Worker-behavior and behavior-behavior interaction networks in the trap-jaw ant Odontomachus chelifer (Latreille, 1802)

Division of labor is among the main factors to explain the evolutionary success of social systems, from the origins of multicellularity to complex animal societies. The remarkable ecological success of social insects seems to have been largely driven by ergonomic advantages stemming from the behavioral specialization of workers. However, little is known about how individuals and their correspondent behavioral repertoire are related to each other within a division of labor context, as this relationship can be viewed as a complex network. Applications of network theory in the study of social insects are almost exclusively used to analyze behavioral interactions between individuals, rather than to the study of relations among individuals and behaviors. Here, we use a new approach to the study of the organization of the behavioral repertoire of ant colonies, which consider both individual-task interactions and task-task interactions, besides colony time budgets. Our study investigates for the first time the organization of division of labor in colonies of the trap-jaw ant Odontomachus chelifer (Latreille 1802). Data from all the behavioral acts (including inactivity) performed within three queenright colonies of different sizes (n = 7, 30, and 60 workers) were studied under controlled laboratory conditions. Each ant within the colonies was individually marked and observed by scan sampling in 10 min intervals for 10 h each (n = 5820 behavioral acts). We describe the network topologies in terms of centrality, specialization, modularity, and nestedness. This study shows that workers of O. chelifer interact in structured networks composed of specialists and generalists with consistent organization, even across colonies of different sizes. Our results underscore the potential of the use of complex networks in order to discover and study novel organizational patterns of social groups in animal behavior.