Individual and group transport: What are the benefits of team work ?

So far, most research on group behavior focused on the great capacities of group to solve problems individuals cannot. Still, some studies in mammals and humans show a decrease of individual performances during cooperative tasks, the so called social loafing. Both phenomena are not mutually exclusive and can work at different levels.

With this in mind, we chose to study the foraging behavior of the Aphaenogaster cockerelli. A. cockerelli is mostly a solitary forager but forms teams to retrieve bulky food items. This very interesting foraging system allowed us to study a system where collective intelligence and social loafing occur. Our experiments were designed to understand how cooperation can improve the completion of a task that a single individual is able to solve. We compared the efficiency of individual transport with that of a pair of individuals cooperating to retrieve the same food item for two conditions. During the easy task, the substrate for the transport was paper which we replaced by fine gravel in the difficult task. When the task is easy, most of the retrieval is done by single ants but duos form when the task gets harder showing that the colony adapts its forces to the task difficulty. Interestingly enough, duos can be forced to form and persist despite the fact that they would not form naturally.