title: Repeatability of baseline and stress-induced corticosterone levels across early life stages in the Florida scrub-jay (Aphelocoma coerulescens).
abstract: Recent studies have posited that the pattern of glucocorticoid secretion within an individual represents a stable, fixed physiological trait. To test this hypothesis, we assessed the repeatability of baseline and stress-induced corticosterone (CORT) secretion across developmental stages and years in Florida scrub-jays. We sampled individuals from multiple cohorts repeatedly from the age of 11 days post-hatch up to 4 years of age. We found a significant degree of repeatability within individuals in stress-induced corticosterone levels, i.e., the amount of hormone secreted during a standardized stress protocol (corrected integrated corticosterone). However, baseline corticosterone levels were not statistically repeatable, although there was some indication that nestling levels predicted levels at 1 year of age. The results of this study indicate that stress-induced CORT levels are consistent within individual scrub-jays, and the degree to which a young jay mounts an acute stress response appears to be somewhat "set" by the age of nutritional independence. Thus stress-induced corticosterone secretion appears to be a stable, repeatable trait within individuals and as such may be subject to natural selection.
authors.affiliation: Department of Biological Sciences, The University of Memphis, 3774 Walker Ave. Memphis, TN 38152, USA. mrensel@ucla.edu
authors.forename: Michelle A
authors.initials: MA
authors.lastname: Rensel
authors.forename: Stephan J
authors.initials: SJ
authors.lastname: Schoech
mesh_terms: D000367:Age Factors; D000818:Animals; D003345:Corticosterone / Q000097:blood*; D046368:Crows / Q000097:blood* / Q000254:growth & development; D007030:Hypothalamo-Hypophyseal System / Q000378:metabolism; D010913:Pituitary-Adrenal System / Q000378:metabolism; D011863:Radioimmunoassay; D015203:Reproducibility of Results; D012098:Reproduction / Q000502:physiology*; D013312:Stress, Physiological
chemical_list: D003345:Corticosterone