Demography and behaviour of polygyne nests of the supercolonial ant Cataglyphis niger: Does kinship matter?

The basic ant colony is presumed to have evolved through kin selection. However, ants show a remarkable diversity in their social organization, from a monogynous-monandrous queen to the more derived states of polygyny with polyandrous queens. The existence of polygyny is an evolutionary enigma, since kin selection theory predicts that while queens should strive for reproductive monopoly, workers are predicted to favor their own matriline in rearing gynes. Using a barcoding system that enables tracking of individual interactions, along with polymorphic DNA microsatellite markers that indicate the matriline and patriline of all individuals, we demonstrate the complex social interactions in polygyne nests of Cataglyphis niger. C. niger is not only polygyne but also constitutes a supercolony at the study site. Our pioneering findings that both queens and workers are not necessarily related to each other support the supercolony structure of the population. Also in line with supercoloniality, we demonstrate that the workers contribute equally to the nest production and rearing of the queens. Unlike invasive supercolonial species, C. niger is native to Israel, raising questions about the driving forces, apart from kin selection, that stabilize this society.