Introduction

The Peacock is considered by many to be the most beautiful butterfly in the world. Its beauty was remarked upon as early as 1634 when Sir Theodore de Mayerne, physician to King Charles 1, noted that the ‘eyes’ on the wings of the Peacock butterfly “shine curiously like stars, and do cast about them sparks of the colours of the Rainbow”.

Peacock Inachis io, Alner’s Gorse, Dorset – Adrian Hoskins

Peacock Inachis io, Hungerford, Berkshire – Adrian Hoskins

The butterfly is distributed throughout most of Europe but is absent from northern Scandinavia, and from most of southern Spain and Portugal. Beyond Europe its range extends across temperate Asia to Japan.

Habitats

In Britain the Peacock is a widespread and common resident, often seen in gardens, woodlands and flowery hillsides in late summer. The butterflies go into hibernation in September, over-wintering in hollow tree trunks, wood stacks, farm buildings, rabbit burrows and other locations where they can find shelter and darkness. In early spring they awaken and can often be often seen basking on bare earth on paths through woodland, along lightly wooded riverbanks, disused railway cuttings, old quarries and farmland.

Peacock Inachis io, Alice Holt forest, Hampshire – Adrian Hoskins

Lifecycle

In April and May, female Peacocks can often be seen flying around clumps of stinging nettle Urtica dioica in woodland glades, country lanes and farmland. They eventually settle under the upper leaves of the nettles, where they lay their dull green spherical eggs in large heaps.

Immediately after hatching, the larvae spin a silken web on the upper leaves of the nettles, and live within this during the early instars, venturing out to feed in warm weather. They all feed and grow at roughly the same rate.

After each moult they divide into increasingly smaller groups, each time moving on to another nearby plant. They are conspicuous, feeding openly in groups on the upper surface of the leaves. If molested they react by ‘reflex bleeding’, i.e. they spurt a foul smelling and noxious fluid from glands behind the head. This acts as a warning to wasps, spiders and predatory birds that they are distasteful and should be left alone.

Molestation also causes the caterpillars to wriggle violently and drop from their leaf into the herbage below, presumably as a defence against parasitoid wasps or flies. Nevertheless at least 90% of Peacock caterpillars fall victim to attack by the Tachinid fly Zenilla vulgaris. Other Tachinids including Pelatachina tibialis, Sturmia bella and Phryxe vulgaris are also recorded as parasitizing Inachis io.

By the time they reach the final instar the larvae become solitary in behaviour. They are handsome velvety black creatures, covered with black spikes, and studded with tiny white tubercles.

Inachis io, 5th instar larva, Hungerford, Berkshire – Adrian Hoskins

In some years Peacocks breed especially successfully and the larvae can be extremely abundant – on 5th July 2013 for example I checked a 400 metre stretch of hedgerow between 2 rape fields at Hungerford in Berkshire and counted no less than 22 separate larval webs comprising an estimated total of 1400 larvae, ranging from 1st to 4th instar.

The chrysalis is pale green with a dark diagonal streak across the wing cases, and can reputedly be found hanging from woody stems or tree trunks in the vicinity of nettles.

Peacocks Inachis io, Noar Hill, Hampshire – Adrian Hoskins

Adult behaviour

Peacocks emerge in late July and throughout August, and generally spend a few days very close to the emergence site, nectaring at thistles, knapweeds, hemp agrimony, ragwort, marjoram and bramble flowers.

At Noar Hill in Hampshire on 31st July 2009 there were an exceptional number of Peacocks present, well in excess of 150, by far the highest concentration of this species I have ever seen. There were often 15 or 20 on a small patch of thistle or a single clump of hemp agrimony. At about 6.30pm the breeze suddenly dropped, and cloud cover obscured the sun. The Peacocks quickly responded by settling in groups of up to 6 to bask on ant hills and patches of bare chalk.

After dispersing from the ‘honey pot’ nectaring areas in the countryside, the adults commonly visit gardens where they nectar at michaelmas daisies, ice plant and buddleia. In September they return once more to the countryside, visiting flowery hillsides where they gorge themselves on the nectar of devil’s bit scabious to prepare themselves for the long winter ahead.

By late September they enter hibernation, usually at woodland sites, where they spend the winter months hidden in hollow tree trunks, log piles, farm out-buildings and other cool dark places where their blackish mottled undersides provide them with excellent camouflage.

They re-awaken on the first sunny days of spring, sometimes as early as January, although mid March is more typical. They are very long lived butterflies, and there are usually a few individuals flying in late May or early June, almost overlapping with the next generation of adults.

Peacock Inachis io, Noar Hill, Hampshire – Adrian Hoskins

In spring Peacocks will use almost any available nectar source, including blackthorn, bugle, sallow catkins, bluebell, cuckoo flower, ground ivy, daisies, wood anemone and dandelion.

During April, at around midday, males establish small territories on the ground, typically choosing sunny sheltered spots close to hedgerows or woodland edges, or along woodland rides. Often as many as a dozen males will set up their territories close together along a woodland track, and each will instantly fly up to chase after any passing bee, fly or butterfly.

In April 2006 I watched 2 males that had set up territories about 5 metres apart, along a ride in Stansted Forest. One male had been chasing after a Comma, and encroached into the territory of the other male Peacock. A sortie then took place, with both males spiralling rapidly to a height of about 20 metres before separating and returning to their original territories.

On another occasion I watched a male Comma defending its territory against a Peacock. Despite the greater size of the Peacock, which repeatedly attempted to occupy the territory, it was successfully ousted by the Comma.

