Traffic rules around the corner: walking of leaf-cutting ants at branching points in trunk trails

CIBILS MARTINA, LUCIANA; ELIZALDE, LUCIANA; FARJI-BRENER, ALEJANDRO

INSECTES SOCIAUX

BIRKHAUSER VERLAG AG

Año: 2017 vol. 64 p. 549 - 555

0020-1812

The existence of transport networks is vital forleaf-cutting ant foraging but may generate overcrowding,reducing the input of food into the nest. We studied how antsturn at branching points, a problematic sector for ant traffic,in leaf-cutting ant species that vary in ant flow and traildesign. If the walking of turning ants reduces the chance ofcollisions, we expected that (a) ants that keep the same lanewhile turning suffer less collisions than those who changelane, (b) the behavior of keeping the same lane will behigher than expected by chance, and (c) lane fidelity ofturning ants should increase as ant flow increases. Werecorded the turning movements of 1355 individuals in trailbifurcations from 25 ant nests. Each ant was categorizedaccording to the fidelity to its traffic lane while turning, thenumber of collisions, and the ant flow at the moment ofturning. Ants faithful to their lane had fewer collisions thanants unfaithful to their lane when turning, but only in the twoAtta species. Lane fidelity when turning was the most frequentbehavior in all species, but this behavior did notincrease with increments in ant flow. Leaf-cutting antsappear to follow simple rules to reduce overcrowding: keepwalking on the same lane when turning. We discussed theinfluence of ant flow and trail design on this behavior andthe dual role of collisions (information exchange and trafficdelay) in trail sectors conflicting for traffic circulation.