U-turns on ant pheronome trails

Many ant species use branching networks of pheromone trails for orientation between nest and resources [1,2,3]. Ants on trails make adaptive U-turns for correcting their course using visual cues [4, 5] or trail geometry information [2]. However, the role of seemingly non-corrective U-turns on trails is poorly understood. We found that a minority of ants consistently make frequent and seemingly inappropriate U-turns during foraging bouts. These frequent U-turners were also highly likely to lay pheromone trail, whilst non-turners rarely did so. Our data suggest that U-turning ants make a greater contribution to trail persistence than do non-turners