O assoalhamento em Bokermannohyla alvarengai (Anura, Hylidae): história natural e adaptações morfo-fisiológicas

• Autor(a) principal: Centeno, Fernanda da Cruz [UNESP]
• Data de Publicação: 2014
• Tipo de documento: Tese
• Idioma: por
• Título da fonte: Repositório Institucional da UNESP
• Texto Completo: http://hdl.handle.net/11449/121972
• topic: Anura; Anuro; Ecofisiologia; Corpo - Temperatura - Regulação; Morfologia (Animais); Fisiologia veterinaria; Anfíbio; Balanço hidrológico

Basking behaviour is uncommon in amphibians as it has the important drawback of increasing the risk of excessive water loss through evaporation (EWL). However, this behaviour seems to be especially relevant in high elevation regions as it allows thermoregulation in order to face the low temperatures. Some anuran species are known to bask efficiently, even in deprived humidity conditions, and generally are accompanied by several adaptations in order to reduce EWL. This is the case of Bokermannohyla alvarengai, a treefrog endemic of campos rupestres (rocky meadows) that inhabits areas above 1000 m of altitude in Southeastern Brazil, whom basking behaviour is associated with physiological changes in skin coloration. Campos rupestres undergo major daily temperature fluctuations with intense solar radiation during the day and rapid cooling at night, and thermoregulation through basking could be advantageous in such habitat. On the other hand, this environment is subjected to water restrictions that exacerbate problems of EWL and, therefore, compromises efficient use of basking in anurans as thermoregulatory strategy. While colour change in this species is known to be involved in the modulation of heat exchanges during sun exposition, with osmoregulatory implications, many questions remain on the behavioural and physiological adaptations underpinning basking, and this study aims at filling this gap of knowledge. In this thesis, I investigated fundamental aspects of the life history of B. alvarengai, such as diet, reproduction, activity patterns and habitat use, but also physiological and morphological features with special reference to their adaptive implications in basking behaviour. Bokermannohyla alvarengai basks all year-round, even far from water sources, accommodating the conflicting aspects involved in water economy and thermoregulation by a suite of behavioural, physiological, and morphological specializations. Besides the adoption of...