Early life adversity predicts shorter adult lifespan in several animal taxa. Yet, work on long-lived primate populations suggests the evolution of mechanisms that contribute to resiliency and long lives despite early life insults. Here, we tested associations between individual and cumulative early life adversity and lifespan on rhesus macaques at the Cayo Santiago Biological Field Station using 50 years of demographic data. We performed sex-specific survival analyses at different life stages to contrast short-term effects of adversity (i.e., infant survival) with long-term effects (i.e., adult survival). Rhesus macaques exposed to adversity at birth suffered a significant increase in mortality risk during infancy with both individual and cumulative adversities having the highest impact among affected females. However, when considering adult lifespan, affected males showed higher vulnerability to both individual and cumulative adversities early in life. Our study shows profound immediate effects of insults at birth on female infant cohorts and suggests that affected female adults are more robust (i.e., viability selection). In contrast, adult males who experienced harsh conditions early in life showed an increased mortality risk at older ages as expected from hypotheses of long-term effects of individual, as well as cumulative, adversity early in life. Our study reveals that mortality risk during infancy is mainly driven by the type of adversity, rather than their accumulation at birth. However, cumulative adversity seems to play a major role in adult survival. Our analysis suggests sex-specific selection pressures on life histories and highlights the need for studies addressing the effects of early life adversity across multiple life stages. This information is critical for planning life stage-specific strategies of conservation interventions.

Extreme climatic events may influence individual-level variability in phenotypes, survival, and reproduction, and thereby drive the pace of evolution. Here, we quantify how experiencing major hurricanes influences individual life courses in the Cayo Santiago rhesus macaques. Our results show that major hurricanes increase heterogeneity in reproductive life courses despite an average reduction in mean fertility and survival, i.e. shortened life courses. In agreement with this, the population is expected to achieve stable population dynamics faster after a hurricane. Our work suggests that natural disasters force individuals into new niches to potentially reduce strong competition during poor environments where mean reproduction and survival are compromised. We also demonstrate that variance in lifetime reproductive success and longevity are differently affected by hurricanes, and such variability is mostly driven by survival.

Raisa Hernández-Pachecoa*, Ulrich K. Steinerb, Alexandra G. Rosatic, Shripad TuljapurkardaCalifornia State University-Long Beach, Department of Biological Sciences, 1250 N Bellflower Blvd, Long Beach, CA, USA 90840-0004bFreie Universität Berlin, Biological Institute, Königin-Luise Str. 1-3,14195 Berlin, Germany; cDepartments of Psychology and Anthropology, University of Michigan, 530 Church St, Ann Arbor, MI, USA 48109 d327 Campus Dr., Rm 233, Stanford University, Stanford, CA, USA 94305*Corresponding author:[email protected] interests statement : None.Abstract . Several social traits including status, integration, early-life adversity, and their interactions across the life course can predict health, reproduction, and mortality in humans. Accordingly, individual sociality plays a fundamental role in the emergence of phenotypes driving the evolution of aging. Recent work placing human social gradients on a biological continuum with other species provides a useful evolutionary context for aging questions, but there is still a need for a unified evolutionary framework for sociality, health, and aging. Here, we first summarize current challenges to disentangle the effects of the social environment on human life courses. Next, we review recent advances in comparative biodemography and propose a biodemographic perspective to address socially driven health phenotype distributions and their evolutionary consequences using a nonhuman primate population. This new comparative approach uses evolutionary demography to address the joint dynamics of populations, sociality, phenotypes, and life history parameters. The long-term goal is to advance our understanding of the link between individual sociality, population-level outcomes, and the evolution of aging.

Adversity early in life can shape the reproductive potential of individuals through negative effects on health and lifespan. However, long-lived populations with multiple reproductive events may present alternative life history strategies to optimize reproductive schedules and compensate for shorter lifespans when experiencing adversities early in life. Here, we quantify the effects of major hurricanes and density-dependence as sources of early-life ecological adversity on the mean age-specific fertility, reproductive pace, and lifetime reproductive success (LRS) of Cayo Santiago rhesus macaque females, and explored demographic mechanisms for reproductive schedule optimization later in life. Females experiencing major hurricanes early in life exhibit a delayed reproductive debut, but maintain inter-birth intervals and show a higher mean fertility during prime reproductive ages relative to females experiencing no hurricanes. Increasing density at birth is associated to a decrease in mean fertility and LRS. When combined, our study reveals that early-life ecological adversities predict a delay-overshoot pattern in mean age-specific fertility that supports the maintenance of LRS. In contrast to predictive adaptive response models of accelerated reproduction, the long-lived Cayo Santiago population presents a novel reproductive strategy where females who experience major natural disasters early in life ultimately overcome their initial reproductive penalty with no overall negative fitness outcomes. Such strategy suggests that investing more energy into development and maintenance at younger ages allows long-lived females experiencing early-life ecological adversity to reproduce at a mean rate equivalent to that of a typical female cohort later in life.