Social differentiation and division of labour in the queenless ant platythyrea schultzei forel 1910 (hymenoptera formicidae)

Abstract

Colonies of Platythyrea schultzei Forel 1910 are obligately queenless, containing only 10–40 morphologically and anatomically similar, monomorphic workers. The role of the queen is filled by a single inseminated worker in each colony. The ovaries of this worker are physiologically active, while oogenesis is repressed in its nestmates.Colony labour is organised into five groups of tasks: care of eggs, care of larvae, care of cocoons, and general colony maintenance, including foraging. The mated worker monopolize the task of caring for the eggs. Organisation of the remaining ants to carry out the other tasks shows a clear pattern of age polyethism, through which all workers except the mated worker pass. There is no indication that division of labour is based on or biased by size differences amongst the workers.The behavioural marker (carrying eggs) for the mated worker allows its experimental removal from each colony. In each case its role is taken over by a single, young, uninseminated worker that undergoes ovarial development and assumes the same behavioural characteristics and control over its nestmates’ oogenesis as the previous mated worker. Thus insemination does not appear to be a prerequisite for the physiological differentiation of an individual to fill the role of reproductive. © 1991 Taylor & Francis Group, LLC.