Meeting Abstract
Life history theory predicts that age-specific mortality favors traits that optimize fitness by balancing investment between growth, reproduction and survival. For example, in songbirds, species with low adult mortality probability tend to have behavioral traits that favor their own survival over the care of offspring when faced with a predator. Physiological studies within species suggest that levels of maternal hormones in egg yolk provided to developing embryos may influence related behavioral traits in adults. Hormones can influence a variety of traits simultaneously, and selection on these hormonal pathways may allow rapid correlated change in important life history traits underlying adaptive strategies. Indeed, comparative studies have shown that yolk androgen concentrations are correlated with nest predation rates and explain growth and developmental rates across species. While offspring mortality is important, the effect of adult mortality on the evolution yolk hormone concentrations remains poorly understood. We examined the relationship between yolk testosterone and corticosterone concentrations, adult mortality probabilities, and behavioral responses to experimental predator presentations across sympatric songbird species, while controlling for nest predation rates. Understanding these relationships promises to shed light on the physiological mechanisms that underlie life history variation and the role of maternal effects in adaptive evolution.
