UK Butterflies

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Green Hairstreak

Callophrys rubi

KA-loh-friss ROO-by

Wingspan
27 - 34 mm

Checklist Number
61.005

Green Hairstreak

Callophrys rubi

KA-loh-friss ROO-by

Wingspan
27 - 34 mm

Checklist Number
61.005


This butterfly is the most widespread of our hairstreaks. However, it is also a local species, forming distinct colonies which can be as small as a few dozen individuals, although other colonies can be much larger. Both sexes always settle with their wings closed, the brown uppersides only ever being seen in flight. The undersides, by contrast, provide the illusion of being green, an effect produced by the diffraction of light on a lattice-like structure found within the wing scales, which provides excellent camouflage as the butterfly rests on a favourite perch, such as a Hawthorn branch. This butterfly will also regulate its body temperature by tilting its wings appropriately to catch the sun's rays. This butterfly is found throughout the British Isles - partly due to the wide variety of foodplants it uses, and the wide range of habitats it frequents. However, it is absent from the Isle of Man, Outer Hebrides, Orkney and Shetland.

This species was first defined in Linnaeus (1758) as shown here (type locality: Sweden).

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 butterfly can be found in a wide variety of habitats, including hillsides, moorland, chalk downland, heathland, railway embankments and valley bottoms. A common feature of all these habitats is the presence of scrubby plants and hedgerows.

This species has the widest range of foodplants of any British species, which includes Bilberry, Bird's-foot Trefoil, Broom, Common Rock-rose, Dogwood, Bramble and Gorse.

Both distribution and population trends show a decline and the conservation status of this butterfly is kept under review as a result.

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
Decrease -30Decrease -41Decrease -14Decrease -34

There is one brood each year, the butterfly typically being seen from mid-April to the end of June, depending on location.

The male of this species is territorial and will have favourite perching sites that it uses to wait for passing females, but will dart out to investigate any passing object. The perches may be on standalone shrubs or part of a hedge and are often reused by different males should the original occupants wander too far. The female, on the other hand, spends most of her time away from the male territories, searching out nectar sources and foodplants on which to lay her eggs.

Adults feed primarily on Bluebell (Hyacinthoides non-scripta), Common Bird's-foot-trefoil (Lotus corniculatus), Common Rock-rose (Helianthemum nummularium), Cowslip (Primula veris), Daisy (Bellis perennis), dandelions (Taraxacum spp.), Gorse (Ulex europeaus), hawthorns (Crataegus spp.), Holly (Ilex spp.), Horseshoe Vetch (Hippocrepis comosa), Wild Privet (Ligustrum vulgare) and Wild Strawberry (Fragaria vesca).


Eggs are laid singly on the foodplant and are a very pale green when first laid, but darken after a few days. Eggs are typically laid on the tenderest shoots or on flower buds. Eggs hatch after a week or two.

"The eggs are laid singly on a variety of plants — either on the young terminal shoots or flower-buds ... On June 22nd, 1902, a female C. rubi was seen to deposit a single egg on the unexpanded flower bud of rock rose (Helianthemum vulgare). This egg hatched on June 30th, remaining eight days in the egg state ... The egg is 0.65 mm. in diameter, of a compressed globular form, the micropyle sunken; it is covered with raised reticulations (very similar to the eggs of the Lycaenidae), which are smallest and form a pitted surface over the micropyle and gradually increase in size, becoming largest on the side, where they form a fine but irregular pattern, being studded with prominent knobs, each connected by less elevated ridges, numbering from five to seven but usually six; these as well as the knobs resemble white frosted glass; the true surface of the egg is granular and of a clear green colour, which remains unchanged for the first four days; on the fifth day it gradually becomes paler and greyer." - Frohawk (1924)


Like the larvae of other Lycaenids, the larva is shaped like a woodlouse. On hatching, the new larva often bores into the tender buds to feed, whereas later instars feed on young leaves and shoots, avoiding more matures leaves altogether. The larvae are cannibalistic after their first moult.

The primary larval foodplants are Alder Buckthorn (Frangula alnus), Bilberry (Vaccinium myrtillus), brambles (Rubus spp.), Broom (Cytisus scoparius), Common Bird's-foot-trefoil (Lotus corniculatus), Common Rock-rose (Helianthemum nummularium), Cross-leaved Heath (Erica tetralix), Dogwood (Cornus sanguinea), Dyer's Greenweed (Genista tinctoria) and Gorse (Ulex europeaus).

1st Instar

"The young larva directly after emergence measures 0.94. mm. long; it is rather stout in proportion, with the segmental divisions deeply cut. There is a medio-dorsal longitudinal furrow; the side sloping and concave; a swollen lateral ridge; numerous long hairs run in longitudinal rows down the body, chiefly situated in pairs on each segment; the first dorsal pair bordering on the furrow are very long with tubercular bases; close to and anterior to these is a smaller one, and between these and the sub-dorsal pair is a lenticle, and a cone-shaped tubercle, both olive-coloured; below the spiracle are four hairs forming a quadrangle, projecting laterally; the sub-dorsal hairs curve backwards; all the hairs are greyish and finely serrated with olive-coloured bulbous bases. On the first segment is a large shining olive-brown dorsal disc and a smaller one on the anal segment. The head is also olive-brown and shining; this and the discs are beset with whitish hairs. On the ventral surface, including the claspers, are simple white hairs. The whole surface is finely granular and studded with tiny black points on a pale olive-yellow ground colour. They feed on the tender central stems of the younger growth of broom, eating out small holes. The larva described in this article were fed entirely on broom, upon which the eggs were laid. Before the first moult it measures 1.7 mm. long; the ground colour is milky-white striped longitudinally with chocolate-brown, comprising a medio-dorsal double stripe, a zigzag spiracular stripe and a fine sub-spiracular line; the lateral ridge forms a white line continuous round both the first and last segments. Several moulted for the first time at the end of July. They remain in the first stage about ten days." - Frohawk (1924)

