"The larger the colony, the more accurately each ant will measure the true state." #readingToday

In general, as Lauren Meyers pointed out to me, the stability of larger colonies could be due to the improved sampling that large size provides. Each ant's interactions with others is a sample of some aspect of the current state of the colony, such as the rate at which foragers are coming in with food, or the relative numbers of foragers and nest maintenance workers currently active. The larger the colony, the more accurately each ant will measure the true state. Or to put it more precisely, the smaller the colony, the more opportunities for sampling error to affect an ant's interaction experience. When there are few ants, each ant is more likely to interact with only a few ants, and those few might not be representative.