Department of Biology, Indiana University, Bloomington, Indiana, USA.
Department of Biology, Duke University, Durham, North Carolina, USA.
Am J Biol Anthropol. 2023 Nov;182(3):357-371. doi: 10.1002/ajpa.24849. Epub 2023 Sep 22.
In many taxa, adverse early-life environments are associated with reduced growth and smaller body size in adulthood. However, in wild primates, we know very little about whether, where, and to what degree trajectories are influenced by early adversity, or which types of early adversity matter most. Here, we use parallel-laser photogrammetry to assess inter-individual predictors of three measures of body size (leg length, forearm length, and shoulder-rump length) in a population of wild female baboons studied since birth.
Using >2000 photogrammetric measurements of 127 females, we present a cross-sectional growth curve of wild female baboons (Papio cynocephalus) from juvenescence through adulthood. We then test whether females exposed to several important sources of early-life adversity-drought, maternal loss, low maternal rank, or a cumulative measure of adversity-were smaller for their age than females who experienced less adversity. Using the "animal model," we also test whether body size is heritable in this study population.
Prolonged early-life drought predicted shorter limbs but not shorter torsos (i.e., shoulder-rump lengths). Our other measures of early-life adversity did not predict variation in body size. Heritability estimates for body size measures were 36%-67%. Maternal effects accounted for 13%-17% of the variance in leg and forearm length, but no variance in torso length.
Our results suggest that baboon limbs, but not torsos, grow plastically in response to maternal effects and energetic early-life stress. Our results also reveal considerable heritability for all three body size measures in this study population.
在许多类群中，不良的早期环境与成年后生长受限和体型较小有关。然而，在野生灵长类动物中，我们几乎不知道轨迹是否、在哪里以及在多大程度上受到早期逆境的影响，或者哪种类型的早期逆境最重要。在这里，我们使用平行激光摄影测量法来评估个体间的预测因子，这些预测因子与我们自出生以来就一直在研究的一个野生雌性狒狒群体的三个身体尺寸（腿长、前臂长和肩臀长）有关。
使用超过 2000 次对 127 只雌性的摄影测量测量，我们提出了一个从青春期到成年的野生雌性狒狒的横截面生长曲线。然后，我们测试了暴露于几种重要早期逆境源（干旱、母亲丧失、低母亲等级或逆境的累积测量）的雌性是否比经历较少逆境的雌性年龄更小。使用“动物模型”，我们还测试了体型在这个研究群体中是否具有遗传性。
长期的早期生命干旱预测了四肢较短，但不是躯干较短（即肩臀长度）。我们早期生活逆境的其他测量值不能预测体型的变化。体型测量值的遗传力估计值为 36%-67%。母体效应解释了腿和前臂长度变异的 13%-17%，但对躯干长度的变异没有影响。
我们的结果表明，狒狒的四肢，但不是躯干，在母体效应和早期生命能量应激的影响下具有可塑性。我们的结果还显示，在这个研究群体中，所有三个身体尺寸测量值都具有相当大的遗传性。
