Interspecific interactions alter the metabolic costs of climate warming

Climate warming is expected to increase the energy demands of ectotherms by accelerating their metabolic rates exponentially. However, this prediction ignores environmental complexity such as species interactions. Here, to better understand the metabolic costs of climate change for ectotherms, we reared three Drosophila species in either single-species or two-species cultures at different temperatures and projected adult metabolic responses under an intermediate climate-warming scenario across the global range of Drosophila . We determined that developmental acclimation to warmer temperatures can reduce the energetic cost of climate warming from 39% to ~16% on average by reducing the thermal sensitivity of metabolic rates. However, interspecific interactions among larvae can erode this benefit of developmental thermal acclimation by increasing the activity of adults that develop at warmer temperatures. Thus, by ignoring species interactions we risk underestimating the metabolic costs of warming by 3–16% on average.