2nd Instar

"Three days after first moult it measures 4.20 mm. long. The segments are strongly humped dorsally, with a medio-dorsal furrow; the side is concave and there is a dilated lateral ridge. The surface of the body is covered with a minutely reticulated network pattern, and rather densely clothed (especially on the dorsal surface) with sharply pointed finely serrated dusky spines of various lengths; the dorsal discs are dusky-olive colour. At first the colouring resembles that previous to moulting, being creamy-white striped with chocolate-brown; the white gradually changes to light green and the brown to olive; the lateral ridge is greenish-white, bordered on either side by an olive stripe; the ventral surface is green, the head shining black. They feed almost entirely on the tender green stems. After the first moult they are cannibals, greedily devouring the younger individuals, especially while the latter are at rest and fixed for moulting; several were eaten by the freshly moulted ones. After moulting the larva partly eats its cast skin." - Frohawk (1924)

3rd Instar

"The second moult occurred on July 5th, 1910. The second stage lasting seven days. Before third moult it measures 8 mm. long. The ground colour is pure green; the greenish-white lateral line and sub-dorsal markings of the previous stage are bright greenish-yellow and the darker markings and stripes are dark green; in other respects it is similar to the last stage. The head is intensely black and shining. The first meal after moulting consists of its cast skin. They still feed upon the stems of broom, and usually a single meal lasts a long time, often for two hours without ceasing." - Frohawk (1924)

4th Instar

"The third moult on July 13th, 1910, the third stage lasting eight days. After the third and last moult, fully grown, it measures 15.9 mm. long when extended crawling. The head is shining ochreous-brown, with a pearl-white band above the mouth and dark eye-spots. The head is hidden while at rest and usually when feeding, being withdrawn into the first segment, which is compressed dorsally and has a central dorsal pale ochreous shield on which are placed some minute lenticles. The segments are strongly humped dorsally, with a medio-dorsal longitudinal furrow; the last three segments slope dorsally and are rounded laterally like the first; the sides are sloping and concave, the lateral ridge dilated. The colour is a brilliant pure green, with a series of sub-dorsal oblique citrine-yellow markings commencing on the third segment, and a lateral line of the same colour. The legs are pale ochreous, feet of claspers whitish. It is rather densely covered with brown spinous hairs of various lengths; many of the smaller ones are serrated. On the tenth segment is a small inconspicuous transverse dorsal gland, smaller but apparently similar to that of the Lycaenidae larvae. They still retain their cannibalistic habits and will attack each other when fully grown. When ready for pupation the larva roams about in search of a suitable recess for the purpose. In captivity they pupated among the litter on the ground, and in some instances were hidden between the stems and leaves of the broom on which they fed. In a natural state they undoubtedly pupate on the ground among moss or other suitable cover." - Frohawk (1924)

Like many other Lycaenids, this species benefits from an association with ants that provide it a level of protection and this association extends to the pupal stage. Pupae have been found in the wild covered in particles of soil, believed to have been put there by ants that are attracted to the pupa. Pupae have also been found deep inside ant nests. It has also been suggested that the pupa is formed at the base of plants among ground litter, occasionally attached to a dead leaf by a silken girdle. However, there appears to be little evidence that this is normal behaviour in the wild.

The Green Hairstreak hibernates as a pupa, which distinguishes it from all other hairstreaks found in the British Isles, which all hibernate as eggs.

An interesting characteristic of the pupa of this species, in common with other Lycaenids, is that the pupa is able to make a sound that is attractive to ants, a phenomenon first discovered in 1774. The noises produced by the pupa when it is disturbed are exceptionally loud and audible to the human ear.

"The pupa is not fixed, but merely loosely spun over with a few silken threads. The pupa measures from 8 mm. to 9.5 mm. long. It is stout, rounded and dumpy in form. Lateral view: The head is slightly angular in front, being somewhat truncated below; thorax rounded, slightly sunken at the waist; abdomen swollen, rounded and curved to the blunt round anal extremity, which is provided with a few minute anchor-shaped cremastral hooks; the ventral outline is almost straight. Dorsal view: Head rounded; sides of thorax, very slightly angular; abdomen bulging across the middle, then tapering off to anal segment, which is rounded and without any cremastral projections. The whole of the dorsal surface of the head, thorax and abdomen is densely clothed with finely serrated spines of a dark brown colour rising from shining wart-like bases. The wings and limbs are without spines. The entire surface is covered with raised reticulations, and along the spiracular region are numerous minute lenticles, some exceedingly small. The spiracles are olive-ochreous, rather large and prominent. The division between the fifth and sixth segments is deeply incised over the dorsal area, reaching to the spiracle. The ground colour is amber-brown, checkered and speckled with black, the most conspicuous forming transverse markings on the abdomen. Some specimens are much more heavily marked than others, giving them a very dark appearance. The pupal state occupies about ten months, that is from about the middle of July to the middle of the following May." - Frohawk (1924)