Illegal Immigrants? (title - courtesy of my wife)

         I did a yellow jacket job this morning, and ran across something I've only encountered about 4-5 times in my 20 years of doing pest control. This is the nest I removed from a barn at a horse farm.

       Pretty routine, except it was in a difficult spot, and required some gymnastics to get at it! What came as a surprise was what was inside it.

        Yep, a black and white yellow jacket. The common yellow jacket is the upper one. My understanding is that these black and white ones are parasitic. Their queens, instead of starting their own nests in the spring, wait around until the common yellow jackets get their nests started and then they move in, kill the existing queen, and proceed to start laying eggs. Over the course of the summer, the workers gradually shift from yellow and black to white and black as the existing jackets die, and new black and white ones emerge from the eggs laid by the new queen.
        Nothing really different with this. They are still dangerous and should be removed, unless they are well away from humans. Just one of those curiosities that nature is always throwing at us!