In April 2007 at Botley Wood I watched a sortie between a male Comma and a male Peacock both of who believed they had ‘ownership’ of a particular birch log. The pair engaged in battle dozens of times during a 20 minute period but eventually the Peacock was driven off, leaving the Comma to occupy the territory.

When female Peacocks pass through the male territories they are instantly intercepted and pursued at high speed. Often the chasing male will inadvertently fly into the dominion of another male, and a territorial battle will take place during which the female will escape. Despite the abundance of the butterfly, neither myself, or as far as I am aware anyone else, has observed the courtship or found a copulated pair.

Peacock Inachis io, Hungerford, Berkshire – Adrian Hoskins

Peacocks often close their wings when settled, but if disturbed suddenly re-open them, producing a rasping or hissing sound created by rubbing the veins on the forewings and hindwings together. The sudden appearance of the ‘peacock eyes’ probably functions to startle attacking birds. The effect is short-lived however and having recovered its senses the bird may still attack.

The ‘eyes’ then serve to divert the attack away from the butterfly’s vulnerable body and onto the outer part of the wings. Butterflies are usually still able to fly well, even with large chunks pecked out of their wings. It is thought that the hissing noise is a defence against bats which may disturb the butterflies when they enter caves or hollow tree trunks to roost or hibernate.

In a study by Stockholm University, the ocelli of several Peacocks were blanked out with a marker pen. When exposed to blue tits, 13 out of 20 were attacked and eaten. A control group of Peacocks with the ocelli intact fared much better, with only a single butterfly attacked out of a group of 34.

It can be concluded that in 97% of encounters with blue tits, the ocelli are effective as a deterrent, and the butterfly will escape unharmed. A project carried out by another biologist found that normally marked Peacocks escaped attacks by yellow buntings 76% more often than Peacocks that had their eyespots painted out.

Peacock Inachis io, Alner’s Gorse, Dorset – Adrian Hoskins

Introduction

Despite it’s rather unflattering vernacular name, this is a lovely insect, worthy of much greater attention than it generally attracts. Old faded butterflies may indeed be a little dingy, but a freshly emerged Dingy Skipper shows itself to be beautifully marked in subtle shades of brown and grey.

The butterfly is quite variable in appearance, populations in woodlands tending to be darker and more strongly marked, compared with the pallid specimens which predominate on chalk landslips, quarries and limestone pavements. Males are duller and more unicolorous, and have a pronounced fold on the leading edge of the forewings. This fold has special wing-scales called androconia that disseminate pheromones, and are used to entice females during courtship.

Dingy Skipper Erynnis tages, male, Noar Hill, Hampshire – Adrian Hoskins

The Dingy Skipper is distributed throughout most of Europe but is absent from northern Scandinavia and most of the Mediterranean islands. There are several other members of the genus found in temperate Asia, North America, and the Andes.

There are no similar species in Britain, but in Turkey, Greece and Albania the butterfly shares it’s habitats and emergence time with a similar species Erynnis marloyi. The latter is distinguished by being darker and much plainer than stages.

Habitat

The Dingy Skipper is localised throughout England and Wales, preferring well drained, lightly grazed dry grassy habitats where the larval foodplant bird’s foot trefoil grows in profusion.

It favours a warm sunny environment with small but profuse patches of bare ground such as those created by cattle poaching or by the erosion of small coombes. Typical habitats include calcareous grassland slopes, undercliffs, coastal landslips, dunes, abandoned quarries, grassy heaths, railway cuttings, spoil heaps, limestone pavements, and woodland clearings.

In Scotland and northern England it is primarily a coastal species, breeding on cliff-tops, shingle banks and sand dunes.

Most colonies are small and very localised – a typical colony will comprise of between 30-50 adults, although the numbers seen on any particular day are usually much lower. The largest known colony, on a stretch of undercliff in Dorset, probably holds about 200-300 adults at peak season.

Dingy Skipper Erynnis tages, male, Cerne Abbas, Dorset – Adrian Hoskins

Lifecycle

The butterflies are normally single brooded in Britain, emerging in May, although at the warmest sites in southern England there may occasionally be a partial second brood in late July or early August. In southern Europe there is usually a partial or complete second brood emergence in July.

Dingy Skipper Erynnis tages, female at roost, Butser Hill, Hampshire ï¿½ Adrian HoskinsThe strongly ribbed eggs are laid singly on the upper surface of leaflets of bird’s foot trefoil Lotus corniculatus, or less commonly on greater bird’s foot trefoil L. uliginosus. At some sites e.g. Ballard Down in Dorset, horseshoe vetch Hippocrepis comosa is usually chosen despite a profusion of bird’s foot trefoil. The eggs are pale yellowish-green when first laid but turn bright orange after 4 days, and hatch about 12 days after being laid.

During daylight hours the larva lives within a loose tent of leaves spun together at the base of the foodplant, and emerges to feed more openly in the early evening. When fully grown it is yellowish green, faintly marked with a dark line along the back, and pale lines along the sides. The head is brown, with dark purplish-black markings.

By early August the larva is almost fully grown, and at this point it enters hibernation, over-wintering within a thin silk tent. It remains inside this hibernaculum until April, when it pupates. Gently pulling apart the silk tent reveals the shiny pupa, which has dark green wing cases and a brown abdomen.

Adult behaviour

On warm but overcast days in late April and May, the butterflies bask with wings held flat, on bare soil, stones or low herbage.

