A-Z of butterflies

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Northern Brown Argus - Photograph by Tom PrescottNBN Map - Northern Brown ArgusMap courtesy of National Biodiversity Network (NBN)View full NBN Gateway profile

Northern Brown Argus

A small butterfly that lives in small colonies scattered through northern England and Scotland. Brown with row of orange spots on outer wing edges, sometimes with white spot on forewing. Similar to Brown Argus but usually has no orange spots on forewing.

ResidentNorthern Brown Argus - Photograph by Jim Asher

Range declining in south.

This small butterfly has a silvery appearance as it flies low to the ground over sheltered flowery grasslands. In Britain and mainland Europe, the pattern of wing spots is highly variable and many local races (and sub-species) have been described.

 

In Scotland, most individuals are of the race artaxerxes and have a characteristic white spot in the middle of the forewing (see photo). In northern England, this spot is generally dark brown or black. The butterfly occurs mainly as small, scattered colonies and has declined in northern England.

Conservation status

  • UK BAP status: Priority Species
  • Butterfly Conservation priority: high
  • European threat status: not threatened
  • Protected in Great Britain for sale only

European/world range

Occurs in Scandinavia and mountainous areas of central Europe as well as North Africa. Recent genetic studies suggest that the Northern Brown Argus found in Britain is not endemic, as some authors argue, but is the same species that occurs throughout Europe. However further work is needed to confirm this in all parts of its range. Declining in some countries.

Foodplants

The most important foodplant is Common Rock-rose (Helianthemum nummularium), though there are rare records of egg-laying (probably accidental) on other plants.

Habitat

The butterfly occurs in well drained, unimproved grasslands where Common Rock-rose grows in a lightly grazed or ungrazed sward. Most sites are sheltered (often with scrub) and have thin, base-rich soils with patches of bare ground, for example coastal valleys, steep slopes, sand dunes, and quarries. In Scotland it may also occur on predominantly neutral and even acidic soils where Common Rock-rose is able to grow if there is some calcareous influence through weathering or flushing.