title: A broad-scale comparison of aerobic activity levels in vertebrates: endotherms versus ectotherms.
abstract: Differences in the limits and range of aerobic activity levels between endotherms and ectotherms remain poorly understood, though such differences help explain basic differences in species' lifestyles (e.g. movement patterns, feeding modes, and interaction rates). We compare the limits and range of aerobic activity in endotherms (birds and mammals) and ectotherms (fishes, reptiles, and amphibians) by evaluating the body mass-dependence of VO2max, aerobic scope, and heart mass in a phylogenetic context based on a newly constructed vertebrate supertree. Contrary to previous work, results show no significant differences in the body mass scaling of minimum and maximum oxygen consumption rates with body mass within endotherms or ectotherms. For a given body mass, resting rates and maximum rates were 24-fold and 30-fold lower, respectively, in ectotherms than endotherms. Factorial aerobic scope ranged from five to eight in both groups, with scope in endotherms showing a modest body mass-dependence. Finally, maximum consumption rates and aerobic scope were positively correlated with residual heart mass. Together, these results quantify similarities and differences in the potential for aerobic activity among ectotherms and endotherms from diverse environments. They provide insights into the models and mechanisms that may underlie the body mass-dependence of oxygen consumption.
authors.affiliation: Department of Biology, University of Florida, Gainesville, FL 32611, USA gillooly@ufl.edu.
authors.forename: James F
authors.identifier: 0000-0002-8516-3268
authors.initials: JF
authors.lastname: Gillooly
authors.affiliation: Department of Biology, University of Florida, Gainesville, FL 32611, USA.|Spatial Epidemiology and Ecology Research Laboratory, University of Florida, Gainesville, FL 32610, USA.
authors.forename: Juan Pablo
authors.initials: JP
authors.lastname: Gomez
authors.affiliation: Florida Museum of Natural History, University of Florida, Gainesville, FL 32611, USA.
authors.forename: Evgeny V
authors.initials: EV
authors.lastname: Mavrodiev
mesh_terms: D000332:Aerobiosis; D000663:Amphibians / Q000378:metabolism*; D000818:Animals; D001717:Birds / Q000378:metabolism*; D005399:Fishes / Q000378:metabolism*; D008322:Mammals / Q000378:metabolism*; D010101:Oxygen Consumption; D010802:Phylogeny; D012104:Reptiles / Q000378:metabolism*
keywords: VO2 max; metabolic rate; metabolic theory; respiration; scaling