TY - CONF
T1 - The variance within: stress hormone levels vary and co-vary within but not among individual wild great tits Parus major
AU - Baugh, A.T.
AU - Van Oers, K.
AU - Dingemanse, N.
AU - Hau, M.
N1 - Reporting year: 2014
Metis note: 5665, AnE, Supplement Symposia and oral Abstracts
PY - 2014
Y1 - 2014
N2 - 114.1 BAUGH, A.T.*; VAN OERS, K.; DINGEMANSE, N.; HAU,M.; Swarthmore College, Netherlands Institute for Ecology, MaxPlanck Institute for Ornithology, Max Planck Institute forOrnithology; abaugh1@swarthmore.eduThe variance within: stress hormone levels vary and co−vary withinbut not among individual wild great tits Parus majorCirculating steroid hormones, such as glucocorticoids, can havediverse and enduring effects on the phenotype and might serve as abasis for individual differences in hormone−mediated traits. Tounderstand the extent and basis of variation in the circulatingconcentrations of hormones themselves it is important to accuratelydecompose within− and among−individual variance components.Previous research in songbirds suggests that concentrations ofglucocorticoids exhibit individual consistency, but the variance andcovariance of plasma hormones in free−living animals remainspoorly understood. In the present study, we repeatedly capturedindividual great tits Parus major from a wild population andmeasured their initial and stress−induced plasma corticosterone(CORT) levels. We evaluated variances and covariances in theseconcentrations using a mixed−modeling (character−state) approach.First, we examined within− and among−individual variances ininitial (CORT0) and stress−induced levels (CORT30) and found littleevidence of repeatability in either measure. Next, we examined thecovariance between CORT0 and CORT30. As predicted, given thelack of repeatability, we found no among−individual covariance inthese two measuresi.e. average initial levels did not correlate withaverage stress−induced levels. We did find, however, strongwithin−individual correlations suggesting that an underlyingenvironmental factor(s) simultaneously modulates changes in initialand stress−induced levels within the same individual. Together, theseresults suggest that plasma glucocorticoid concentrations aredetermined principally by acute environmental or state−dependentfactors.
AB - 114.1 BAUGH, A.T.*; VAN OERS, K.; DINGEMANSE, N.; HAU,M.; Swarthmore College, Netherlands Institute for Ecology, MaxPlanck Institute for Ornithology, Max Planck Institute forOrnithology; abaugh1@swarthmore.eduThe variance within: stress hormone levels vary and co−vary withinbut not among individual wild great tits Parus majorCirculating steroid hormones, such as glucocorticoids, can havediverse and enduring effects on the phenotype and might serve as abasis for individual differences in hormone−mediated traits. Tounderstand the extent and basis of variation in the circulatingconcentrations of hormones themselves it is important to accuratelydecompose within− and among−individual variance components.Previous research in songbirds suggests that concentrations ofglucocorticoids exhibit individual consistency, but the variance andcovariance of plasma hormones in free−living animals remainspoorly understood. In the present study, we repeatedly capturedindividual great tits Parus major from a wild population andmeasured their initial and stress−induced plasma corticosterone(CORT) levels. We evaluated variances and covariances in theseconcentrations using a mixed−modeling (character−state) approach.First, we examined within− and among−individual variances ininitial (CORT0) and stress−induced levels (CORT30) and found littleevidence of repeatability in either measure. Next, we examined thecovariance between CORT0 and CORT30. As predicted, given thelack of repeatability, we found no among−individual covariance inthese two measuresi.e. average initial levels did not correlate withaverage stress−induced levels. We did find, however, strongwithin−individual correlations suggesting that an underlyingenvironmental factor(s) simultaneously modulates changes in initialand stress−induced levels within the same individual. Together, theseresults suggest that plasma glucocorticoid concentrations aredetermined principally by acute environmental or state−dependentfactors.
M3 - Abstract
T2 - SICB 2014
Y2 - 1 April 2014
ER -