Better tired than lost: how ant colony trail networks maintain coherence

What is it about?

To create and maintain a backbone routing network is a basic challenge in many engineered and biological systems, from wireless sensor networks and robot swarms to neural circuits and blood circulation. Optimal routing in such networks often seeks to minimize transport delay or response times. Here we report on the routing backbones of turtle ants, an arboreal species that forages in the tree canopy of tropical forests, constrained by the variable terrain of the vegetation, comprised of entwined branches and vines. Ants put down trail pheromone as they walk and at each junction in the vegetation, an ant is likely to take the one most reinforced. However, sometimes ants take a different path, which allows the colony to explore. Thus each node or junction in the trail is an opportunity for searching but also a chance that ants will get lost. We mapped turtle ant trail networks and the surrounding vegetation and compared the observed trails with random, hypothetical trails. We found that trails do not minimize average edge length; instead they minimize the total number of nodes in the backbone, and favor nodes whose 3-D configuration makes them more likely to be rapidly reinforced with pheromone. Thus trail networks take advantage of natural variation in the environment to build coherence, ensuring that the routing backbone is maintained. Without any assessment from any individual ant, the ants have evolved an algorithm that allows the colony to use physical variation in the environment to ensure that the routing backbone is maintained.

Featured Image

Photo by James Wainscoat on Unsplash

Photo by James Wainscoat on Unsplash

Why is it important?

Without any assessment from any individual ant, the ants have evolved an algorithm that allows the colony to use physical variation in the environment to ensure that the routing backbone is maintained.