Maintenance mechanisms of the division of labor in social insects

Abstract

The hallmark of eusocial insects, such as honeybees, ants, and termites, is the division of labor among colony members, which is a crucial feature in realizing ecological success in various environments. A colony generally comprises two subgroups, known as castes, that are related to different tasks: the reproductive caste, which is responsible for reproduction, and the non-reproductive worker caste, which performs all other tasks. Moreover, workers are engaged in different tasks in the colony. Maintenance mechanisms of the division of labor among workers have been extensively studied, from the individual to the colony level. Here, we review recent advances in the maintenance mechanisms of the division of labor. In particular, we focus on how workers’ behavioral plasticity shapes the division of labor as a group level phenotype. First, we explain two mechanisms that maintain the division of labor, i.e., age polyethism and flexible task allocation, and then introduce the method to quantify the degree of division of labor. Second, we explore the response threshold involved in workers’ decision-making and how it enables them to perform specific tasks, resulting in the division of labor. Third, we summarize the physiological basis of the division of labor, with a particular focus on juvenile hormone, Vitellogenin, and Vitellogenin-related genes. Fourth, we discuss the mechanisms of task shifting in workers, which is a crucial factor in reorganizing the division of labor in fluctuating environments. Finally, we describe the future directions of research into the division of labor in insect societies.