- Family: Brushfooted Butterflies – Nymphalidae
- Subfamily: Admirals and relatives – Limenitidinae
- Wing span: Very large, 57–90 mm (2.7–3.5 in.). One of Finland’s largest butterflies. Females larger than males. (Female’s white bands broader than male’s.)
- Wing upper side: Black with broad white stripe on mid-wings. Margin of hind wing with row of red arc-shaped blotches. Leading edge of forewing (besides of broad white stripe blotch) with one white blotch and apex with white and red embroidery.
- Wing underside: Rust-reddish orange, with white pattern resembling upper side. Bluish grey margins with row of black blotches. Base of wings bluish grey.
- Habitat: Aspen forests.
- Flying time: July.
- Overwintering form: Caterpillar.
- Larval foodplant: Aspen (Populus tremula), also poplars in parks.
Brushfooted butterflies (Nymphalidae) are the largest butterfly family in the world with over 6,000 species. In Finland the family is represented by around 60 species, which are nowadays usually divided into five subfamilies. The subfamily Admirals and relatives is represented in Finland by two species.
The poplar admiral is most common in south-eastern Finland and it is one of Finland’s largest butterflies. It can be confused with the white admiral and the purple emperor. However, the white admiral lacks the poplar admiral’s typical row of red blotches along the margin of the upper side of the hind wing. The purple emperor has an eyespot on the back corner of the hind wing which the poplar admiral lacks.
Males defend their territory, which is often at the top of hilltop trees, as they wait for females to arrive. The poplar admiral is often seen flying low over damp gravel roads, and these are usually males. Females lay their eggs individually on aspen leaves.
Way up north
Poplar admiral belongs to those butterflies whose range margin has during last years moved a lot nortwards – circa 300 km during last 10 years – as a consequence of climate change. The other species that have moved up north as much are silver-washed fritillary, black-veined white, and holly blue.