Efeito da temperatura sobre a ventilação, metabolismo e preferência térmica em duas populações de lagarto da espécie Tropidurus torquatus

Abstract

Several studies have demonstrated the environment's influence on the ecology and physiology of organisms and that environmental variations can promote behavioral and physiological adaptations of an individual, thus tracing its life's story. Ambient temperature, in particular, is a factor that has large influence on the physiological processes, which can cause changes in breathing patterns and metabolism in some species. Hence, the objective of this study was to evaluate the ventilatory, metabolic and thermal preference responses of two populations of lizards of the Tropidurus torquatus specie, coming from different regions of Brazil: one collected in the Pampa biome and the other one collected in areas of sandbanks in the Mata Atlântica biome. To assess the ventilatory and metabolic responses of both populations, individuals were acclimated at different temperatures (20, 25 and 30°C) and exposed to three experimental temperatures (20, 25 and 30°C). The thermal preference was also obtained after a period of acclimatization of the animals to the above temperatures. Our data on the thermal preference showed no significant difference among the studied populations, which leads us to suggest that the preferred body temperature of these animals is a phylogenetically conserved trait. Regarding ventilation and metabolism data, our studies showed that both the population from the south of Brazil, as the population of the Northeast, showed the same metabolic rate, however, the population of the Pampas showed a greater ventilation, reflecting a hyperventilation of these lizards. Thus, we suggested that the lizards collected in South and Northeast may have different strategies to maintain the same metabolic rates. Finally, we found that the acclimation temperature did not affect the studied variables, except for tidal volume, which was significantly lower in animals acclimated to 20°C, and that oxygen consumption that was significantly less to the experimental temperature of 20ºC.