EntomoNews

Les ponts formés par leurs corps leur servent à former des raccourcis lors de leurs redoutables parties de chasse. Des chercheurs en ont percé le secret.

• Army ants dynamically adjust living bridges in response to a cost–benefit trade-off, PNAS, 23.11.2015
  http://www.pnas.org/content/early/2015/11/18/1512241112.abstract

Complex systems, from ant colonies to stock markets, share a common property: sophisticated group-level structure emerges from simple individual-level behaviors. Using simple interaction rules, Eciton army ants construct complex bridges from their own bodies to span forest-floor gaps. These living bridges are uniquely complex in both their dynamic properties and the number of animals involved and so are of considerable interest for understanding emergent structures in complex systems. In field experiments, we show that construction interacts with traffic rate and environmental geometry, causing bridges to lengthen, widen, and migrate. Bridges provide a shortcut for foraging ants, at the cost of sequestering workers. We show that bridge location represents a cost–benefit trade-off, with potential implications for human engineered self-assembling systems.

[Image] Au lieu de bâtir un pont à l’endroit où il formerait le raccourci le plus rapide, (ligne rouge), les fourmis légionnaires choisissent un emplacement qui oblige les chasseuses à faire une petite déviation… car cette structure plus courte peut être obtenue à l’aide d’un plus petit nombre de fourmis. – Crédit : PNAS / Chris Reid.

[collective behavior / self-assembly / swarm intelligence / self-organization / optimization]