Hornet robberfly

Hornet Robberfly

Hornet Robberfly ©Cécile Bassaglia

Hornet robberfly

Scientific name: Asilus crabroniformis
With black-and-yellow markings, the Hornet robberfly looks like its namesake, but is harmless to us. This mimicry helps to protect it from predators while it perches in the open, waiting for its own prey.

Species information


Body length: 2.5cm

Conservation status

Priority species under the UK Post-2010 Biodiversity Framework.

When to see

June to October


The Hornet robberfly is a predator, sitting and waiting on a suitable perch (such as a stone or pile of animal dung) for smaller insects to fly past, which it catches on the wing. It prefers dung beetles, but will also eat bees and grasshoppers. It breeds in animal dung on heathland and downland, the larvae hatching and feeding on beetle grubs in the soil.

How to identify

The Hornet robberfly has a brown thorax and a black-and-yellow abdomen, just like its namesake. There are 28 species of robberfly in the UK, which can be very difficult to tell apart; the Hornet robberfly is one of the largest.


Southern England and South Wales.

Did you know?

The main reason for the decline in the Hornet robberfly is the transferral of harmful chemicals from the treatments farmers use on their livestock, to the dung in which the insects live. In turn, this kills, or causes serious deformities in, the robberflies that feed on the dung.

How people can help

The Wildlife Trusts work closely with farmers, landowners and planners to ensure that our wildlife is protected and to promote wildlife-friendly practices. By working together, we can create Living Landscapes: networks of habitats stretching across town and country that allow wildlife to move about freely and people to enjoy the benefits of nature. Support this greener vision for the future by joining your local Wildlife Trust.