Cluster Fly vs Box Tree Moth

Side-by-side species comparison

Attribute Cluster Fly Box Tree Moth
Scientific Name Pollenia rudis Cydalima perspectalis
Order Diptera Lepidoptera
Family Calliphoridae Crambidae
Size 8-10 mm 35-45 mm wingspan
Habitat Gardens Gardens
Diet Parasites Wood Feeders
Regions Europe, North America Native to East Asia; invasive in Europe and North America
Conservation Least Concern Least Concern

Cluster Fly

A medium-sized, dark gray fly with golden-brown hairs on the thorax. In autumn, it gathers in large clusters inside buildings to hibernate, sometimes in the thousands.

💡

Did You Know?

The larvae of this fly are earthworm parasites, burrowing into the worm through its skin and consuming it alive from the inside over several weeks.

Box Tree Moth

A white moth with iridescent brown wing borders that has become one of Europe's most destructive invasive species. Its caterpillars can completely defoliate ornamental boxwood hedges.

💡

Did You Know?

Since arriving in Europe around 2007, it has devastated centuries-old boxwood gardens across the continent.