Worker demography and behavior in a supercolonial ant colony: The case of the desert ant Cataglyphis niger

Insect societies headed by multiple queens (polygyny) raise evolutionary questions, such as how does genetic heterogeneity among colony members affect in-nest interactions; or, are all queens equally reproductive or equally treated by workers? Answering such questions requires intensive and continuous observations of in-nest behavior. Here, we addressed these questions in the polygyne supercolonial ant, Cataglyphis niger, using a barcoding system that enables the tracking of individual interactions, together with polymorphic DNA microsatellite markers that indicate the matriline and patriline of all individuals. Our findings that both queens and workers have low interrelatedness corroborate earlier reports regarding the supercolony structure of C. niger. Ovary inspection and worker genotyping revealed that all the queens contribute similarly to nest demography. Tracking positions of individual workers through time revealed that only a small proportion of them are constantly engaged in tending the queens and can be considered as retinue workers. However, genotyping these workers and the attended queens revealed no relationship to genetic relatedness, again typical of a true polygyne and supercolonial species. Unlike invasive supercolonial species, C. niger is native to Israel, enabling us to address questions regarding the driving forces, other than kin selection, that stabilize this society.