DOI: 10.5061/dryad.hmgqnk9sb
title: Thermal tolerance plasticity and dynamics of thermal tolerance in Eublepharis macularius: Implications for future climate-driven heat stress

description: The intensity and duration of heat waves, as well as average global
 temperatures, are expected to increase due to climate change. Heat waves
 can cause physiological stress and reduce fitness in animals. Species can
 reduce overheating risk through phenotypic plasticity, which allows them
 to raise their thermal tolerance limits over time. This mechanism could be
 important for ectotherms whose body temperatures are directly influenced
 by available environmental temperatures. Geckos are a large, diverse group
 of ectotherms that vary in their thermal habitats and times of daily
 activity, which could affect how they physiologically adjust to heat
 waves. Data on thermal plasticity are scarce for reptiles, with only one
 study in geckos. Understanding thermal tolerance and plasticity, and their
 relationship, is essential for understanding how some species are able to
 adjust or adapt to changing temperatures. In this study, we estimated
 thermal tolerance and plasticity, and their interaction, in the
 crepuscular gecko, Eublepharis macularius, a species that is
 emerging as a model for reptile biology. After estimating basal thermal
 tolerance for 28 geckos, thermal tolerance was measured for each
 individual a second time at several time points (3, 6, or 24 h) to
 determine thermal tolerance plasticity. We found that thermal tolerance
 plasticity (1) does not depend on the basal thermal tolerance of the
 organism, (2) was highest after 6 hours from initial heat shock, and (3)
 was negatively influenced by individual body mass. Our findings contribute
 to the increasing body of work focused on understanding the influence of
 biological and environmental factors on thermal tolerance plasticity in
 organisms and provide phenotypic data to further investigate the molecular
 basis of thermal tolerance plasticity in organisms.
description: In this study, we established the critical thermal maximum (basal
 upper thermal tolerance), inferred the thermal tolerance plasticity, and
 assessed their relationship in the gecko, <em>Eublepharis
 macularius. </em>Thermal tolerance plasticity through heat hardening
 has been measured as the change in the critical thermal maximum
 (CT<sub>max</sub>) over time. CT<sub>max
 </sub>corresponds to the upper thermal tolerance of an organism,
 which is the internal body temperature at which the organism loses
 physiological function and cannot tolerate any higher temperatures. In
 addition to measuring heat hardening capacity and thermal tolerance
 within<em> E. macularius</em>, in this work, we also
 investigate the influence of individual body mass, body size, and sex on
 heating rates across CT<sub>max</sub> experiments.
description: # Thermal tolerance plasticity and dynamics of thermal tolerance in
 *Eublepharis macularius*: Implications for future climate-driven heat
 stress ## Summary: The datasets described here include individual cloacal
 body temperatures, measurements for critical thermal maximum, heating
 rates, and individual characteristics (i.e., body size, mass, sex, time
 group, etc.). ## Software used: * R v4.3.0 for statistical analyses, with
 required packaged loaded at the top of the included
 *CTmax_Plasticity_Script.R* ## Description of data files: ###
 Gecko\_Cloacal\_Temps.csv Describes measurements of cloacal body
 temperatures collected from each individual during CTmax experiments and
 includes individual characteristics (i.e., body size, sex, mass, etc.).
 All temperature measurements are in degrees Celsius. Variables are
 described as follows: **Time_min**: Time in minutes when cloacal body
 temperature data was recorded for each individual during experiments.
 **Temp**: Cloacal temperature in degrees Celsius for the individual.
 **Individual**: Number of the individual. **Sex**: The sex of the
 individual (either "M" for male or "F" for female).
 **SVL_cm**: The snout-vent-length of the individual measured in
 centimeters (cm) before experiments. **Mass_g**: The mass of the
 individual measured in grams (g) before basal CTmax experiments.
 **Time_group**: The time interval in hour(s) (either 0, 3, 6, or 24) when
 individual cloacal body temperature was measured. ###
 CTmax\_Plasticity\_Data.csv Describes measurements of CTmax collected from
 each individual during experiments, heating rates, adjusted and unadjusted
 plasticity values, and individual characteristics (i.e., body size, sex,
 mass, etc.). CTmax values are measured in degrees Celsius and heating
 rates are measured as degrees Celsius per minute. "NA" values
 represent variables that were not measured for the individual. Variables
 are described as follows: **Individual**: Number of the individual.
 **Sex**: The sex of the individual (either "M" for male or
 "F" for female). **SVL_cm**: The snout-vent length of the
 individual measured in centimeters (cm) before experiments. **Mass_g**:
 The mass of the individual measured in grams (g) before basal CTmax
 experiments. **Mass_after_basal_CTmax_g**: The mass of the individual
 measured in grams (g) before the final CTmax experiments. **Basal_CTmax**:
 The critical thermal maximum of the individual measured as the cloacal
 body temperature in degrees Celsius. This measurement was taken at time 0
 hours during basal CTmax experiments. **Final_CTmax**: The critical
 thermal maximum of the individual measured as the cloacal body temperature
 in degrees Celsius. This measurement was taken at either time 3 hours, 6
 hours, or 24 hours after basal CTmax measurement. **Group**: The randomly
 assigned time-interval treatment group of the individual (either 3h, 6h,
 or 24h). **Change in CTmax**: The calculated difference between basal
 CTmax and final CTmax of the individual measured in degrees Celsius.
 **Adjusted_Plasticity**: The adjusted change in CTmax values in degrees
 Celius for the 3h time-interval group and unadjusted change in CTmax
 values in degrees Celsius for the 6h and 24h time-interval groups.
 **Basal_Heating_Rate**: The calculated slope value for each individual
 corresponding to the change in cloacal body temperature over time measured
 every minute at time 0h during basal CTmax experiments. Units are in
 degrees Celsius per minute. **Final_Heating_Rate**: The calculated slope
 value for each individual corresponding to the change in cloacal body
 temperature over time measured every minute at time 3h, 6h, or 24h during
 final CTmax experiments. Units are in degrees Celsius per minute.
 **Heating_Rate_Difference**: The calculated difference between basal and
 final heating rates for each individual. Units are in degrees Celsius per
 minute.