According to entomologist David Faulkner, if you have a 10 x10 foot (3 x 3 m ) patio slab, you could have a million or more individuals and possibly 20 or 30 queens. They get along fine because they're all related to the original colonizers in Lousiana, perhaps from the original gravid (pregnant) female who arrived there. Workers live a month or more as adults, but queens live up to 10 years or more. With other ants, when the queen dies, the one-queen colony dies because no more ants are being produced. With multi-queen Argentine ants, another queen simply moves in and takes over the role of the deceased queen. In fact, a queen from San Diego would probably be accepted in a colony elsewhere in California.
http://waynesword.palomar.edu/ww0403.htm
I was watching a T.V. show while eating and people had trouble eliminating Argentine ants from their house and people said it is because they have multiple queens so when you poison the ants if you kill the Queen it does not matter and they also said that Argentine ants spread very quickly compared with other ants because they have multiple queens. I am not giving there exact words but just paraphrasing.