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| Author(s): |
Braz Titon Junior
Total Authors: 1
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| Document type: | Doctoral Thesis |
| Press: | São Paulo. |
| Institution: | Universidade de São Paulo (USP). Instituto de Biociências (IBIOC/SB) |
| Defense date: | 2015-09-04 |
| Examining board members: |
Fernando Ribeiro Gomes;
Denis Otavio Vieira de Andrade;
Carlos Arturo Navas Iannini
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| Advisor: | Fernando Ribeiro Gomes |
| Abstract | |
Anuran amphibians, in general, are characterized by low skin resistance to evaporative water loss, high rates of hydration through the skin and high tolerance to dehydration. However, interspecific differences of these water balance traits can be related to environmental characteristics of the areas of occurrence. In Brazil, there are biomes with contrasting climatic conditions and rich anuran fauna, which constitute an interesting model for studies on water balance evolution in anurans. Through a comparative approach, this study tested the hypotheses that, when compared to anuran species that inhabit more mesic environments, species from xeric environments should show: (1) increased resistance to evaporative water loss, (2) higher rates of rehydration, (3) low sensitivity of locomotor performance to dehydration and (4) increased sensitivity of the locomotor performance at lower temperatures and lower sensitivity of it at higher temperatures. Rehydration rates and skin resistance to evaporative water loss showed, respectively, positive and negative allometric relations with body mass, indicating the evolution of compensatory mechanisms to changes in the relationship between surface area and volume with body size variation. Anurans from environments characterized by higher restriction in water availability and higher temperatures had higher rates of hydration, lower sensitivity of locomotor performance at higher temperatures and higher sensitivity of it at lower temperatures, indicating patterns of physiologic adaptation to environmental characteristics. The variation in sensitivity of the locomotor performance to dehydration showed more complex relation patterns with environmental variables. These relations were dependent on the environments and phylogenetic groups sampled (AU) | |
| FAPESP's process: | 10/16804-3 - Water balance and locomotor performance in Bufonids inhabiting thermal and hygric contrasting biomes |
| Grantee: | Braz Titon Junior |
| Support Opportunities: | Scholarships in Brazil - Doctorate |