1Department of Anthropology, Northwestern University, 2Cells to Society: The Center on Social Disparities and Health, Institute for Policy Research, Northwestern University
Friday 11:00-11:15, Galleria South
Life histories reflect strategies for allocating finite energy and time. Energetic constraints place limits on expenditures like growth and reproduction, while time constraints, such as reflected in high mortality rates, reduce optimism about living into the future and thus are predicted to lead to a “faster” life history strategy. In human females, theory predicts that both favorable nutrition and cues of high extrinsic mortality will lead to earlier maturity and more rapid reproductive scheduling. However, energetically stressful environments are often characterized by higher mortality, making it difficult to parse the relative effects of each on variation in life history trajectories. Here we simultaneously evaluate the importance of nutritional conditions and cues of mortality risk as influences on two key life history traits: age at maturity and reproductive scheduling. Data were collected across more than two decades in a large sample (n=669-784) of young adult women followed prospectively since birth as part of the Cebu Longitudinal Health and Nutrition Survey, in Cebu City, the Philippines. We find that measures of favorable energetic status, such as childhood growth outcomes, strongly predict earlier menarcheal age, whereas cues of environmental harshness are unrelated to maturational tempo. Adjusting for differences in menarcheal age, cues of environmental harshness do predict an earlier age of first sex, and among women who had had sex by 2009, higher parity. Our findings suggest that energetic conditions play a fundamental role as a constraint on maturational tempo in this Filipino population, whereas time constraints primarily shape reproductive scheduling.
JMB is supported by an NSF Graduate Research Fellowship.