I have been keeping Camponotus castaneus for a while and I have several colonies of various ages and sizes. One particular colony that I have will be completing their third year at the end of the summer, and I must say they have been quite successful! However, among all the colonies I have ever had, I have never seen something like this before. Two weeks ago, workers started to eclose from this colony's brood that looked a little different from their older sisters. I didn't think much of it at first, seeing as they were the same pale yellow color C. castaneus callows usually are. The only thing that really stood out were their greyish heads, but I thought they would eventually turn dark orange. Well, it has been two weeks and the callows are much darker now, and their heads have become a dark grey! If you look closely at the pictures, you will see that the dark-headed workers look very much like Camponotus americanus workers. This is when I began to suspect that maybe my queen mated with several males, and one of them was a C. americanus male. I know both species exist in the nature park by my neighborhood. My queens are all collected after their nuptial flights here in Alexandria, Virginia. What do you think? Could this be possible?