Document Type

Article

Publication Date

2-2012

Publication Title

Journal of Experimental Biology

Publisher

The Company of Biologists Ltd

Abstract

Physiological ecologists have long sought to understand the plasticity of organisms in environments that vary widely among years, seasons and even hours. This is now even more important because human-induced climate change is predicted to affect both the mean and variability of the thermal environment. Although environmental change occurs ubiquitously, relatively few researchers have studied the effects of fluctuating environments on the performance of developing organisms. Even fewer have tried to validate a framework for predicting performance in fluctuating environments. Here, we determined whether reaction norms based on performance at constant temperatures (18, 22, 26, 30 and 34°C) could be used to predict embryonic and larval performance of anurans at fluctuating temperatures (18–28°C and 18–34°C). Based on existing theory, we generated hypotheses about the effects of stress and acclimation on the predictability of performance in variable environments. Our empirical models poorly predicted the performance of striped marsh frogs (Limnodynastes peronii) at fluctuating temperatures, suggesting that extrapolation from studies conducted under artificial thermal conditions would lead to erroneous conclusions. During the majority of ontogenetic stages, growth and development in variable environments proceeded more rapidly than expected, suggesting that acute exposures to extreme temperatures enable greater performance than do chronic exposures. Consistent with theory, we predicted performance more accurately for the less variable thermal environment. Our results underscore the need to measure physiological performance under naturalistic thermal conditions when testing hypotheses about thermal plasticity or when parameterizing models of life-history evolution.

Comments

This document may be reprinted and distributed for non-commercial and educational purposes only, and not for resale. No resale use may be made of material on this web site at any time. Publisher may require a subscription to access this version. All other rights reserved. The published version may be found here: http://jeb.biologists.org/content/215/4/694.full?sid=39cf4756-8f9b-49ba-b09a-bc0a08d8f3dc

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