An experimental analysis of the heritability of variation in glucocorticoid concentrations in a wild avian population

Glucocorticoid hormones (CORT) are predicted to promote adaptation to variable environments, yet little is known about the potential for CORT secretion patterns to respond to selection in free-living populations. We assessed the heritable variation underlying differences in hormonal phenotypes using...

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Bibliographic Details
Published in:Proceedings of the Royal Society. B, Biological sciences Biological sciences, 2014-09, Vol.281 (1790), p.20141302-20141302
Main Authors: Jenkins, Brittany R., Vitousek, Maren N., Hubbard, Joanna K., Safran, Rebecca J.
Format: Article
Language:English
Subjects:
Adaptation, Physiological - physiology
Animal Model
Animals
Animals, Newborn
Barn Swallow
Corticosterone - blood
Corticosterone - genetics
Cross-Foster
Environmental Variation
Female
Genotype
Glucocorticoids
Glucocorticoids - blood
Glucocorticoids - genetics
Heritability
Hirundo rustica erythrogaster
Male
Stress, Physiological - physiology
Swallows - genetics
Swallows - growth & development
Swallows - physiology
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Summary:Glucocorticoid hormones (CORT) are predicted to promote adaptation to variable environments, yet little is known about the potential for CORT secretion patterns to respond to selection in free-living populations. We assessed the heritable variation underlying differences in hormonal phenotypes using a cross-foster experimental design with nestling North American barn swallows (Hirundo rustica erythrogaster). Using a bivariate animal model, we partitioned variance in baseline and stress-induced CORT concentrations into their additive genetic and rearing environment components and estimated their genetic correlation. Both baseline and stress-induced CORT were heritable with heritability of 0.152 and 0.343, respectively. We found that the variation in baseline CORT was best explained by rearing environment, whereas the variation in stress-induced CORT was contributed to by a combination of genetic and environmental factors. Further, we did not detect a genetic correlation between these two hormonal traits. Although rearing environment appears to play an important role in the secretion of both types of CORT, our results suggest that stress-induced CORT levels are underlain by greater additive genetic variance compared with baseline CORT levels. Accordingly, we infer that the glucocorticoid response to stress has a greater potential for evolutionary change in response to selection compared with baseline glucocorticoid secretion patterns.
ISSN:0962-8452
1471-2945
1471-2954
DOI:10.1098/rspb.2014.1302