In sunny conditions they are very active, zipping and whirring about, usually no more than a few inches above the ground; stopping occasionally to bask for a moment or two on a grass head, or to nectar at their favourite wild flowers – bird’s foot trefoil, common vetch, horseshoe vetch, buttercups, ground ivy, cranesbills, speedwells and bugle.

Dingy Skippers generally hold the wings flat when nectaring, but in warm weather they raise them at an angle of about 45 degrees, or sometimes if very warm they hold the wings erect.

Dingy Skipper Erynnis tages, male perching, Bentley Wood, Hampshire – Adrian Hoskins

When male Dingy Skippers encounter each other a sortie takes place, with both butterflies whirling about in tight circles close to the ground, occasionally making physical contact. After about a minute the pair suddenly rocket skyward to a height of about 3 metres, at which point the intruding male is chased off, and the original occupant of the territory returns to continue search of a female.

Copulation takes place mid-late morning, at a sheltered spot, typically at the base of a hill. During copulation both sexes spread their wings flat.

Dingy Skipper Erynnis tages, female at roost on knapweed, Noar Hill, Hampshire – Adrian Hoskins

As evening approaches, Dingy Skippers migrate to the last remaining sunlit spots in their habitat. There they settle to bask on grass heads, or more often on the dead flower heads of knapweeds or St Johns wort. As the temperature drops, and the last rays of sunshine fade, they adjust their position, wrapping their wings tightly around the flower heads, upon which they roost overnight.

During extended periods of inclement weather, Dingy Skippers can aestivate for long periods – on 14th May 2006 I found a pristine and distinctively marked female, roosting at dusk on a dead knapweed flower head at Noar Hill in Hampshire. That night the weather suddenly deteriorated, and it remained wet and windy for the next 2 weeks. I returned on 27th May and was surprised to find the butterfly still alive, and still at roost on the same flower head, from which it had been unable to move in the intervening period.

Introduction

There are about 50 known species in the genus Pyrgus, which has representatives in North, Central and South America, and in temperate Asia, as well as in Europe. The genus is instantly recognisable from the pattern of squarish white spots on a grizzled greyish ground colour, and by the prominent chequered fringes to the wings. All Pyrgus males have the basal half of the forewing costa folded back. Within the fold are hundreds of specialised scales called androconia, from which pheromones are disseminated to entice females into copulation.

The Grizzled Skipper flies very rapidly and erratically just above the surface of the ground, making it difficult to follow in flight. It is easily overlooked and certainly under-recorded. Transect analysis however provides evidence that the butterfly has declined in numbers in the last 20 years, and it is now regarded as a localised and fairly scarce species.

It is distributed throughout most of Europe but absent from Scotland, Ireland, northern Scandinavia and most Mediterranean islands. Beyond Europe it occurs from northern Turkey, across temperate Asia to northern China and Korea.

Confusingly the butterfly has undergone many name changes, being originally known as the Marsh Fritillary, a name that is now applied to a totally different insect in the Nymphalidae ! Other former names include “Mr Dandridge’s Dark Fritillary”, “Spotted Skipper” and “The Grizzle”.

The sexes can be distinguished easily – males have a fold along the leading edge of the forewings. This fold contains androconia which release pheromones to entice females into copulation.

Both sexes are prone to variation in the size and extent of the white markings. The ground colour is black when the butterflies are freshly emerged, but soon fades to a dark earthy brown. A recessive gene causes the periodic appearance of an aberrant form at some sites. This form, known as taras, has the white markings on the forewings greatly elongated and enlarged.

The Grizzled Skipper cannot be mistaken for any other species in Britain, but in continental Europe there are several similar Pyrgus, Spialia and Muschampia species with which it can be confused.

Grizzled Skipper Pyrgus malvae, male, Stockbridge Down, Hampshire – Adrian Hoskins

Habitats

In Britain this species is widespread throughout the central and southern counties, but it’s range has contracted dramatically in recent years. It is now very localised, but can still be found in reasonable numbers on many chalk grassland sites. Small colonies also persist in certain woodlands, where it breeds in clearings, and along the edges of sunny forest tracks. Other habitats include scree slopes, railway cuttings and embankments, abandoned quarries, spoil heaps and limestone pavements.

Grizzled Skippers are always found in sheltered and well drained locations. Their breeding sites are characterised by having substantial areas of broken ground such as rabbit scrapes or eroded banks. These areas of bare soil encourage germination of the caterpillar’s foodplants and provide the warm micro-climate which is essential to the butterfly.

Grizzled Skipper Pyrgus malvae, male, Magdalen Hill Down, Hampshire – Adrian Hoskins

Lifecycle

The flight season varies according to climatic conditions in early spring. In forward seasons Grizzled Skippers can appear in early April, but they may not emerge until May in a cool or wet spring. Their numbers tend to build up gradually throughout May, and in late seasons they can often still be found in mid-June. In Europe a partial 2nd brood emerges in August, but records of a 2nd brood in Britain are extremely rare.

The greenish white dome-shaped eggs are laid singly on the undersides of leaves of wild strawberry Fragaria vesca, creeping cinquefoil Potentilla repens or agrimony Agrimonia eupatoria. More rarely young suckers of bramble Rubus fruticosus may be used. The eggs hatch after about 10 days.

When small the caterpillar is yellowish and rests under a thin veil of silk spun over the midrib on the upper surface of leaves. It leaves a characteristic pattern of little blotches nibbled out of the cuticle. When older it lives within a folded leaf spun together with a few strands of silk. The mature larva is green with narrow brown stripes along the back and sides.

