Mixed signals thermal performance of zebrafish Danio rerio in uncertain environments

Meeting Abstract

91.10  Wednesday, Jan. 7  Mixed signals: thermal performance of zebrafish Danio rerio in uncertain environments. CONDON, C.H.**; CHENOWETH, S.F.; WILSON, R.S.; The University of Queensland; The University of Queensland; The University of Queensland c.condon@uq.edu.au

Thermal performance curves (TPC) represent the performance of an individual across a temperature range. Reversible acclimation can alter the thermal performance of a plastic trait via changes in the height (vertical shift), the thermal optimum (horizontal shift), or in a trade-off between the height and width (generalist-specialist shift) of a TPC. Here we investigate variation in TPC of two traits in the zebrafish, Danio rerio by examining the effect of environmental cue reliability on thermal performance. The TPC of a reversible plastic trait is predicted to be narrow and specialised when an individual receives highly reliable cues, while less reliable cues should induce a broad, generalist phenotype to cope with uncertain conditions. We acclimated D. rerio to reliable and contrasting seasonal temperature (16 and 30C) and day-length (10:14, 12:12, 14:10 L:D) cues and examined the thermal performance of burst swimming and feeding rate between 8-38C. Acclimation temperature had a significant effect on TPC shape for both traits via a horizontal shift in the thermal optimum. For feeding performance, day-length and day-length x temperature interactions altered both the thermal optimum and the performance maximum of TPC but not the width. Cue reliability did not induce a significant generalist-specialist trade-off in TPC shape. Horizontal and generalist-specialist variation together captured 66% of the total variation in swimming TPCs and 95% for feeding rate. Our results suggest that TPCs for reversible performance traits in D. rerio vary chiefly in these two directions. As far as we are aware, this study represents the first use of the template mode of variation (TMV) method for examining TPCs of reversible phenotypes in multiple environments.

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