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.