Hornet Robberfly

The Hornet Robberfly, Asilus crabroniformis, is a species of predatory insect. It is one of the largest flies in the United Kingdom. It feeds on grasshoppers, dung beetles and other flies. Unlike an actual hornet, the Robberfly only has one yellow patch on its abdomen and one pair of wings. The larvae are believed to feed on dung beetle larvae and other detritivores (Typical detritivorous animals include millipedes, woodlice, dung flies, slugs etc).

Generally, A. crabroniformis can be found in woodland clearings and well-drained areas of heaths and downs covering Southern England and South & West Wales. It is reliant on the availability of rabbit or cattle dung.

However, there is a thriving colony in a Cholsey garden, the highest count being of over 30 individuals.

It is a member of the robberfly family Asilidae, subfamily Asilinae and is included in the list of endangered species in the British Isles.

Thanks to Tony Rayner for the info.

 

Mammal trapping in the garden today turned up pregnant/lactating Bank and Field Voles and Pigmy Shrew. Two female domestic Mallards appeared on the brook together with 12 piebald ducklings (one brood or two?).

Thanks to RB for info.