White-letter Hairstreak vs Birch Catkin Bug

Side-by-side species comparison

Attribute White-letter Hairstreak Birch Catkin Bug
Scientific Name Satyrium w-album Kleidocerys resedae
Order Lepidoptera Hemiptera
Family Lycaenidae Lygaeidae
Size Wingspan 26-30mm 4-5 mm
Habitat Hedgerows Woodlands
Diet Seed Feeders Seed Feeders
Regions Europe, Asia Europe, northern Asia, North America
Conservation Near Threatened Least Concern

White-letter Hairstreak

A small dark butterfly with a distinctive W-shaped white line on the hindwing underside. Breeds on elm.

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Did You Know?

Has declined dramatically due to Dutch elm disease destroying its food plant across Europe.

Birch Catkin Bug

A small, oval brown seed bug that feeds on birch and alder catkins. It is very common in northern Europe and can form large swarms in autumn. It sometimes enters buildings in large numbers seeking overwintering shelter.

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Did You Know?

In autumn, enormous swarms of thousands can descend on buildings near birch trees, alarming homeowners despite the bugs being completely harmless.