Thermal biology and behavioural ecology of Liolaemus archeforus and Liolaemus silvanae

Description

This repository contains raw field and laboratory data on the thermal biology and behaviour of two sympatric endemic Patagonian lizards, Liolaemus archeforus and Liolaemus silvanae (Squamata: Liolaemidae), collected on the Buenos Aires Lake Plateau, Santa Cruz Province, Argentina, during three austral summer field campaigns (2022, 2023, and 2024). The dataset is organized into two sheets. The "Field data" sheet includes the date and time of capture for each individual, sex, body temperature (Tb), substrate temperature (Ts), and air temperature (Ta), along with behavioral variables (body posture, sun exposure, and perch type). It also includes the structural and thermal microhabitat used by each lizard, as well as operative temperatures (Te). The "lab data" contain experimental measurements of preferred body temperatures (TsetMin, Tset, and TsetMax), indices of thermal quality and thermoregulatory precision (de and db), critical thermal limits (CTmin and CTmax), and locomotor performance measured across a range of experimental temperatures (18–38 °C). They also include parameters derived from thermal performance curves, such as maximum performance (Vmax) and optimal temperature (To), as well as the lower and upper limits and the breadth of the 80% and 95% performance intervals (B80 and B95). Taken together, these data allow for the assessment of interspecific differences in thermoregulatory behavior and thermal physiology under the environmental conditions of the Patagonian steppe.

Steps to reproduce

Field and laboratory data were collected during three austral summer field campaigns (2022, 2023, and 2024) on the Buenos Aires Lake Plateau, Santa Cruz Province, Argentina. Individuals of Liolaemus archeforus and Liolaemus silvanae were captured during their daily activity period using a noose. Immediately after capture, body temperature (Tb) was measured by placing an ultrafine thermocouple against the flank of the lizard. Substrate temperature (Ts) was recorded at the exact capture point, directly on the substrate, whereas air temperature (Ta) was measured 1 cm above the substrate. At each capture, we also recorded sex, time, body posture, exposure to solar radiation, and perch type. Microhabitat structure was characterized around each capture point by estimating the percentage cover of rocks, bare soil, shrubs, herbs, crevices, and vegetation. These variables were used to characterize microhabitat use and calculate microhabitat richness. The thermal characteristics of the microhabitats used by lizards were additionally assessed using a thermal imaging camera. Operative environmental temperatures (Te) were recorded with temperature dataloggers placed in representative available microhabitats. These data were used to describe the thermal environment and to calculate habitat thermal quality (de) and thermoregulatory accuracy (db), based on the relationship between operative, selected, and field body temperatures. For laboratory measurements, captured individuals were maintained under controlled conditions before experiments. Preferred body temperatures were determined in a thermal gradient that allowed lizards to freely select their body temperature. Body temperatures were recorded repeatedly during the trial to estimate the selected thermal range, defined by its lower (TsetMin) and upper (TsetMax) limits, and the central selected temperature (Tset). Critical thermal limits were determined experimentally by progressively decreasing or increasing body temperature. CTmin and CTmax were defined using loss of righting response as the endpoint, i.e., the temperature at which an individual was unable to right itself when placed on its back. Locomotor thermal performance was evaluated at six experimental body temperatures (18, 22, 26, 30, 34, and 38 °C). Individuals were brought to each target temperature before performing locomotor trials, and running performance was recorded at each temperature. These measurements were used to construct individual thermal performance curves and estimate maximum performance (Vmax), optimal temperature (To), and the thermal ranges over which performance remained at or above 80% and 95% of maximum performance (B80 and B95, respectively), including their lower and upper thermal limits.

Institutions

• National University of Comahue

  Neuquen, Neuquén

Categories

Funders

• Neotropical Grassland Conservancy

  California, Carmichael

Licence