Metabolism drives demography in an experimental field test

Lukas Schuster, Hayley Cameron, Craig R. White, Dustin J. Marshall

Research output: Contribution to journalArticleResearchpeer-review

9 Citations (Scopus)

Abstract

Metabolism should drive demography by determining the rates of both biological work and resource demand. Long-standing “rules” for how metabolism should covary with demography permeate biology, from predicting the impacts of climate change to managing fisheries. Evidence for these rules is almost exclusively indirect and in the form of among-species comparisons, while direct evidence is exceptionally rare. In a manipulative field experiment on a sessile marine invertebrate, we created experimental populations that varied in population size (density) and metabolic rate, but not body size. We then tested key theoretical predictions regarding relationships between metabolism and demography by parameterizing population models with lifetime performance data from our field experiment. We found that populations with higher metabolisms had greater intrinsic rates of increase and lower carrying capacities, in qualitative accordance with classic theory. We also found important departures from theory—in particular, carrying capacity declined less steeply than predicted, such that energy use at equilibrium increased with metabolic rate, violating the longstanding axiom of energy equivalence. Theory holds that energy equivalence emerges because resource supply is assumed to be independent of metabolic rate. We find this assumption to be violated under real-world conditions, with potentially far-reaching consequences for the management of biological systems.

Original languageEnglish
Article numbere2104942118
Number of pages7
JournalProceedings of the National Academy of Sciences of the United States of America
Volume118
Issue number34
DOIs
Publication statusPublished - 24 Aug 2021

Keywords

  • Competition
  • Damuth’s law
  • Energy equivalence
  • Increased intake hypothesis
  • Metabolic theory

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