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Narrow safety margin in the phyllosphere during thermal extremes

The thermal limit of ectotherms provides an estimate of vulnerability to climate change. It differs between contrasting microhabitats, consistent with thermal ecology predictions that a species’ temperature sensitivity matches the microclimate it experiences. However, observed thermal limits may dif...

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Autores principales: Pincebourde, Sylvain, Casas, Jérôme
Formato: Online Artículo Texto
Lenguaje:English
Publicado: National Academy of Sciences 2019
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6431205/
https://www.ncbi.nlm.nih.gov/pubmed/30782803
http://dx.doi.org/10.1073/pnas.1815828116
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author Pincebourde, Sylvain
Casas, Jérôme
author_facet Pincebourde, Sylvain
Casas, Jérôme
author_sort Pincebourde, Sylvain
collection PubMed
description The thermal limit of ectotherms provides an estimate of vulnerability to climate change. It differs between contrasting microhabitats, consistent with thermal ecology predictions that a species’ temperature sensitivity matches the microclimate it experiences. However, observed thermal limits may differ between ectotherms from the same environment, challenging this theory. We resolved this apparent paradox by showing that ectotherm activity generates microclimatic deviations large enough to account for differences in thermal limits between species from the same microhabitat. We studied upper lethal temperature, effect of feeding mode on plant gas exchange, and temperature of attacked leaves in a community of six arthropod species feeding on apple leaves. Thermal limits differed by up to 8 °C among the species. Species that caused an increase in leaf transpiration (+182%), thus cooling the leaf, had a lower thermal limit than those that decreased leaf transpiration (−75%), causing the leaf to warm up. Therefore, cryptic microclimatic variations at the scale of a single leaf determine the thermal limit in this community of herbivores. We investigated the consequences of these changes in plant transpiration induced by plant–insect feedbacks for species vulnerability to thermal extremes. Warming tolerance was similar between species, at ±2 °C, providing little margin for resisting increasingly frequent and intense heat waves. The thermal safety margin (the difference between thermal limit and temperature) was greatly overestimated when air temperature or intact leaf temperature was erroneously used. We conclude that feedback processes define the vulnerability of species in the phyllosphere, and beyond, to thermal extremes.
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spelling pubmed-64312052019-03-28 Narrow safety margin in the phyllosphere during thermal extremes Pincebourde, Sylvain Casas, Jérôme Proc Natl Acad Sci U S A PNAS Plus The thermal limit of ectotherms provides an estimate of vulnerability to climate change. It differs between contrasting microhabitats, consistent with thermal ecology predictions that a species’ temperature sensitivity matches the microclimate it experiences. However, observed thermal limits may differ between ectotherms from the same environment, challenging this theory. We resolved this apparent paradox by showing that ectotherm activity generates microclimatic deviations large enough to account for differences in thermal limits between species from the same microhabitat. We studied upper lethal temperature, effect of feeding mode on plant gas exchange, and temperature of attacked leaves in a community of six arthropod species feeding on apple leaves. Thermal limits differed by up to 8 °C among the species. Species that caused an increase in leaf transpiration (+182%), thus cooling the leaf, had a lower thermal limit than those that decreased leaf transpiration (−75%), causing the leaf to warm up. Therefore, cryptic microclimatic variations at the scale of a single leaf determine the thermal limit in this community of herbivores. We investigated the consequences of these changes in plant transpiration induced by plant–insect feedbacks for species vulnerability to thermal extremes. Warming tolerance was similar between species, at ±2 °C, providing little margin for resisting increasingly frequent and intense heat waves. The thermal safety margin (the difference between thermal limit and temperature) was greatly overestimated when air temperature or intact leaf temperature was erroneously used. We conclude that feedback processes define the vulnerability of species in the phyllosphere, and beyond, to thermal extremes. National Academy of Sciences 2019-03-19 2019-02-19 /pmc/articles/PMC6431205/ /pubmed/30782803 http://dx.doi.org/10.1073/pnas.1815828116 Text en Copyright © 2019 the Author(s). Published by PNAS. https://creativecommons.org/licenses/by-nc-nd/4.0/ This open access article is distributed under Creative Commons Attribution-NonCommercial-NoDerivatives License 4.0 (CC BY-NC-ND) (https://creativecommons.org/licenses/by-nc-nd/4.0/) .
spellingShingle PNAS Plus
Pincebourde, Sylvain
Casas, Jérôme
Narrow safety margin in the phyllosphere during thermal extremes
title Narrow safety margin in the phyllosphere during thermal extremes
title_full Narrow safety margin in the phyllosphere during thermal extremes
title_fullStr Narrow safety margin in the phyllosphere during thermal extremes
title_full_unstemmed Narrow safety margin in the phyllosphere during thermal extremes
title_short Narrow safety margin in the phyllosphere during thermal extremes
title_sort narrow safety margin in the phyllosphere during thermal extremes
topic PNAS Plus
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6431205/
https://www.ncbi.nlm.nih.gov/pubmed/30782803
http://dx.doi.org/10.1073/pnas.1815828116
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