UK Butterflies

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Small Skipper

Thymelicus sylvestris

thy-ME-lee-kuss sill-VESS-triss

Wingspan
27 - 34 mm

Checklist Number
57.006

Small Skipper

Thymelicus sylvestris

thy-ME-lee-kuss sill-VESS-triss

Wingspan
27 - 34 mm

Checklist Number
57.006


This golden skipper is often found basking on vegetation, or making short buzzing flights among tall grass stems. Despite its name, 4 skipper species found in the British Isles are the same size or smaller than the Small Skipper. The male is distinguished from the female by the sex brand on its forewings, which is a slightly curved line of specialised scent scales. This butterfly is widespread on the British mainland, south of a line running between Westmorland in the west and North Northumberland in the east. It is absent from Ireland, the Isle of Man and the Channel Islands. This species lives in discrete colonies of both small and large populations.

This species was first defined in Poda (1761) as shown here (type locality: Graz, Austria).

 
Family:HesperiidaeLatreille, 1809
Subfamily:HesperiinaeLatreille, 1809
Tribe:  
Genus:ThymelicusHübner, [1819]
Subgenus:  
Species:sylvestris(Poda, 1761)

Description to be completed.

The distribution data (2000-2009) has been made available through the generosity of Butterfly Conservation and any subspecies distribution is taken from Riley (2007). Click here to see the distribution of this species together with site information overlaid.

This species inhabits rough grassland, where tall grasses grow, and may occur on roadside verges, beside hedgerows, on overgrown downland, in woodland clearings and along woodland rides. The main foodplant is Yorkshire-fog, a common grass in the British Isles, although other grasses are also used.

The status of the Small Skipper is considered stable and this delightful little skipper has even expanded its distribution slightly in recent years.

The table below shows the occurrence (distribution) and abundance (population) trends, using information from The State of the UK's Butterflies 2015 (Fox, 2015). Any UK BAP status is taken from the UK Biodiversity Action Plan (UK BAP) (2007 review).

UK BAP Status
Occurrence Change
1976-2014 (%)
Abundance Change
1976-2014 (%)
Occurrence Change
2005-2014 (%)
Abundance Change
2005-2014 (%)
Not Listed
Stable -7Large Decrease -75Stable -1Increase +27

The adults are on the wing in late June, through July, and into August.

The male Small Skipper is territorial, and can be found resting on suitable perches from which it intercepts any passing butterfly. The male is the more active of the two sexes; females being more sedentary. Females exhibit unusual behaviour when egg-laying. The female will alight on a dead stem of Yorkshire-fog, and then move backwards down the stem, probing the sheath as she moves. When a suitable opening in the furled sheath has been found, she will lay several eggs inside. Both sexes are nectar-loving, and can be found visiting flowers such as Thistles and Red Clover.

Adults feed primarily on Betony (Betonica officinalis), brambles (Rubus spp.), Common Bird's-foot-trefoil (Lotus corniculatus), Common Fleabane (Pulicaria dysenterica), dandelions (Taraxacum spp.), Devil's-bit Scabious (Succisa pratensis), hawkbits (Leontodon spp.), knapweeds (Centaurea spp.), Red Clover (Trifolium pratense), restharrows (Ononis spp.), Sainfoin (Onobrychis viciifolia), Selfheal (Prunella vulgaris), thistles (Carduus spp. and Cirsium spp.), vetches (Vicia spp.) and Wild Marjoram (Origanum vulgare).

As many as 8 oval-shaped eggs may be laid in a row inside a leaf sheath of the foodplant. They are white when first laid, but gradually turn pale yellow. Eggs hatch in around 3 weeks.

"On July 17th, 1912, between 3.45 and 4.30 p.m., the author watched three females depositing on cat's-tail grass (Phleum pratense) and soft creeping grass (Holcus mollis). All three went through precisely the same act of depositing. After flying with a slow, steady, buzzing flight in and out among the taller stems of the mixed grasses growing in a dense mass of varied herbage in a wild uncultivated spot on the slope of a chalk hill in Kent, the butterfly now and again settled for a moment on a grass stem, but as it was obviously not suited for her eggs, would quickly fly off and settle on another; if suitable, she would settle on the upper sheath and immediately slide down tail first, and at once start feeling for the division along the sheath with the ovipositor, working partly or wholly round it, and slowly crawling upwards during the process until she found the exact place to suit her requirements, in the choice of which she seemed very particular; she then rested with her wings closed over her back, antennae lowered in a line with her body, and the abdomen curved with the extremity closely pressed on or just in the crevice of the sheath, and the ovipositor deeply inserted. In this attitude she remained for three or four minutes ... While thus resting, she laid four eggs in a row along the inner surface of the sheath opposite the aperture, quite hidden from view. The other females observed behaved precisely the same in their actions ... Apparently the normal number of eggs laid at a time is from three to five. After depositing the butterfly gradually raises the abdomen from the grass-stem, opens her wings, and, after resting for about a minute, flies off. The egg measures 0.85 mm. across its greatest diameter, of a compressed oval shape, about half the width in height; it is much more rounded in form than either A. acteon or A. lineola. The micropyle is rather sunken and finely reticulated, and the rest of the surface is covered with extremely delicate reticulations of an irregular network pattern, which is only practically visible in high light; otherwise the shell has the appearance of being smooth and glistening, with rather an opalescent lustre. The habit of depositing the eggs within a sheath of a plant of grass is most developed in this species. A. acteon, its near ally, acts similarly, however, though this species occasionally deposits the eggs on the ridge of a sheath. When first laid it is pearly-white, faintly tinged with primrose-yellow. It remains unchanged for some days, and then gradually becomes a deeper ochreous-yellow, afterwards again becoming paler, of a greyish-pearly hue, when the larva is clearly visible through the delicate shell, its dark head showing as a leaden blotch. Some of the wild eggs found on July 17th started hatching on August 3rd; those laid on that day (July 17th) started hatching on August 9th, remaining twenty-three days in the egg state." - Frohawk (1924)

