Cluster Flies
Cluster Flies are found throughout Europe and the United Kingdom. The name 'cluster' refers to the fly’s habit of clustering and hibernating in large numbers in buildings, usually in roof spaces and lofts.
Life cycle:The adult female fly lays her eggs in damp soil and beneath decaying leaves. The larvae normally hatch after a week, they will then seek earthworms for food by burrowing through the earthworms wall to paralyse it. The fly maggot develops in the earth worm and at or the near death of the earth worm the larvae bore out and then pupate in the soil until it hatches out as a fly.
Signs of presence:Flies arrive in roof spaces to start hibernation usually when the weather gets cold around October time. They will come out of hibernation when the weather gets warmer around March time when you will find flies flying around upstairs windows and in loft conversions around loft windows you may find dead ones at the bottom of the window as the photo shows below.
Cluster Fly ( pollenia rudis)
Dead Cluster Flies in window bottom
