Absence of Nepotism in Worker-Queen Care in Polygynous Colonies of the Ant Ectatomma tuberculatum

The question of the occurrence of nepotism in insect societies is central to inclusive fitness theory. Here we investigated the existence of nepotism in the facultative polygynous ant Ectatomma tuberculatum because various characteristics of this species may have favored the evolution of nepotistic behavior toward queens. We thus studied worker-queen care toward their mother queen vs. an unrelated unfamiliar queen, to determine if workers cared preferentially for their mother. Although we tried to facilitate the expression of nepotistic behaviors, we did not detect significant nepotism confirming the general trend of an absence of nepotism in social insects. We discuss about the specific causes that can explain the absence of nepotism in E. tuberculatum regarding the particular social organization of this species and its ecological dominance in the mosaic of arboreal ants.