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

雌性根据其环境的身体条件，如死亡风险和资源质量和可获得性，调整其生殖策略。然而，在智人中，社会条件在繁殖中也起着关键作用。我的长期目标是开发一个综合模型，将影响人类女性一生生育轨迹的所有社会生态因素整合在一起。我之前研究过女性在生殖阶段(第一胎到最后一胎)的生殖适应，我的短期目标是研究哺乳动物女性的两个罕见的生殖特征：异常长的、亚繁殖力的生殖过渡，结束了她们的生殖寿命：a)月经初潮到第一胎，b)围绝经期到更年期。这些转变在种群内和种群间表现出显著的起效时间、持续时间以及繁殖力水平的差异。我推测，这种变异是直接健康和间接健康收益之间复杂权衡的结果，这些健康收益与向近亲(生殖成熟前的兄弟姐妹、侄子和侄子；更年期的子女和孙辈)提供异体母系护理有关。*方法：为了实现我的目标，我将继续对107名危地马拉Kakchiquel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，我将在2019/20年度通过人体测量评估、月经日记和生殖生物标志物的量化来监测他们生殖状态的年龄相关变化。将通过社会、人口、饮食和资源可获得性访谈以及发病率和死亡风险数据来评估社会生态条件在社区和个人层面上的作用。个人的能量状态和生理压力水平将通过饮食日记和尿液生物标记物的量化进行监测。我将把这些信息与我从2000年以来从相同个人那里收集的数据结合起来。*影响：拟议的研究将产生迄今为止最完整的前瞻性数据集，以调查在传统的、自给自足的、自然生育的人口中，人类女性如何根据其累积的社会生态环境调整其生殖策略。我的研究结果还将加深我们对社交网络在女性生殖发育和衰老方面的作用的理解。关于人类雌性在这两个罕见的生殖转变中直接和间接适应之间的权衡所获得的知识，应该会为塑造人类雌性生殖生活史的选择性过程提供新的理论见解，并指导对其他合作繁殖物种中类似现象的研究。

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.