Proceedings of the Royal Society of London, Series B 2003,
270, 139-146.
Self-organised lane formation and optimised
traffic flow in army ants
Iain D. Couzin1* and Nigel R. Franks2
1Department of Ecology and Evolutionary Biology, Princeton University,
Princeton, NJ 08544, USA
2Centre for Behavioural Biology, School of Biological Sciences, University
of Bristol, Bristol BS8 1UG, UK.
*Author for correspondence (icouzin@princeton.edu).
We show how the movement rules of individual ants on
trails can lead to a collective choice of direction and the formation
of distinct traffic lanes that minimise congestion. We develop, and
evaluate the results of, a new model with a quantitative study of the
behaviour of the army ant Eciton burchelli. Colonies of this
species have up to 200,000 foragers and transport more than 3,000 prey
items an hour over raiding columns that exceed 100m. It is an ideal
species to test the predictions of our model because it forms pheromone
trails that are populated densely with very swift ants. The model explores
the influence of turning rates and local perception on traffic flow.
The behaviour of real army ants is such that they occupy the specific
region of parameter space in which lanes form and traffic flow is maximised.
