Adult flies are between 2.5 and 3 mm long with a wingspan of around 5 mm.
The adults are yellow and black with a distinctively striped thorax, three large black stripes on the yellow background.
The wings have sparse but clear venation.
Females lay their eggs in the soil where the young larvae emerge.
The larvae feed on the juvenile stages of root aphids.
Pupation takes place in the soil and then the adults emerge.
Adults are to be found in large numbers amongst rough grassy vegetation and then in the autumn they frequently inhabit buildings in huge numbers where they overwinter. This has led to their common name of yellow cluster flies.
While not of any real public health significance, the fact that these flies can accumulate in such huge numbers during the autumn and winter months means that they are frequently a nuisance pest.
Please call East Lancashire Pest Control on 0800 023-6116