Small Pearl-bordered Fritillary

Boloria selene (boh-LOR-ee-uh sell-EE-nee)

Small Pearl-bordered Fritillary 2010
Photo © Gruditch
 

Wingspan
Male: 35 - 41mm
Female: 38 - 44mm

Checklist Number
59.015

Family:NymphalidaeRafinesque, 1815
Subfamily:HeliconiinaeSwainson, 1827
Tribe:ArgynniniSwainson, 1833
Genus:BoloriaMoore, 1900
Subgenus:ClossianaReuss, 1920
Species:selene([Denis & Schiffermüller], 1775)

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Introduction

The Small Pearl-bordered Fritillary is a delightful butterfly found in discrete colonies. Patrolling males can be seen flying a couple of feet from the ground, alternating a burst of rapid wing beats with a short glide, searching out freshly-emerged females in the surrounding scrub. The wing pattern, however, makes the adult butterfly difficult to follow in flight, it being much easier to observe this species when it is basking or nectaring on flowers of Bugle and other plants.

This butterfly, like the Pearl-bordered Fritillary, gets its name from the series of "pearls" that run along the outside edge of the underside of the hindwing. The two species may be seen together at certain sites, although the Pearl-bordered Fritillary emerges a couple of weeks before the Small Pearl-bordered Fritillary and generally appears much paler as a result. This strongholds of this species are found throughout much of Scotland and Wales, and in the north-western and south-western counties of England with scattered colonies elsewhere. It is absent from the Outer Hebrides, Orkney, Shetland, Ireland, the Isle of Man and the Channel Islands. This butterfly is found in discrete colonies containing anything between a couple of dozen and 100 adults at peak.

Taxonomy Notes

Freyer (1852) used the name f. selenia to describe the summer generation and, until recently, ssp. insularum was recognised, as defined in Harrison (1937), but is not present in current taxonomy. This subspecies was found in north-west Scotland in several islands that make up the South Ebudes, Mid Ebudes and North Ebudes and the adjacent mainland, reaching into parts of Argyllshire, West Inverness-shire, West Ross and West Sutherland. It is somewhat brighter in colour and markings, on both upper and undersides, than the subspecies selene. Ford (1945) questions its taxonomic status: "it is perhaps doubtful if it merits a distinct name". Dennis (1977) has a similar view: "It is allegedly brighter in colour and markings on both surfaces than English B. selene, with greater contrast on the undersurface. On this basis the writer finds them difficult to separate from series collected at high altitudes in north Wales".

Boloria selene

This species was first defined in Denis & Schiffermüller (1775) as shown here (type locality: Vienna, Austria).

The British population is represented by the nominate subspecies.
Small Pearl-bordered Fritillary male - Park Corner Heath, Sussex 23-May-2017

Male
Photo © Neil Hulme

Small-Pearl-bordered-Fritillary- 5D39703  N Yorks July 2015

Male Underside
Photo © IainLeach

Small Pearl-bordered Fritillary female -  Abbot's Wood, Sussex 28-May-2017

Female
Photo © Neil Hulme

Small-Pearl-bordered-Fritillary- 5D35483 Powys 2 July 2013

Female Underside
Photo © IainLeach

Photo Album ...


History

The table below shows a chronology of vernacular names attributed to this species. Any qualification of the name (e.g. male, female) is shown in brackets after the name.

YearNameReference
1710April FritillaryRay (1710)
1742Small Pearl Border FritillaryWilkes (1742)
1766Small Pearl Border FritillariaHarris (1766)
1795May FritillaryLewin (1795)
1803Pearl-bordered FritillaryHaworth (1803)
1819Pearly Border LikenessSamouelle (1819)
1824Small Pearl-bordered FritillaryJermyn (1824)
1832Silver Spot FritillaryRennie (1832)

Conservation Status

Despite some stability in the west and north, this species has suffered a long-term decline in both distribution and population. The cessation of coppicing in woodlands, which creates the right habitat for the adult and that encourages vigorous growth of the foodplant, is believed to be a primary cause of the decline. This species is therefore a priority species for conservation efforts.

