Some great videos of a great golden digger wasp by Georgia Virnig inspired this blog. The example above was one I found in 2015 stumbling along on its last legs. I picked it up after it died for pictures. It is in the Sphecidae family of thread-waist wasps whose skinny waist you can see in the picture below.
We will start with her story.
"We've been fascinated watching several very industrious female great golden digger wasps excavating tunnels between some paving bricks off our porch. I witnessed one dragging a katydid into it's burrow, but of course I didn't have my phone at that moment. The diggers were very gracious in letting me video them dig though! There were several wasps working in this area, and I watched them for a week or so. I saw 2 working at one time on separate tunnels. Whether these two came back day after day or if there were others working is a question! There are probably 8 or so tunnel sites."
The great golden digger wasp's (GGD) formal name is Sphex ichneumoneus, named "ichneumoneus" for the Greek for tracker. They are close kin to giant cicada killer wasp, Sphecius speciosus, and both can be well over an inch long and have threatening aposematic colors. They are not threatening to humans although I wouldn't want to pick one up as a test.
The adult wasps feed on sap fluids and nectar but are most famous for tracking down large prey to package as baby food for their larvae. The GGD specializes on orthoptera (crickets, grasshoppers and katydids), hauling them into nesting tunnels. Although not considered social nesters, it is common to find several in the same area, more like a popular suburb,
"This species spends about 1–2 months as an adult before dying. Females excavate long vertical main tunnels in the ground, with nest cells located in short side tunnels. Most nests have 2 or 3 cells, and a female usually digs 5 or 6 nests during her few months of summer activity. Sometimes two females will jointly provision a single nest. The young pass the winter underground in their nest burrows before emerging as adults the following year." MDC Discover Nature
In Georgia Virnig's video here you can see the GGD females hard at work digging their nests and then covering them up. At 0:07 you can see one move a rock that doesn't meet its standards. At 1:38 there is a good demonstration of using its head to tamp down the rocks while vibrating which packs them tighter. psyche.entclub
So "what good are they" we are asked as if everything should be good for humans. Well, they have a role in nature like all of us. They pollinate flowers, control populations of orthoptera that chew garden plants and in turn are consumed by snakes, birds and some mammals. Like many other animals, they even have their own specialized parasites, another branch of the food web. And they areate the soil with their tunnels. What is not to like!
More detail is at Texas A&M Beneficial Insects.
