Aim: to determine presence, associated environmental conditions and an up-to-date, accurate picture of distribution.
The UK's largest fly lives in Essex.
We need your help to find colonies of this spectacular fly – have you seen it?
Although the Hornet robberfly (Asilus crabroniformis) is large and distinctive, the adults spend much of their time sitting on cow or horse pats,where they are quite well camouflaged.
Adults are found mainly between late July and early September.They often only fly when disturbed and then only go short distances to another dung pat. They prey on other insects such as grasshoppers and flies, and never feed on flowers, so they are actually easy to miss unless you disturb them as you walk.
The Hornet Robberfly does not bite and is completely harmless to people and animals.
If you think you have seen this fly, please complete and return the survey card (a photograph would be a great help). Thank you.
Download the Hornet Robberfly survey information leaflet (PDF 343KB)
Download the Hornet Robberfly press release (PDF 8KB)