Butterflies of
Britain & Europe
Small Pearl-bordered
Fritillary
Clossiana
selene
DENIS & SCHIFFERMULLER, 1775
Family - NYMPHALIDAE
subfamily -
HELICONIINAE
Tribe - ARGYNNINI
introduction
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habitats |
lifecycle |
adult behaviour
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Small Pearl-bordered Fritillary
Clossiana selene, male at roost |
Introduction
This
species is distributed throughout northern Europe, but is absent from Ireland,
the southern half of the Iberian peninsula, Italy, Greece and the Mediterranean
islands. It is
found in temperate Asia as far east as Mongolia and Korea; and in North
America.
It
often shares it's habitats with the very similar
Pearl-bordered Fritillary,
which flies a week or two earlier in the season.
The flight periods of the 2 species overlap, so worn
specimens of euphrosyne can often be
seen in the company of fresh specimens of
selene. The latter is easily
distinguished by examining the undersides, which have additional silver spots in the median area,
and distinct black chevrons on the inner edge of the silvery submarginal
lunules. The uppersides of selene have darker veins
and more linear markings than euphrosyne.
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Small Pearl-bordered Fritillary
Clossiana selene, female |
Habitats
In England this species
breeds primarily in sheltered, sunny and damp woodland clearings, often
in the vicinity of irrigation ditches or small streams beside which it's larval foodplants -
common dog violet and marsh violet - grow lush and in profusion. In Cornwall the
butterfly is found along cliff tops. The butterfly is very sedentary in
behaviour, forming small discrete colonies often comprising less than 20 adults
at peak flight season, although populations can be as large as 100 adults at the
best sites.
In Scotland and Wales
it breeds in woodland clearings, and also in more open
habitats on moors, heaths and rough grassland, usually in wet areas close to
lakes, lochs or mountain streams. There the
butterfly is much more widespread,
and can be found at low densities over extensive areas.
In
Europe the butterfly occurs commonly in damp meadows, moist heathland, and on
mountainsides in the Alps, Pyrenees and Massif Central.
Lifecycle
The Small Pearl-bordered
Fritillary is single brooded in the northern part of it's range,
but produces a partial or complete 2nd brood in warmer areas in
the south.
The 1st brood emerges in June, and the 2nd ( where and when it
occurs ) emerges in August.
The straw coloured eggs are laid singly in early June ( and
again in August if there is a 2nd brood )
on the leaves and stems of violets or nearby herbaceous plants.
Often the eggs are dropped quite randomly as the female flutters
about, edging her way through the vegetation.
The
larvae hatch after about 12
days, and eat their egg-shells before wandering in search of violet
leaves. They feed
diurnally on
the leaf lobes of
Viola palustris,
V. riviniana
and sometimes on
V. hirta. In September, when in the 3rd or early 4th instar, they enter
hibernation within a dead curled up leaf. They awaken the
following March and resume feeding, becoming fully
grown by late April.
The presence of the larvae, which are dark brown, and adorned
with distinctive orange spikes, is given away by the
semi-circular nibble marks left on the edges of violet leaves.
Pupation takes place amongst low
vegetation. The chrysalis is dark brown, with paler wing cases, marked with darker
streaks, and has small silvery spots on the thorax.
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Small
Pearl-bordered Fritillary
Clossiana selene, male, Wiltshire, England |
Adult behaviour
Early on sunny mornings the
butterflies spend long periods basking on bracken. By about 9.00
am they are fully active, and can be seen nectaring at wood
spurge,
ragged robin, thistles, and less frequently at tormentil,
bugle or heather.
The
very similar
Pearl-bordered Fritillary which often flies in company with this
species, nectars almost exclusively at bugle and dandelion - a useful
identification point.
In the late
mornings the males patrol back and forth across the breeding
sites, flying low over the ground in search of females. I have not
observed any courtship behaviour, and it is likely that copulation
occurs almost immediately when the sexes meet. Mated pairs can
sometimes be found at rest on low herbage. Copulation lasts
for about 2 hours during which time the pair may both bask with
wings outspread
if the temperature drops.
The butterflies
roost overnight on bracken fronds, dead flower-heads of St Johns
wort, or on the flowers of rushes or pendulous sedge, in sheltered
glades.
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Small Pearl-bordered Fritillary
Clossiana selene, at roost on
bracken frond |
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