A model for group-size-dependent behaviour decisions in insects using an oscillator network.

Aggressive behaviour within pairs of male crickets leads to the establishment of a dominance hierarchy. Defeated males avoid their victorious adversaries for several hours before regaining aggressiveness. However, the defeated male does not regain aggressiveness if repeated fighting occurs. Loss of individual aggressiveness is limited by group size, which constrains the number of crickets fighting at any given time. Thus, group aggressive behaviour is modulated by an environmental factor, group size, which is ultimately determined by individual actions, i.e. fighting between two individuals. We developed a robot model to elucidate the mechanism of group-size-dependent behaviour alternation in crickets. The behaviour of individual robots was evaluated experimentally with mobile robots and the group behaviour of the robots was evaluated by computer simulation. We demonstrated that the group-size-dependent strategy in crickets could be generated by local interactions between robots, where the behaviour was governed by an oscillator and memory of the outcome of previous fights.