I'm curious as to how common polygyny in this species is; so far I'm unable to locate any literature stating they're even remotely polygynous. All of the colonies (6, to be exact) I've excavated in a particular small patch of woodland located within housing development have had more then one queen, with numbers ranging from 3 to as high as 12. While a few were incipient and appeared to be in their first year, the largest colonies (9 and 12 queens) were both in the middle of raising a large amount of reproductives, making pleometrosis not the only explanation. The queens of which nests certainly seem to coexist within captivity well together.
I recently dug up a colony producing a small amount of alates from a more natural sandhill pine forest, with a total of around 400 workers and a single queen, which prompted the question.