Crotch's Bumblebee vs Common Thick-headed Fly

Side-by-side species comparison

Attribute Crotch's Bumblebee Common Thick-headed Fly
Scientific Name Bombus crotchii Sicus ferrugineus
Order Hymenoptera Diptera
Family Apidae Conopidae
Size 10-16 mm 8-12 mm
Habitat Heathland Underground
Diet Nectar Feeders Nectar Feeders
Regions California, western USA Europe
Conservation Endangered Least Concern

Crotch's Bumblebee

A western North American bumblebee that has declined by over 90% from its historical range. Once common in California's Central Valley. Threatened by pesticides and habitat loss.

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Did You Know?

Has vanished from most of California's agricultural Central Valley where it was once the dominant bumblebee.

Common Thick-headed Fly

A distinctive orange-brown fly with a disproportionately large, inflated head and a curved abdomen. It perches conspicuously on flowers waiting to intercept passing bumblebees.

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Did You Know?

The parasitized bumblebee eventually dies and buries itself in the ground, where the fly larva pupates inside the bee.