Pearl-bordered Fritillary
Encyclopedia
The Pearl-bordered Fritillary (Boloria euphrosyne) is a butterfly
Butterfly
A butterfly is a mainly day-flying insect of the order Lepidoptera, which includes the butterflies and moths. Like other holometabolous insects, the butterfly's life cycle consists of four parts: egg, larva, pupa and adult. Most species are diurnal. Butterflies have large, often brightly coloured...

 of the Nymphalidae family.

It is orange with black spots on the upperside of its wing and has a wingspan of 38–46 mm. On the underside of the wings there is a row of silver pearly markings along the edge, which give the species its name. It is often confused with the Small Pearl-bordered Fritillary
Small Pearl-bordered Fritillary
The Small Pearl-bordered Fritillary , called the Silver-bordered Fritillary in North America, is a butterfly of the Nymphalidae family...

, but can be distinguished from it by the red chevrons along its pearl border (the Small Pearl-bordered has black chevrons) as well as the presence of a single silver spot in the middle of a row of yellow spots. The female has both darker markings and rounder wings than the male. The caterpillar
Caterpillar
Caterpillars are the larval form of members of the order Lepidoptera . They are mostly herbivorous in food habit, although some species are insectivorous. Caterpillars are voracious feeders and many of them are considered to be pests in agriculture...

s are black with white or yellow spines along their backs.

Like other species of fritillary, the males have special scent glands on their wings so that they can be recognised by females of their own species and therefore find a suitable partner.

Distribution

It is widespread throughout Europe
Europe
Europe is, by convention, one of the world's seven continents. Comprising the westernmost peninsula of Eurasia, Europe is generally 'divided' from Asia to its east by the watershed divides of the Ural and Caucasus Mountains, the Ural River, the Caspian and Black Seas, and the waterways connecting...

, ranging from Scandinavia
Scandinavia
Scandinavia is a cultural, historical and ethno-linguistic region in northern Europe that includes the three kingdoms of Denmark, Norway and Sweden, characterized by their common ethno-cultural heritage and language. Modern Norway and Sweden proper are situated on the Scandinavian Peninsula,...

 to northern Spain
Spain
Spain , officially the Kingdom of Spain languages]] under the European Charter for Regional or Minority Languages. In each of these, Spain's official name is as follows:;;;;;;), is a country and member state of the European Union located in southwestern Europe on the Iberian Peninsula...

 and from Ireland
Ireland
Ireland is an island to the northwest of continental Europe. It is the third-largest island in Europe and the twentieth-largest island on Earth...

 eastwards towards Russia
Russia
Russia or , officially known as both Russia and the Russian Federation , is a country in northern Eurasia. It is a federal semi-presidential republic, comprising 83 federal subjects...

 and Asia
Asia
Asia is the world's largest and most populous continent, located primarily in the eastern and northern hemispheres. It covers 8.7% of the Earth's total surface area and with approximately 3.879 billion people, it hosts 60% of the world's current human population...

. In England and Wales (plus another 10 countries) it has declined rapidly in number and is a highly threatened species - nbn gateway distribution map.

Subspecies

  • B. e. euphrosyne Central Europe, Siberia
  • B. e. fingal (Herbst
    Johann Friedrich Wilhelm Herbst
    Johann Friedrich Wilhelm Herbst was a German naturalist and entomologist from Petershagen, Minden-Ravensberg....

     , 1804) Northern Europe, Siberia
  • B. e. rusalka (Fruhstorfer
    Hans Fruhstorfer
    Hans Fruhstorfer was a German explorer, insect trader and entomologist who specialised in Lepidoptera. He collected and described many new species of exotic butterflies, especially in Seitz's Macrolepidoptera of the World...

     , 1909) Southern Europe, West Siberia
  • B. e. orphana (Fruhstorfer, 1907) Transbaikalia, Amur, Ussuri
  • B. e. kamtschadalus (Seitz
    Adalbert Seitz
    Adalbert Seitz was a German entomologist who specialised in Lepidoptera.He was the editor of Die Gross-Schmetterlinge der Erde . This is a sixteen volume work with four supplements published in German, French, and English. For details see Griffin, F. J....

     , [1909]) Kamchatka, North Sakhalin
  • B. e. umbra (Seitz, [1909]) Altai, Sayan
  • B. e. dagestanica (Sovinsky, 1905) Caucasus, Transcaucasia
  • B. e. nephele (Herrich-Schäffer
    Gottlieb August Wilhelm Herrich-Schäffer
    Dr Gottlieb August Wilhelm Herrich-Schäffer was a German entomologist and physician. He was born, and died, in Regensburg. Herrich-Schäffer studied and collected particularly butterflies and moths...

     , [1847]) Urals, Siberia

Foodplants and Eggs

After mating, the female will lay her eggs on dead bracken
Bracken
Bracken are several species of large, coarse ferns of the genus Pteridium. Ferns are vascular plants that have alternating generations, large plants that produce spores and small plants that produce sex cells . Brackens are in the family Dennstaedtiaceae, which are noted for their large, highly...

 Pteridium aquilinum,or leaf litter near to violet
Violet (plant)
Viola is a genus of flowering plants in the violet family Violaceae, with around 400–500 species distributed around the world. Most species are found in the temperate Northern Hemisphere; however, viola species are also found in widely divergent areas such as Hawaii, Australasia, and the Andes in...

 plants - Common Dog-violet Viola riviniana
Viola riviniana
Viola riviniana, the Common Dog-violet, is a species of the genus Viola. It is also called wood violet or dog violet. It is a perennial herb of woodland rides, grassland and shady hedge banks...

