Thermal and reproductive responses to harsh environments in Patagonia, Argentina.

MEDINA, MARLIN AND IBARGUENGOYTIA, NORA; IBARGÜENGOYTÍA, NORA RUTH

San Carlos de Bariloche

Congreso; V Southern Connection Congress; 2010

In southern temperate ecosystems, environmental temperatures strongly influence the distribution and activity of reptiles and their ability to obtain energy to grow and reproduce. Thermoregulatory activity and the timing of reproductive events influence the aptitude of the species and it is expected that variation among individuals and among species exists in responses to different environmental conditions.We examined ecotypic differences in reproductive and thermal physiology at two latitudes (43° and 46°S) in three lizard species:  L. bibronii and L. boulengeri (oviparous), and L. lineomaculatus (viviparous). Body and operative temperatures were measured in the field, and preferred body temperatures were estimated in the laboratory.   We calculated the efficiency of thermoregulation and describe the reproductive cycles of males and females of each species. Body temperatures were low and similar among species; however the efficiency of thermoregulation showed that the oviparous species are better thermoregulators than the viviparous L. lineomaculatus. The reproductive cycles of the three species are similar but, because L. lineomaculatus lives at higher latitudes than the oviparous species, the lower temperatures that their eggs experience in the nest could limit development, and consequentlyconstrain the timing of incubation periods and the performance of hatchlings, and their ability to attain and maintain body temperatures appropriate for growth and reproduction.