Seriously if you find a colony of one of these types how can you tell its not the other ?? Is there a way as they look the same to me...
you probly need a microscope to spot the diffrences, afraid i dont know what exactly you have to look for tho
Mirmica rubra is much more common in Europe so the change it are Mirmica rubra is high but it is hard to know for sure. They look pretty much the same. ;) Like miszt said, i think you need a microscope to vigor that out. (Me nether, maybe you can look it up at the net... :))