Cluster Fly

Pollenia species


Over all length 7 - 8mm. The commonest Cluster Fly is probably Pollenia rudis and they can often be seen in gatherings, on sunny spots on tree trunks or leaves. It is a dull, grey-brown fly with golden hairs on the thorax and some pale grey and black markings on the last two segments of the abdomen. The various species of this genus are very hard to identify and need microscopic observation.


Woodland edge and hedgerows. Can come into houses in large numbers to hibernate. The larvae develop as parasitoids of worms.

Status and distribution

The genus is widespread in Britain with a tendency to the west and especially Wales. Regularly seen at the reserve.

Best time to see

All year.