In humans and other long-lived species, harsh conditions in early life often lead to profound differences in adult life expectancy. In response, natural selection is expected to accelerate the timing and pace of reproduction in individuals who experience some forms of early life adversity. However, the adaptive benefits of reproductive acceleration following early adversity remain untested. Here we test a recent version of this theory, the internal predictive adaptive response (iPAR) model, by assessing for the first time whether accelerating reproduction following early life adversity leads to higher lifetime reproductive success. We do so by leveraging 48 years of continuous, individual-based data from wild female baboons in the Amboseli ecosystem in Kenya, including prospective, longitudinal data on early life adversity, reproductive pace, and lifetime reproductive success.We find that while adversity in early life led to dramatically shorter lifespans, individuals who experiencedearly adversity didnot accelerate their reproduction compared to those who did not experience early adversity. Further, while accelerated reproduction predicted increased lifetime reproductive success overall, these benefits were not specific to females who experienced early life adversity. Instead, females only benefited from reproductive acceleration if they also led long lives. Our results call into question the theory that accelerated reproduction is an adaptive response to early life adversityin baboons and other long-lived species.

See the attached ReadMe file for instruction on how to use the data files.