Cooperative transport in ants: a review of proximate mechanisms

The behavioral mechanisms that lead to cooperation in social insects are often unknown or poorly understood. Cooperative transport, or the movement of an object by two or more individuals, is a particularly impressive example of collaboration among workers. Many ant species perform this behavior, but there is extreme interspecific variation in efficiency. Why are some ant species so efficient at cooperative transport, while others are so inefficient? Surprisingly, the scientific community has little proximate understanding of the adaptations that make certain species excel at this behavior. This work provides a review of the behavioral rules that separate the efficient cooperative transporters from the inefficient. We present two measures of efficiency of cooperative transport as well as a flowchart of the cooperative transport process. By identifying the steps and flow of information, the flowchart enables careful modeling of cooperative transport from a mechanistic perspective. Previous studies of each of the four phases of cooperative transport are discussed, including decision, recruitment, organization, and transport. We also present hypotheses regarding behavioral mechanisms that may modulate efficiency.