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Butterfly taxonomy (classification) The skippers The swallowtails The whites The hairstreaks, coppers and blues. Includes the Duke of Burgundy. The nymphalids, fritillaries and browns. Includes the Monarch.
White-letter Hairstreak - female - Thatcham - 23-May-14 [REARED]
Wingspan
25 - 35mm
Photo © Pete Eeles
White-letter Hairstreak

Satyrium w-album
sa-TI-ree-um
double you-AL-bum
Number: 61.006
B&F No.: 1558
Family:Lycaenidae (Leach, 1815)
Subfamily:Theclinae (Butler, 1869)
Tribe:Eumaeini (Doubleday, 1847)
Genus:Satyrium (Scudder, 1876)
Subgenus: 
Species:w-album (Knoch, 1782)
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  Introduction  

The White-letter Hairstreak is one of our more-elusive butterflies as it flits high in the treetops, often appearing as a dark speck against the sky. It gets its name from the letter "W" that is formed from a series of white lines found on the underside of the hindwings.

Elm is the sole foodplant and this species suffered as a result of Dutch elm disease in the 1970s and early 1980s, especially in southern sites. All species of elm were affected and there was concern that this species of butterfly might become extinct in the British Isles as a result. Surviving colonies were subsequently looked for, to obtain a better understanding of the distribution of this species. Several new colonies were found which gave new hope for the future of this butterfly. In addition, there has been a concerted effort to find disease-resistant elms that exhibit the appropriate qualities to support this butterfly (such as flowering at the right time of year since young larvae generally rely on flower buds as a food source).

This butterfly forms discrete colonies which are sometimes very small containing only a few dozen individuals. Colonies are typically focused on a small clump of trees or even an individual tree. These butterflies are not great wanderers and will reuse the same site year after year. This butterfly is found throughout England, south of a line stretching between South Lancashire in the west and South Northumberland in the east. This species is found more locally in Wales, and is not found in Scotland, Ireland or the Isle of Man.

Satyrium w-album

This species was first defined in Knoch (1782) as shown here (type locality: Leipzig, Germany).


Male
White-letter-Hairstreak-Fermyn 24 June 2011 03C2316
Male Underside
Photo © IainLeach
Female
White letter hairstreak, female, July, Hants
Female Underside
Photo © Pauline

  Phenology  

The adults emerge toward the end of June, building up to a peak in mid-July. There is one brood each year.


The chart(s) above have been correlated with the phenology plot below, taken from the UK Butterfly Monitoring Scheme. The blue line gives average counts over the full data set from 1976 to date, and the red line gives the average for the last year.


  Habitat  

This butterfly is never found far from its larval foodplant of elm, Wych Elm being preferred. Flowering elms are usually essential for successful larval development and this therefore suggests a certain maturity of tree, although there is some evidence that this species has successfully used non-flowering elms on occasion. Favourite sites are elms on the edge of deciduous woodland, but this species can also be found in more open habitat such as roadside verges if suitable elms are present.

  Larval Foodplants  

The primary larval foodplants are English Elm (Ulmus procera), Small-leaved Elm (Ulmus minor) and Wych Elm (Ulmus glabra).

  Nectar Sources  

Adults feed primarily on Honeydew / Sap (). Bramble (Rubus fruticosus), Hogweed / Angelica (Umbelliferae), Marjoram (Origanum vulgare), Privet (Ligustrum vulgare), Ragwort (Senecio jacobaea) and Thistles (Cirsium spp. and Carduus spp.) are also used.

  Imago  

The adult butterflies are best seen early in the morning or late in the afternoon, when they will come down from their treetop resting place to nectar on various flowers, Thistle, Bramble and Privet being favourites. Most of the time, however, they remain elusive as they feed on honeydew in the tree tops. Like the Black and Green Hairstreaks, the adults never settle with their wings open.

When egg-laying, the female exhibits the same behaviour of many other hairstreaks, slowly crawling along twigs of the foodplant looking for suitable places in which to deposit her eggs.


