Seasonal variation in the thermal biology of a terrestrial toad, Rhinella icterica (Bufonidae), from the Brazilian Atlantic Forest

Autor(es)

de Oliveira Anderson, Rodolfo Cesar ^[1] ; Bovo, Rafael Parelli ^{[1, 2]} ; Andrade, Denis Vieira ^[1]

Afiliação do(s) autor(es)

^[1] Univ Estadual Paulista, Inst Biociencias, Dept Zool, UNESP, BR-13506900 Rio Claro, SP - Brazil

^[2] Univ Sao Paulo, Dept Fisiol, Inst Biociencias, BR-05508090 Sao Paulo, SP - Brazil

• Tipo de documento: Artigo Científico
• Fonte: Journal of Thermal Biology; v. 74, p. 77-83, MAY 2018.
• Citações Web of Science: 4

Resumo

As ectotherms, amphibians may exhibit changes in their thermal biology associated with spatial and temporal environmental contingencies. However, our knowledge on how amphibian's thermal biology responds to seasonal changes in the environment is restricted to a few species, mostly from temperate regions, in a marked contrast with the high species diversity found in the Neotropics. We investigated whether or not the seasonal variation in climatic parameters from a high-montane ombrophilous forest in the Brazilian Atlantic Forest could lead to concurrent adjustments in the thermal biology of the terrestrial toad Rhinella icterica. We measured active body temperature (T-b) in the field, and preferred body temperature (T-pref) and thermal tolerance (critical thermal minimum, CTmin, and maximum, CTmax) in the laboratory, for toads collected at two distinct seasons: warm/wet and cold/dry. We also measured operative environmental temperatures (T-e) using agar toad models coupled with dataloggers distributed in different microhabitats in the field to estimate accuracy (d(b)) and effectiveness (E) of thermoregulation of the toads for both seasons. Toads had higher T-pref in the warm/wet season compared to the cold/dry season, even though no seasonal change occurred in field T-b's. In the warm/wet season, toads decreased the accuracy of thermoregulation and avoided thermally favorable microhabitats, while in the cold/dry season they increased the accuracy of thermoregulation and exhibited high degree of thermo-conformity. This result may encompass thermoregulatory adjustments to seasonal changes in T-c's, but may also reflect seasonal differences in compromises between T-b regulation and other ecologically relevant activities (reproduction, foraging). Toads did not exhibit changes in CTmin or CTmax, which indicates a low risk of exposure to extreme temperatures in this particular habitat, at both seasons, possibly combined with a low flexibility of this trait. Overall, our study shows seasonal acclimatization in some aspects of the thermal biology of the toad, R. icterica. (AU)

• Processo FAPESP: 13/04190-9 - Fisiologia termal e balanço de água em anfíbios anuros ao longo de um gradiente altitudinal da Floresta Atlântica
• Beneficiário: Denis Otavio Vieira de Andrade
• Modalidade de apoio: Auxílio à Pesquisa - Regular
• Processo FAPESP: 10/20061-6 - Fisiologia termal e balanço hídrico de anfíbios anuros em gradientes altitudinais da Floresta Atlântica
• Beneficiário: Rafael Parelli Bovo
• Modalidade de apoio: Bolsas no Brasil - Doutorado
• Processo FAPESP: 14/05624-5 - Ecologia fisiológica de anfíbios: uma abordagem utilizando a modelagem
• Beneficiário: Rafael Parelli Bovo
• Modalidade de apoio: Bolsas no Exterior - Estágio de Pesquisa - Doutorado
• Processo FAPESP: 17/10338-0 - Integrando processos fisiológicos, ecológicos e evolutivos para compreensão de respostas populacionais e de espécies às mudanças ambientais
• Beneficiário: Rafael Parelli Bovo
• Modalidade de apoio: Bolsas no Brasil - Pós-Doutorado