Group navigation in the face of obstacles during cooperative transport

During cooperative transport, groups must form a consensus about travel direction, which is especially difficult when facing obstacles. We studied obstacle navigation in Paratrechina longicornis, to see whether they use a simple strategy or a more robust, but complex, strategy. Simple navigation strategies require little information, but some obstacles cannot be navigated this way. We blocked transport teams with easy and challenging obstacles. Challenging obstacles were designed to thwart the simplest strategies. We found that the obstacle-navigation strategy of P. longicornis is flexible. Initially, ants employ a simple strategy that will work for easy obstacles; if that fails, they switch to a strategy that is time-intensive, but always successful. This more complex strategy involved moving larger and larger distances away from their goal over time, which allowed them to more thoroughly explore the space. Groups navigated easy obstacles more quickly, but even with the challenging obstacles, they always succeeded.