Mapping Trail Networks of Turtle Ants in a Tropical Dry Forest of Western Mexico

Arboreal ants are important in the trophic ecology of tropical forests. They function as “ecosystem engineers”, yet their behavior remains largely a mystery. In the tropical dry forest of western Mexico, colonies of the arboreal turtle ants Cephalotes goniodontus nest and forage. They work as a collective colony to develop and maintain a network using pheromones to establish and reinforce foraging trails. These trails are constrained by the current network of surrounding vegetation such as tree branches, shrubs, and vines. During June-August 2019, I investigated how turtle ant trail networks change over time at Estación de Biología Chamela. I worked with Stanford professor Deborah Gordon to map three separate colonies in the surrounding forest. Each main trail was evident from heavy traffic of ants. Nodes on the main trail were labeled with fine wire and tape to easily track the network from day to day. Distance (cm) was measured from node to node and the repeatability, or likelihood of the exact path being reinforced, was determined. Surrounding nodes were also measured and recorded, extending at least 5 nodes away from the main trail. Over ten days, we recorded how each colony network was maintained or adjusted, and developed maps to represent the change over time. Though drastic changes occurred from day to day, the network ultimately remained stable.