VTMaxHerp: A data set of voluntary thermal maximum temperatures of amphibians and reptiles from two Brazilian hotspots

Abstract

Amphibians and reptiles are ectothermic animals and therefore depend on environmental temperatures to maintain their physiological functions.Despite being poorly documented, data on thermal behavioral thresholds to avoid overheating in their habitats are essential to improve the understanding of their thermal ecology and physiology. Here we provide a data set of 312 individual voluntary thermal maximum (VT Max ) values, the maximum

Linking body condition and thermal physiology in limping crickets: Does limb autotomy incur costs concerning behavioral thermal tolerance?

“…The central aim of our study was to investigate whether and to which extent suboptimal body conditions, after autotomy result in changes in the animals Voluntary Thermal Maximum, VT Max . First, our study provides the first scientific evidence that crickets ( G. assimilis ) express a voluntary thermal maximum response when exposed to high temperatures, in line with what has been shown for other ectotherms (e.g., lizards: Camacho & Rusch, 2017; Díaz‐Ricaurte & Serrano, 2020a, Díaz‐Ricaurte et al, 2022; snakes: Díaz‐Ricaurte & Serrano 2020b; Díaz‐Ricaurte et al, 2022; frogs: Díaz‐Ricaurte et al, 2020, 2022; Guevara‐Molina et al, 2020). The voluntary avoidance of temperatures that exceed the preferred thermal range creates a thermal safety margin for ectotherms, to avoid critical levels of body temperature that could compromise their physiology and performance and, consequently, their survival (Guevara‐Molina et al, 2020).…”

“…For the experiments, animals were placed individually inside a metallic cylinder (16 cm length × 6 cm width), open at one end, and coated with a thermal resistance (Camacho & Rusch, 2017; Díaz‐Ricaurte & Serrano, 2020a, 2020b; Díaz‐Ricaurte et al, 2022; Guevara‐Molina et al, 2020). A type‐T thermocouple was placed inside the cylinder, adhered to its surface, to record the temperatures during experiments.…”

“…When an individual left the box, its body temperature was instantly picked up with the thermal camera. This body temperature was considered the individual's VT Max given that it was the maximum body temperature that led the individual to voluntarily leave the hot box (see Díaz‐Ricaurte et al, 2020, 2022; Guevara‐Molina et al, 2020). This method is not lethal and by gradual continuous heating allows estimating the VT Max of individuals based on behavioral changes of individuals when leaving a hot shelter.…”

“…Behavioral adjustments and the expression of VT Max have been widely explored in ectothermic vertebrates, especially in lizards (Cadena & Tattersall, 2009; Camacho et al, 2018; Cowles & Bogert, 1944; Díaz‐Ricaurte & Serrano, 2020a; Díaz‐Ricaurte et al, 2022; Hertz, 1979; Kingsbury, 1993) and, more recently, in anurans and Neotropical pitvipers (Guevara‐Molina et al, 2020; Díaz‐Ricaurte & Serrano 2020b; Díaz‐Ricaurte et al, 2022). These studies have shown that both dehydration (e.g., shown for anurans; Guevara‐Molina et al, 2020) or elevated heating rates (shown for the Neotropical pitvipers Bothrops pauloensis ; Díaz‐Ricaurte & Serrano 2020b), may alter the VT Max .…”

Behavioral thermal tolerance: implications for ecology and conservation of amphibians and reptiles

“…Ectothermic organisms use physiological and behavioral mechanisms for thermoregulation (e. g., . When unable to tolerate the increase of environmental temperatures, they can change their behavior to avoid overheating by adjusting the body posture or moving to another place to reduce its body temperature (e. g., , DIAZ-RICAURTE et al, 2022a. Thus, the distribution of ectotherms can be shaped by behavioral and physiological thermal tolerances, so identifying thermal tolerance thresholds (i. e., measurable thermal limits) allows for the identification of challenges that directly affect their behavioral and physiological response in face of recent climate change.…”