Vestal Cuckoo Bumblebee vs Polar Willow Gall Sawfly

Side-by-side species comparison

Attribute Vestal Cuckoo Bumblebee Polar Willow Gall Sawfly
Scientific Name Psithyrus vestalis Euura arcticum
Order Hymenoptera Hymenoptera
Family Apidae Tenthredinidae
Size 15-20 mm 3-5 mm
Habitat Underground Tundra & Arctic
Diet Parasites Gall Makers
Regions Europe Arctic Canada, Alaska, Greenland, Arctic Scandinavia, Svalbard
Conservation Least Concern Least Concern

Vestal Cuckoo Bumblebee

A brood parasitic bumblebee that takes over colonies of the Buff-tailed Bumblebee. The female kills or subdues the host queen and uses the workers to raise her own offspring.

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Did You Know?

Females infiltrate host bumblebee nests and take them over by force, enslaving the workers to raise cuckoo brood.

Polar Willow Gall Sawfly

A tiny sawfly that induces galls on Arctic willow stems by injecting chemicals during egg-laying. The larva develops safely inside the swollen plant tissue. Adults are small and dark with clear wings.

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Did You Know?

The gall provides the larva with both food and insulation, maintaining temperatures several degrees warmer than the outside air.