Data from: Reproductive trade-offs in extant hunter-gatherers suggest adaptive mechanism for the Neolithic expansion

The Neolithic demographic transition remains a paradox, because it is associated with both higher rates of population growth and increased morbidity and mortality rates. Here we reconcile the conflicting evidence by proposing that the spread of agriculture involved a life history quality–quantity trade-off whereby mothers traded offspring survival for increased fertility, achieving greater reproductive success despite deteriorating health. We test this hypothesis by investigating fertility, mortality, health, and overall reproductive success in Agta hunter-gatherers whose camps exhibit variable levels of sedentarization, mobility, and involvement in agricultural activities. We conducted blood composition tests in 345 Agta and found that viral and helminthic infections as well as child mortality rates were significantly increased with sedentarization. Nonetheless, both age-controlled fertility and overall reproductive success were positively affected by sedentarization and participation in cultivation. Thus, we provide the first empirical evidence, to our knowledge, of an adaptive mechanism in foragers that reconciles the decline in health and child survival with the observed demographic expansion during the Neolithic.

新石器时代人口转型（Neolithic demographic transition）至今仍是一个未解悖论：该过程既伴随着人口增长率的提升，同时也出现了发病率与死亡率的升高。对此，我们提出农业扩张过程中存在生活史质量-数量权衡（life history quality–quantity trade-off）假说以调和这一矛盾证据：即母亲们以子代存活率为代价换取更高的生育力，即便自身健康状况恶化，仍能获得更高的繁殖成功率。我们以营地定居程度、流动性以及参与农业活动水平存在差异的阿格塔（Agta）狩猎采集人群为研究对象，通过调查其生育力、死亡率、健康状况与整体繁殖成功率，对上述假说进行检验。我们对345名阿格塔人开展了血液成分检测，结果发现，随着定居程度的提升，病毒与蠕虫感染率以及儿童死亡率均显著升高。尽管如此，经年龄校正的生育力与整体繁殖成功率均随定居程度提升以及农耕参与度增加而呈现正向提升。据我们所知，本研究首次为狩猎采集人群中存在适应性机制提供了实证证据，该机制能够调和新石器时代健康状况与子代存活率下降与观测到的人口扩张之间的矛盾。