Data from: Developmental constraints in a wild primate

Early life experiences can dramatically affect adult traits. However, the evolutionary origins of such early life effects are debated. The 'predictive adaptive response' (PAR) hypothesis argues that adverse early environments prompt adaptive phenotypic adjustments that prepare animals for similar challenges in adulthood. In contrast, the 'developmental constraints' hypothesis argues that early adversity is generally costly. To differentiate between these hypotheses, we studied two sets of wild female baboons: those born during low rainfall, low-quality years and those born during normal rainfall, high-quality years. For each female, we measured fertility-related fitness components during years in adulthood that matched and mismatched her early conditions. We found support for the developmental constraints hypothesis: females born in low-quality environments showed greater fertility declines during drought years than females born in high-quality environments, even though
drought years matched the early conditions of females born in low-quality environments. Additionally, we found that females born in low-quality years to high status mothers did not suffer reduced fertility during drought years. These results indicate that early ecological adversity did not prepare individuals to cope with later life ecological challenges. Instead, individuals that experienced at least one high-quality early environment—either ecological or social—were more resilient to later life ecological stress. Together, these data suggest that early adversity carries lifelong costs, consistent with the developmental constraints hypothesis.