Testing the metabolic theory of ecology: allometric scaling exponents in mammals

Richard P. Duncan, David Forsyth, Jim Hone

    Research output: Contribution to journalArticle

    99 Citations (Scopus)

    Abstract

    Many fundamental traits of species measured at different levels of biological organization appear to scale as a power law to body mass (M) with exponents that are multiples of ¼. Recent work has united these relationships in a “metabolic theory of ecology” (MTE) that explains the pervasiveness of quarter-power scaling by its dependence on basal metabolic rate (B), which scales as M0.75. Central to the MTE is theory linking the observed −0.25 scaling of maximum population growth rate (rm) and body mass to the 0.75 scaling of metabolic rate and body mass via relationships with age at first reproduction (α) derived from a general growth model and demographic theory. We used this theory to derive two further predictions: that age at first reproduction should scale inversely to mass-corrected basal metabolic rate α ∝ (B/M)−1 such that rm ∝ (B/M)1. We then used phylogenetic generalized least squares and model selection methods to test the predicted scaling relationships using data from 1197 mammalian species. There was a strong phylogenetic signal in these data, highlighting the need to account for phylogeny in allometric studies. The 95% confidence intervals included, or almost included, the scaling exponent predicted by MTE for B ∝ M0.75, rm ∝ M−0.25, and rm ∝ α−1, but not for α ∝ M0.25 or the two predictions that we generated. Our results highlight a mismatch between theory and observation and imply that the observed −0.25 scaling of maximum population growth rate and body mass does not arise via the mechanism proposed in the MTE
    Original languageEnglish
    Pages (from-to)324-333
    Number of pages10
    JournalEcology
    Volume88
    Issue number2
    DOIs
    Publication statusPublished - 2007

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    mammal
    mammals
    basal metabolic rate
    ecology
    body mass
    testing
    population growth
    phylogeny
    prediction
    selection methods
    growth models
    least squares
    confidence interval
    phylogenetics
    demographic statistics
    power law
    rate

    Cite this

    Duncan, Richard P. ; Forsyth, David ; Hone, Jim. / Testing the metabolic theory of ecology: allometric scaling exponents in mammals. In: Ecology. 2007 ; Vol. 88, No. 2. pp. 324-333.
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    Testing the metabolic theory of ecology: allometric scaling exponents in mammals. / Duncan, Richard P.; Forsyth, David; Hone, Jim.

    In: Ecology, Vol. 88, No. 2, 2007, p. 324-333.

    Research output: Contribution to journalArticle

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