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Download paper Released 2022-09-15

Behind the scene of body mass allometries

The life history variation in birds and mammals illustrates the natural selection of body mass allometries.

The inter-specific body mass allometries are predicted by population dynamic feedback selection (Witting, 1995, 2017). This selection is an entangled process that links the frequency-independent selection of the physiology to the density-frequency-dependent feedback selection of the intra-specific interactive competition.

In the release on bioRxiv I use the covariance among life history estimates for 90% of all birds and mammals to visualize some of the underlying natural selection causes. This illustrates:

  • How the primary selection of resource handling and mass-specific metabolism generates the net energy of individuals.
  • How the selected net energy generates population dynamic feedback selection, where intra-specific interactive competition selects body masses that scale in proportion with net energy on the timescale of natural selection.
  • How the feedback selection of mass buffers the ecological variation in survival.
  • How the primary selection of metabolism explains a curvature, where the residual mass-specific metabolism---relative to the expectation of the mass-rescaling allometry---is a declining function of mass in terrestrial placentals and birds, but not in marsupials and bats.
  • How the joint selection of body mass and optimal foraging select the exponents of body mass allometries from the dominant spatial dimensionality of the feeding ecology (Fig. 1).
  • Fig. 1 Allometric representation of the invariant population regulation by local exploitation (top plot) and interference competition (middle plots), with the theoretical predictions (the 2 red lines) solved in the bottom plot for the mass-rescaling exponents for home range and mass-specific metabolism for 1D, 2D and 3D ecological interactions. For details see Witting (2022).


    • Witting, L. 1995. The body mass allometries as evolutionarily determined by the foraging of mobile organisms. Journal of Theoretical Biology 177:129--137, https://doi.org/10.1006/jtbi.1995.0231.
    • Witting, L. 2017. The natural selection of metabolism and mass selects allometric transitions from prokaryotes to mammals. Theoretical Population Biology 117:23--42, https://dx.doi.org/10.1016/j.tpb.2017.08.005.
    • Witting, L. 2022. Behind the scene of body mass allometries. Preprint at bioRxiv https://dx.doi.org/10.1101/2022.09.13.507740.