Physiological mechanisms mediating the trade-off between survival and reproduction in birds

Abstract

Despite an abundance of evidence in support of a trade-off between survival and reproduction in birds, we still have a limited understanding of the physiological mechanisms allowing this trade-off to persist. In this review, I discuss three of physiological pathways hypothesized to mediate the trade-off between survival and reproduction in birds: 1) baseline corticosterone, 2) oxidative stress, and 3) immune function. While I found evidence in the literature in support of each of these pathways as a mechanism mediating this trade-off, there are still many questions that remain unanswered for each of the proposed mechanisms. In particular, given that these mechanisms are unlikely to be mutually exclusive, there is currently a lack of research incorporating interactions between mechanisms. I suggest that future research should include multiple mechanisms and their interactions, as a sufficient effect size of the trade-off between survival and reproduction may only be detected when these are considered.