Abstract
Ecologists have long debated the universality of the energetic equivalence rule, which posits that population energy use should be invariant with average body size due to negative size–density scaling. We explore size–density and size–energy use scaling across 183 geographically–distributed soil invertebrate food webs (comprising 55,054 individual soil invertebrates) to investigate the universality of these fundamental energetic equivalence rule assumptions across trophic levels and varying food web structure. Additionally, we compare two measures of energy use to investigate size–energy use relationships: population metabolism and energy fluxes. We find that size–density scaling does not support energetic equivalence in soil communities. Furthermore, evidence of energetic equivalence is dependent on the estimate of energy use applied, the trophic level of consumers, and food web properties. Our study demonstrates a need to integrate food web energetics and trophic structure to better understand how energetic constraints shape the body size structure of terrestrial ecosystems.
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Data availability
The data generated in this study has been deposited in the figshare repository https://doi.org/10.6084/m9.figshare.25591254.v1. The raw EFForTS and ECOWORM data are protected and are not available due to data privacy laws. Source data are provided with this paper.
Code availability
The code generated in this study has been deposited in the figshare repository https://doi.org/10.6084/m9.figshare.25591227.v1.
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Acknowledgements
Our project was supported by the Marsden Fund Council from Government funding managed by Royal Society Te Apārangi (grant MFP-23-UOW-029), and the People, Cities, and Nature research programme (Ministry of Business, Innovation and Employment, grant UOWX2101). We thank the numerous people that assisted in the field and laboratory and mana whenua (Indigenous people) of the land our sites were on. We acknowledge the use of data drawn from the EFForTS and ECOWORM projects. All authors gratefully acknowledge the support of iDiv, which is funded by the German Research Foundation (DFG – FZT 118, 202548816). N.E. and O.F. thank the DFG (Ei 862/29–1; Ei 862/31–1) for funding. Fig. 1, and Fig. 2 were created with Canva.com using images and elements of these images created by authors (see supplementary code). A.P. was funded by the Deutsche Forschungsgemeinschaft (DFG, German Research Foundation) – Projektnummer 493345801.
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P.J.R. and A.D.B. conceived the study. P.J.R., A.D.B., A.P., B.R., G.M., K.J.W., M.J., S.S., D.O., M.R.H., U.B., N.E., and O.F. collected and processed the soil data. A.C.A. curated and processed the EFForTS and ECOWORM soil data. P.J.R. and B.G. analysed the data. P.J.R. and A.D.B. wrote the first draft of the manuscript, and all authors contributed substantially to revisions.
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Romera, P.J., Gauzens, B., Antunes, A.C. et al. Detection of energetic equivalence depends on food web architecture and estimators of energy use.
Nat Commun (2025). https://doi.org/10.1038/s41467-025-67615-6
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DOI: https://doi.org/10.1038/s41467-025-67615-6
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