Cluster Fly vs Bee Fly

Side-by-side species comparison

Attribute Cluster Fly Bee Fly
Scientific Name Pollenia rudis Bombylius major
Order Diptera Diptera
Family Calliphoridae Bombyliidae
Size 8-10 mm 8-18 mm
Habitat Gardens Underground
Diet Parasites Nectar Feeders
Regions Europe, North America Europe, North America, Asia
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.

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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.

Bee Fly

A fuzzy bee mimic with a long fixed proboscis used for hovering in front of flowers to drink nectar. Despite its innocent appearance, larvae are parasites of solitary bee nests.

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Did You Know?

Bee flies are aerial bombers — females flick their eggs into the entrance holes of ground-nesting bee burrows while hovering, never landing.