Pupation takes place in August. The pupa is formed within a thin net-like cocoon spun near the base of the foodplant. It is very distinctive, with the abdomen and thorax dark brown, and the wing cases greenish white. The pupal stage lasts from August until the following April or May.

Adult behaviour

Grizzled Skipper Pyrgus malvae, male perching on ribwort plantain – Adrian Hoskins

The butterflies are extremely active, zigzagging or buzzing erratically in tight circles just above the surface of the ground. They are very difficult to track, and can easily be mistaken in flight for large flies. Neither sex tends to ever stray more than a few metres from their established breeding areas, so consequently it can take many years for the butterfly to colonise new sites.

Grizzled Skippers are usually seen in small groups, with 2 or 3 males having overlapping territories, typically in sheltered pockets at the bottom of hillsides. Each male habitually perches on a favoured leaf or stone – a territorial lookout post from which it will instantly dart up to challenge any fly, bee or butterfly that comes within range. When 2 males meet, they spiral rapidly together to a height of about 2 metres, after which each returns to it’s original perching place.

When a male intercepts a female, he flies close behind her until she settles on the ground. He lands alongside and then buzzes excitedly around her, wafting his pheromones over her antennae to try and entice her to copulate. If she is receptive she raises her wings, allowing the male to move into position alongside her. The male then curves his abdomen around to make sexual contact. The pair then readjust position to face away from each other. Copulation takes place in the late morning and lasts for about an hour during which time both sexes generally keep their wings fully outspread.

In overcast but warm weather the butterflies commonly bask on bare ground or on small stones but in sunny conditions they spend most of their time buzzing from flower to flower, nectaring avidly at bird’s foot trefoil, bugle, dandelion, ground ivy, violets, daisies, buttercups and hawkbit.

In late afternoon they go to roost on dead flower-heads, particularly favouring St John’s wort and marjoram, but will also roost on grass heads or at the tips of bramble sprigs.

Pyrgus malvae, female roosting on St John’s wort, Magdalen Hill Down – Adrian Hoskins

Pyrgus malvae, female roosting on dandelion, Magdalen Hill Down, Hampshire – Adrian Hoskins

Introduction

There are 15 Carterocephalus species. The genus is centred on China, but 3 species reach Europe including palaemon.

Older literature treats Carterocephalus as a member of the Hesperiinae, but the genus is currently placed in the Heteropterinae due to differences in the structure of the antennae, palpi and venation. There are only a few members of the Heteropterinae which occur in the northern hemisphere. In South America there are many related species in the genus Dalla – largely montane species from the Andes; and another similar genus, Metisella, occurs in the tropics of Africa.

All Carterocephalus species are dark brown with yellow or cream markings. The pattern is repeated on the underside, but in muted colours.

In Britain palaemon is known as the Chequered Skipper, but in the USA and Canada it is usually referred to as the Arctic Skipper or Arctic Skipperling. The butterfly is found across most of central and northern Europe, although absent from Spain, Portugal, peninsular Italy and the Mediterranean coast. Beyond Europe it occurs across much of temperate Asia to Siberia, China and Japan. It is the only Carterocephalus species found in North America where it occurs in California, southern Alaska and across most of Canada.

Carterocephalus palaemon, Kercaszomor, Hungary – Peter Bruce-Jones

Habitats

In England the Chequered Skipper was once quite widespread, occurring across most of the central and eastern counties, but it contracted it’s range, partly as a consequence of drainage of the Great Fen, which led to the large scale conversion of land to agriculture. By the early 20th century the species was thought to be confined to a few counties in the east Midlands, and although it remained fairly common in certain areas until the early 1960’s, within a decade populations at all its English sites had collapsed, and by 1975-76 it had become extinct. Reintroduction trials have taken place since 1990 with varying degrees of success.

The butterfly’s presence in Scotland was not known until 1942 when it was discovered by a collector Mackworth-Praed in Western Inverness. The butterfly had in fact been known from another nearby locality for 3 years previously, having been found by Evans, but that site was a well kept secret.

In 1982 I surveyed the Highlands for this species, and found it widespread, discovering 14 colonies including 4 that were previously unknown. Since that time further studies have been carried out by Butterfly Conservation, and it is estimated that the butterfly currently ( 2009 ) breeds in about 10 core areas. Within that total area there are about 40 discrete colonies.

In Scotland the butterfly is found at warm, sheltered, damp sites where the larval foodplant, purple moor grass Molinea caerulea grows in lightly wooded areas, often in the vicinity of small streams. Examples include open oak woods, lightly wooded gullies on hillsides and mountains, sunny glades in birch woodland, young conifer plantations, damp scrubby areas on northern and eastern shores of Lochs, woodland clearings, and roadside verges in wooded areas. Most Scottish colonies occur at altitudes between sea level and about 200m. Colonies vary considerably in size, some comprising no more than a couple of dozen insects breeding in a woodland glade, while others may comprise of several hundred butterflies spread over a 5 mile stretch of lightly wooded valley bottom.

In mainland Europe the Chequered Skipper occurs at altitudes up to about 1600m and it is far less fussy about its habitats, although it occurs primarily in damp, sunny glades and woodland clearings.

Climate change is likely to cause local extinctions in more southern localities, but the butterfly may successfully colonise new areas further north e.g. in Scotland and Fennoscandia. Existing colonies in Scotland and the Alps will probably be forced to move to higher altitudes as the lowlands become too warm to support the butterfly and its habitat.

Lifecycle

In Scotland the butterflies emerge in late May and fly until mid June.

