Nitschke Matthew C, Kumar Viney, Milliner Katrina E, Hawkes Kristen, Kim Peter S
School of Mathematics and Statistics, The University of Sydney, Sydney, NSW, 2006, Australia.
Department of Anthropology, University of Utah, Salt Lake City, UT, 84112, USA.
Bull Math Biol. 2025 Jan 30;87(3):37. doi: 10.1007/s11538-025-01414-4.
Compared to our closest primate relatives, human life history involves greater longevity, which includes a distinctive postmenopausal life stage. Given mammalian reproductive physiology in which females build a finite stock of cells that can become oocytes early in life, which then continuously deplete mostly through cell death while males produce new sperm throughout adulthood, the postmenopausal stage makes the sex ratio in the fertile pool, called the adult sex ratio (ASR), male biased. Additionally, this affects a more fine-grained ratio, the operational sex ratio (OSR), defined as the ratio of males to females currently able to conceive. Here, we construct an ODE model in which males compete for paternities using either a multiple-mating or mate-guarding strategy. Our focus is on investigating the differences of strategy choice between populations with varying life histories, which include a distinct post-fertile stage for adult females. By simulating the system, we determine the dominant strategy and its dependence on various parameter combinations. Our results show that an increase in OSR and ASR correlates well with a change in the dominant strategy from multiple mating to guarding.
与我们关系最近的灵长类亲属相比，人类的生命历程包括更长的寿命，其中绝经后期是一个独特的生命阶段。鉴于哺乳动物的生殖生理，雌性在生命早期会生成有限数量的可发育成卵母细胞的细胞储备，这些细胞随后主要通过细胞死亡而持续消耗，而雄性在成年期会不断产生新的精子，绝经后期使得可生育群体中的性别比例，即成年性别比（ASR），偏向雄性。此外，这还会影响一个更细化的比例，即操作性别比（OSR），它被定义为当前能够受孕的雄性与雌性的比例。在此，我们构建了一个常微分方程模型，其中雄性使用多配偶或配偶守卫策略来竞争父权。我们的重点是研究具有不同生命历程的群体之间策略选择的差异，这些生命历程包括成年雌性独特的生育后期阶段。通过模拟该系统，我们确定了主导策略及其对各种参数组合的依赖性。我们的结果表明，OSR和ASR的增加与主导策略从多配偶到守卫的转变密切相关。
