Metabolic theories in ecology

The Metabolic Theory of Ecology (MTE) and the earlier theory of Dynamic Energy Budgets (DEB) are both founded on simple mechanistic descriptions of how individual organisms take up and use energy and material. Such descriptions should enable predictions to be made of pools and flows of energy and matter in populations, communities and ecosystems. MTE builds on the idea that the transport of resources through a fractal-like branching network causes the supply rate to cells to scale as a (3/4) power of body mass, whereas DEB is based on the concept that rates of basic physiological processes are proportional to surface area or to body volume. Here, I critically compare both theories, highlight similarities and inconsistencies, and show where the approaches deviate. I argue that, to arrive at a sound theoretical basis of the energy budget of individual organisms, both views should be tested fully, but only after inconsistencies have been addressed.