Butterflies of
Britain & Europe
Dark Green
Fritillary
Argynnis aglaia
LINNAEUS, 1758
Family - NYMPHALINAE
subfamily -
HELICONIINAE
Tribe - ARGYNNINI
introduction
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habitats |
lifecycle |
adult behaviour
Dark Green Fritillary
Argynnis aglaia,
female, Pitt Down, Hampshire
Introduction
The Dark Green Fritillary,
formerly known as the
Queen of England Fritillary, is
widely distributed across Europe, but is absent from most Mediterranean islands. It is also found throughout temperate
Asia as far east as Japan, and occurs in the Atlas mountains of
Morocco.
The common name of the butterfly refers to
the bronzy-green underside wings, which are spangled with large silver
spots.
Dark Green Fritillary
Argynnis aglaia, female at rest,
Hampshire, England
The upperside wings of males are a bright
unicolorous orange colour. Females are quite variable in colour,
some having a dull reddish brown ground colour while others have
a distinct bronzy sheen. In all females the colour is much paler
( often whitish ) near the apex and wing margins, while the
basal area of the forewings is noticeably dark. In Scotland both
sexes
tend to be larger and more heavily marked than elsewhere in the
butterfly's range.
The butterfly can easily be confused with the
High Brown Fritillary Argynnis adippe,
but the male of that species has the sex brands on veins 2 and 3
( as opposed to veins 1 and 2 in aglaia
). The High Brown Fritillary also has slightly concave outer
margins to the forewings. On the underside
adippe has a more yellowish ground colour, and an
additional band of small silver sub-marginal spots that are
ringed with dark red.
On Corsica the Dark Green Fritillary is absent, being replaced
by the endemic
Argynnis elisa, which is very
similar to aglaia but is smaller
and has greatly reduced black markings on the upperside.
Habitats
This is the most
widespread and least threatened of Fritillaries in Britain. In southern England
it is a butterfly of wild, windswept open grasslands and cliff-tops, but also
occurs on heathlands, dunes and in forest clearings. In northern counties it is
found on moors and mountain valleys, and can also be found in the company of the
High Brown Fritillary in grassland / woodland mosaics on limestone.
In Scotland the
butterfly is found on moors and mountainsides, in woodlands, and on open grassy
habitats. It is the only Fritillary which occurs on the windswept islands of the
Orkneys and Outer Hebrides.
Although it is
very widespread and utilises a very broad range of habitats, populations are
localised with very little movement between sites. They also tend to be confined
to particular areas of each site, often restricted to sheltered pockets where
the soil is deep, and violets grow in large clumps.
European
populations are far less restricted by habitat, being found in lowland meadows,
limestone gorges, sub-alpine hay meadows and many other habitats.
Dark Green
Fritillary
Argynnis aglaia, female ab.
obsoleta, Hampshire,
England
Lifecycle
The eggs are straw coloured
with purplish bands, and laid in July or early August, on leaves and
stems in the vicinity of the larval foodplants; e.g. at Dean Hill in July 2007
I observed a female enter a clump of dead grasses and twigs, upon which she laid
6 eggs dotted about on different stems over a period of 2 or 3 minutes. Violet
plants Viola hirta
were profuse in the area, the nearest plant being about a metre from the
oviposition site.
At chalk and limestone grassland sites the
usual foodplant is hairy violet Viola hirta,
but in southern woodlands common dog violet V. riviniana
is normally used. On heaths in the New Forest, and on moors in Cumbria and
Scotland, V. palustris
is favoured.
The
caterpillars hatch in August, about 16 days after the eggs are laid. After
eating their empty egg-shells, they immediately enter hibernation. They
over-winter in curled up dead leaves, or in chinks on the bark of bushes. The
following year, in March, they awaken to feed on violet leaves, eating large
chunks out of the lobes.
In southern England
they become fully grown in early May. In
Scotland I have often found fully grown larvae wandering across country roads, as late as the first week of
June.
When
fully grown they are mottled in black and grey, adorned along the back and sides
with rows of branched black spikes, and have a yellow stripe along the back.
There is a row of dark reddish spots low down on the sides, and the head is
black and glossy.
The
chrysalis is shiny, with black wing-cases and a dark brown abdomen. I have found
it in the wild in Scotland formed
amongst bracken and leaf litter, suspended by the tail from a dry stem, and
protected amongst a cluster of dead leaves spun together with silk.
Adult behaviour
At grassland sites in southern
England the butterflies strongly favour knapweeds, almost to the
exclusion of other nectar sources, but in woodland will feed at
bramble, thistles, bird's foot trefoil, red clover, buddleia and hawkbit. They
usually spend several seconds nectaring at a particular flower,
before flying very rapidly to another plant perhaps 100 metres
distant, even if many other flowers are situated more closely.
They are very alert, powerful on the wing,
extremely agile, and seem to positively relish
flying in the face of the strong breezes which prevail at
their open windswept habitats. During showers they
settle deep amongst grasses but still remain very alert, flying up at
the least disturbance, zig-zagging rapidly back and forth in
search of a new resting place.
Throughout the day males patrol relentlessly
back and forth across their habitat, soaring effortlessly in the
face of the strongest winds, and dipping down periodically in
search of the females, which sit deep in grass tussocks prior to
mating. When a virgin female is located, copulation takes place
almost immediately. Mated pairs occasionally fly in tandem to
nectar at flowers, but spend most of the time sitting hidden among
the grasses, with the wings held erect or half open.
Dark Green Fritillary
Argynnis aglaia, female, Hampshire, England
In
overcast or cool conditions the butterflies often remain fairly
active, but spend long periods basking in rabbit scrapes, patches
of bare earth, or amongst grasses. At Martin Down in Hampshire I once discovered a
male Dark Green Fritillary which had settled to bask on a coiled
grass snake !
Shortly before dusk on sunny days,
the butterflies migrate across their habitat to bask in the last
remaining sunlit areas, and can often be seen in the company of
Marbled Whites, soaking up the last rays of the sun. As the sun
dips below the horizon, they undertake a final flight to locate a
roosting site - often this can be high in a tree, but more
frequently they roost hanging from grass heads in areas where the
grasses grow tall, or on
low bushes of dogwood or buckthorn.
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