Thermoregulation in the Andean lizard Anolis heterodermus (Squamata: Dactyloidae) at high elevation in the Eastern Cordillera of Colombia.

Termorregulación en el lagarto andino Anolis heterodermus (Squamata: Dactyloidae) a una alta elevación en la Cordillera Oriental de Colombia

ABSTRACT

Low thermal quality environments, such extreme latitudes or high elevation regions, are highly expensive for reptiles in terms of thermoregulation. Thus, physiological adaptations or behavioral adjustments to live in these habitats have evolved in some species. Anolis heterodermus (Duméril, 1851) is an anole lizard that lives at high elevations in the Andes region. In this paper, we attempted to elucidate the thermoregulation strategy of a population of this species from the eastern cordillera of Colombia during wet and dry seasons. We measured body temperatures (T_b), operative temperatures (T_e) and preferred temperatures (T_pref). Based on these data, we obtained accuracy (_b ), environmental thermal quality (_e ) and efficiency of thermoregulation (E) indexes. There were no significant differences of T_b or _b between seasons, sexes, ages, and for T_pref between sexes or ages, but we found differences in T_e and _e between seasons. The indexes suggested high thermoregulatory accuracy, low thermal environment quality and indicated that A. heterodermus was an active thermoregulator in both seasons. Broad ranges of T_b and the species association with microhabitats with high solar radiation suggest eurythermy and heliothermy. Anolis heterodermus lives in a low thermal quality habitat, using exposed perches, which seems the most efficient thermal microhabitats. We concluded that A. heterodermus performed behavioral adjustment for compensating seasonal variation in the environmental thermal costs.

KEYWORDS
Thermal quality; thermoregulatory accuracy; seasonal variation; heliothermy