The shiny white spherical eggs are laid singly on the underside of grass blades. Oviposition occurs primarily on grasses growing in dappled sunlight beneath bog myrtle bushes. They are usually laid on Molinea caerulea, but occasionally on Brachypodium sylvaticum, which was the grass used by the species at it’s former English sites. A much wider range of grasses are used in Europe and North America.

The caterpillar makes it’s first meal of the eggshell. It later constructs a shelter made by rolling a blade of grass into a tube, held together with strands of silk. As it grows, it moves to other grass blades and constructs larger tubes. It feeds diurnally, eating little notches out of the grass blade above and below where it rests.

Like other grass-feeding skippers, the larva is equipped with a pair of prongs at the tail end, which it uses to flick away it’s droppings. This helps to prevent the grass shelter from becoming fouled, and also removes evidence of the larva’s whereabouts, which might otherwise attract parasitoids or predators.

In late September, when the larva is fully grown, it constructs a silken tent amongst the grass blades, where it hibernates until April. The mature larva is pale green, but during the autumn the colour gradually changes to pale straw, matching the surroundings.

Prior to pupation in early May, the larva constructs yet another shelter, made from dead grasses and silk. The long thin chrysalis is formed within the shelter. It is pale ochreous, marked with dark lines along the back and sides. The pupal stage lasts for about 2 weeks.

Adult behaviour

On sunny mornings males establish perches on bushes. They use these vantage points to survey passing females and defend the territories vigorously against all passing insects. Other males are promptly ousted from the vicinity. When a female is intercepted she is chased until she settles, and copulation then takes place immediately. The pair remain joined for about an hour, during which time they sit with wings held erect, on grass blades or other low foliage.

Both sexes spend long periods basking on the terminal leaves of shoots of bog myrtle, birch, and other small trees or shrubs. Unlike Hesperiine skippers, but like the Pyrginae, they usually bask with their wings spread flat, usually with the forewings draped slightly backwards.

They nectar, with wings closed, at dandelion and bugle, but also visit marsh lousewort, bluebells, and orchids. In Scotland, and in the French Alps, I have often found them mud-puddling, always singly, at ditches or wet soil.

In dull dry weather and overnight, the butterflies roost on the terminal leaves of small bog myrtle bushes, or sometimes on bracken fronds or clumps of heather. In wet weather they hide themselves deep within grass tussocks.

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.

Introduction

The Small Skipper is a very common species occurring throughout most of Europe, but it is absent from Scotland, Scandinavia and most Mediterranean islands. Its range extends to include Morocco, Algeria, Turkey, the Middle East, Iran and eastward to the Black Sea.

It is easy to confuse this species with the Essex Skipper Thymelicus lineola, which often shares the same habitats. In lineola the band of dark androconial scales on the forewings of the male is very narrow, and runs parallel to the costa. The tips of the underside of the antennae are glossy black. In sylvestris however the band of androconial scales is prominent and runs slightly diagonally. The tips of the underside of the antennae are orange or dark reddish. The simplest way to determine 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.

Small Skipper Thymelicus sylvestris, male, Stansted Forest, West Sussex – Adrian Hoskins

Note: It is also possible to confuse this species with T. hamza, which is more dusky in colour, and found only in north Africa; and with T. hyrax, which is slightly larger, more olive in colour, and found only in Greece, Turkey, and the Middle East.

Habitats

In Britain the butterfly is widely distributed, but its range does not extend into the north of England, Scotland or Ireland. The larval foodplant is the grass Yorkshire fog, and the butterfly breeds almost anywhere where this species grows, particularly in places where it is ungrazed and allowed to grow tall. Thus it occurs in woodland rides, on chalk and limestone grassland, on heathlands and moors, around field edges, and along hedgerows and railway cuttings. It quickly colonises new habitats, so small colonies often develop along road verges, motorway and railway embankments, wasteland or set-aside farmland.

Small Skipper Thymelicus sylvestris Castle Copse, Wiltshire – Adrian Hoskins

Lifecycle

The adults emerge in late June or early July, and lay their eggs in rows of 4 or 5, inserted into the sheaths of grass stems, most commonly on Yorkshire fog Holcus lanatus although Phleum pratense and Brachypodium sylvaticum are also sometimes used. The oviposition behaviour is fascinating to watch – the female alights near the top of a grass stem, and then edges backwards down the stem while slowly spinning around, and probing with the tip of her abdomen to locate a slit into which she will inject her eggs.

The caterpillars hatch after about 10-12 days. They immediately consume their eggshells, and then spin tiny cocoons inside the grass sheaths, where they hibernate until March or April of the following year. In the spring they disperse and live solitarily. They construct shelters by rolling grass blades into tubes, held together by a few strands of silk. On dry days they leave their shelters to feed on nearby blades, creating characteristic wedge-shaped feeding notches. The fully grown caterpillar is pale green with darker stripes along the back, and rests openly on grass blades in early June. The chrysalis, which is green and shiny, with pink palpi projecting from the head, is formed within a flimsy net-like cocoon amongst tufts of grass.

Adult behaviour

The males are active in sunshine, and have a rapid buzzing flight, ‘skipping’ from flower to flower. Favoured nectar sources include clovers, bird’s foot trefoil, vetches, thistles, knapweeds and ox-eye daisies. Females are much more sedentary – they spend much of the time at rest with their wings held erect, but in weak sunshine they can be found sitting on grass blades or stems, basking in the characteristic Hesperiine posture. In dry weather both sexes roost on grass stems overnight, but during wet spells they hide deep in tussocks.

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 – infemales this is very prominent, but in males it is very obscure and often absent.

