A modelling framework for understanding social insect foraging

The foraging of an insect society is a complex process involving large numbers of individuals collecting food from many different sources. Differential equation models have shown how quite simple communication mechanisms can produce complex and functional group-level foraging patterns. In this paper we review previous differential equation models for pheromone trails, honey bee dances and other methods of communication used during foraging. We develop a general framework for modelling social insect foraging systems that incorporates each of the previous models. This framework identifies the different behaviours that insects undertake while foraging, along with generalised rate functions that determine how the insects switch between behaviours. We describe how to tailor our framework to specific insect societies, by incorporating the details of specific behavioural mechanisms into appropriate expressions for rates of discovery of, recruitment to, and retirement from food sources. Our framework thus provides an experimental tool for improved understanding of the foraging behaviour of particular species, as well as a system for meaningful comparisons of foraging behaviour across species. We end this article by linking our framework to inclusive fitness theory. We demonstrate how understanding of the proximate mechanisms involved in social insect foraging ultimately furthers understanding, not only of how insect societies function, but also of how these mechanisms are used to optimise colony fitness and survival.