay decreases the total probability of survival, the delay results in larger body sizes which we assume, based on some fish species, to result in higher fecundity. We examine two scenarios: density independent survival and cohort density dependent survival of immature individuals. For the mature and immature individuals, we consider two different, but popular, survival functions: the Beverton-Holt model and the Ricker model. Overall, we identify a positive maturation delay that maximizes the population size, which we refer to as "optimal maturation delay".