White-Letter Hairstreak - imago - Mount Orvilos, Greece - 13-Jun-09 (13)-2
Photo © Pete Eeles
13-Jun-2009
Black Hairstreak - imago - Thatcham - 17-Jun-10 (2) {REARED}
Photo © Pete Eeles
17-Jun-2010
White-letter Hairstreak - imago - Thatcham - 03-Jun-10 (1) {REARED}
Photo © Pete Eeles
03-Jun-2010
White-letter Hairstreak - imago - Thatcham - 04-Jun-10 (2) {REARED}
Photo © Pete Eeles
05-Jun-2010
White-letter Hairstreak - imago - Thatcham - 17-Jun-10 (2) {REARED}
Photo © Pete Eeles
17-Jun-2010
cloud wood 03 02.07.11 058
Photo © steveb
White-letter-Hairstreak-Nottingham 19 July 2010 03C5804-v
Photo © IainLeach
White-letter-Hairstreak-Fermyn 24 June 2011 03C3065
Photo © IainLeach
White-letter-Hairstreak-Fermyn 24 June 2011 03C2866
Photo © IainLeach
White-letter-Hairstreak-Fermyn 24 June 2011 03C2316
Photo © IainLeach
White-letter-Hairstreak-Fermyn 24 June 2011 03C2110
Photo © IainLeach
White-letter Hairstreak (f) Seaford. 15/7/2010.
Photo © badgerbob
15-Jul-2010
White-letter Hairstreak. Seaford. 30/6/2011.
Photo © badgerbob
30-Jun-2011
White letter hairstreak, female, hants
Photo © Pauline
05-Jul-2012
White letter hairstreak, female, July, Hants
Photo © Pauline
08-Jul-2012
White-letter Hairstreak (male), East Sussex (20 July 2012)
Photo © Mark Colvin
20-Jul-2012
White-letter Hairstreak female - Littlington, Sussex 8-July-2010
Photo © Neil Hulme
08-Jul-2010
White Letter Hairstreak (male) Littlington 24/6/2011.
Photo © badgerbob
24-Jun-2011
White Letter Hairstreak (female) Littlington 15/7/2010
Photo © badgerbob
15-Jul-2010
White-letter Hairstreak pair - Hadleigh Castle CP, Essex 23-June-2011
Photo © essexbuzzard
23-Jun-2011
WLH oviposting female, Cosham, 12/07/2013
Photo © Pauline
12-Jul-2013
White-letter Hairstreak male - Cosham, Surrey 5-July-2013
Photo © Neil Hulme
05-Jul-2013
White-letter Hairstreak - Female - Bedford Purlieus - 24.06.2011
Photo © PhiliB
24-Jun-2011
White-letter Hairstreak - Female - Bedford Purlieus - 26.07.2013
Photo © PhiliB
26-Jul-2013
White-letter Hairstreak - female - Thatcham - 23-May-14 [REARED]
Photo © Pete Eeles
23-May-2014
White-letter Hairstreak - male - Thatcham - 23-May-14 [REARED]
Photo © Pete Eeles
23-May-2014

  Aberrations  

Description to be completed.

Click here to see a full list of aberrations for this species.

ab. albovirgata (Tutt.Brit.Lep.1907.9.p.149.pl.1.f.4.)

The four wings on the underside present a wide white band which occupies on the hindwings the whole space comprised between the white line and the fulvous band. On the forewings it has an equal width.


White-letter Hairstreak ab albovirgata
Photo © Rosalyn
03-Jul-2010

  Ovum  

Eggs are laid singly at all heights on elm trees and are a most-curious shape - a flattened sphere that has been compared to a flying saucer, with a flattened rim surrounding a central dome. It is typically laid on the scar that separates new and old growth and is green when first laid, but soon changes to a dark brown. The fully-formed caterpillar remains in the egg until the following spring.


White-Letter Hairstreak - ovum - Unknown location - Unknown date [REARED] [Reg Fry]
Photo © Reg Fry
White-Letter Hairstreak - ovum - Thatcham - 12-Mar-10 (2) {REARED}
Photo © Pete Eeles
12-Mar-2010
White-Letter Hairstreak - ovum - Thatcham - 12-Mar-10 (1) {REARED}
Photo © Pete Eeles
12-Mar-2010
White-letter Hairstreak ovum - Stafford Castle 8-March 2012
Photo © Tony Moore
08-Mar-2012
WLH ovum
Photo © Tony Moore
13-Sep-2013
White Letter Hairstreak - Ovum - Somerset - 19/01/14
Photo © William
19-Jan-2014
White-letter Hairstreak - ovum - Thatcham - 16-Dec-13 [REARED]-3
Photo © Pete Eeles
16-Dec-2013
White-letter Hairstreak - ovum - Thatcham - 16-Dec-13 [REARED]-4
Photo © Pete Eeles
16-Dec-2013
White-letter Hairstreak - ovum - Thatcham - 16-Dec-13 [REARED]
Photo © Pete Eeles
16-Dec-2013

