Regulation of harvester ant foraging as a closed-loop excitable system
Fig 1
Diagram of the closed-loop model with two components inside the nest and one component outside the nest.
The “Interactions” component maps the sequence of incoming foragers λin to a stimulus s to represent the result of interactions of available foragers inside the nest entrance chamber with incoming food-bearing foragers. The mapping uses a leaky integrator that increases by a fixed magnitude with every incoming forager and has a natural decay rate. The “Response of available foragers” component maps s to the sequence of outgoing foragers λout using the nonlinear FitzHugh-Nagumo oscillator dynamics. Each oscillation represents an ant leaving the nest to forage. The “Foraging” component maps λout to λin using a random time delay with an associated probability distribution to represent the time an ant spends outside the nest foraging.