Thermal ecology and activity patterns of six species of tropical night lizards (Squamata: Xantusiidae: Lepidophyma) from Mexico

Abstract

Activity patterns in ectotherms rely on the structure of the thermal environment and thermoregulatory opportunities during activity periods. A dichotomy between diurnal and nocturnal ectotherms is not clear in every case, and temperature can directly affect the daily activity period in these organisms during both photophase and scotophase. In the present study we evaluate the thermal ecology of six tropical night lizards (genus Lepidophyma) from Mexico. Our results indicate a thermoconformer strategy in most of the studied species. In these species, thermal tolerances are associated with environmental temperatures to which they are exposed. Furthermore, thermal quality of the environment directly determines the daily activity period. Therefore, we argue that diurnal activity in Lepidophyma species is determined by local thermal conditions.

Keywords: Cathemerality; Critical temperatures; Diurnality; Environmental thermal quality; Nocturnality; Thermoregulation.