Meeting Abstract
Different behavioral and physiological phenotypes that may impact the fitness of an individual exist within populations across taxa. These individual differences are often repeatable across the lifetime of an individual. In our study species, the Florida scrub-jay (Aphelocoma coerulescens), repeatable, long-term physiological phenotypes (high to low corticosterone response) impact reproductive success and survival, although in opposite directions for males and females. It remains unclear when and how these phenotypes develop, although evidence suggests that it occurs early in development, and that early exposure to environmental factors shape phenotypes to match the conditions an individual experiences. In this study we investigated the hypothesis that the adult phenotype is established before or during early development by monitoring individual Florida scrub-jays over the long-term (nestling through adulthood). We monitored nestling mass at hatch, growth and begging rate across the nestling period, as well as an individual’s physiological stress response at 11 days of age. Additionally, we assessed all individuals’ physiological stress responsiveness (i.e., corticosterone response to capture and handling) at 1 year of age. Our results suggest the phenotype is established early on in development, as mass within a few hours of hatching predicted an individual’s future stress response. We also found that begging rate was correlated with adult corticosterone but the direction of the relationship changed as the individual aged. Further, nestling mass at hatching and begging rates were correlated in males only, suggesting a different developmental strategy for the sexes. These results reveal that the physiological phenotype of an individual is established early on in life, but that males and females differ early in development.