UK BAP StatusOccurrence Change
1976-2014 (%)
Abundance Change
1976-2014 (%)
Occurrence Change
2005-2014 (%)
Abundance Change
2005-2014 (%)
Priority Species
Click here to access the Biodiversity Action Plan (BAP) for this species.
Large Decrease-76
Large Decrease-58
Decrease-25
Stable+3

The table above shows the occurrence (distribution) and abundance (population) trends, using information from The State of the UK's Butterflies 2015 (Fox, 2015). Any UK BAP status is taken from the UK Biodiversity Action Plan (UK BAP) (2007 review).

Habitat

Most English colonies are found in open areas within deciduous woodland, such as woodland clearings. These colonies are generally small, consisting of a few dozen adults at most, and this butterfly is also relatively-sedentary with only a limited capacity for colonising new areas. Colonies in the north are also found in more exposed situations such as marshland and moorland. These are larger colonies of up to 100 individuals, typically spread across extensive areas of land and butterflies in these colonies are relatively-mobile as a result. In Cornwall, colonies occur on moorland and cliffs. At all sites damp areas are preferred, where the foodplants grow particularly vigorously.

Distribution

 

Click here to see the distribution of this species or here to see the distribution of this species together with specific site information overlaid.

Life Cycle

This butterfly first emerges in south-west England, where it may be seen from the beginning of May. This species emerges in the second half of May in other parts of England, and does not make an appearance in Scotland until June. The early emergence of the species in south-west England gives rise to a partial second brood there, which appears in August.

The chart(s) above have been correlated with the phenology plot below, taken from the UK Butterfly Monitoring Scheme. The blue line gives average counts over the full data set from 1976 to date, and the red line gives the average for the last year.

Imago

The male butterfly can be seen patrolling low over the breeding sites in search of a mate. When a virgin female is found, the pair quickly mate and generally remain hidden low down in vegetation. Egg-laying females are easy to follow as they flutter slowly and deliberately low down over vegetation, searching out suitable areas of foodplant on which to lay. Both sexes are avid nectar feeders, and can be seen at flowers of Bugle, Buttercup, Bird's-foot Trefoil, Wood Spurge, Ragged-robin and other plants.

Adults feed primarily on Bugle (Ajuga reptans). Bird's-foot Trefoil (Lotus corniculatus), Bluebell (Hyacinthoides non-scriptus), Buttercups (Ranunculus spp.), Dandelion (Taraxacum agg.), Hawkweeds (Hieracium/Hypochoeris), Heather (Calluna vulgaris / Erica spp.), Ragged Robin (Lychnis flos-cuculi), Thistles (Cirsium spp. and Carduus spp.), Thyme (Thymus polytrichus) and Wood Spurge (Euphorbia amygdaloides) are also used.

Boloria selene

Small-Pearl-bordered-Fritillary Bargoed 14 May 2011 03C2698

Photo © IainLeach

Small Pearl-Bordered Fritillary Male - Park Corner Heath, Sussex 12-June-09

Photo © Vince Massimo
12-Jun-2009

Small Pearl-Bordered Fritillary - imago - Pamber Forest - 28-May-05 (10)

Photo © Pete Eeles
28-May-2005

Small Pearl-bordered Fritillary Male - Park Corner Heath, Sussex 27-May-11

Photo © Vince Massimo
27-May-2011

Small Pearl-Bordered Fritillary - imago - Bentley Wood - 21-May-08 (11)

Photo © Pete Eeles
21-May-2008

P1040715-800 Small PBF, Bentley Wood, 01/06/2012

Photo © Pauline
01-Jun-2012

Small Pearl-bordered Fritillary - imago - Glasdrum Wood - 28-May-12-1

Photo © Pete Eeles

Small Pearl-Bordered Fritillary - imago - Bentley Wood - 22-May-09 (5)

