VERY VERY FUNNY!!! I read b#lls of steel and at first thought you meant steel wool, or a brillo pad to put in the hole of the wasp's next. My husband, however, a beekeeper in another stage of his life, read your post and knew immediately what you meant by b#lls of steel.
Heh heh heh.
On a more serious note, the picture of yellow jackets (a.k.a. German wasps) making their presence felt to the North end of N.Z. in humongous numbers may be a picture of a future invasion of swarms of Chinese or Indonesians.