Effects of early life adversity on maternal effort and glucocorticoids in wild olive baboons

Abstract: Adverse experiences during early life exert important effects on development, health, reproduction, and social bonds, with consequences often persisting across generations. A mother’s early life experiences can impact her offspring’s development through a number of pathways, such as maternal care, physiological signaling through glucocorticoids, or even intergenerational effects like epigenetic inheritance. Early life adversity in female yellow baboons (Papio cynocephalus) predicts elevated glucocorticoids, reduced sociality, shortened lifespan, and higher offspring mortality. If baboon mothers with more early life adversity, experience poorer condition and struggle to provide for their offspring, this could contribute to the persisting transgenerational effects of adversity. Here, we examined the effects of mothers’ early life adversity on their maternal effort, physiology, and offspring survivability in a population of olive baboons, Papio anubis. Mothers who experienced more adversity in their own early development exerted greater maternal effort (i.e., spent more time nursing and carrying) and had higher levels of glucocorticoid metabolites than mothers with less early life adversity. Offspring of mothers with more early life adversity had reduced survivability compared to offspring of mothers with less early life adversity. There was no evidence that high maternal social rank buffered the effects of early life adversity. Our data suggest early life experiences can have lasting consequences on maternal effort and physiology, which may function as proximate mechanisms for intergenerational effects of maternal experience. Significance statement: Animals exposed to early life adversity experience both immediate and lasting consequences. If early life adversity exerts developmental constraints that affect a mother’s ability to provide for her offspring, this could explain the transgenerational effects of early life adversity. In our study of wild olive baboons, we examined how a mother’s own early life adversity predicts her maternal effort (i.e., nursing and carrying time), maternal fecal glucocorticoid levels, and offspring outcomes. We found that female baboons who experienced more early life adversity had higher glucocorticoid levels during pregnancy and lactation, exerted more maternal effort, and produced offspring with higher mortality risk than females with less early life adversity. Our results suggest that female baboons with more early life adversity experience developmental constraints and struggle to invest in offspring, which likely contributes to persisting effects of early life adversity across generations.