Does anyone know what this is and whether I should be alarmed?? In researching, I found a similar insect called a 'horse guard wasp', a ground dwelling wasp that feeds on horseflies. My main concern in IDing it is it's nesting habits. (and the possibility of stepping into a nest) TIA DGers
Well, I'm not absolutely sure about this one. It appears to be a female, and is definitely in the scoliid wasp family (Scoliidae). The horse guard wasp (Bembix sp.) is a member of the sphecid wasp family, which typically do not have branching spined (or hairy) legs as can be seen in your photo.
It could be a female of the genus Campsomeris or Trielis.
However, I am leaning towards Scolia dubia, the blue-winged wasp. This is one of the more common scoliids in the U.S., ranging from Florida to New England west to the Rockies.
Like all scoliids, this wasp parasitizes scarab beetle grubs. The female stings the grub, deposits eggs on the grub, and the hatching larvae feed on the living grub, which never recovers. The female creates a chamber underground containing the grub and her progeny.
Although intimidating, scoliids in general are not aggressive, fortunately. We have many scoliid wasps in our garden (primarily Campsomeris tolteca), which are probably parasitizing june beetle (Cotinus mutibilis), Parathyce and/or Cyclocephala grubs. I enjoy seeing the wasps all over our flowers in the late summer months.
Thanks once again, Guy! This is just the type of info we need. I saw a few of these around, almost stepped on one once so was a bit concerned about their habits. You hear alot of tragic stories about people that get into ground dwelling wasp nests.