Delayed Reproduction as a Driver of Longevity

Cameron MacDonald

Understanding the evolutionary forces that shape aging is central to both biology and medicine. While classic theories—such as Medawar’s mutation accumulation, Williams’ antagonistic pleiotropy, and Kirkwood’s disposable soma—have provided foundational insights, the population-level consequences of reproductive timing remain underexplored. Here, I propose that delayed reproduction may intensify selection on alleles that enhance survival and late-life reproductive success, potentially shaping lifespan evolution.

Supported by conceptual models and comparative life history data, this perspective suggests that reproductive timing is not solely a consequence of life history evolution, but may itself influence the direction and strength of selection on longevity. This framework complements classical aging theory by drawing attention to potential feedback dynamics—where delayed reproduction favors longevity, which in turn enables further reproductive delay.

By highlighting reproductive timing as a possible driver of long-term selection on aging traits, this work offers a testable hypothesis that invites further empirical investigation and theoretical refinement across taxa.