La óptima térmica para la incubación de los huevos de la "iguana colorada" (Tupinambis rufescens: Sauria, Teiidae)

Abstract

The thermal optimum for the incubation of "red teyu" eggs (Tupinambis rufescens: Sauria, Teiidae). Tupinambis rufescens (Gunther, 1871), is a large lizard from semiarid regions in Bolivia, Paraguay and Argentina. The species lays non-cleidoic eggs with a parchment-like shell permeable to gases and also to liquid water. Mass and volume of these eggs increase during embrionary development, as a function of the gaseous interchange rate and a very dynamic in-out water balance. The effect of temperature on this balance prevails in importance upon the variation in metabolic rate. Temperature and water disponibility were critical factors in egg incubation, determining clutch success and offspring size. This work tries to assess the optimal temperature and the higher limit for the thermic tolerance of the developing embryos of T. rufescens, while maintaining fixed the water potential in the substrate. The efficiency of the incubation process was examined at different temperatures and by means of direct interpretation parameters, as are offspring size and the utilization of energetic reserves within the egg.