Effects of dehydration on thermoregulatory behavior and thermal tolerance limits of Rana catesbeiana (Shaw, 1802)

Autor(es)

Guevara-Molina, Estefany Caroline ^[1] ; Gomes, Fernando Ribeiro ^[1] ; Camacho, Agustin ^[1]

Afiliação do(s) autor(es)

^[1] Univ Sao Paulo, Inst Biosci, Dept Physiol, Lab Behav & Evolutionary Physiol, BR-05508090 Sao Paulo - Brazil

• Tipo de documento: Artigo Científico
• Fonte: Journal of Thermal Biology; v. 93, OCT 2020.
• Citações Web of Science: 1

Resumo

Predicting the effects of high environmental temperatures and drought on populations requires understanding how these conditions will influence the thermoregulatory behavior and thermal tolerance of organisms. Ectotherms show proportional (fine-tuned) and all-or-none (abrupt) responses to avoid overheating. Scattered evidence suggests that dehydration alters these behavioral responses and thermal tolerance, but these effects have not been evaluated in an integrative manner. We examined the effects of hydration level on the behavioral thermoregulation and behavioral and physiological thermal limits of the ``bullfrog{''} (Rana catesbeiana), a well-studied and important invasive species. To examine the effects of dehydration on proportional responses, we compared the Preferred Body Temperatures (PBT) of frogs with restricted and unrestricted access to water. To assess the effect of dehydration on all-or-none responses, we measured and compared the Voluntary Thermal Maximum (VTMax) at different hydration levels (100%, 90%, 80% of body weight at complete hydration). Finally, to understand the effect of dehydration on physiological thermal tolerance, we measured the Critical Thermal Maximum (CTMax) of frogs at matched hydration levels. PBT, VTMax, and CTMax all decreased in response to higher dehydration levels. However, bullfrogs changed their PBT more than their VTMax or CTMax in response to dehydration. Moreover, some severely dehydrated individuals did not exhibit a VTMax response. We discuss the implications of our results in the context of plasticity of thermoregulatory responses and thermal limits, and its potential application to mechanistic modeling. (AU)

• Processo FAPESP: 14/16320-7 - Impactos das mudanças climáticas e ambientais sobre a fauna: uma abordagem integrativa
• Beneficiário: Carlos Arturo Navas Iannini
• Modalidade de apoio: Auxílio à Pesquisa - Programa de Pesquisa sobre Mudanças Climáticas Globais - Temático
• Processo FAPESP: 17/14382-3 - Interação do comportamento e fisiologia dos anuros em resposta ao estresse térmico e hídrico: uma abordagem para entender a vulnerabilidade dos anuros às mudanças climáticas
• Beneficiário: Estefany Caroline Guevara Molina
• Modalidade de apoio: Bolsas no Brasil - Mestrado