Mean CO2 release rates (μmol CO2 h–1; averaged across all individuals tested) at normoxia as a function of mean fresh mass (mg; log–log plot) for tenebrionid (filled circles) and scarabaeid species (open circles) examined in this study. Mean CO2 release rates (μmol CO2 h–1; averaged across all individuals tested) at normoxia as a function of mean fresh mass (mg; log–log plot) for tenebrionid (filled circles) and scarabaeid species (open circles) examined in this study. The slope is shown as ordinary least squares regression analysis on species means. Hilary M. Lease et al. J Exp Biol 2012;215:2524-2533 © 2012.