von baumarkthammer » 30. Sep 2013 15:40
Most desert ants are carnivorous to some extend. I assume you are searching for a species that hunts very actively. Problem with them is that they need quite some space and often are expansive (since African ants are just expansive). You might look into Ectatomma, hunt actively and are very aggressive but they are American Ponerinae which means that they don't really like a climate that is too dry.
If money is no factor than I would recommand looking into Tetraponera rufonigra (I will sned you a link via PM), they are probably one of the most active hunters among ants I know of and extremly interesting to watch!
You can try with Cataglyphis velox, I'm not saying that there is no chance that it will work. I'm only saying that I can't imagine that it will be the best solution. However it will be interesting to see if you succeed.
About the original question about the way to keep a colony small: The easiest way to do it is to give only a small amount of food. Trying to control the size by space will be tricky, ants fit in the smallest spaces and when there is no other way they might even use the whole basin as a nest.
Probably the best way of keeping a colony small is killing some workers off by hand. I say it is the best way because you have the best control over how many ants you take away and after some time you will have the nessesary experiance to know which number is enough and how fast the colony grows.