I spend a lot of time in Lanzarote and I encounter this insect almost every day. They are quite large and can be up to 1.5 inches long (about 3.5 cm.) They are quite different to the common wasp because they don't have any yellow markings. The only colours on their bodies seem to be either brown or dark brown.
Their build hemispherical 'huts' with a hole in the apex. These individual hemispheres have a base diameter of just over 1 inch. These ‘huts’ can be found singly or clustered together in rows. The substance of the walls of these huts is similar to dried mud, again different to the paper-like walls of the common wasp found in the UK.
Recently I discovered a single ‘hut’ on the reveal of a window. In order to discourage these fearsome-looking wasps from nesting so close to my room, I had to break it, and a green caterpillar fell out.
A couple of months ago I kept hearing faint rapid knocking noises at regular intervals. Now I think the noise was probably linked to these insects building their mud structures somewhere in the house.
If any insect expert can identify this particular species of wasp or hornet, I would be very grateful. Thanks in advance,