Butterflies of
Britain & Europe
Lulworth Skipper
Thymelicus acteon
ROTTEMBURG, 1775
Family - HESPERIIDAE
subfamily -
HESPERIINAE
introduction
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habitats |
lifecycle |
adult behaviour
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Lulworth Skipper
Thymelicus acteon, male,
Swanage, Dorset, England |
Introduction
The
Lulworth Skipper is named after the locality Lulworth Cove in Dorset, where the
butterfly
was first discovered in Britain. It is found throughout most of southern and
central Europe, but is absent from Scandinavia, Holland, Corsica, Sardinia and
the Baltic region. Beyond Europe it occurs in the Middle East, and over much of
north-west Africa.
The
male is smaller, much duller, and more olive in colour than other European skippers, but
could be confused with another north African species,
Thymelicus hamza. The female Lulworth Skipper
is slightly larger, almost as big as a Small Skipper, but has a pale golden
brown ground colour. Both sexes are marked on the outer forewings with a "horseshoe" pattern of suffused golden spots
- in
females this is very prominent, but in males it is very
obscure and often absent.
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Lulworth Skipper
Thymelicus acteon, male,
Swanage, Dorset, England |
Habitats
In Britain this species
is at the northern limit of it's range, and is only found at grassland sites
less than about 8 kilometres inland of the coast of south-west England.
Most
Lulworth Skipper colonies in Britain are located along the steep chalk and limestone undercliffs between
Swanage and Weymouth in Dorset, but there are additional colonies a few miles
inland on south-facing grassland hillsides, and small isolated colonies on the
southern coast of Devon.
The
best sites are characterised by having extensive swathes of tor grass,
growing ungrazed or very lightly grazed on warm south facing scrubby grassland slopes. It's very
noticeable for example at Swanage, where this grass carpets the hillsides, that
the species is scarce on the open cattle-grazed hillsides, but abundant along
the base of the hills where it breeds along a narrow fenced-off strip of land
which is out of reach of grazing animals, and sheltered by bushes.
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Lulworth Skipper
Thymelicus acteon, male,
Swanage, Dorset, England |
Lifecycle
The adults normally emerge in late
July and throughout August, but in recent years have begun to
appear much earlier, e.g. on 31st May 2008 at Ballard Down I
recorded no less than 5 males flying in a sheltered coombe; and
in the hot spring of 2007 I saw a single male at the same site
on 25th April.
The straw-coloured oval eggs are
inserted in rows of between 5-15 into the dry sheaths of tor
grass
Brachypodium pinnatum, and hatch after about 10 days.
Females are very choosy about where they oviposit - selecting
tall clumps of flowering grasses that grow in sunny sheltered
nooks, often in coombes or close to bushes. In mainland Europe additional grasses are used, including false
brome
Brachypodium sylvaticum,
couch
Agropyron repens,
and wood small-reed
Calamagrostis epigejos.
After
about 20 days the eggs hatch. The caterpillars
partly eat their egg shells, and then spin little silk cocoons
within the dead grass sheaths. They immediately enter a state of
diapause, aestivating and then hibernating, and do not awaken
until March of the following year. At this time they disperse
and live the remainder of their lives solitarily, resting during
daylight hours within a shelter made by rolling grass blades
into a tube, fastened with strands of silk.
The fully grown caterpillar is
pale green, with a dark line along the back, narrow cream lines
along the sides, and dark green prolegs. It feeds nocturnally,
eating small notches out of the grass blades above and below the
tube, a habit shared with several other grass feeding skippers.
The chrysalis is formed in a loose
silk shelter at the base of grass tufts, and is long and thin,
bright green, with pale green wing cases, and a dark lines along
the back.
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Lulworth Cove,
Dorset, where
Thymelicus acteon was first
discovered in Britain |
Adult behaviour
Lulworth Skippers are only
active in warm, sunny and calm weather, at which time their rapid
zig-zagging flight is very difficult to follow. They rarely cover
more than 3 or 4 metres distance on each flight, but during the
course of their lives they may range over a hundred metre stretch
of habitat.
They
nectar avidly at rest-harrow, thistles, bird's foot trefoil,
marjoram and other wild flowers. When not nectaring they bask in
the usual Hesperiine posture, half hidden amongst blades of tor
grass, or occasionally
on
bramble bushes.
Copulation occurs
at about midday, without any observed pre-nuptial ritual. Mated
pairs are very reluctant to fly, and usually settle with wings fully
closed, amongst tussocks of tor grass.
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