The larva eats its eggshell on hatching, and subsequently spins a dense silk cocoon around itself, still inside the grass sheath. The larva hibernates within the cocoon, alongside other cocoons formed by its siblings. The larva emerges from the cocoon in April to live a solitary existence. It forms a tube by spinning together the edges of a leaf and, in early instars, feeds within the tube. In later instars the larva feeds outside the tube, leaving characteristics notches in the grass blade. The larva will move to new leaves, creating new suitably-sized tubes, as needed. The larva has 5 instars in total.

The primary larval foodplant is Yorkshire-fog (Holcus lanatus). Cock's-foot (Dactylis glomerata), Creeping Soft-grass (Holcus mollis), False Brome (Brachypodium sylvaticum), Meadow Foxtail (Alopecurus pratensis) and Timothy (Phleum pratense) are also used.

1st Instar

"The young larva directly after emergence measures while crawling 1.8o mm. long. The head is pale olive-ochreous, roughly granular and beset with a few white hairs; eyes pale, surrounded with blackish; the clypeus outlined with dark brown. The body is stoutest in the middle and tapering posteriorly; on the first segment is a dorsal transverse chitinous band of a similar surface and colour to the head. The segments have five sub-divisions, the first on each segment being the widest; the second one runs below the spiracle, where it curves and runs off to the anterior segmental division. There are three sub-dorsal shining brown discs, each bearing a minute brown hair, placed in a triangle on each segment above the spiracle, and two others below; a few minute simple hairs are scattered over the ventral surface and on the anal extremity. The surface is roughly granulated and of a pale citron-yellow colour. The larva eats almost all the shell after emerging, only leaving a portion of the base adhering to the surface of the sheath, and shortly after this meal it commences spinning itself over with silk until it is completely enveloped in a little, dense, elongated, oval white cocoon, spun in the same spot where the egg is laid, so that a row of cocoons takes the place of the eggs, the little larvae not moving from where they hatched. In these compact cocoons the larvae are completely hidden and protected for hibernation. In this respect, excepting its near ally A. acteon, this very remarkable habit is unique among our native butterflies, and is a wonderful provision for the preservation of the species, as the eggs are but slightly fixed to the surface of the sheath on which they are laid and become detached if only very lightly touched; upon the decaying of the grass during the winter, when it would become fractured and split up, the eggs would fall out and perish on the ground in consequence, but nature has provided safety for the species by the hatching of the eggs in summer and the self-preservation of the larva to construct an indestructible covering, incapable of dislodgment from its site, in which it can safely remain concealed throughout the winter months, and in the spring, when the fresh tender blades of the grass plant spring up among the fallen flower-stalks and sheaths, the little larva on awakening can then find its natural food. The first emerged from hibernation on April 16th, 1913, by eating its way out of the cocoon, and shortly after fed on a tender blade of grass; it ate away a notch from the edge. After each meal it rested, lying along the centre of the blade. After feeding two or three times it spun two cords of silk from edge to edge of the blade, drawing them partly together, in which it lived. On the seventh day six cords were spun across the blade." - Frohawk (1924)

2nd Instar

"The first moult took place on May 6th, twenty days after hibernation. After first moult the ground colour is very pale greenish-ochreous, greenest over the middle segments. Head ochreous, clypeus darker, eye spots dark, surface granular, sparsely sprinkled with little black knobbed processes; the body has a granulated surface resembling lizard skin and is beset with tiny black stud-like knobs. A medio-dorsal green line extends from the head to the eleventh segment, which is uniformly pale ochreous without any markings, and beset laterally with sharply pointed simple white hairs; the medio-dorsal line is edged with light ochreous; a fine sub-dorsal whitish line edged with green; the spiracles are outlined with dark brown; legs and claspers ochreous. There is no dorsal collar on the first segment." - Frohawk (1924)

