UK Butterflies - Brown Hairstreak

Wingspan
Male: 36 - 41mm
Female: 39 - 45mm

Brown Hairstreak

Thecla betulae

THECK-luh
bet-YOU-lee

Linnaeus, 1758

Ref: 1556

Superfamily:	Papilionoidea
Family:	Lycaenidae
Subfamily:	Theclinae
Genus:	Thecla
Subgenus:
Species:	betulae

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Introduction
Distribution
Annual Cycle
Habitat
Larval Foodplants
Nectar Sources

Imago
Ovum
Larva
Pupa
Similar Species
Videos

Sites
Conservation Status
Links
References

Brown Hairstreak - imago - Thatcham - 30-Jul-09 (1) {REARED}

Male

Brown Hairstreak - imago - Thatcham - 19-Aug-09 (2) {REARED}

Male Underside

Female

Female Underside

	Introduction

This is the largest hairstreak found in the British Isles. It is a local species that lives in self-contained colonies that breed in the same area year after year. This species can also prove elusive, since it spends much of its time resting and basking high up in tall shrubs and trees. The female is particularly beautiful, with forewings that contain large orange patches, and was once considered to be a separate species known as the "Golden Hairstreak".

	Distribution

This species is found in the southern half of England and Wales, and also around the Burren in Ireland.

	Annual Cycle

There is one generation each year. This is one of the latest species to emerge in the British Isles, with adults first seen on the wing in late July or early August.

	Habitat

This species lives in habitats where Blackthorn, the primary larval foodplant, is abundant, such as hedgerows and woodland.

	Larval Foodplants

The primary larval foodplant is Blackthorn (Prunus spinosa). Bullace (Prunus domestica) is also used.

	Nectar Sources

Adults feed primarily on Honeydew / Sap. Bramble (Rubus fruticosus agg.), Devil's-bit Scabious (Succisa pratensis), Hemp Agrimony (Eupatorium cannabinum), Hogweed / Angelica (Umbelliferae), Ragwort (Senecio jacobaea) and Thistles (Cirsium spp. and Carduus spp.) are also used.

	Imago

Adults emerge in the morning and males generally appear a few days before females. This is a warmth-loving butterfly, and is rarely seen on overcast days. On sunny days the adults will rest with wings open, absorbing the sun's rays on their dark brown wings which gradually close as they warm up. In flight, the adults are easily mistaken for the Gatekeeper, which flies at the same time.

The males are the more-elusive of the two sexes, congregating high on ash "master trees" that are positioned around the breeding area, where they feed on honeydew. They occasionally come down to feed on various nectar sources, such as Hemp Agrimony, probably when honeydew is scarce. When they do come down, however, they can be remarkably tame and easy to observe. Mating occurs without any discernable courtship, typically high in a tree.

Females also spend their time on the master trees until the eggs have matured and they are ready to lay. They then disperse and alternate between basking in the warm sunshine, feeding from nectar sources, and egg-laying. Egg-laying sites are typically in sheltered areas at the edges of woodland or hedgerows where younger growth that is south-facing is favoured. The female will crawl among the branches of the foodplant, feeling the branches for appropriate sites, when egg-laying.

Brown Hairstreak - imago - Noar Hill - 21-Aug-04 (2)

Photo © Pete Eeles
21-Aug-2004

Brown Hairstreak - imago - Thatcham - 23-Jul-06 (0458) [REARED]

Photo © Pete Eeles
23-Jul-2006

Brown Hairstreak - imago - Thatcham - 28-Jul-06 (0629) [REARED]

Photo © Pete Eeles
25-Jul-2006

Brown Hairstreak - imago - Thatcham - 28-Jul-06 (0630) [REARED]

Photo © Pete Eeles
30-Jul-2006

Photo © Paul

Photo © geniculata
09-Aug-2009

Photo © Pete Eeles
17-Aug-2009

Photo © Pete Eeles
19-Aug-2009

Photo © Pete Eeles
30-Jul-2009

Brown Hairstreak - imago - nr Brill - 06-Aug-04 [Dave Wilton]

Photo © Dave Wilton

Photo © Gruditch
16-Aug-2009

Photo © PhiliB
19-Aug-2009

Brown Hairstreak, Steyning, 16 August 2009

Photo © Sussex Kipper
16-Aug-2009

	Aberrations

Description to be completed

Brown Hairstreak - imago - Thatcham - 23-Jul-06 (0459) [REARED]

Photo © Pete Eeles
23-Jul-2006

Photo © geniculata

Brown Hairstreak - imago - Thatcham - 31-Jul-09 (1) {REARED}

Photo © Pete Eeles
31-Jul-2009

Brown Hairstreak - imago - Thatcham - 31-Jul-09 (2) {REARED}

Photo © Pete Eeles
31-Jul-2009

Brown Hairstreak (f) ab unclilinea 100dpi Whitecross Green Wood 080729 9161 [David Newland]

Photo © David Newland
29-Jul-2008

	Ovum

The sea urchin-shaped eggs are laid singly on the bark of the foodplant, typically at a fork in a branch that is on one- or two-year old growth that is in a sheltered area exposed to the sun. Eggs are laid at low density over large areas, but 2 or 3 eggs are found together on occasion. The larva partially develops within the egg before entering hibernation for the winter. Overwintering eggs are particularly vulnerable to hedge-trimming since they are laid on the youngest growth of the foodplant.