Photo © Pete Eeles
22-May-2009

Small Pearl-bordered Fritillary Male - Park Corner Heath, Sussex 27-May-11

Photo © Vince Massimo
27-May-2011

Small Pearl-bordered Fritillary - Bentley Wood - 19 May 2014

Photo © craigbirdphotos
19-May-2014

Small Pearl-bordered Fritillary - imago - Glasdrum Wood - 28-May-12-2

Photo © Pete Eeles

Small-Pearl-bordered-Fritillary- 5D35655 Aberbargoed 9 June 2013

Photo © IainLeach

Small Pearl-bordered Fritillary - imago - Bentley Wood - 02-Jun-10 (2)

Photo © Pete Eeles
02-Jun-2010

Small Pearl-bordered Fritillary pair, Park Corner Heath, 1 June 2009

Photo © Neil Hulme
01-Jun-2009

Small Pearl Bordered Fritillary Male - Park Corner Heath, Sussex 9-June-10

Photo © Vince Massimo
09-Jun-2010

P1040648-800 Small PBF, Bentley Wood, 01/06/2012

Photo © Pauline
01-Jun-2012

Small-Pearl-bordered-Fritillary- 5D39238  N Yorks July 2015

Photo © IainLeach

Small-Pearl-bordered-Fritillary- 5D30029  N Yorks July 2015

Photo © IainLeach

Small Pearl-Bordered Fritillary - imago - Bentley Wood - 22-May-09 (2)

Photo © Pete Eeles
22-May-2009

Small-Pearl-bordered-Fritillary Bargoed 14 May 2011 03C2529

Photo © IainLeach

Photo Album (79 photos) ...


Ovum

Eggs are laid singly and are initially straw-coloured, becoming grey prior to hatching. They are typically laid on the underside of a leaf of the foodplant, but may also be laid on surrounding vegetation. There is evidence that females will drop eggs while in flight, but only where the female has detected the presence of the foodplant. This stage lasts around 2 weeks.

"Eggs laid on June 18th, 1890, hatched on June 29th, remaining eleven days in the egg state. The eggs are laid singly, chiefly on the under surface of the leaves of dog violet (Viola canina). The egg measures 0.6 mm. high, of a conical shape. The micropyle is sunken and the bast is slightly rounded. There are from eighteen to twenty longitudinal keels, irregularly formed and varying in length; about half the number run from the crown to the base; they form an irregular angulated brim round the micropyle; others originate at different distances from the crown. The spaces between the keels are rather deeply concave and have about twenty transverse ribs. When first laid the colour is a greenish-orange, soon afterwards becoming paler, and finally turning a pale ochreous, with the crown dull slate-grey, caused by the dark head of the larva showing through the shell." - Frohawk (1924)

SPBF ovum - Cannock Chase 29.06.15. Focus stack of 35 images (Zerene Stacker)

Photo © Tony Moore
29-Jun-2015

Boloria selene - Ovum [Wolfgang Wagner]

Photo © Wolfgang Wagner
www.pyrgus.de

SPBF ovum. Laid at base of grass tussock among Marsh Violet. Hareford, Berwickshire, Scottish Borders 23/06/2015.

Photo © IAC

Small Pearl-bordered Fritillary - ovum - Ariundle - 13-Jun-16-2

Photo © Pete Eeles
13-Jun-2016

Small Pearl-bordered Fritillary - ovum - Ariundle - 13-Jun-16

Photo © Pete Eeles
13-Jun-2016

Small Pearl-bordered Fritillary - ovum - Ariundle - 21-Jun-16

Photo © Pete Eeles
21-Jun-2016

Photo Album (6 photos) ...


Larva

The larva eats its eggshell on emerging and feeds by day. Unlike the larvae of its close cousin, the Pearl-bordered Fritillary, larvae of the Small Pearl-bordered Fritillary tend to avoid direct sunlight when not feeding. This makes them particularly difficult to locate, since they are never found basking on dead bracken or leaf litter. The larvae do, however, leave distinct crescents where they have fed on the heart-shaped leaves of their foodplant. After moulting for the third time, the larva enters hibernation, emerging in the spring to complete its growth. There are 5 instars in total.

