Body size shifts influence effects of increasing temperatures on ectotherm metabolism. Issue 8 (24th August 2018)

• Record Type: Journal Article
• Authors: Riemer, Kristina; Anderson‐Teixeira, Kristina J.; Smith, Felisa A.; Harris, David J.; Ernest, S. K. Morgan
• Is Part Of: Global ecology & biogeography. Volume 27:Issue 8(2018)
• Page Start: 958
• Page End: 967
• Publication Date: 2018-08-24
• Subjects: body size -- ectotherms -- indirect effects -- metabolic rate -- metabolic theory -- physiology -- warming temperatures; Ecology -- Periodicals; Biogeography -- Periodicals; Biodiversity -- Periodicals; Macroevolution -- Periodicals; 577
• DOI: 10.1111/geb.12757
• Languages: English
• ISSNs: 1466-822X

Abstract

Abstract: 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.