title: A common scaling rule for abundance, energetics, and production of parasitic and free-living species.
abstract: The metabolic theory of ecology uses the scaling of metabolism with body size and temperature to explain the causes and consequences of species abundance. However, the theory and its empirical tests have never simultaneously examined parasites alongside free-living species. This is unfortunate because parasites represent at least half of species diversity. We show that metabolic scaling theory could not account for the abundance of parasitic or free-living species in three estuarine food webs until accounting for trophic dynamics. Analyses then revealed that the abundance of all species uniformly scaled with body mass to the -&frac34; power. This result indicates "production equivalence," where biomass production within trophic levels is invariant of body size across all species and functional groups: invertebrate or vertebrate, ectothermic or endothermic, and free-living or parasitic.
authors.affiliation: Marine Science Institute and Department of Ecology, Evolution, and Marine Biology, University of California, Santa Barbara, CA 93106, USA. hechinger@lifesci.ucsb.edu
authors.forename: Ryan F
authors.initials: RF
authors.lastname: Hechinger
authors.forename: Kevin D
authors.initials: KD
authors.lastname: Lafferty
authors.forename: Andy P
authors.initials: AP
authors.lastname: Dobson
authors.forename: James H
authors.initials: JH
authors.lastname: Brown
authors.forename: Armand M
authors.initials: AM
authors.lastname: Kuris
mesh_terms: D000818:Animals; D044822:Biodiversity; D018533:Biomass; D001717:Birds / Q000378:metabolism / Q000502:physiology; D049628:Body Size; D001831:Body Temperature; D017753:Ecosystem; D004734:Energy Metabolism; D005399:Fishes / Q000378:metabolism / Q000502:physiology; D020387:Food Chain; D007448:Invertebrates / Q000378:metabolism / Q000502:physiology*; D016014:Linear Models; D010271:Parasites / Q000378:metabolism / Q000502:physiology*; D011157:Population Dynamics; D012044:Regression Analysis; D014714:Vertebrates / Q000378:metabolism / Q000502:physiology*