The primary larval foodplants are Common Dog-violet (Viola riviniana) and Marsh Violet (Viola palustris).

1st Instar

"Directly after emergence the larva measures 1.4 mm. in length, and is uniformly pale ochreous-yellow. The head is shining black and beset with hairs similar to those on the body. When a week old the body is slightly tinged with green. The fourth, sixth, eighth and tenth segments are banded with dull orange. There are longitudinal rows of shining olive-brown tubercles, each bearing a long, curved, pale buff, serrated hair, very slightly clubbed at the apex, those above the spiracles curve forwards; below each spiracle is a cluster of five hairs placed on a brown disc, and slightly above and behind it is a smaller disc bearing a single hair. All the hairs below the spiracles are directed laterally. On the claspers are simple, sharply pointed hairs. Before first moult it measures 3.2 mm. long. The ground colour is ochreous; the four bands, which at first were orange, are now brown, giving the larva quite a banded appearance. Some of the larvae remained over twenty days in the first stage, when others were ready for their second moult." - Frohawk (1924)

2nd Instar

"After first moult the colour is pale olive-green, deepest on the back. There are six longitudinal rows of black spines; they are longest on the dorsal surface, the lateral series being the smallest, and are all furnished with bristles. The head is black and beset with bristles, legs black, and the claspers are the same colour as the body. Description of the larva when twenty-five days old." - Frohawk (1924)

3rd Instar

"After second and shortly before third moult the larva is 6.3 mm. long, and has a grey-white dorsal line, a sub-dorsal longitudinal series of dull yellow spots, and a pale ochreous lateral stripe; the general ground colour is pale greyish-brown. The head and legs are shining black." - Frohawk (1924)

Small Pearl-Bordered Fritillary - larva - Thatcham - 10-Sep-06 (0798) [REARED]

Photo © Pete Eeles
09-Oct-2006

Small Pearl-Bordered Fritillary - larva - Thatcham - 17-Mar-07 (1005) [REARED]

Photo © Pete Eeles
17-Mar-2007

Small Pearl - Bordered Fritillary Larva - 4th Instar - Clatworthy Reservoir - 21/03/17

Photo © William
21-Mar-2017

Small Pearl - Bordered Fritillary Larva - 4th Instar - Clatworthy Reservoir - 21/03/17

Photo © William
21-Mar-2017

3rd Instar SBPF 1 (reared in Sussex 2017)

Photo © Gary.N

3rd Instar SBPF 2 (reared in Sussex 2017)

Photo © Gary.N

3rd Instar SBPF 3 (reared in Sussex 2017)

Photo © Gary.N

Photo Album (7 photos) ...


4th Instar

"The larvae hibernate after the third moult, in normal seasons at the end of August. In 1893, the hot summer, eggs were laid as early as May 25th, which hatched the end of the first week in June, and the larva commenced hibernating in July, but a few continued feeding at intervals throughout the greater part of August, but all had entered hibernation by the beginning of September. On March 2nd, 1894, two larvae were seen to leave the hibernaculum, which consisted of the dead, withered leaves, the larvae usually hiding in the curled-up portion of the leaf (which is practically of the same hue as the larva), which forms both shelter and protective colouring. Directly after hibernation, about 270 days old, it measures while crawling 9.5 mm. long. The ground colour is pale ochreous checkered with chocolate-brown; the dorsal stripe is pale primrose-yellow, broken up by two small black warts and three brown spots on each segment, and between the dorsal and sub-dorsal spines is a square pale orange blotch, in all forming a longitudinal band; the spines of the lateral series are on a paler orange band, and those of the sub-dorsal series are on a brown band; all the spines or tubercles are black, short and stumpy, and densely covered with spinelets, the anterior pair are longest. The head is shining black and covered with bristles of various lengths; the legs and claspers are dark shining brown." - Frohawk (1924)

SPBF 4th Instar Larva (reared in Sussex 2017)

Photo © Gary.N

Photo Album (1 photos) ...


