DOI: 10.5061/dryad.th03671
title: Data from: Macroevolutionary patterning in glucocorticoids suggests different selective pressures shape baseline and stress-induced levels

description: Glucocorticoid (GC) hormones are important phenotypic mediators across
 vertebrates, but their circulating concentrations can vary markedly. Here
 we investigate macroevolutionary patterning in GC levels across tetrapods
 by testing seven specific hypotheses about GC variation, and evaluating
 whether the supported hypotheses reveal consistent patterns in GC
 evolution. If selection generally favors the “supportive” role of GCs in
 responding effectively to challenges, then baseline and/or stress-induced
 GCs may be higher in challenging contexts. Alternatively, if selection
 generally favors “protection” from GC-induced costs, GCs may be lower in
 environments where challenges are more common or severe. The predictors of
 baseline GCs were all consistent with supportive effects: levels were
 higher in smaller organisms, and in those inhabiting more energetically
 demanding environments. During breeding, baseline GCs were also higher in
 populations and species with fewer lifetime opportunities to reproduce.
 The predictors of stress-induced GCs were instead more consistent with the
 protection hypothesis: during breeding, levels were lower in organisms
 with fewer lifetime reproductive opportunities. Overall, these patterns
 indicate a surprising degree of consistency in how some selective
 pressures shape GCs across broad taxonomic scales; at the same time, in
 challenging environments selection appears to operate on baseline and
 stress-induced GCs in distinct ways.
description: BaselineCort_Vitousek_AmNatContains data on baseline glucocorticoid levels, and associated phenotypic, life history, and environmental data. Column names: Species, Vert_Group, Sex, Therm (‘ECT’ – Ectotherm/’END’ – Endotherm), Pop_ID (identifies the population from which samples were collected), BC_Mean (mean baseline glucocorticoid level in ng/mL), Lab_ID, Breeding_season, LongevityMax (maximum longevity), Max Breed (maximum lifetime reproductive attempts), Mass, MR (metabolic rate), Social_measured (degree of social grouping during season of measurement), Temp_Season (mean monthly temperature during season of measurement), Precip_Season (mean monthly precipitation during season of measurement), TempSD_Season (intra-seasonal variation in temperature – standard deviation), PrecipSD_Season (intra-seasonal variation in precipitation – standard deviation), TempSD_InterSeason (inter-seasonal variation – standard deviation), PrecipSD_InterSeason (inter-seasonal variation in precipitation – standard deviation), VarPC1 (first principal component score of environmental variation, VarPC2 (second principal component score of environmental variation).StressedCort_Vitousek_AmNatContains information on stress-induced glucocorticoid levels, and associated phenotypic, life history, and environmental data. Column names: Species, Vert_Group, Sex, Therm (‘ECT’ – Ectotherm/’END’ – Endotherm), Pop_ID (identifies the population from which samples were collected), BC_Mean (mean baseline glucocorticoids in ng/mL), SC_Mean (mean stress-induced glucocorticoids in ng/mL), Lab_ID, Breeding_season, LongevityMax (maximum longevity), Max Breed (maximum lifetime reproductive attempts), Mass, MR (metabolic rate), Social_measured (degree of social grouping during season of measurement), Temp_Season (mean monthly temperature during season of measurement), Precip_Season (mean monthly precipitation during season of measurement), TempSD_Season (intra-seasonal variation in temperature – standard deviation), PrecipSD_Season (intra-seasonal variation in precipitation – standard deviation), TempSD_InterSeason (inter-seasonal variation – standard deviation), PrecipSD_InterSeason (inter-seasonal variation in precipitation – standard deviation), VarPC1 (first principal component score of environmental variation, VarPC2 (second principal component score of environmental variation).