This striking-looking wasp impressed me when I first saw it in my garden by the incredible length of its ovipositor. The wasp is a cleptoparasite, meaning that it will steal food from other species to feed its young. In this case it is done by laying its egg in the nest hole of the host species. The larva then kills the young and eats the food-store left there.

There is a similar species - G. assectator - which has a considerably shorter ovipositor. Both are widespread.