  Larva  

The larva emerges in the spring by eating a hole in the top of the egg and, without eating the remaining eggshell, moves to a nearby flower bud where it feeds by burrowing its head deep within the tissues. The larva changes colour as it grows, always having excellent camouflage. It continues to feed on flower buds, leaving the bud scales intact, before gradually moving to young leaf buds and eventually mature leaves. The larva changes colour to a dull purple just prior to pupation.


White-Letter Hairstreak - larva - Bathampton Down - 27-Apr-07 [Chris Iles]
Photo © Chris Iles
White-Letter Hairstreak - larva - Unknown location - Unknown date (2) [Tom Sleep]
Photo © Tom Sleep
White-letter Hairstreak larva (reared) Stafford 5-April-2011
Photo © Tony Moore
05-Apr-2011
White-letter Hairstreak - larva - Thatcham - 04-May-10 (1) {REARED}
Photo © Pete Eeles
04-May-2010
White-letter Hairstreak - larva - Thatcham - 04-May-10 (2) {REARED}
Photo © Pete Eeles
04-May-2010
White-letter Hairstreak - larva - Thatcham - 07-Apr-10 (2) {REARED}
Photo © Pete Eeles
07-Apr-2010
White-letter Hairstreak - larva - Thatcham - 09-Apr-10 (1) {REARED}
Photo © Pete Eeles
09-Apr-2010
White-letter Hairstreak - larva - Thatcham - 13-Apr-10 (1) {REARED}-2
Photo © Pete Eeles
13-Apr-2010
White-letter Hairstreak - larva - Thatcham - 17-Apr-10 (1) {REARED}
Photo © Pete Eeles
17-Apr-2010
White-letter Hairstreak - larva - Thatcham - 17-Apr-10 (2) {REARED}
Photo © Pete Eeles
17-Apr-2010
White-letter Hairstreak - larva - Thatcham - 17-Apr-10 (3) {REARED}
Photo © Pete Eeles
17-Apr-2010
White-letter Hairstreak - larva - Thatcham - 18-Apr-10 (1) {REARED}
Photo © Pete Eeles
18-Apr-2010
White-letter Hairstreak - larva - Thatcham - 18-Apr-10 (2) {REARED}
Photo © Pete Eeles
18-Apr-2010
White-letter Hairstreak - larva - Thatcham - 20-Apr-10 (1) {REARED}
Photo © Pete Eeles
20-Apr-2010
White-letter Hairstreak - larva - Thatcham - 20-Apr-10 (2) {REARED}
Photo © Pete Eeles
20-Apr-2010
White-letter Hairstreak - larva - Thatcham - 28-Apr-10 (1) {REARED}
Photo © Pete Eeles
28-Apr-2010
White-letter Hairstreak - larva - Thatcham - 28-Apr-10 (2) {REARED}
Photo © Pete Eeles
28-Apr-2010
White-letter Hairstreak - larva - Thatcham - 28-Apr-10 (3) {REARED}
Photo © Pete Eeles
28-Apr-2010
White-Letter Hairstreak - larva - Thatcham - 20-Apr-11 (1) {REARED}
Photo © Pete Eeles
White-letter Hairstreak larva reared from wild eggs 17-Mar-2014
Photo © Tony Moore
19-Mar-2014
WLH larva reared form wild eggs 17-Mar-2014
Photo © Tony Moore
17-Mar-2014
White-letter Hairstreak - larva (2nd instar) - Thatcham - 23-Mar-14 [Reared]
Photo © Pete Eeles
23-Mar-2014
White-letter Hairstreak - larva (2nd instar) - Thatcham - 26-Mar-14-6
Photo © Pete Eeles
26-Mar-2014
White-letter Hairstreak - larva (2nd instar) - Thatcham - 26-Mar-14-8
Photo © Pete Eeles
26-Mar-2014
White-letter Hairstreak - larva (2nd instar) - Thatcham - 26-Mar-14
Photo © Pete Eeles
26-Mar-2014
White-letter Hairstreak - larva (final instar) - Thatcham - 17-Apr-14 [REARED]-2
Photo © Pete Eeles
17-Apr-2014
White-letter Hairstreak - larva (final instar) - Thatcham - 17-Apr-14 [REARED]
Photo © Pete Eeles
17-Apr-2014

  Pupa  

The pupa is fastened to a leaf or stem by a silk girdle and the cremaster and is similar in colour to an elm bud. This stage lasts between 3 and 4 weeks.


