UK Butterflies

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Gatekeeper

Pyronia tithonus

py-ROH-nee-uh ti-THOH-nuss

Wingspan
♂ 37 - 43 mm, ♀ 42 - 48 mm

Checklist Number
59.011

Gatekeeper

Pyronia tithonus

py-ROH-nee-uh ti-THOH-nuss

Wingspan
♂ 37 - 43 mm, ♀ 42 - 48 mm

Checklist Number
59.011


The Gatekeeper, also known as the Hedge Brown, is a golden butterfly that provides a welcome sight in the middle of summer, when the fresh adults start to emerge. This butterfly spends much of its time basking with wings open, when the sexes are easy to tell apart - only the male has the distinctive sex brands on the forewings. In England and Wales this common and widespread species is found south of a line between Westmorland in the west and South-east Yorkshire in the east. In Ireland it is confined to coastal areas of the south and south-east counties. The butterfly is also found in the Channel Islands, but is absent from Scotland and the Isle of Man. The habitat this butterfly requires is found over most of the British Isles, and so we can only assume that the restriction to its range is governed primarily by climate. Colonies vary greatly in size, depending on the available habitat, ranging from a few dozen individuals to several thousand.

The species was first defined in Linnaeus (1771) as shown here (type locality: Germany). The nominate subspecies has not been recorded in Britain or Ireland.

This subspecies was first defined in Verity (1915) as shown here (type locality: England). Records from Britain and/or Ireland are of this subspecies.

 
Family:NymphalidaeRafinesque, 1815
Subfamily:SatyrinaeBoisduval, 1833
Tribe:ManioliniGrote, 1897
Genus:PyroniaHübner, [1819]
Subgenus:  
Species:tithonus(Linnaeus, 1771)
Subspecies:britanniae (Verity, 1915)

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 can be found wherever shrubs grow close to rough grassland. In fact, some of the largest colonies can be found at field edges and along hedgerows and we can expect to find this butterfly in scrubby grassland, woodland rides, country lanes, hedgerows and the like anywhere within its range.

This butterfly is relatively stable in terms of both distribution and population and it is not currently a species of conservation concern.

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
Increase +15Decrease -41Stable +1Decrease -44

There is one generation each year, with adults emerging at the end of June in favourable years, peaking at the end of July and early August, with only a few adults remaining until the end of the month. In contrast with its close relative, the Meadow Brown, this butterfly has a relatively-short flight period.

Pyronia tithonus ssp. britanniae

Males set up small territories, often centred on a particular shrub or bush, and will fly up from their perch to investigate passing butterflies in the hope of finding a mate. Pairing occurs without any obvious courtship and, once mated, a female will typically lay between 100 and 200 eggs.

Although both sexes feed from honeydew, they will also feed from whatever nectar sources are available - Bramble and Ragwort being particular favourites.

Adults feed primarily on brambles (Rubus spp.), Common Fleabane (Pulicaria dysenterica) and ragworts (Jacobaea spp.). Devil's-bit Scabious (Succisa pratensis), Hemp-agrimony (Eupatorium cannabinum), Red Clover (Trifolium pratense), thistles (Carduus spp. and Cirsium spp.), Water Mint (Mentha aquatica), Wild Privet (Ligustrum vulgare) and Wild Thyme (Thymus polytrichus) are also used.

Eggs are laid singly, usually in shade underneath a shrub, either on the foodplant, on nearby vegetation or at random - ejected into the air over a suitable patch of foodplant. Eggs are pale yellow when first laid but soon develop brown patches, giving a mottled effect. They darken further as the larva develops within the egg. This stage lasts between 2 and 3 weeks.

"On August 11th, 1905, the author captured two females; they deposited about three dozen eggs on the following two days on the blades of grass (Poa annua). These eggs hatched on September 1st, 1905, remaining in the egg state twenty days. The egg is very small in proportion to the butterfly; the shape is a truncated cone, flattened at either end and widest at the base. It is equal in height and breadth, measuring 0.65 mm. in diameter. There are either sixteen or seventeen (usually sixteen) keels running from the crown to base; the surface between the keels is concave, finely granulated, and fairly regularly ribbed transversely by about fourteen ribs down each interval. On the flattened crown the keels and ribs form a kind of network pattern, decreasing at the micropyle, where they are very small; round the crown they form, as it were, a series of steps leading over the brim. When first laid the colour is a pale yellow, which gradually changes to pearly-white, showing the yellow only in shadow, and mottled and zoned with rust-red markings when about four days old. The markings very gradually deepen in colour until they assume different shades of drab-brown." - Frohawk (1924)

The larva eats its eggshell on hatching and proceeds to feed on the tenderest parts of the foodplant by day, before hibernating after its first moult at the base of a grass clump, usually within a withered grass blade. Larvae resume feeding in the spring and typically only feed at night. There are 2 colour forms of the larva - light brown and green and there are 5 instars in total.

The primary larval foodplants are bents (Agrostis spp.), fescues (Festuca spp.) and meadow-grasses (Poa spp.).

