Butterflies of
Britain & Europe
Essex Skipper
Thymelicus lineola
OCHSENHEIMER, 1808
Family - HESPERIIDAE
subfamily -
HESPERIINAE
Thymelicus lineola
Note
the tiny crab spider lying in wait on the flower! ©
Adrian Hoskins
Essex Skipper
Thymelicus lineola, Farlington
Marshes, Hampshire ©
Adrian Hoskins
Introduction
The Essex
Skipper is a very common and widely distributed species in Europe, occurring
throughout the region with the exceptions of Sardinia and northern Scandinavia.
It's range extends eastward across Asia from Turkey to Amurland. In Africa it is
common north of the Sahara, particularly on the Mediterranean coast of Morocco
and Algeria.
The butterfly
was accidentally introduced into Canada in 1910, and within a few decades had
spread across much of North America where it is known as the European Skipper.
It is believed that the major cause of this expansion was the transportation of
hay bales - in one study over 5000 lineola eggs
were found in a single bale.
It is easy to confuse this butterfly with the Small Skipper Thymelicus
sylvestris
which often shares the same habitats.
In
sylvestris the band of androconial scales is prominent and runs
diagonally. The tips of the underside of its antennae are orange or dark
reddish. In lineola
however
the band of dark androconial scales on the forewings of the male is very
narrow and runs parallel to the costa, and the tips of the underside of the
antennae are glossy black. The
simplest way to find out which of these 2 species are present at a site is
to visit just before dusk, when the butterflies will be sitting quietly on grass
stems. They can then easily be examined without
resorting to capture.
Habitats
The Essex Skipper has always been under-recorded due to its
similarity to the Small Skipper, so its distribution,
particularly in former times, is poorly understood. In Britain
it was first discovered in 1888 in Essex, and for many years it
was thought to be restricted to south-east England. In truth it
has probably always occurred over a much wider area, but equally
there is little doubt that it is now far commoner and more
widespread than in earlier times.
It is likely that during
periods when rabbit grazing was a major problem the butterfly
was relatively scarce, but that when myxomatosis caused rabbit
numbers to dwindle in the 1950's it began to spread rapidly. It
is also believed that expansion of the road network,
particularly the advent of motorways, instigated further
colonisations, as Essex Skippers are commonly found breeding on
the dry grassy embankments, which form a man-made migration
corridor.
Whatever its history, the
species is now common and widespread on rough grassland throughout much of
central and south-eastern England, with smaller isolated colonies in Dorset,
Devon and Cornwall.
Essex Skipper
Thymelicus lineola, female,
Farlington Marshes, Hampshire ©
Adrian Hoskins
The butterfly
is commonest at ungrazed habitats where grasses grow tall but fairly sparsely,
and it generally prefers drier habitats than its close relative
sylvestris. Typical habitats of
lineola include roadside
verges, motorway embankments, railway cuttings, field headlands, sand dunes,
coastal grasslands and undercliffs. At grazed sites it breeds
mainly along the base of hedgerows or close to bushes - areas which rabbits and
domestic livestock tend to avoid. Thus scrubby grassland sites tend to have
stronger populations than more open habitats.
Essex Skipper
Thymelicus lineola, female, Farlington Marshes,
Hampshire ©
Adrian Hoskins
Lifecycle
The butterflies emerge
slightly later than the Small Skipper, in mid-late July.
The eggs, which are
lozenge-shaped and milky white in colour, are laid in strings of 3 or 4,
inserted into the flower sheaths of cocksfoot Dactylis glomerata,
creeping soft grass
Holcus mollis,
timothy Phleum
pratense,
and tor grass
Brachypodium pinnatum,
but never on Yorkshire fog grass
Holcus lanatus,
the main foodplant of the Small Skipper. The eggs are laid in late July, and by
early August the tiny caterpillars are fully developed within, but do not hatch until the following April.
The
caterpillars live within a shelter made by rolling a blade of grass into a tube,
which is held together with strands of silk. It hides within the tube during the
daytime, and feeds at dusk, although fully grown caterpillars can sometimes by
found basking in full sunlight on grass blades.
The
chrysalis, which is thin, green, and has white palpi, is formed within a very
loose shelter constructed by spinning together rolled grass blades, at the base
of a tussock.
Essex Skipper
Thymelicus lineola, female,
Stansted Forest, West Sussex ©
Adrian Hoskins
Adult behaviour
The
adults usually occur in sizeable colonies, where populations may
run into hundreds or thousands of individuals.
In common with
most other grass-feeding skippers, the butterflies have a rapid,
buzzing, purposeful flight, "skipping" from flower to flower.
They nectar at a wide range of wild flowers including small scabious,
thistles, knapweed, red clover, white clover, marjoram, ox-eye daisy, wild
mignonette, thyme, tufted vetch, self-heal, betony, ragwort,
yarrow,
fleabane, wild basil, hedge bedstraw and bird's foot trefoil.
In overcast
weather they are inactive, but in hazy sunlight they spend long
periods basking, in the characteristic Hesperiine posture, half
hidden amongst tall grasses. In hot weather they commonly settle with their wings
fully closed, usually on grass flowerheads or high on the stems.
As dusk
approaches, Essex and Small Skippers migrate to sheltered sunlit
areas of tall grasses, where they sometimes roost in hundreds, often with 2
or 3 individuals sharing a single grass head. At this time it is
easy to approach the insects, and the ideal time to examine them
in determine which of the 2 species are present, and in what
ratio.
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