These patterns were revealed from an analysis of Argentinean ants (Linepithema humile.) The patterns have been noted on both an individual and collective level, as a mass of soldier ants move. This dark ant — native to northern Argentina, Uruguay, Paraguay, and southern Brazil — is an invasive species. The ants commonly set up quarters in the ground, loose leaf litter, in cracks in concrete walls, and in spaces between boards and timbers.
As the researchers gathered data, they noted the ants moved in different ways. The changes in direction were found to correspond to mathematical patterns. These patterns matched mathematical laws of probability (a mixture of Gaussian and Pareto distributions). These types of probability are used by mathematicians to predict seemingly random changes. In the case of the ants, the models predicted how often an ant ‘turns’ at each step and the direction it will next travel in.
Two factors seemingly affect the movement of ants. First is called “persistence,” which means an ant will not change its direction while there are no obstacles in its path. The second is “reinforcement,” which means that it knows which areas have previously been visited (based on a pheromone trail).
The research is not just of biological interest. It may be possible to learn from the discovery in order to coordinate the movement of microrobots, designed to clean-up areas that have become toxic. This could result from a fusion of biology and physics.
The findings have been published in the journal Mathematical Biosciences. The research is called “From individual to collective dynamics in Argentine ants (Linepithema humile).”
