Table 1. Overview of processes, parameters and default values used in the model.

Colony size	500 agents
Leaving rate of idle foragers	(2/1000 * no. agents in the nest)/sec
Crowding threshold	8, 24, 72, 216
Drinking time	60 time steps (60 seconds)
Return-to-nest time	ca. 40 time steps
Unloading time	60 time steps
Time delay between introduction of both food sources	0 time steps (Part C); 900 time steps (Part D)
Amount (c) of chemical deposited per patch	60 pheromone units
Pheromone decay rate r	0.4 (corresponds to a decay in c. 2700 time steps or 45 min)
Amount of pheromone at t	Ci(t) = Ci(t–1)×(100−r)/100
Pheromone detection threshold per patch	0.05 pheromone units