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Reversal of the adipostat control of torpor during migration in hummingbirds

Many small endotherms use torpor to reduce metabolic rate and manage daily energy balance. However, the physiological ‘rules’ that govern torpor use are unclear. We tracked torpor use and body composition in ruby-throated hummingbirds (Archilochus colubris), a long-distance migrant, throughout the s...

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Autores principales: Eberts, Erich R, Guglielmo, Christopher G, Welch, Kenneth C
Formato: Online Artículo Texto
Lenguaje:English
Publicado: eLife Sciences Publications, Ltd 2021
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8719877/
https://www.ncbi.nlm.nih.gov/pubmed/34866575
http://dx.doi.org/10.7554/eLife.70062
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author Eberts, Erich R
Guglielmo, Christopher G
Welch, Kenneth C
author_facet Eberts, Erich R
Guglielmo, Christopher G
Welch, Kenneth C
author_sort Eberts, Erich R
collection PubMed
description Many small endotherms use torpor to reduce metabolic rate and manage daily energy balance. However, the physiological ‘rules’ that govern torpor use are unclear. We tracked torpor use and body composition in ruby-throated hummingbirds (Archilochus colubris), a long-distance migrant, throughout the summer using respirometry and quantitative magnetic resonance. During the mid-summer, birds entered torpor at consistently low fat stores (~5% of body mass), and torpor duration was negatively related to evening fat load. Remarkably, this energy emergency strategy was abandoned in the late summer when birds accumulated fat for migration. During the migration period, birds were more likely to enter torpor on nights when they had higher fat stores, and fat gain was positively correlated with the amount of torpor used. These findings demonstrate the versatility of torpor throughout the annual cycle and suggest a fundamental change in physiological feedback between adiposity and torpor during migration. Moreover, this study highlights the underappreciated importance of facultative heterothermy in migratory ecology.
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spelling pubmed-87198772022-01-05 Reversal of the adipostat control of torpor during migration in hummingbirds Eberts, Erich R Guglielmo, Christopher G Welch, Kenneth C eLife Ecology Many small endotherms use torpor to reduce metabolic rate and manage daily energy balance. However, the physiological ‘rules’ that govern torpor use are unclear. We tracked torpor use and body composition in ruby-throated hummingbirds (Archilochus colubris), a long-distance migrant, throughout the summer using respirometry and quantitative magnetic resonance. During the mid-summer, birds entered torpor at consistently low fat stores (~5% of body mass), and torpor duration was negatively related to evening fat load. Remarkably, this energy emergency strategy was abandoned in the late summer when birds accumulated fat for migration. During the migration period, birds were more likely to enter torpor on nights when they had higher fat stores, and fat gain was positively correlated with the amount of torpor used. These findings demonstrate the versatility of torpor throughout the annual cycle and suggest a fundamental change in physiological feedback between adiposity and torpor during migration. Moreover, this study highlights the underappreciated importance of facultative heterothermy in migratory ecology. eLife Sciences Publications, Ltd 2021-12-06 /pmc/articles/PMC8719877/ /pubmed/34866575 http://dx.doi.org/10.7554/eLife.70062 Text en © 2021, Eberts et al https://creativecommons.org/licenses/by/4.0/This article is distributed under the terms of the Creative Commons Attribution License (https://creativecommons.org/licenses/by/4.0/) , which permits unrestricted use and redistribution provided that the original author and source are credited.
spellingShingle Ecology
Eberts, Erich R
Guglielmo, Christopher G
Welch, Kenneth C
Reversal of the adipostat control of torpor during migration in hummingbirds
title Reversal of the adipostat control of torpor during migration in hummingbirds
title_full Reversal of the adipostat control of torpor during migration in hummingbirds
title_fullStr Reversal of the adipostat control of torpor during migration in hummingbirds
title_full_unstemmed Reversal of the adipostat control of torpor during migration in hummingbirds
title_short Reversal of the adipostat control of torpor during migration in hummingbirds
title_sort reversal of the adipostat control of torpor during migration in hummingbirds
topic Ecology
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8719877/
https://www.ncbi.nlm.nih.gov/pubmed/34866575
http://dx.doi.org/10.7554/eLife.70062
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