A new type of collective behavior in ants has been revealed by an international team of scientists, headed by biologist Professor Iain Couzin, co-director of the Cluster of Excellence "Centre for the Advanced Study of Collective Behavior" at the University of Konstanz and director at the co-located Max Planck Institute of Animal Behavior, and Matthew Lutz, a postdoctoral researcher in Couzin's lab. Their research shows how ants use self-organized architectural structures called 'scaffolds' to ensure traffic flow on sloped surfaces. Scaffold formation results from individual sensing and decision-making, yet it allows the colony as a whole to adjust dynamically to unpredictable environmental challenges.