Yes, Karl, I saw an article about them moving into LA. I have yet to find their nest, and I don't know if the nest can be managed, but the ant I have seen several times is constantly on the move looking for insects. I have not seen it eat a leaf miner larvae, but I have seen many leaf miner trails that seem to have ended a lot sooner than normal where I have seen the ant and larvae appear to be one of their preferred foods.
In searching for info to identify this ant I found an article about an ant that has been cultivated in China for centuries to protect citrus. Links to a couple article are posted below.
http://www.fadr.msu.ru/rodale/agsieve/txt/vol1/1/art9.html
http://www.springerlink.com/content/j576171058543352/