University of Oulu

Riddell, E. A., Mutanen, M., & Ghalambor, C. K. (2023). Hydric effects on thermal tolerances influence climate vulnerability in a high-latitude beetle. Global Change Biology, 29, 5184–5198.

Hydric effects on thermal tolerances influence climate vulnerability in a high-latitude beetle

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Author: Riddell, Eric A.1; Mutanen, Marko2; Ghalambor, Cameron K.3,4
Organizations: 1Department of Ecology, Evolutionary, and Organismal Biology, Iowa State University, Ames, Iowa, USA
2Ecology and Genetics Research Unit, University of Oulu, Oulu, Finland
3Department of Biology and Graduate Degree Program in Ecology, Norwegian University of Science and Technology, Trondheim, Norway
4Department of Biology, Colorado State University, Fort Collins, Colorado, USA
Format: article
Version: published version
Access: open
Online Access: PDF Full Text (PDF, 5 MB)
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Language: English
Published: John Wiley & Sons, 2023
Publish Date: 2023-10-30


Species’ thermal tolerances are used to estimate climate vulnerability, but few studies consider the role of the hydric environment in shaping thermal tolerances. As environments become hotter and drier, organisms often respond by limiting water loss to lower the risk of desiccation; however, reducing water loss may produce trade-offs that lower thermal tolerances if respiration becomes inhibited. Here, we measured the sensitivity of water loss rate and critical thermal maximum (CTmax) to precipitation in nature and laboratory experiments that exposed click beetles (Coleoptera: Elateridae) to acute- and long-term humidity treatments. We also took advantage of their unique clicking behavior to characterize subcritical thermal tolerances. We found higher water loss rates in the dry acclimation treatment compared to the humid, and water loss rates were 3.2-fold higher for individuals that had experienced a recent precipitation event compared to individuals that had not. Acute humidity treatments did not affect CTmax, but precipitation indirectly affected CTmax through its effect on water loss rates. Contrary to our prediction, we found that CTmax was negatively associated with water loss rate, such that individuals with high water loss rate exhibited a lower CTmax. We then incorporated the observed variation of CTmax into a mechanistic niche model that coupled leaf and click beetle temperatures to predict climate vulnerability. The simulations indicated that indices of climate vulnerability can be sensitive to the effects of water loss physiology on thermal tolerances; moreover, exposure to temperatures above subcritical thermal thresholds is expected to increase by as much as 3.3-fold under future warming scenarios. The correlation between water loss rate and CTmax identifies the need to study thermal tolerances from a “whole-organism” perspective that considers relationships between physiological traits, and the population-level variation in CTmax driven by water loss rate complicates using this metric as a straightforward proxy of climate vulnerability.

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Series: Global change biology
ISSN: 1354-1013
ISSN-E: 1365-2486
ISSN-L: 1354-1013
Volume: 29
Issue: 18
Pages: 5184 - 5198
DOI: 10.1111/gcb.16830
Type of Publication: A1 Journal article – refereed
Field of Science: 1172 Environmental sciences
Funding: This work was supported by funding from the Kone Foundation (Application 201710256). We also thank the Ecology and Genetics Research Unit at the University of Oulu for support and hosting this research.
Dataset Reference: The data that support the findings of this study are openly available in Zenodo at
Copyright information: © 2023 The Authors. Global Change Biology published by John Wiley & Sons Ltd. This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.