Meeting Abstract

29.4  Friday, Jan. 4  Growing up in an unstable environment: Consequences of diel thermal variation to developing anurans NIEHAUS, AC*; ANGILLETTA, MJ; FRANKLIN, CE; WILSON, RS; University of Queensland a.niehaus@uq.edu.au

Ecologists have long sought to understand the plasticity of organisms in environments that vary widely among years, seasons, and even hours of the day. Though environmental change is ubiquitous, relatively few empirical studies have considered the consequences of diel temperature variation on developing organisms, instead comparing phenotypes among un-natural stable conditions. Here, we determined whether reaction norms based on stable environments (18, 22, 26, 30 and 34�C) could be used to predict hatchling, larval and metamorphic phenotypes of anurans in variable environments (18-28�C and 18-34�C). We used existing theory to evaluate how acclimation to stable conditions might produce inaccuracy in these predictions. Our empirical models did not accurately predict anuran phenotypes in fluctuating temperatures, suggesting that extrapolation from studies conducted under unrealistic, stable conditions may lead to erroneous conclusions. Overall, development was generally faster than expected in variable environments, but the predictability of growth differed widely among treatments and stages of development. The inaccuracy of our predictions was not always in the direction expected if acclimation occurred in the stable conditions, suggesting that other mechanisms are responsible for modifications to growth and development in fluctuating conditions. Finally, we discuss our results in light of current life-history models and suggest ways to improve the ecological relevance of future theoretical and empirical studies.