There are two lookalike, large black and yellow wasps that we see in the Skiatook area, the cicada killer and the horse guard wasp. The cicada killer is 2 inches long, the horse guard wasp a third smaller. Both have brownish/black bodies with yellow markings and orange legs and wings. The horse guard wasp has broader bands of yellow on its abdomen.
The horse guard wasp is a fast-flying sand wasp that is found around horses and cattle where it feeds mainly on horse flies. A female wasp will make a nest in the sand and lay a single egg. She brings up to 60 paralyzed flies to the nest, filling the chamber with them. Then she closes the entrance to the burrow and builds another nest. Female wasps often nest in colonies. After the egg hatches, the larva feeds on the flies until it is mature, then it digs its way out of the sand.
If a person happens to be in a pasture with horses and cattle, the wasp will often buzz around the person as it looks for flies. Their in-your-face behavior can be intimidating but the wasp is no threat to us, just horse flies. It’s a beneficial wasp and a great friend of livestock.