1st Instar

"The larva emerges from the egg by eating away the crown, and after exit devours part of the empty shell. Directly after emergence the larva measures 1.6 mm. long. The head is large, ochreous, with dark brown eye spots and rust-brown mouth parts. The surface is finely reticulated and covered with fine, pale ochreous, serrated hairs. The body is cylindrical, and the segmental and sub-divisions deeply defined. It almost exactly resembles the young E. ianira [Maniola jurtina, Meadow Brown] larva in every detail. The anterior half of the segment is swollen dorsally, and bears the longest curved dorsal hair; immediately below the spiracle is a large bulbous swelling, on which two hairs are placed, one being directed backwards and one downwards; another above the spiracle is directed forwards; on the posterior half of the segment is a much smaller dorsal hair, only half the length of the other. All are serrated with fine cleft tips, and are white with dark greyish swollen bases. The hairs above the claspers are simple, straight and finely pointed. The colour is a very pale cream, with a medio-dorsal and sub-dorsal longitudinal rust-coloured stripe, and indistinct super-spiracular and spiracular lines of the same colour, and a lateral blotchy band of rusty-red hue. After feeding the larva gradually becomes tinged with green, and finally quite green, with a whitish lateral line, before the first moult; the head remains ochreous." - Frohawk (1924)

2nd Instar

"The larvae feed slowly during September, and moult the first time at the beginning of October, and shortly after hibernate. Larva which hatched during early September, 1908, hibernated in October after the first moult. They apparently remained motionless during the whole winter, which continued very cold until the end of March, 1909, and did not feed until the weather was mild. At the beginning of April, 1909, after first moult and after hibernation, 180 days old, it measures 6.3 mm. long. The whole of the body is a clear, light green, with darker green longitudinal medio-dorsal, indistinct sub-dorsal and whitish lateral lines; head olive-green, legs ochreous and claspers green. Both the head and body are rather densely sprinkled with dusky bristles, varying in length and slightly serrated; the longest are curved. The larvae are very sluggish in movement, and pass the day at the base of the grass stems, feeding at night." - Frohawk (1924)

3rd Instar

"The second moult occurred the middle of April, 1909. After second moult, and shortly before third, about 218 days old, it is 10.5 mm. long. Excepting being more densely clothed with hairs, which are whitish, mottled with dark brown, of various lengths, slightly curved and serrated, and pale brown spiracles, it is similar to the previous stage, being entirely green with a slightly ochreous-green head. During the day they rest head downwards at the base of the grass." - Frohawk (1924)

4th Instar

"Some moulted the third time at the beginning of May, 1909. After the third moult, and shortly before the fourth, 227 days old, it is 15.9 mm. long. The body is pale green, with a darker green medio-dorsal stripe and a sub-spiracular olive-green line, bordered below by a greenish-white line; double waved indistinct sub-dorsal lines, composed of short streaks and speckles of a dull green colour; between these lines is a pale line. The whole of the surface is freckled; the anal points are pinkish, the head and legs ochreous. In all other respects it is similar to the previous stage. They avoid sunlight and hide as before at the base of the stems. Some in this stage are ochreous, with brown markings, resembling in colour the fully grown larva." - Frohawk (1924)

5th Instar

"The fourth moult on May 21st. The process of moulting is exceptionally slow and gradual; they remain fixed for the purpose four or five days. During the day they rest in a straight position on the under surface of the basal stems of grass, and usually select those of the same colour as themselves, consequently they are then very inconspicuous. They do not eat the cast skins. After the fourth and last moult, fully grown, 240 days old, it measures 23 mm. long. The body is slug-shaped, tapering at each end. The head is bi-lobed, ochreous, slightly speckled with brown; eye spots black and mouth parts dusky; it is covered with whitish bristles of various lengths, slightly serrated, and pronged at the tips. The segmental divisions are rather indistinct, like the sub-divisions, which form five transverse wrinkles; the anal points, legs and claspers are ochreous. The ground colour is pale greenish-ochreous with an olive-black medio-dorsal longitudinal stripe, a rather indistinct sub-dorsal wavy stripe, composed of claret-coloured markings, bordered below by the pale ground colour, forming a band; then a broad irrorated band of claret-coloured markings, bounded by a darker claret-coloured band, bordering the whitish lateral band, which is divided by a fine claret-coloured line; the ventral surface is ochreous, with a series of dusky markings along each side and a fainter and finer medio-ventral line. The entire body, like the head, is covered with whitish serrated bristles with pronged points and bulbous bases; the surface is granulated. The ground colour varies in different specimens in the amount of the green tinge; some are more inclined to a greenish ground and some are ochreous; the markings also vary in extent, some being more densely scrolled and speckled than others. The larva is very sluggish in its movements, resting by day at the base of the grass stems and feeding by night. One larva that spun up on June 24th, pupated on June 27th, 1909. The larval state occupies about 240 days." - Frohawk (1924)

The pupa is formed low down in vegetation, hung upside down and attached by the cremaster. This stage lasts around 3 weeks.

"The pupa measures from 11 mm. to 12.7 mm. long, and stout in proportion. Side view: The head is slightly beaked; the meso-thorax swollen, sunken at the meta-thorax; abdomen rising in a gentle curve, extremity embedded in the larval skin, which remains firmly attached to the cremaster, which is without hooks and covers the ventral surface of the abdomen; the wings bulging and curving to the head. Dorsal view: The head somewhat square, with angulated corners forming points; base of wings angular, inner margin straight; abdomen attenuated. The ground colour is a pale creamy-drab, and ochreous-cream on the dorsal surface of the middle of the abdomen; the head and thorax in some specimens inclining to pale greenish-grey. It is more or less streaked and blotched with brown and brownish-black. The chief markings are those on the wings, forming longitudinal streaks and a bold stripe along the inner margin. The antennae and legs are strongly marked in some and plain in others; the thorax and abdomen have sub-dorsal series of dusky blotches and a spiracular and lateral band of similar markings. The eyes, thorax and abdomen are rather densely sprinkled with minute blackish knobbed bristles. Some specimens are but slightly marked and of a paler ground colour. The pupa is attached to a pad of silk, spun on a grass stem, by the larval skin; the pronged tipped hairs are securely fastened to the silk, which serve in place of cremastral hooks. The pupal state lasts about twenty-two days." - Frohawk (1924)