Lulworth Skipper Thymelicus acteon, male, Swanage, Dorset – Adrian Hoskins

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.

Lulworth Skipper Thymelicus acteon, male, Swanage, Dorset – Adrian Hoskins

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.

Lulworth Cove, Dorset, where Thymelicus acteon was first discovered in Britain – Adrian Hoskins

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.

Introductio

The Silver-spotted Skipper is widely distributed in Europe, but absent from northern Britain, lowland regions of Spain and Portugal, southern Italy, the Mediterranean islands, and the Balkans. Beyond Europe it occurs in the Atlas mountains of Morocco, and across temperate Asia to Amurland. It also occurs over much of Canada and the western USA, where it is called the Holarctic Grass Skipper.

In Europe this butterfly can’t be confused with any other species except the Large Skipper Ochlodes venata, which is more brightly marked above, and lacks the distinctive silver spots on the underside hindwings of comma.

Silver-spotted Skipper Hesperia comma, Hampshire – Adrian Hoskins

Habitats

In Europe this butterfly can be found in a very wide range of grassy habitats, and even occurs high on limestone mountains at altitudes of up to 2300m.

In Britain the butterfly was formerly found across most of southern and central England. Its range contracted severely during the 20th century, largely due to the elimination of it’s larval foodplant sheep’s fescue grass from many former sites as a result of agricultural improvement, afforestation, and urbanisation. The spread of myxomatosis greatly reduced the populations of rabbits during the latter half of the 20th century leading to a mass of local extinctions as sites on deeper soils quickly became overgrown with rank grasses. Since about 2002 the rabbit population has recovered from the affects of myxomatosis and consequently many grassland sites in southern Britain have become more heavily grazed and are now being slowly recolonised by this species.

Silver-spotted Skipper Hesperia comma, male, Stockbridge Down, Hampshire – Adrian Hoskins

In England Hesperia comma is restricted to a few well drained and thinly soiled calcareous grassland sites in the southern counties where sheep’s fescue grass grows sparsely. On Silver-spotted Skipper sites extensive areas of bare ground are vital, and the sward is typically pock-marked with myriads of small bare patches exposed by rabbit excavations.

At most sites the populations are restricted to a limited area, typically on the upper slopes of south or east facing hillsides. However, at sites which are particularly exposed to the wind, or at higher altitudes, the populations tend to be limited to sheltered areas at the base of hills.

Silver-spotted Skipper Hesperia comma, male, Stockbridge Down, Hampshire -Adrian Hoskins

Lifecycle

In Europe and most of North America the butterfly is univoltine, but in Alaska the lifecycle takes two years to complete, the first winter being spent as an egg and the second as a fully grown caterpillar or chrysalis. In the hotter parts of the Mediterranean Hesperia comma over-winters as a fully grown caterpillar, amongst grass roots. In the UK the species always over-winters in the egg stage.

In Britain the butterflies emerge in mid-late July, and have a short flight period – no more than 2 or 3 weeks. At higher altitude sites such as Old Winchester Hill in Hampshire, the emergence time is generally about a week later than elsewhere.

Published material by Thomas states that females seeking egg-laying sites habitually settle in rabbit scrapes or on other small patches of bare ground, and then hop and walk until they locate a tiny tuft of sheep’s fescue grass, nearly always choosing plants that abut onto bare ground. My experience is that this is often not the case – most of the females which I have followed at Old Winchester Hill and Broughton Down dart about over short fescue sward and alight randomly on short grasses, usually well away from rabbit scrapes or other bare ground. They then thrust their abdomen forward to lay a single egg on a grass blade without any investigative hopping or walking about. After ovipositing they usually remain on the spot for a while before flying to another similar nearby spot where they repeat the process. Egg-laying behaviour probably varies from site to site according to local habitat and climatic conditions.

The straw-coloured eggs are laid singly on the narrow leaf blades of sheep’s fescue grass Festuca ovina. Suitable plants may be revisited by the same female several times, or they may be used by several different females, so it is possible to find up to a dozen eggs placed very close together.

The larvae are fully developed within the eggs by early autumn, but do not hatch until the following March. They feed nocturnally on the fine tender leaf blades, sheltering by day in a flimsy silken tent spun at the base of a grass tuft. When fully grown they are dark green, with a black head, and very wrinkled in appearance.

The chrysalis has a dark brown abdomen, and blackish wing cases and head. It is formed within a cocoon of coarse silk, at the base of grass tufts. The butterfly develops very quickly, emerging after only about 7 days.

Silver-spotted Skipper Hesperia comma, male, Stockbridge Down, Hampshire – Adrian Hoskins

Adult behaviour

Silver-spotted Skippers only fly on warm sunny days. They are then extremely active, with a very rapid flight, zipping and darting about in every direction just above the surface of the ground. Once cloud begins to obscure the sun they settle to bask in rabbit scrapes, hoof prints, or on low foliage.

When conditions become too cool for flight they rest temporarily in tussocks of grass that abut onto bare ground, or settle on low foliage ( the male illustrated below for example was found on a tiny field maple sapling ). At such times they become extremely torpid. Overnight, they shelter in small bushes or amongst patches of dense foliage.

Both sexes nectar avidly at low growing flowers including stemless thistle, carline thistle, eyebright, stonecrop, bird’s foot trefoil, self heal, small scabious, lady’s bedstraw, hawkbit, devil’s bit scabious, red clover and autumn gentian. Their favourite nectar source however is wild basil – as illustrated by the activities of a male which I watched in August 2007 at Broughton Down. The butterfly visited 17 different wild basil plants in quick succession, completely ignoring all other flowers. After about 4 minutes I lost track of the butterfly when it got into a dog-fight with another male, but I continued to watch various other males that afternoon, and all showed a strong preference for wild basil, despite a profusion of other nectar sources.