Brown Hairstreak - ovum - Thatcham - 17-Mar-07 (1003) [REARED]

Photo © Pete Eeles
17-Mar-2007

Brown Hairstreak - ovum - Noar Hill - 20-Jan-08 [Robin Turner]

Photo © Robin Turner

Brown Hairstreak - ovum - Unknown location - 2004 (2) [REARED] [Reg Fry]

	Larva

The larva emerges from the egg in spring by cutting a hole in the top of the egg and immediately enters a developing bud. The eggshell is not eaten and may be found some time after the larva has emerged. After the first moult, the larva will rest by day on a silk pad situated on the underside of a leaf, feeding away from its resting place at night, and returning to rest as dawn approaches. The bright green larva is extremely well-camouflaged, blending perfectly with the leaf on which it sits. The fully-fed larva leaves the foodplant prior to pupation, changing colour to a dull purple to maintain the excellent camouflage as it rummages around in leaf litter. There are 3 moults in total.

Brown Hairstreak - larva - Thatcham - 10-Jun-06 (0249) [REARED]

Brown Hairstreak - larva - Thatcham - 24-May-05 [REARED]

Brown Hairstreak - larva - Thatcham - 04-Jul-09 (1) {REARED}

Brown Hairstreak - larva - Thatcham - 04-Jul-09 (2) {REARED}

	Pupa

The pupa is formed in a crevice in the ground, amongst the leaf litter or at the base of a plant. It has been known for a pupa to be buried by ants, which find it highly attractive, in a loose cell of dry earth. It is believed that mice and shrews are responsible for eating large numbers of pupae in the wild. This stage lasts around 4 weeks.

Brown Hairstreak - pupa - Thatcham - 05-Jul-05 [REARED]

Brown Hairstreak - pupa - Thatcham - 31-May-05 [REARED]

	Similar Species

No similar species found.

	Videos

Play Video

	Sites

Click here to see the distribution of this species overlaid with specific site information. Alternatively, select one of the sites listed below.

Rating	Sites
	Alner's Gorse
	Grafton Wood, Ifield, Noar Hill, Shipton Bellinger, Whitecross Green Wood
	Chambers Farm Wood

	Carymoor Environmental Centre
Not rated	Anstey's Cove, Asham Meads, Bernwood Forest, Bernwood Meadows, East Poldens Reserves, Hatton Meadows, Langford Heathfield, Levin Down, Little Breach, Lough Bunny, Lydlinch Common, Mount Fancy Reserve, Orley Common, Otmoor RSPB Reserve, Piddington Wood, Rushbeds Wood, Somerford Common, Steyning Downs, Stoke Common Meadows, Thurlbear Quarrylands, Witch Lodge Fields

	Conservation Status

The long-term trend for this species shows a severe decline and it is therefore a priority species for conservation efforts. Unsympathetic farming practices that involve the flailing of hedgerows containing overwintering eggs are considered to be one factor in this demise.

UK BAP Status	Distribution Trend	Population Trend
Priority Species Click here to access the Biodiversity Action Plan (BAP) for this species.		Insufficient Data

From The State of Butterflies in Britain and Ireland and the UK Biodiversity Action Plan (UK BAP) (2007 review).

	Links

The following links provide additional information on this butterfly.

	References

The species description provided here has been derived from the author's own observations and the information contained in the following works:

A Natural History of British Butterflies, by F.W.Frohawk.
British and Irish Butterflies, by Adrian M. Riley
South's British Butterflies, by T.G.Howarth (which is based extensively on the classic work, "The Butterflies of the British Isles", by Richard South).
The Butterflies of Britain and Ireland, by Jeremy Thomas and Richard Lewington.
The Millennium Atlas of Butterflies in Britain and Ireland, by Jim Asher, Martin Warren, Richard Fox, Paul Harding, Gail Jeffcoate, Stephen Jeffcoate.
The Moths and Butterflies of Great Britain and Ireland Volume 7 (1) Hesperiidae to Nymphalidae (the Butterflies), by A. Maitland Emmet and John Heath (editors).
The State of Butterflies in Britain and Ireland, Richard Fox, Jim Asher, Tom Brereton, David Roy and Martin Warren.