Dehydration in Southern Toads (Anaxyrus terrestris): Metabolic Costs and Effects of Temperature Selection

Southern toads (Anaxyrus terrestris) are ectothermic terrestrial amphibians. As such they are sensitive to thermal and hydric variability. The interactive effect of hydration state and body temperature is not well understood. The aim of this study is to determine if the costs of dehydration vary at...

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Bibliographic Details
Main Author: Forster, Claire E
Format: Others
Published: Scholarship @ Claremont 2013
Subjects:
Online Access:http://scholarship.claremont.edu/scripps_theses/161
http://scholarship.claremont.edu/cgi/viewcontent.cgi?article=1151&context=scripps_theses
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Summary:Southern toads (Anaxyrus terrestris) are ectothermic terrestrial amphibians. As such they are sensitive to thermal and hydric variability. The interactive effect of hydration state and body temperature is not well understood. The aim of this study is to determine if the costs of dehydration vary at different temperatures and if so, whether toads will select different temperatures to minimize these costs. Costs of dehydration were evaluated by measuring metabolic rate at 100% and 85% hydration state, at 30 and 20 oC. Temperature selection of toads at 100% and 85% hydration state was measured using a thermal gradient. Body temperature, but not hydration state, was determined to have a significant effect on metabolic rate. No significant difference in temperature selection was found between toads at 100% and 85% hydration state. Thus, thermoregulatory behavior as influenced by hydration state could not be predicted in Anaxyrus terrestris.