Collection of data
We identified published studies documenting the rate of change in whole-body measurements of thermal tolerance in response to manipulation of ambient temperature. Specifically, we sought to identify papers where the study organisms, having been acclimated to an initial temperature for a given period of time, were transferred to a ‘new’ temperature, after which thermal tolerance was measured on subsamples of these individuals at different points in time. Our search criteria included studies that addressed tolerance of both high and low temperatures and performed measurements of critical temperatures (i.e. CTmax, CTmin), time to death or immobility, or mortality rate at a stressful temperature. An additional criterion was that measurements of thermal tolerance were made at a minimum of three time points. Using these criteria, relevant papers were identified using the following procedure. First, we included eight papers identified by Burton et al. (2022) that were based on a search in Web of Science (see Burton et al. for procedure). Second, we conducted two searches on Google Scholar during January 2022. In the first search, we used the terms ”temperature” and ”rate of acclimation”. The 739 hits were sorted based on relevance, and the first 200 abstracts were scanned for inclusion, resulting in a total of 55 papers (none of these appeared among the last 30 scanned abstracts). In the second search, we used the terms ”temperature”, ”acclimation”, ”time course” and ”critical”. This resulted in 30200 hits, which also were sorted based on relevance, and where the first 200 abstracts were scanned for inclusion. For this second search, 7 additional papers were identified (the majority of relevant hits had been identified in the initial search). Finally, the reference lists of papers identified above were scanned for reference to additional papers not located in any of the previous searches, resulting in a further 18 papers. Thus, a total of 88 papers were identified during this procedure. For each paper, we determined whether it presented the required data in an accessible form. Fifty-nine of the papers identified above were found to contain suitable data. Many of these contained data from several experiments (different species and/or different acclimation temperatures), and data from a total of 308 acclimation experiments from a total of 114 species were extracted from these papers. For most of the papers, data were presented in figure format only, usually as the mean tolerance of groups of individuals that had experienced the ‘new’ temperature for differing lengths of time prior to being measured for the chosen tolerance trait. We digitized such data using the WebPlotDigitizer (https://apps.automeris.io/wpd/). In addition to thermal tolerance data we extracted information for the following variables: taxonomic class, species name, mean body mass of individuals used in the experiment, and acclimation temperature. For experiments where body mass information was absent we used the following procedure to obtain such data. First, we searched for information on minimum and maximum adult body size (length or mass) for the species in question. If only data on body length were available, we searched for allometries between length and mass for that species, or for species within the same genus, and used these to convert body lengths to mass. We then calculated the mean of the minimum and maximum body mass values. If no data on minimum or maximum size was found, we searched for studies that presented body sizes of adult individuals during field surveys and used the mean of these. Combining body size estimates from each of these sources yielded measurements for 290 of the 308 experiments described above, representing a total of 107 species from the following classes of ectotherms; amphibians, reptiles, insects, osteichtyes and malacostraca. For simplicity the latter two will be referred to as fishes and crustaceans, respectively.