Tetanocera elata, the Field Buff Snailkiller.
Really like the common English name for this weeks #FlyFriday
Came across this stunner in the middle of last August and possibly before that too few times around the same area, but those individuals managed to evade me well enough to not be captured on camera.
There are 2 Tetanocera species around my area that looks almost the same (some areas has 3!), but with better look at specific details, it is easy to tell the difference between the T. elata and T. phyllophora that is the 2nd one found around here.
In this case, that excellent small detail is the dark patch on the occiput (behind the head, at the "neck"), which T. phyllophora lacks of.
The 3rd Tetanocera sp. that looks very much like this, is T. punctifrons and to ID that, it needs a closer look at the femora in the mid legs.
These 3 Tetanocera species differs from the rest of the Tetanocera spp. by the dark wing margins, which are especially clear when the flies have their wings folded on top of each other.
The T. elata is a member of the family Sciomyzidae, which are commonly known as the Marsh Flies, or some, especially Tetanocera spp. as Snail-killing Flies.
It is a widespread species in the Scandinavia and UK, with few sightings in Germany and nearby. Adults can be found through May to August (September in UK apparently) from various type of habitats, including forest clearings and edges, dry grasslands, heathlands, etc. This individual I found at the edge of a forest clearing, in some bushes among the Thistles and Nettles.
The larvae of the T. elata has been studied quite a lot as possible biological control agents of few different slug species. The first 2 instars of T. elata larvae is a parasitoid of slugs, as it penetrates the slug after hatching and feeds on them from the inside for several days. After the death of the slug, the larvae becomes a predator, rather than a parasitoid and it will seek out several more slugs to kill and feed of, before it completes its development as a larvae and pupates.