A large, strong-flying butterfly restricted to the Norfolk Broads, although migrants are occasionally seen elsewhere. Pale yellow wings with black veins and blue margins.

This is one of our rarest and most spectacular butterflies. The British race britannicus is a specialist of wet fenland and is currently restricted to the Norfolk Broads. Here the adults can be seen flying powerfully over open fen vegetation, stopping to feed on flowers such as thistles and Ragged-Robin.

One of only three species of this family that are found in the British Isles. The adults fly during at night but can sometimes be seen resting during the day on tree trunks. The adults are incapable of feeding. The caterpillars can be found from August to the following May. They overwinter two or three times as larvae in the stems and branches of trees.

A white moth with small black spots on the forewing, however the number of black spots varies greatly from largely white examples which are almost entirely plain to those with many more spots that may even join together to form streaks along the wing veins.

The white wing colour can also vary with creamy-buff or even brown examples often found in Scotland.

The hairy larvae can be seen from July to September which then overwinter as pupae among plant debris.

The caterpillars have a similar colouration to the adults and can be seen from late August to the following June, overwintering on the food plant.

The adults can sometimes be found at rest on Bramble and other low foliage. They are attracted to light.

The white wings have blackish clouding in the outer area of the forewing. The extent and intensity of the clouding varies, generally stronger in males, and is usually accompanied by two central forewing spots and an additional mark at the centre of the trailing edge.

The larvae can be seen from late June to late August before they overwinter as pupae on the ground amongst plant debris. The adults are often seen flying at dusk, especially along hedgerows.

The forewings are a yellowish-buff to whitish-buff colour. The number and size of the black dots on the wings vary but a distinctive diagonal row of elongated spots running from the forewing tip to trailing edge can distinguish it from the White Ermine. A mostly black form has been bred in captivity but is much rarer in the wild.

The hairy larvae can be seen from July to October which then overwinter as pupae among plant debris.

  • Family - Waves (Sterrhines)
  • Small Sized

Conservation status

  • UK BAP:  not listed
  • Priority Species in Wales (‘Section 42’ list)
  • Nationally Notable

Particular Caterpillar Food Plants

Probably Heathers. Other moorland plants may also be used but this requires confirmation.

Distribution

A fairly large clearwing moth, which is mostly black with two narrow yellow bands on the abdomen. The tail fan is a striking feature, being large and orange in colour. The caterpillar feeds for several years on the inner bark of old birch trees.

This Fritillary is similar in size and habitats to the Pearl-bordered Fritillary but is more widespread and occurs in damper, grassy habitats as well as woodland clearings and moorland.

The adults fly close to the ground, stopping frequently to take nectar from flowers such as Bramble and thistles. It can be idenfidied from the more numerous whitish pearls on the underside hind wings, the outer ones bordered by black chevrons and from the larger black central dot.

Very similar to red forms of the Dark-barred Twin-spot Carpet, although the Red Twin-spot Carpet tends to have brighter markings, with a clearer whiter band bordering the central red band and has a more banded appearance.

Rests during the day on shaded rocks, stone walls, bushes, hedges and tree trunks from which it is easily disturbed. Flies from dusk and into the night.

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