Butterfly ID
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Field guide · Sweden
Brush-footed butterflies · Sweden

Northern wall brown

Lasiommata petropolitana

Northern wall brown is an early spring-flying grass butterfly that often rests on sun-exposed cliffs and rocks in woodland areas. It is very similar to large wall brown, but smaller.

Status in this countryCommon in SwedenLC (Least concern)
Northern wall brown
Photo: Harald Süpfle · CC BY-SA 3.0

Flight period

The flight period lasts from the first week of May to the end of June, from north to the beginning of July. The males always hatch approximately one week before the females.

Habitat

Primarily, forest soils on poor moraine soils, featuring exposed, sun-baked cliffs and rocks, where the butterflies are commonly found. On Gotland, also open, flat limestone outcrops. More common in coniferous forests than in deciduous forests.

Identifying features

Wingspan 34–42 mm. The upper side of the wings is dark brown with black, white-centred eye spots: on the forewing, a larger eye spot and often two eye points, and on the hindwing, 3–4 smaller eye spots. Red and yellow patches spread around the eye spots. The underside of the hindwing is grey-brown with mottled, wavy bands and 6–7 eye spots. The female lacks scent scales, is larger than the male, and has more extensive red and yellow patches.

Similar species

Very similar to large wall brown (Lasiommata maera), but Northern wall brown is smaller and typically has more and clearer dark cross-lines on the forewing, and sometimes a cross-line on the hindwing.

Distribution

Sweden represents a fairly common lowland species, rarer along the mountain ranges and along the west coast; possibly absent from Scania, absent from Öland but common on Gotland. Denmark found only temporarily. Its global distribution extends from isolated occurrences in the Pyrenees and the Alps, and more consistently from Fennoscandia through western Russia and Siberia to the Amur River. It is considered viable in Europe, but close to threatened within the EU.

Biology

The eggs are laid scattered on the heath and redwing, possibly also on rocky hills; egg development takes 1–2 weeks. The larvae feed on leaves, are well camouflaged and difficult to find, and growth until pupation takes 3–5 weeks. Overwintering always occurs in the pupal stage, with the pupa attached to rocks. The butterflies are very shy, fly quickly and erratically when disturbed, and are locally loyal.