Self-organized traffic via priority rules in leaf-cutting ants

Ants, termites and humans often form well-organized and highly efficient trails between different locations. Yet the microscopic traffic rules responsible for this organization and efficiency are not fully understood. Recent experimental work with leaf-cutting ants (Atta colombica) on a very narrow trail has suggested a set of priority rules thought to govern the traffic dynamics. Here we implement an agent-based model to investigate the sufficiency of these rules with respect to producing the observed spatio-temporal properties of the traffic. We compare the model results to four statistics of the real ant flow and find that they share several key characteristics. Then we extend the model to a wider trail and compare the simulation results with new experimental data from this setting. We find that the extended model is able to reproduce the general features of the flow seen in the experiments, including the formation of three-lane traffic. The experimental finding that Atta colombica indeed organize the flow into three-lane traffic is important in its own right and contradicts the previously held belief that Atta in general do not. Due to the simplicity of the proposed rules we believe that they may be responsible for organizing the traffic flow on trails in other species of ant, and perhaps even other trail forming animals such as termites and humans. Title in manuscript: Self-organized traffic via priority rules in leaf-cutting ants Atta colombica