5th Instar

"Both the above-mentioned larvae moulted the fourth and last time on April 1st, 1894. After the fourth moult, fully grown and 310 days old, it measures while resting 12.2 mm. long. The body tapers at either end, but mostly so anteriorly. There are twelve longitudinal rows of short, conical, ochreous-coloured tubercles, each bearing a number of short, stiff, black bristles; all the tubercles are of uniform size except the dorsal pair on the anterior segment, which are long, slender, and directed forwards and slightly up-curved. The ground colour is sienna-brown, freckled with minute cream-white spots, each emitting a very minute black bristle. The dorsal and sub-dorsal tubercles are situated on a black transverse band, which is broken up into portions by whitish-buff lines. These surround the upper or dorsal patch, which is triangular, and form a longitudinal series bordering on the black medio-dorsal stripe; both the anterior and posterior segments are rather paler in colour, the former having a slight greenish hue and gradually deepen-ing in colour on reaching the fourth segment. The sub-spiracular rows of tubercles are situated on a whitish-buff dilated ridge; the spiracles are black outlined with white, excepting those on the eleventh segment, which are entirely black and the largest; the ventral surface is sienna-brown, including the claspers; the legs are black. The head is shining black, the high lights having ruby reflections, and it bears a number of black bristles. The larva feed principally by day in both sunshine or shade and rest in a straight position, and do not roll in a ring or fall from the plant when disturbed. One larva spun up for pupation April 16th, 1894, and pupated April 18th, the larval stage being 317 days. The second larva spun up April 18th and pupated on the 20th." - Frohawk (1924)

Small Pearl-Bordered Fritillary - larva - Thatcham - 17-Apr-07 (2) {REARED}

Photo © Pete Eeles
17-Apr-2007

Photo Album (1 photos) ...


Pupa

The pupa is formed head-down in leaf litter, attached by the cremaster. The stage lasts between 2 and 3 weeks.

"The pupa is 14.5 mm. long. Lateral view: The head is blunt and rounded, the thorax swollen, rising into a central dorsal conical point; it is deeply sunken at the waist. The second and third abdominal segments are swollen; the body then runs in a slight curve to the seventh segment, where it abruptly turns at a right angle to the extremity; the ventral surface of the abdomen is contracted; the wings are swollen near the apex; the leg joints are prominent, forming a serrated edge. Dorsal view: The head is square, with very small lateral points, and an angular point at base of wing, the inner margin of the wing is developed into a prominent dilated ridge, and the middle of the wing concave. The abdomen is broadest across the third and fourth segments, the remainder being of conical form. There are two (sub-dorsal) rows of blunt conical projections, a pair on each thoracic division and abdominal segment and head. Those on the head, thorax and first two abdominal segments (in all five pairs) are flattened out into brilliant silver-gilt discs of a highly burnished appearance. The largest is on the meta-thorax, those on the third abdominal segment are more elevated and partly metallic, and those on the last two anal segments are reduced to mere black clots. There is also a medio-dorsal series of exceedingly small points; super-spiracular and sub-spiracular rows are represented by dark brown dots, each row being placed on a pale ochreous line; the spiracles are black. The ground colour is lilac-buff, reticulated with dark brown and blotched with black, the most conspicuous markings being on the dorsal surface of the fifth, sixth and seventh abdominal segments in the shape of broad V markings uniting the sub-dorsal points; the other dorsal points are black in front. Two broad blotches of black occur on the wing, both commencing on the hind margin and running obliquely across; the hind marginal band is pale grey and there is a sub-marginal series of whitish dots; along the inner edge of the inner margin is a black band. The front of the head below is edged with pearly-white. The wings and whole of the ventral surface have the ground colour deeper than the dorsal surface and more densely reticulated and freckled with brown and black. The pupa is suspended by the cremastral hooks to a pad of silk spun on the stem or leaf stalk of a plant." - Frohawk (1924)

Small Pearl-Bordered Fritillary - pupa - Thatcham - 29-Apr-07 (1) {REARED}

Photo © Pete Eeles
29-Apr-2007

SPBF Pupa (reared in Sussex 2017)

Photo © Gary.N

Photo Album (2 photos) ...


