At least in my apartment complex, what I believe to be Brachymyrmex patagonicus (they are definitely a black variety of Brachymyrmex though)...they have taken over HUGE areas inside the complex.
The Argentine ant workers run away from them, usually injured and die later on. Brachymyrmex have entered Argentine ant nests in one area and driven them out. They are very aggressive to other ants, too. They are all over the place, expanding to great amounts. However, Brachymyrmex tend to leave larger colonies of Solenopsis alone and the Dorymyrmex bicolor colony seems to be mostly left alone too.
From my understanding, Brachymyrmex don't tend to be so aggressive and a lot smaller colonies. Down in San Diego, they were barely populated and had very small colonies. They ignored the Argentine ants down there. But, here in my apartment complex in Irvine...they really dominate. The only place Argentine ants see any "victory" is down by the river, but everywhere inside the complex they lose to mostly the Brachymyrmex. This year, the Brachymyrmex have expanded even more and dominate the pool areas where the Argentine ants used to dominate.
Anyone else see any of this with Brachymyrmex?