Ants adjust their pheromone deposition to a changing environment and their probability of making errors

Animals must contend with an ever-changing environment. Social animals, especially eusocial insects such as ants and bees, rely heavily on communication for their success. However, in a changing environment communicated information can become rapidly outdated. This is a particular problem for pheromone-trail using ants, as once deposited pheromones cannot be removed. Here we study the response of ant foragers to an environmental change. Ants were trained to one feeder location, and the feeder was then moved to a different location. We found that ants responded to an environmental change by strongly up-regulating pheromone deposition immediately after experiencing the change. This may help maintain the colony’s foraging flexibility, and allow multiple food locations to be exploited simultaneously. Our treatment also caused uncertainty in the foragers, by making their memories less reliable. Ants returning to the nest after eventually finding the food source up-regulated pheromone deposi...