3rd Instar

"Second moult on May 19th, the second stage occupying thirteen days. After the second moult it measures 7 mm. long; the ground colour is bright green; a medio-dorsal darker green stripe bordered by a pale yellowish line; a fine sub-dorsal whitish line bordered on each side by a darker green line, and a whitish lateral line. The head is light greenish-ochreous, clypeus and medio-frontal line darker and continuous with the body stripe, eye spots black; the surface is finely granular and sprinkled with minute black points. The body is likewise granular and is beset with minute black stud-like processes; the anal segment is fringed with whitish hairs; the ventral surface is flattened. If disturbed when out of its dwelling it falls to the ground and rolls in a complete ring, remaining so for a short time." - Frohawk (1924)

4th Instar

"The third moult on May 27th. After the third moult it measures 14 mm. long. Head very pale whitish-ochreous-green with a slightly darker central band continuous with the medio-dorsal stripe, clypeus very indistinct, otherwise it is similar to the previous stage. The light-coloured spiracles are placed on a very fine pale line." - Frohawk (1924)

5th Instar

"The fourth moult on June 6th. After the fourth and last moult, fully grown, the larva measures 21 mm. long. The head is globular, the surface reticulated and sprinkled with minute white bristles, eyes dark, ground colour ochreous-green with a slightly darker green band down the centre, but very faint. The body is swollen in the middle, tapering at the ends. The first segment is small and narrow, the anal segment terminating in a projecting flap, the segments sub-divided into six divisions, the first one being much the widest. The ground colour is grass-green, with a rather darker green longitudinal medio-dorsal band, intersected by a central paler line and bordered on either side by a pale yellowish line and a similar sub-dorsal line. The small yellow spiracles are situated on a fine pale line, followed by a conspicuous yellowish-white lateral stripe; the ventral surface is darker green; on each clasper is a whitish crescentic mark. The first and last segments are wholly green; the legs fleshy-ochreous. Between the 9-10 and 10-11 segments is a ventral patch of white, waxy substance. It has an anal comb for the ejectment of the excreta similar to the other Hesperidae larvae which live in tubular dwellings. The larva became fully grown and spun up for pupation on June 15th and pupated June 17th, the larval state occupying 311 days." - Frohawk (1924)

When fully-grown, the larva spins a tent of leaves at the base of the foodplant within which it pupates. The pupa is attached to a grass blade within the tent, attached by a silken girdle and the cremaster. The pupal stage lasts around 2 weeks.

"The pupa varies in length from 16 mm. to 19 mm. long. It is slender and tapering. Dorsal view: The head bears a short frontal conical point, from the base of which the head slopes off to the rather prominent eyes; across the neck it is slightly contracted; base of wings slightly swollen and very slightly narrowed across the middle; the abdomen gradually tapering to the long cremastral horn, which is furnished with a cluster of projecting amber-coloured hooks. Lateral view: Head rounded, with a central conical point; thorax rounded, which is the greatest diameter of the pupa; slightly sunken at the meta-thorax; the abdomen gradually tapering to the anal segment, which terminates in a long, flattened cremaster with a cluster of hooks only at the extremity; the ventral surface forms almost a straight line. The long tongue-case, which is free from the apex of the wings, reaches to the anal segment. The entire surface is granular and thickly covered with white powdery bloom of a waxy nature. On the head horn are a few fine whitish bristles. Colouring: Immediately after the pupation the head, thorax and basal half of the wings are pure rich brilliant green, the apical half of wings paler, the abdomen yellow-green; the detached terminal portion of the tongue-case is deep ochreous, the cremaster and head point flesh colour. It is striped longitudinally like the larva. By slow degrees the colouring matures and loses the brilliancy, the abdomen becomes whiter and the wings and thorax duller. When seven days old the head is green, suffused with a pinkish bloom, the frontal point deeper lilac-pink, thorax grass-green, wings greyer-green, abdomen whitish-yellow-green with a medio-dorsal longitudinal grass-green stripe, the last two segments fading into pale lilac, cremaster darker. Just before emergence the pupa assumes a dull smoky-black, segmental divisions pale greenish and wings dark copper-red. It is attached to the grass blades by a cincture round the middle and by the cremaster hooks to a pad of silk spun on the surface of the blades; usually three or four blades are spun together, forming a tubular shelter in which the pupa is more or less concealed. The pupal period extends from twelve to seventeen days, according to temperature. The individual described, which pupated on June 17th, produced a male imago on July 4th, remaining seventeen days in the pupa. One that pupated July 3rd, 1912, emerged July 16th (a female); remained thirteen days in pupa. Another which pupated on July 10th, 1912, and emerged on July 22nd, also a female, was twelve days in the pupal state." - Frohawk (1924)