, Heath Dog-violet Viola canina
Viola canina
Viola canina is a species of the genus Viola, native to Europe, where it is found in the uplands of box hill in Dorset, heaths, fens, and moist woodlands, especially on acidic soils....

, Marsh Violet Viola palustris
Viola palustris
Viola palustris is a perennial forb of the genus Viola. It inhabits moist meadows, marshes, and streambanks in northern parts of North America and Eurasia....

. Sometimes they are laid on the leaves of the foodplant itself. They are laid singly, not in one large group such as Marsh Fritillary
Marsh Fritillary
The Marsh Fritillary, Euphydryas aurinia, is a butterfly of the Nymphalidae family.It is widespread in the Palaearctic region from Ireland in the West to Yakutia in the East, and to North-west China and Mongolia in the South.E. aurinia is represented by many subspecies.The most widely accepted...

. The mosaics that they prefer are typically one-third grass and two-thirds bracken.

Eggs can be found on the foodplant from mid-May to the end of June. They are a pale yellow colour. They then hatch after 10–14 days.

Caterpillar, Pupa and Adult

The emerging caterpillars begin feeding immediately and will moult three times within the first 5–6 weeks. Each caterpillar will then hibernate in a shrivelled leaf at the base of the plant, usually at the end of July. When they awaken the following March, they are half their previous size having shrunk during hibernation. After a period of feeding and growth, during which it moults one last time, the caterpillar is full size and ready to pupate. The chrysalis stage is formed amongst the leaf litter, and lasts just 10–14 days.

The adult butterfly flies between late April and June, being one of the earliest fritillaries to emerge. It will feed on the nectar from early spring flowers such as Bugle
Bugle (plant)
Ajuga , also known as Bugleweed, Ground pine or Carpet bugle, is a genus of about 40–50 species of annual and perennial herbaceous flowering plants in the mint family Lamiaceae, with most species native to Europe, Asia, and Africa, but also two species in southeastern Australia...

, Dandelion (Taraxacum officinale), and Lesser celandine.

There is a second brood during August.

Habitat

  • Woodland clearings - recently coppiced or clear-felled, with bracken
    Bracken
    Bracken are several species of large, coarse ferns of the genus Pteridium. Ferns are vascular plants that have alternating generations, large plants that produce spores and small plants that produce sex cells . Brackens are in the family Dennstaedtiaceae, which are noted for their large, highly...

    , or leaf litter provided by oak
    Oak
    An oak is a tree or shrub in the genus Quercus , of which about 600 species exist. "Oak" may also appear in the names of species in related genera, notably Lithocarpus...

     and bramble
    Bramble
    Brambles are thorny plants of the genus Rubus, in the rose family . Bramble fruit is the fruit of any such plant, including the blackberry and raspberry. The word comes from Germanic *bram-bezi, whence also German Brombeere , Dutch Braam and French framboise...

    .
  • Well-drained habitats with mosaics of grass, bracken, and light scrub
  • Hot and freshly cut material
  • abundant foodplants growing in short, sparse vegetation, where there is abundant dead plant material, bracken
    Bracken
    Bracken are several species of large, coarse ferns of the genus Pteridium. Ferns are vascular plants that have alternating generations, large plants that produce spores and small plants that produce sex cells . Brackens are in the family Dennstaedtiaceae, which are noted for their large, highly...

     is preferred
  • Scrub edges - can provide good breeding conditions. E.g. gorse, which if cut rotation should maintain any violets growing in short vegetation.

Management

  • A network of paths running through Bracken
    Bracken
    Bracken are several species of large, coarse ferns of the genus Pteridium. Ferns are vascular plants that have alternating generations, large plants that produce spores and small plants that produce sex cells . Brackens are in the family Dennstaedtiaceae, which are noted for their large, highly...

     and opening up its canopy, allows sunlight to help germinate any violet foodplants. This can be achieved through grazing especially during winter and early spring. Cattle
    Cattle
    Cattle are the most common type of large domesticated ungulates. They are a prominent modern member of the subfamily Bovinae, are the most widespread species of the genus Bos, and are most commonly classified collectively as Bos primigenius...

     are better than sheep as their extra weight helps to trample to break up any dense standing trash. Also there is a risk that sheep tend to eat plants that provide nectar for the adult Pearl Bordered Fritillary.

Another way of achieving this is by cutting and bruising the bracken, a proportion of the site at a time, during May and early June.
  • Burning - can be useful for reducing bracken
    Bracken
    Bracken are several species of large, coarse ferns of the genus Pteridium. Ferns are vascular plants that have alternating generations, large plants that produce spores and small plants that produce sex cells . Brackens are in the family Dennstaedtiaceae, which are noted for their large, highly...

     litter, although follow up management is required as extra bracken growth will have been stimulated as a result. This will kill a proportion of invertebrates, and therefore only burning a proportion of the site, e.g. 20% is suggested.

  • Spraying - can again be useful for reducing high densitites bracken
    Bracken
    Bracken are several species of large, coarse ferns of the genus Pteridium. Ferns are vascular plants that have alternating generations, large plants that produce spores and small plants that produce sex cells . Brackens are in the family Dennstaedtiaceae, which are noted for their large, highly...

     litter, but care should be taken to no severely reduce the density and allow the grass to develop, as this will harm the breeding habitat.

  • Woodland create sunny clearings and rides, but avoid using clearings that are dominated by other plants such as Dogs Mercury (Mercurialis perennis), Common Bluebell
    Common Bluebell
    Hyacinthoides non-scripta, commonly known as the common bluebell, is a spring-flowering bulbous perennial plant. -Taxonomy:...

     and vigorous grasses.

External links

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