Living in the Extremes: The Thermal Ecology of Communal Nests of the Highland Andean Lizard Anadia bogotensis (Squamata: Gymnophthalmidae)

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Nesting in tropical highlands is challenging due to the fluctuations of temperature, including extreme cold, and humidity. For most reptiles in the highland tropical region the thermal and hydrological profiles of nests have not been described, and it is therefore uncertain how future climate change may affect this ontogenetic stage. We monitored 17 communal nests of Anadia bogotensis at a highland locality in Colombia. The soil humidity and temperature of the nests and the air temperature were recorded for almost a year, together with other physical and biotic nest characteristics. Nests exhibited high temporal and spatial thermal variation unrelated to the nests’ physical characteristics. The maximum and minimum temperatures of the nests and air exhibited a linear and positive relationship, whereas the thermal variance (CV) exhibited a linear and positive relationship with maximum air temperature. Furthermore, CV of the heating phase was higher than that of the cooling phase for the nest and air temperature and it was similar between nests with and without viable eggs. However, it was different between each nest type and air temperature. During the cooling phase the average CV was different between nests with and without viable eggs and between nests and air temperature. In conclusion, the temperature of the nests exhibits strong daily fluctuation, and most of the nests follow the same fluctuation as air temperature. However, it seems that the rock covering some nests prevents the nest temperature from falling as quickly as the air temperature and from reaching the minimum environmental value.