Silver-spotted Skipper Hesperia comma, male, Broughton Down, Hampshire – Adrian Hoskins

Males occupy loosely defined overlapping territories where they dart from flower to flower, stopping periodically to bask on patches of bare ground or on low herbage. They fly up instantly from these perches to intercept and investigate any small rapidly flying insect including flies, bees and wasps as well as other butterflies. They are very pugnacious in nature, and will chase off even the largest and most powerful butterflies, including Painted ladies and Dark Green Fritillaries, but rather oddly they completely ignore Burnet moths.

During male / male encounters, the butterflies zigzag rapidly, close to the ground, and then spiral upwards in tight circles until the weaker male is ousted, whereupon the other male returns to within a few metres of it’s original position.

When a virgin female is encountered she is abruptly forced to land on the ground, usually in a tuft of grass, where she vibrates her wings rapidly. The male lands alongside her, and buzzes excitedly around her, showering her with pheromones from his androconial scales. The female then flies in a series of short hops, until she finds a comfortable spot to settle, and the male then settles by her side, curving his abdomen round until he engages her. He then slowly turns to face away from her, after which the pair remain stationary in copulation for about 2 hours.

When a gravid female is encountered the ritual begins the same way, but after settling together 3 or 4 times in succession without successfully copulating the male flies off. There does not appear to be any visual rejection signal given to the unwanted male, so presumably mating only takes place of the female is receptive to the male pheromones.

Silver-spotted Skipper Hesperia comma, female, Broughton Down, Hampshire – Adrian Hoskins

Introduction

The Large Skipper, in common with most members of the sub-family Hesperiinae, feeds in the larval stage on grasses.

Adult butterflies in this sub-family frequently adopt a characteristic resting posture as shown above, with the forewings held at 45 degrees, and the hindwings held almost flat. Another characteristic is the presence of a dark streak of androconia ( pheromone producing scales ) on the forewings of males, as shown above.

There are a vast number of very similar species found throughout the world. In Britain however the only similar species is the Silver-spotted Skipper, which can easily be told apart by the presence on the latter of prominent silvery spots on the underside hindwings.

This butterfly has previously always been known by the scientific name Ochlodes venatus. However recent research has revealed that venatus only occurs in China. Korea, Siberia and Japan; and that the species occurring in Britain and Europe is actually Ochlodes sylvanus ( also known as faunus ).

Large Skipper Ochlodes sylvanus female, Fermyn wood, Northamptonshire – Adrian Hoskins

Habitats

Large Skippers can be found commonly throughout England and Wales in almost any grassy habitat but they tend to favour damp but sunny sites such as woodland glades and rides, humid heaths, wild meadows and riversides. Almost all sites are characterised by the presence of bramble bushes and stands of bracken. Open grasslands are also used but populations tend to be much lower.

Large Skipper Ochlodes sylvanus male, Wiltshire – Adrian Hoskins

Lifecycle

The Large Skipper is single brooded throughout it’s range, normally emerging in mid-late June, and living for about 3 weeks. A small number of individuals emerge later during July and old faded specimens can often be seen in August.

The pale straw coloured dome-shaped egg is laid singly on the underside of grass blades, typically on cock’s foot or false brome. It hatches after about 10 days.

The larvae feed on soft lush grasses, favouring cock’s foot Dactylis glomerata on alkaline or neutral soils, and purple moor grass Molinea caerulea on acid soils. Less frequently used larval foodplants include red fescue Festuca rubra and false brome Brachypodium sylvaticum.

The larva spends the early stages of it’s life within a tube of grass made by joining together 2 grass blades with strands of silk. It periodically emerges from the tube to eject it’s droppings, which are catapulted some distance by flicking them with a comb-like device on it’s tail. It hibernates within a newly constructed tent of grasses and resumes feeding in the spring. When fully grown in early May it rests openly on the upperside of grass blades, but retires to it’s grass tube in poor weather. The mature larva is green and unmarked, with a purplish black head.

The chrysalis is dark brown and shiny, with the long detached proboscis case projecting almost to the tip of the abdomen. It is formed within the larval shelter, head-upwards, and secured by bristles on the head and cremaster. The pupal stage lasts about 2 weeks.

Large Skipper Ochlodes sylvanus male, Glapthorn, Northamptonshire – Adrian Hoskins

Adult behaviour

Large Skippers have a rapid whirring flight, ‘skipping’ from leaf to leaf. They bask with wings held in the characteristic position as illustrated, typically on bramble leaves, bracken, or grass heads.

Males patrol back and forth across their breeding sites in the late morning on warm sunny mornings to search for freshly emerged females. If unsuccessful at this time they switch to a ‘perch and wait’ tactic in the afternoon. Typically a male will then seek a sheltered, sunny spot in a woodland glade, a ride intersection, or at the base of a grassy hillside. There he will sit on a tall grass head or on a leaf of bracken or bramble. He perches with wings either erect or in the characteristic Hesperiine posture, and darts up to intercept every small passing insect.

Large Skipper Ochlodes sylvanus male, Hungerford, Berkshire – Adrian Hoskins

Other males are challenged aggressively and driven off. During these territorial sorties the males buzz frenetically around each other, while flying rapidly in broad circles, soaring to a height of about 4-5 metres above ground level. At this point they separate and the ‘owner’ of the territory returns to it’s original perch – or very nearby, while the intruder moves on to set up a territory elsewhere.

