Ants 'speed up' when to accommodate larger crowd

Ants increase their speed in order to accommodate more ants following their way.

In a new study, when the researchers at the University of Halle-Wittenberg in Germany increased the supply of food by leaving food next to the trail, ants accelerated their speed by 50 percent. This was despite more than double the density of traffic.

The number of encounters between outbound and incoming ants increases With this increase in ant density. Researchers suggest that the encounters provide an opportunity for ants to swap information and to change their behavior according to conditions.

The researchers also identified rules of ant etiquette. For example, workers returning to the colony more often moved to the left than to the right to avoid colliding with an oncoming ant. Rather than segregating strictly into lanes like human traffic, the ants used only a degree of segregation, with inbound ants more frequently using the left side of the trail.

The observations were made in the black-meadow ant, Formica pratensis, a species that lives mainly in open grassland and forages on aphid honeydew as its carbohydrate source.

Christiane Honicke, co-author of the study, said that even under the highest densities, there was no traffic jams observed, and the ants increased their pace and were driven off the central lanes of the trail, resulting in a self-organized optimization of the traffic.

The research is published in Springer's journal The Science of Nature - Naturwissenschaften.