Wintertime tales: How the lizard Liolaemus lineomaculatus endures the temperate cold climate of Patagonia, Argentina

MEDINA, MARLIN SUSANA; BAUDINO, FLORENCIA; CECCHETTO, NICOLÁS R.; IBARGÜENGOYTÍA, NORA

ANAIS DA ACADEMIA BRASILEIRA DE CIENCIAS.

ACAD BRASILEIRA DE CIENCIAS

Lugar: Rio de Janeiro; Año: 2022 vol. 94

0001-3765

In temperate, polar and montane environments, ectotherms must find ways toendure throughout the coldest months of the year. Lizards search for microsites wheretemperatures remain warm or alter their biochemical balance to tolerate freezing oravoid it by supercooling. We evaluated the cold hardiness and potential winter refugesof two populations of Liolaemus lineomaculatus, from a temperate site (42°S) and acold site (50°S). We analysed the role of possible cryoprotectants by comparing a groupof cooled-down lizards with a control group of lizards that were not exposed to cold.The populations of this study are not freeze tolerant and the biochemical analysisshowed no evidence of metabolites significantly changing concentration after exposureto cold. However, the species remained several hours at their Supercooling Point (SCP),suggesting they can supercool. The analysis of potential winter refuges showed thatlizards using these potential refuges would spend almost no time at all at temperaturesclose to or below their SCP. Furthermore, lizards from the cold site were able to survivebelow 0°C temperatures with a lower SCP than lizards from the temperate site. Liolaemuslineomaculatus developed physiological mechanisms that can help them survive whentemperatures drop sharply, even when lizards are in suitable shelters.