When females are encountered they are chased until they settle, usually on a bush or small tree; and copulation follows after a brief courtship ritual. Copulated pairs can often be found settled on bramble or buckthorn bushes, bracken leaves or coarse grasses in late morning or early afternoon. When copulated both insects keep their wings either closed or held very slightly apart, and are reluctant to fly, but will do so if disturbed.

At grassland sites the butterflies nectar at bird’s foot trefoil, clovers and vetches, but in woodlands they particularly favour bramble blossom and thistles. On heathlands the most common nectar sources are cross-leaved heath and bell heather.

Ochlodes sylvanus territorial male perching on grass head, Ballard Down, Dorset – Adrian Hoskins

Introduction

The Scotch Argus is widely distributed in central and eastern Europe, but is absent from Ireland, Spain, Portugal, western France, peninsular Italy, Scandinavia and the Mediterranean region. Its range extends to northern Turkey and across temperate Asia to western Siberia.

The sexes are virtually identical on the upperside – males have a large patch of dark androconial scales on the forewings, but this can only be seen under certain lighting conditions. The underside hindwings of the male are dark reddish brown, with a broad grey post median band. In females the ground colour beneath is a paler earthy brown, banded with olive.

In mainland Europe there are several other Erebia species which closely resemble aethiops. These include ligea, euryale, medusa and triaria. The various species can be distinguished by examining the number and configuration of the ocelli. The patterns on the undersides also differ. A good field guide is essential for determination.

There are no similar species in Britain, although aethiops could be confused in flight with the Ringlet Aphantopus hyperantus. The Arran Brown Erebia ligea is similar to aethiops but has prominent white markings on the underside hindwings. It was allegedly found in Scotland in the 19th century, but all records are regarded as highly dubious – unfortunately early entomologists often made false claims about the butterflies they collected, habitually importing European specimens and claiming they had captured them in Britain.

Erebia aethiops, male, Arnside Knott, Cumbria – Adrian Hoskins

Habitats

The Scotch Argus forms large colonies often numbering dozens, hundreds or sometimes thousands of individuals in the best habitats.

In Britain it is confined almost exclusively to Scotland. In England it formerly occurred at several sites in Cumbria, Yorkshire, Northumberland and County Durham; and probably also in Lancashire, but is now only found only at 2 sites – Arnside Knott in Cumbria, and Smardale Gill in Yorkshire.

Unlike most members of the genus Erebia, the Scotch Argus is not a montane species. It occurs at elevations below 500m, in warm, sheltered and damp situations where the grasses Molinea caerulea or Sesleria caerulea grow in tall, lush, dense tussocks.

In Scotland the butterfly is commonly found in valley bottoms, and at damp grassland / woodland mosaic habitats, particularly those along riverbanks, or around the edges of lochs. Colonies also occur on warmer, more sheltered areas of lightly wooded moorland, on scrubby damp heaths and hillsides on the islands of the Inner Hebrides, as well as on the mainland.

The 2 sites in northern England are very different in nature – at Arnside Knott it occurs on limestone where rough grassland is sheltered by woodland; and at Smardale Gill it is abundant along a disused railway line running through a limestone grassland / woodland mosaic.

Lifecycle

The butterflies emerge in late July and fly throughout August.

The eggs are attached singly to grass blades and stems, at the base of tussocks of purple moor grass Molinea caerulea in Scotland, or blue moor grass Sesleria caerulea in Cumbria and Yorkshire. A much wider range of grasses is used in mainland Europe including Bromus, Brachypodium, Poa, Festuca and Dactylis. At some sites in Europe eggs are laid on the sedge Carex sempervirens.

The eggs are spherical, finely ridged, and straw coloured. After a few days they develop a pattern of dark purplish speckles, finally turning grey just before the larva hatches.

The larvae hatch in late August, nibbling a circular groove around the upper egg shell, creating a lid through which they exit. They then eat the remaining shell which contains vital nutrients, and having finished their meal rest for a while before starting to eat tender young grass blades. They only feed for a few weeks before entering into hibernation at the base of grass tussocks. There they remain until April when they awaken to resume feeding. When fully grown they are dull umber in colour, with dark green stripes and speckles along the back and sides. Like most Satyrine larvae they are crepuscular by nature, feeding in the early evening and again at dawn.

The fully grown larva leaves the foodplant in mid June, and wanders a short distance to pupate in a small silk-lined cavity excavated amongst mosses. The pupa is pale brown, with the thorax, wing cases and eye covers pale purplish in colour.

Erebia aethiops, male, Arnside Knott, Cumbria – Adrian Hoskins

Adult behaviour

The butterflies dislike hot weather, and at such times sit motionless on bushes or amongst grasses, with their wings firmly closed. They are most active in warm sunny conditions when the males can be seen gently bobbing about just above the tall grasses, fluttering and weaving tirelessly in search of potential mates. If there is a slight drop in temperature, or cloud temporarily obscures the sun, they settle to bask on bracken, bramble leaves or other low foliage; but quickly disappear deep into grass tussocks if it becomes too cool, or if there is any threat of rain.

Copulation takes place in late morning amongst grasses, and lasts for about an hour. Females are quiescent until mated, after which they can be seen flying in and out amongst grass tussocks in hot sunshine to oviposit.

Both sexes nectar avidly at almost any available flowers including thistles, knapweeds, bramble, hawkweeds, heather and meadowsweet; fluttering from flower to flower, and usually holding the wings half-open while feeding.