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Meeting Abstract

SICB+    Cooking eggs: Testing for Plasticity in the heat tolerance of lizard embryos Gleason, GS*; Gunderson, A; Tulane University; Tulane University ggleason@tulane.edu

Plasticity in heat tolerance is an important mechanism by which ectotherms can adjust to global climate change . Heat tolerance plasticity in adult ectotherms is well studied. In contrast, the capacity of embryos to plastically elevate heat tolerance during warming is relatively unknown. This is important to know because embryonic stages cannot behaviorally thermoregulate as well as motile adults to avoid heat stress. In this study, we assessed thermal tolerance plasticity in embryos of a lizard, the brown anole (Anolis sagrei). We exposed embryos to a nonlethal heat shock and subsequently assessed their ability to tolerate a more extreme high temperature. We also estimated the effect of heat shock on energetic expenditure by measuring heart rate before and after the heat shock event. We found that embryos exposed to prior nonlethal heat shock had a 50% survival rate when exposed to subsequent heat, while those not exposed to the prior heat shock only had a 33% survival rate. We observed a trend of heart rate increasing after the nonlethal heat shock exposure, though the difference was not significant. This project furthers our understanding of thermal tolerance plasticity of embryos, an important but understudied aspect of organismal vulnerability to rising temperatures.