The implicit assumptions of classic functional responses and their multi-species extensions

Abstract

AbstractFunctional responses are central to describe consumer-resource interactions. Defined as the per capita average feeding rate of consumers, since Holling’s seminal papers, they have been widely used in ecology. Holling’s central observation was that they often saturate as resource density increases. If the interference between consumers is strong, they also decrease with consumer density. Here we emphasize the link between individual feeding processes and emergent population-averaged feeding rates and the associated probability distributions of the different behavioral types. We do so by revisiting a classic approach based on the formulation of feeding interactions in terms of chemical reaction schemes. We highlight the common assumptions leading to the different functional forms. Our work has clear implications, on the one hand, for both model selection and parameter inference from feeding experiments, and, on the other, for the use of multi-species extensions of these functional responses in population-level food web dynamic models.