DOI: 10.5061/dryad.ttdz08m6c
title: Data from: The two environmental drivers of thermoregulatory costs: Interactions between thermal mean and heterogeneity influence thermoregulation

description: Ectotherms often thermoregulate behaviourally within variable thermal
 environments in their attempts to acquire optimal body temperatures.
 Thermoregulation accrues benefits, but also incurs costs, which are
 crucial for understanding thermoregulatory behaviour. Costs of
 thermoregulating are influenced by two key attributes of the thermal
 environment – heterogeneity of thermal microhabitats and the deviation of
 the mean temperature from an animal’s preferred temperature. However,
 empirical research has rarely distinguished between these two drivers of
 thermoregulatory costs or examined them concurrently. Our experiment used
 a novel thermoregulatory arena to examine the independent and interactive
 effects of the two environmental drivers of costs of thermoregulation on
 the thermoregulatory behaviour of a small ectotherm, the jacky dragon
 (Amphibolurus muricatus). Following previous theory we predicted that i)
 thermoregulation would be higher in environments with greater thermal
 heterogeneity (body temperatures closer to preferred temperatures, higher
 thermoregulatory accuracy, and higher effectiveness of thermoregulation);
 and ii) changes in thermoregulation as a function of mean environmental
 temperatures would differ depending on thermal heterogeneity. We found
 support for our prediction that these two environmental attributes had an
 interactive effect on thermoregulation, but not for our prediction that
 thermal heterogeneity would impact thermoregulation independently.
 Individuals in highly heterogeneous environments maintained greater
 thermoregulatory accuracy compared with those in less heterogeneous
 environments as the mean environment increasingly deviated from the
 preferred temperature range. The results emphasise the crucial conceptual
 distinction between thermal mean and heterogeneity as drivers of
 thermoregulatory costs and how this distinction underpins variation in the
 thermal behaviour of ectotherms.
description: # Data from: The two environmental drivers of thermoregulatory costs:
 Interactions between thermal mean and heterogeneity influence
 thermoregulation
 [https://doi.org/10.5061/dryad.ttdz08m6c](https://doi.org/10.5061/dryad.ttdz08m6c) This dataset presents the results from a behavioural experiment examining how environmental temperatures influence animal thermoregulation. The experiment was conducted in a lab setting using the jacky lizard, Amphibolurus muricatus (Agamidae). ## Description of the data and file structure The data are presented in a single .csv file. Each row in the file is a single individual lizard whose thermoregulatory behaviour was recorded in a trial. The experimental design manipulated the mean environmental temperature (continuously) as well as the heterogeneity of environmental temperatures (3 categories) within a custom-built arena. Environmental temperatures, lizard body temperatures, and lizard movement in the arena were recorded and analyzed across 4 hours. Each column in the file presents trial information and calculated thermoregulatory metrics. Column descriptions are as follow: **Trial:** the unique identifier number for a trial.          **Scenario:** the main treatment of heterogeneity in environmental temperatures. High = high heterogeneity; Low = low heterogeneity; Homo = Homogeneous.       **Animal:** unique ID for the individual lizard used in the trial. **Sex:** sex of the individual lizard used in the trial. M = Male; F = Female.   **SVL (mm):** Snout-vent length of the individual lizard, measured to 1mm. **Mass (g):** Mass of the individual lizard, measured to 0.5g.   **RecordsTb:** The number of records (minutes) over which lizard body temperature was recorded. This value is 240 minutes unless there was a failure in the datalogger or the probe fell out of the lizard’s cloaca.         **AverageEnvironTemp:** The average environmental temperature measured by 25 ibuttons within copper operative models placed at intervals around the arena. Each ibutton recorded temperature each 1 minute over 4 hours. Used to compare the trial conditions across scenarios. **AverageEnvironSD:** The average per-minute standard deviation of environmental temperatures measured by 25 ibuttons within copper operative models placed at intervals around the arena. Each ibutton recorded temperature each 1 minute over 4 hours. Used to compare the trial conditions across scenarios. **AverageMeande:** The average per-minute mean deviation of environmental temperatures from the selected temperature range of the jacky lizard. Environmental temperatures were measured by 25 ibuttons within copper operative models placed at intervals around the arena. Each ibutton recorded temperature each 1 minute over 4 hours. Used to compare the trial conditions across scenarios. **AverageEnvironTemp.omit:** The average environmental temperature measured by 25 ibuttons within copper operative models placed at intervals around the arena. Each ibutton recorded temperature each 1 minute over 4 hours. In this calculation, entire minutes of records may have been omitted to remove times during the trial when a lizard’s movement was restricted by snags in the thermocouple cord.  Used for analyzing thermoregulatory behaviour.        **AverageBodyTemp.omit:** Average body temperature of the individual lizard measured each 1 minute over 4 hours. In this calculation, body temperature records may have been omitted to remove times during the trial when a lizard’s movement was restricted by snags in the thermocouple cord.     **Averagedb.omit:** Average deviation in body temperature of the individual lizard from the selected temperature range of the jacky lizard. Body temperature was measured each 1 minute over 4 hours. In this calculation, body temperature deviation records may have been omitted to remove times during the trial when a lizard’s movement was restricted by snags in the thermocouple cord.           **MedianE.omit:** Median per-minute Effectiveness of thermoregulation for the individual lizard, calculated using the per-minute deviation in body temperature and per-minute mean deviation in environmental temperatures. In this calculation, Effectiveness records may have been omitted to remove times during the trial when a lizard’s movement was restricted by snags in the thermocouple cord.          **Time.unsnagged:** Number of minutes where the movement of the lizard was not apparently restricted by the thermocouple cord.        **Time.Visible:** Number of minutes when the lizard was visible on the video recording.            **PropTime.Visible:** Proportion of unsnagged minutes when the lizard was visible on the video recording.    **Moves:** A count of lizard movements between grid cells within the arena. Grid cells were defined as the rhomboid around each operative model.            **Moves.p.Time:** Lizard movements (counts) divided by the time visible. **Comments:** Indicates when video recordings were not available. ## Sharing/Access information The data are not accessible in any other location. ## Code/Software No code is included.