Meeting Abstract
There are three main hypotheses regarding the effects of glucocorticoids on fitness. The CORT-tradeoff hypothesis suggests that elevated CORT reallocates energy away from non-essential processes, such as reproduction, and towards survival. The CORT-adaptation hypothesis suggests that elevated CORT can enhance reproduction. The CORT-fitness hypothesis posits that since CORT is elevated when environmental or internal conditions deteriorate, elevated CORT will be associated with a decline in fitness overall (likely declines in both survival and reproduction). Tests of these hypotheses have produced highly variable results. We propose that the discrepancy in results may be due to variation in resource availability. In free-living animals, trade-offs may be masked by high resource availability in good years, but evident in poor years. Current literature testing between these hypotheses rarely incorporates metrics of resource availability. In 1986 Van Noordwijk and de Jong proposed the acquisition/allocation model to explain positive vs. negative correlations between reproduction and survival across individuals. Their model identifies resources as critical to evaluating individual allocation strategies (favoring reproduction vs survival), and therefore provides the ideal model for testing across the three CORT hypotheses. Here we 1) evaluate current literature on CORT and fitness in light of resource availability and 2) suggest methods for testing the three hypotheses using Van Noordwijk and de Jong’s framework.