White-Letter Hairstreak - pupa - Bathampton Down - 16-May-07 [Chris Iles]
Photo © Chris Iles
White-Letter Hairstreak - pupa - Saltram Estate - 13-Apr-93 [REARED] [Tom Sleep]
Photo © Tom Sleep
White-letter Hairstreak - pupa - Thatcham - 16-May-10 (1) {REARED}
Photo © Pete Eeles
16-May-2010
White-letter Hairstreak - pupa - Thatcham - 02-May-14 [REARED]-2
Photo © Pete Eeles
02-May-2014
White-letter Hairstreak - pupa - Thatcham - 02-May-14 [REARED]
Photo © Pete Eeles
02-May-2014

  Similar Species  

Black Hairstreak

Both Black Hairstreak and White-letter Hairstreak are very local species, but do fly together on rare occasions. There are two features that distinguish these species. The first is that the Black Hairstreak has a row of distinctive black dots running along the inside of the orange band on the underside of the hindwing, that is absent in the White-letter Hairstreak. The second is that the White-letter Hairstreak has a more pronounced white line on its hindwing, forming a letter "W" from which the White-letter Hairstreak gets its name. This line is less prominent in the Black Hairstreak.


Black Hairstreak (left) and White-letter Hairstreak (right)
  Videos  

Video © HaltonCouncil
White-letter hairstreak

  Sites  

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

Sites
Alexander Park, Alner's Gorse, Attenborough Nature Reserve, Baggeridge Country Park, Ballard Down, Bannerdown, Barton Hills, Beachy Head, Bentley Wood, Bishop's Wood, Bourne Woods, Bovey Valley Woodlands, Brampton Wood, Broaks Wood, Brotheridge Green, Bunny Lane - Romsey, Bunny Old Wood Nature Reserve, Chaddesley Woods, Chambers Farm Wood, Church Wood, Cloud Wood, Croes Robert Wood, Devil's Ditch, Downe Bank, Draycote Water, Earl's Hill, East Poldens Reserves, Ebbor Gorge, Eyarth Rocks, Fermyn Wood, Finemere Wood, Footscray Meadows, Forest Farm Meadows, Friday Woods, Gallow Hill, Grafton Wood, Hadleigh Country Park, Hayes Farm, Holkham Meals, Homefield Wood, Horsenden Hill, Hounslow Heath LNR, Langdon Reserve, Lathkill Dale, Launde Woods, Leftwich Meadows, Leigh Woods, Limekiln Wood, Loggerheads Country Park, Loshes Meadow, Maidenhead Thicket, Maldon Wick, Mattersey Wood, Meanwood Park, Mildenhall Woods, Monk's Wood, Narborough Reserve, Northward Hill, Peartree Common, Potteric Carr, Preston Park, Prior's Coppice, Redscar and Tunbrook Woods, Rhyd y Gaseg, Rivacre Valley, Roundhay Park, Rudge End Quarry, Stockbridge Down, Stow Maries Halt, Sydlings Copse, Thorndon Country Park, Ufton Fields, Weelsby Woods, West Middlesex Golf Club, Weston Big Wood, White Hill Reserve, Whiteley Pastures, Wigg Island, Willesley Wood, Witch Lodge Fields, Wyre Forest

  Conservation Status  

This species is in serious decline and is therefore a priority species for conservation efforts.

UK BAP StatusDistribution Trend (%)Population Trend (%)
Priority Species
Click here to access the Biodiversity Action Plan (BAP) for this species.
Increase+32Large Decrease-55

The table above shows the distribution and population trends of species regularly found in the British Isles. The distribution trend represents a comparison between data for the periods 1995-1999 and 2005-2009. The information provided is taken from the Butterfly Conservation report The State of the UK's Butterflies 2011. The UK BAP status is taken from 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 references the following publications:

ReferenceDetails
Knoch (1782) Knoch, A.W.: Beiträge zur Insektengeschichte. 1782.

  Copyright © Peter Eeles 2002-2014
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