The Wasp in Designer Sunglasses

There's a small colony of this little solitary wasp, which is in the genus Ectemnius, in our garden. There are about 10 species in this genus in the UK but they are notoriously difficult to identify from photographs. It's only about half the size of a typical wasp but has disproportionately large eyes that remind me of designer sunglasses.

It also has formidable jaws which it uses to catch hoverflies, which it then uses as provisions for its young. When it's not hunting it seems to have a taste for honeydew which collects on the day lily leaves where I took these photographs.

I recently discovered where these little wasps nest, in an old cherry tree stump that has rotted until it almost has the consistency of balsa wood. The wasps have chewed a nest hole that you can just see on the underside of the log, just above the centre on the left-hand side of the picture above. 

Inside the main tunnel there are side-tunnels, each with an egg and a collection of dead hoverflies that each wasp's larva will eat during its development. The only reason that I noticed this nest site was that the sawdust produced by the tunnellers has collected in spiders' webs under the hole.

My thanks to Brian Little at the wonderful iSpot web site for confirming the identity of this wasp.