Aberrations

Description to be completed.

Click here to see the aberration descriptions and images for this species.

Similar Species

Pearl-bordered Fritillary

The Pearl-bordered Fritillary and Small Pearl-bordered Fritillary are most easily distinguished by their undersides. Both species have a row of 7 white "pearls" running along the edge of the hindwing (hence their vernacular names). However, the remainder of the underside of the hindwing is quite different. The Pearl-bordered Fritillary exhibits 2 very distinct additional "pearls", whereas the Small Pearl-bordered Fritillary has a mozaic of white, oranges and browns and, as such, has the more colourful underside.


Pearl-bordered Fritillary (left) and Small Pearl-bordered Fritillary (right)

It is much more difficult to distinguish Pearl-bordered Fritillary and Small Pearl-bordered Fritillary based on their uppersides. However, there are two general differences. The first is with regard to the row of chevrons at the edge of the forewings. In the Pearl-bordered Fritillary, these chevrons are often "floating" and not attached to the outer margin, whereas these chevrons are attached to the edge of the forewing in the Small Pearl-bordered Fritillary. The second is with regard to the row of spots found next to these chevrons. In the Pearl-bordered Fritillary, each of these spots is positioned midway between neighbouring markings. In the Small Pearl-bordered Fritillary, the dots are not midway, but distinctly closer to the chevrons.


Pearl-bordered Fritillary (left) and Small Pearl-bordered Fritillary (right)

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The following links provide additional information on this butterfly.

References

The species description provided here references the following publications:

ReferenceDetails
Denis & Schiffermüller (1775) Denis, J.N.C.M. and Schiffermüller, I. (1775) Systematischez Verzeichniss der Schmetterlinge der Wienergegend.
Dennis (1977) Dennis, R.L.H. (1977) The British Butterflies - Their Origin and Establishment.
Ford (1945) Ford, E.B. (1945) Butterflies.
Freyer (1852) Freyer, C.F. (1852) Neue Beitrage zur Schmetterlingskunde mit Abbildungen nach der Natur.
Frohawk (1924) Frohawk, F.W. (1924) The Natural History of British Butterflies.
Harris (1766) Harris, M. (1766) The Aurelian. Edition 1.
Harrison (1937) Harrison, J.W.H. (1937) Rhapolocera on the Island of Scalpay, with an account of the occurrence of Nymphalis io on Raasay. The Entomologist.
Haworth (1803) Haworth, A.H. (1803) Lepidoptera Britannica.
Jermyn (1824) Jermyn, L. (1824) The Butterfly Collector's Vade Mecum: or a Synoptical Table of English Butterflies.
Lewin (1795) Lewin, W. (1795) The Papilios of Great Britain.
Moore (1900) Moore, F. (1900) Lepidoptera indica.
Rafinesque (1815) Rafinesque, C.S. (1815) Analyse de la nature ou Tableau de l'univers et des corps organisés.
Ray (1710) Ray, J. (1710) Historia Insectorum.
Rennie (1832) Rennie, J. (1832) A conspectus of the butterflies and moths found in Britain, with their English and systematic names, times of appearances, sizes, colours, their caterpillars, and various localities.
Reuss (1920) Reuss, T. (1920) Die Androconien von Yramea cytheris Drury und die nächststehenden analogen Schuppenbildungen bei Dione Hbn. und Brenthis Hbn. (Lep.). Entomologische Mitteilungen.
Samouelle (1819) Samouelle, G. (1819) The Entomologist's Useful Compendium.
Swainson (1827) Swainson, W. (1827) A Sketch of the Natural Affinities of the Lepidoptera Diurna of Latreille. The Philosophical magazine : or Annals of chemistry, mathematics, astronomy, natural history and general science.
Wilkes (1742) Wilkes, B. (1742) Twelve New Designs of English Butterflies.