Data from: Body size shifts influence effects of increasing temperatures on ectotherm metabolism

Aim: Warmer temperatures directly increase metabolic rates of ectotherms,
but temperature also indirectly affects metabolic rates. Higher
temperatures result in smaller body sizes and associated decreases in
metabolic rates, and it remains unknown whether this indirect effect of
temperature increase could mitigate the direct positive effect of
temperature on metabolic rate. Here, we assess whether temperature‐induced
shifts in body size are likely to offset the direct influence of
temperature on metabolic rate. Location: Global. Time period: 1940–2011.
Major taxa studied: Ectotherms. Methods: We compiled literature‐derived
data on mass and temperature for 109 ectotherm species raised at various
constant temperatures. Using an allometric equation to estimate metabolic
rate from size and temperature, we determined the body masses necessary
for species to maintain constant metabolic rates under increased
temperatures. We also calculated and compared (a) change in metabolic rate
attributable to increased temperature where body size does not change with
(b) change in metabolic rate including empirical size change. Results:
Warmer temperatures resulted in increased metabolic rate estimates, but
this was partly offset by decreased body sizes for the majority of
species. For most species, observed decreases in body size at higher
temperatures were insufficient to avoid metabolic rate increases. Main
conclusions: Although the indirect effect of temperature on metabolic rate
via body size is not sufficient to counterbalance the direct effect, it
limits the magnitude of the increase in metabolic rate. Thus, in a warming
climate, ectotherms are likely to experience increases in energy use that
are smaller than anticipated. Given that metabolic rates have substantial,
diverse impacts on individuals, populations, and ecosystems, these
indirect effects of temperature change will have complex cascading effects
on ecological communities, but the impacts of increases in metabolic rate
of these varying magnitudes are unknown.