Koichi Kurumatani, Electronical Laboratory (ETL), Amagasaki, Hyogo, Japan
In previous study, we proposed a model for foraging behavior of an ant colony composed of many ants who behave to collect foods from food sites to a nest. Their behavior was modeled as follows: At first, an ant walks randomly in search of food and recruit pheromone. If it finds food, it carries food straight to the nest laying recruit pheromone. The pheromone evaporates soon, and gradually diffuses. If a searching ant perceive the pheromone, it is recruited to the food site. As a result of an interaction among micro-scale behaviors of many ants, macro-scale foraging behavior of a colony is organized. We performed simulation of above model, and observed a competition process of recruitment among food sites, which results in over-concentrated recruitment to a single site. Then, we made a desensitization assumption, as "when an ant perceives over-concentrated recruitment around itself, it becomes desensitized to recruited pheromone for a while", so that some of ants might be desensitized to circumvent such unwanted over-concentration. In this presentation, we set the desensitization rule as "when an ant misses food at food sites, it gets desensitized", to improve foraging efficiency. We performed further simulations, and observed that the system organizes different recruitment pattern and selects appropriate foraging strategy according to rate of food supply. When food supply is sufficient, concentrated recruitment to a single site is organized, and when food supply is not sufficient, stable distributed recruitment to several sites is organized. Mechanism of changing the foraging strategies could be explained.