Socio-Ecologic Modulators of Human Females' Reproductive Maturation and Senescence: A Life History Approach

人类女性生殖成熟和衰老的社会生态调节因素：生活史方法

• 批准号: RGPIN-2018-06750
• 负责人: Nepomnaschy, Pablo
• 金额: $ 4.81万
• 依托单位: Simon Fraser University
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2022
• 资助国家: 加拿大
• 起止时间: 2022-01-01 至 2023-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=757065
• 关键词: Socio; Ecologic; Modulators; Human; Females

Females adjust their reproductive strategies according to their environments' physical conditions, such as mortality risks and resource quality and availability. In Homo sapiens, however, social conditions also play a critical role in reproduction. My long-term goal is to develop a synthetic model that integrates all socio-ecological factors affecting human females' reproductive trajectories across their lifespan. Having previously studied female reproductive adaptations during the reproductive phase (first to last birth), my short-term goal is to study two rare reproductive traits for mammalian females: the unusually long, sub-fecund, reproductive transitions bookending their reproductive lifespans: a) menarche to first birth and b) peri-menopause to menopause. These transitions exhibit marked within- and among-population variation in the timing of their onset, duration as well as in fecundability levels. I hypothesize that this variation is the result of complex trade-offs between direct fitness and indirect fitness gains associated with the provision of allomaternal care to close relatives (siblings, nieces and nephews before reproductive maturation; children and grandchildren during menopause). Methods: To achieve my goals I will continue a cohort study of 107 Guatemalan Kakchiquel Mayan mothers and 100 of their daughters that I initiated in 2000. To study reproductive maturation and senescence, in 2019/20, I will monitor age related changes in their reproductive status through anthropometric evaluations, menstrual diaries and quantification of reproductive bio-markers. The role of socio-ecological conditions at the community and individual levels will be evaluated through social, demographic, dietary, and resource availability interviews as well as morbidity and mortality risk data. Individuals' energy status and physiologic stress levels will be monitored through dietary diaries and the quantification of urinary biomarkers. I will integrate this information with data I have collected since 2000 from the same individuals. Impact: The proposed research will yield the most complete prospective dataset to date to investigate how human females adjust their reproductive strategies according to their cumulative socio-ecological environments in a traditional, subsistence, natural-fertility population. My results will also further our understanding of the role that social networks have on female reproductive development and senescence. The knowledge gained regarding human females' trade-offs between direct and indirect fitness during these two rare reproductive transitions should both, yield novel theoretical insights into the selective processes that have shaped human females' reproductive life histories and guide the study of similar phenomena in other cooperatively-breeding species.

雌性根据环境的物理条件（例如死亡风险以及资源质量和可用性）调整其生殖策略。然而，对于智人来说，社会条件在繁殖中也发挥着关键作用。我的长期目标是开发一个综合模型，整合影响人类女性一生生殖轨迹的所有社会生态因素。之前研究过女性在生殖阶段（从头胎到末胎）的生殖适应，我的短期目标是研究哺乳动物雌性的两种罕见的生殖特征：异常漫长的、生育力不足的生殖过渡，决定了它们的生殖寿命：a）初潮到第一胎，b）围绝经期到更年期。这些转变在其发生时间、持续时间以及生育力水平方面表现出明显的种群内和种群间差异。我假设这种差异是直接适应性和间接适应性增益之间复杂权衡的结果，这些适应性增益与向近亲（生殖成熟前的兄弟姐妹、侄女和侄子；绝经期间的孩子和孙辈）提供异母照顾有关。方法：为了实现我的目标，我将继续对 107 名危地马拉卡克奇克尔玛雅母亲和她们的 100 名女儿进行队列研究，这项研究是我在 2000 年发起的。为了研究生殖成熟和衰老，在 2019/20 年，我将通过人体测量评估、月经日记和生殖生物标记物量化来监测她们生殖状态的年龄相关变化。将通过社会、人口、饮食和资源可用性访谈以及发病和死亡风险数据来评估社会生态条件在社区和个人层面的作用。将通过饮食日记和尿液生物标志物的量化来监测个人的能量状态和生理压力水平。我会将这些信息与我自 2000 年以来从同一个人收集的数据整合起来。影响：拟议的研究将产生迄今为止最完整的前瞻性数据集，以调查人类女性如何根据传统的、自给自足的、自然生育的群体中累积的社会生态环境来调整其生殖策略。我的研究结果还将进一步加深我们对社交网络对女性生殖发育和衰老的作用的理解。关于人类女性在这两次罕见的生殖转变期间直接和间接适应性之间的权衡所获得的知识，应该既可以为塑造人类女性生殖生活史的选择过程提供新颖的理论见解，也可以指导其他合作繁殖物种中类似现象的研究。