Holly Blue vs Western Bumble Bee

Side-by-side species comparison

Attribute	Holly Blue	Western Bumble Bee
Scientific Name	Celastrina argiolus	Bombus occidentalis
Order	Lepidoptera	Hymenoptera
Family	Lycaenidae	Apidae
Size	26-34 mm wingspan	10-22 mm
Habitat	Underground	Mountains
Diet	Nectar Feeders	Nectar Feeders
Regions	Europe, North Africa, Asia, North America	Western North America
Conservation	Least Concern	Vulnerable

Holly Blue

Pale silvery-blue butterfly with small black dots on the underside. Alternates between holly and ivy as host plants between spring and summer broods.

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Did You Know?

Population numbers cycle dramatically every few years due to a parasitic wasp that tracks its abundance.

Western Bumble Bee

A once-common bumble bee of western North America that has experienced dramatic population declines since the late 1990s. They nest underground in abandoned rodent burrows.

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Did You Know?

Their catastrophic decline is linked to a pathogen accidentally spread through commercial bumble bee rearing facilities.