Elm hairstreak

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Elm hairstreak
Elm hairstreak (♂)

Elm hairstreak (♂)

Systematics
Class : Insects (Insecta)
Order : Butterflies (Lepidoptera)
Family : Bluebirds (Lycaenidae)
Subfamily : Hairstreak (Theclinae)
Genre : Satyrium
Type : Elm hairstreak
Scientific name
Satyrium w album
( Knoch , 1782)

The Elm Hairstreak ( Satyrium w-album , Syn. : Strymonidia w-album ) is a butterfly ( butterfly ) from the family of Gossamer (Lycaenidae).

features

butterfly

The moths have a wingspan of 30 to 40 millimeters. Their wings are dark gray-brown on top with a faint orange spot in the anal corner . On the gray-brown underside of the wing there is a white line in the post-disk region , which takes the form of a "W", as well as an orange submarginal band that is limited to the hind wing and tapering upwards. In the disk and basal region there are no points or marks, only a faint, light gray scale. The Elm Hairstreak can be confused with other Hairstreak butterflies , but the differences are clear (especially the "W") and allow photographic evidence.

Caterpillar

The caterpillars have a pale green body. Diagonal stripes in light pink and dark green stripes on the back are characteristic of the species.

habitat

Elm hairstreak egg
Elm hairstreak egg on an elm

The elm hairstreak is not tied to a specific habitat type, but it is bound to the presence of elms capable of flowering . According to the natural distribution of the three elm species native to Central Europe, mountain elm ( Ulmus glabra ), white elm ( Ulmus laevis ) and field elm ( Ulmus minor ), the elm hairstreak is found in alluvial forests of plains and valleys (e.g. in the Upper Rhine Plain ), in ravine forests ( e.g. on the eaves of the Swabian Alb ), as well as in different types of deciduous (mixed) forests. In many places, Satyrium w-album also benefits from elm plantings in human settlement areas: in the middle of cities (elm avenues, parks, front gardens) as well as along streets or even highways, populations of the elm hairstreak can be found. Occasionally single standing elms are also used in open fields. Overall, Satyrium w-album prefers locations that are sheltered from the wind (forest coats, embankments, hedges, parks or the like).

Due to the dying of the Dutch elm , some Green Offices only plant special elm breeds, mostly crosses with Asian elm species, which are resistant to the infestation of the tube fungus Ophiostoma novo-ulmi . The extent to which these newer breeds are also used by the elm hairstreak has not yet been investigated.

Way of life

Elm hairstreak lead a very inconspicuous existence in the crown area of ​​trees. It is rather rare to see butterflies in the herb layer while sucking on various flowering plants. Because of this hidden way of life, the species is often overlooked. For its development, the elm hairstreak depends on the presence of elms (capable of flowering). Females usually lay their eggs at the base of buds, both flower and leaf buds. End buds of main and side branches are preferred, but eggs can also be found on the branches, i.e. the transition points to the fresh shoots. Based on the typical egg shape, which is reminiscent of a dark gray bowl with a white rim, the species can be detected much more effectively in winter than by looking for butterflies at flight time.

The elm hairstreak overwinters in the egg stage, the caterpillars hatch when the flower buds break in spring and feed first on the fresh flower shoots, then later on the leaves. According to Asher (2001) and Thust (2006), caterpillars were also found on non-flowering elms. There is still a need for research here, as the caterpillars usually hatch in March, sometimes as early as the end of February, and so would have to do without food until the leaves emerge in April / May.

All three elm species native to Central Europe are used as host trees for the caterpillars: Sycamore elm ( Ulmus glabra ), field elm ( Ulmus minor ) and white elm ( Ulmus laevis ). In England, the English elm is also used ( Ulmus procera ). It is still unclear to what extent the purge buckthorn ( Rhamnus cathartica ) can be used as a host plant.

Much less often, elm cultivated forms are accepted by the females for laying eggs, some of the elm cultivations are apparently avoided entirely. Since a wide range of European, American and Asian elm species are used in the breeding of resistant elms, which are often referred to as "resista" elms, such as Ulmus pumila , Ulmus japonica , Ulmus americana and Ulmus crassifolia , the respective parent shares can be in the Hardly address the outdoors properly. Investigations that look into the question of which cultivated forms are deposited and whether the caterpillars can develop successfully have not yet been carried out.

Flight time

Satyrium w-album is one -brood , that is, it produces only one generation that flies from mid-June to late July / August.

distribution

Worldwide

Satyrium w-album is widespread from northern Spain to Japan . In the north, the species occurs as far as northern England and southern Fennoscandinavia , while Italy , Turkey and Kazakhstan are safely populated to the south . The species is absent in Ireland and Portugal .

Germany

The species occurs only locally in the north German lowlands and is very rare to quite rare there. There are gaps in distribution particularly in north-western Lower Saxony and western Schleswig-Holstein . The species becomes more common towards the south, the main areas of distribution are in southern Germany (the Palatinate , Baden-Württemberg , Bavaria , Thuringia , Saxony ) and apparently also in Saxony-Anhalt . A network of populations takes place regionally, especially through continuous planting of elms on motorways and federal highways (e.g. federal motorway 81 south of Stuttgart ). Due to the hidden way of life and the sometimes unusual habitats - motorway embankments and urban settlement areas are neglected by butterfly enthusiasts - the species is certainly much more common regionally than previously assumed. Even in less populated parts of northern Germany, local occurrences that have not yet been discovered can be assumed.

swell

Individual evidence

  1. ↑ Elizabeth Balmer: Butterflies: Recognize and Determine. Parragon Books Ltd., 2007, ISBN 9781407512037 , p. 75
  2. ↑ Lepidopterists working group: Butterflies and their habitats , Volume 1, Swiss Confederation for Nature Conservation, 1994, ISBN 3-85587-402-6
  3. ↑ Gabriel Hermann: Looking for butterflies in winter. Zipfelfalter, Schillerfalter und Eisvögel / Searching for Butterflies in Winter. Hairstreaks, Purple Emperors, Poplar Admiral & White Admirals , Books on Demand, 2007, ISBN 978-3-8334-9643-1

literature

General literature

  • Tom Tolman, Richard Lewington: The butterflies of Europe and Northwest Africa . Franckh-Kosmos, Stuttgart 1998, ISBN 3-440-07573-7 .
  • Hans-Josef Weidemann: Butterflies: observe, determine . Naturbuch-Verlag, Augsburg 1995, ISBN 3-89440-115-X .
  • Josef Settele, Roland Steiner, Rolf Reinhard, Reinhart Feldmann: Ulmer Naturführer: Butterflies. The butterflies of Germany . 1st edition. Ulmer, Stuttgart 2005, ISBN 3-8001-4167-1 .
  • Frits A. Bink: Ecological Atlas van de Dagvlinders van Noordwest-Europa , Schuyt & Co 1992, ISBN 90-6097-318-6

Country and regional faunas

  • Ulrich Lobenstein: The butterfly fauna of central Lower Saxony , Naturschutzbund Deutschland e. V., 2003, ISBN 3-925815-27-9
  • Detlef Kolligs: Butterflies of Schleswig-Holstein. Atlas der Tagfalter, Dickkopffalter und Widderchen , Wachholtz Verlag, 2003, ISBN 3-529-07330-X
  • Rolf Reinhardt, Heinz Sbieschne, J. Settele, U. Fischer & G. Fiedler: Butterflies of Saxony. in Contributions to the insect fauna of Saxony , Volume 6, Verlag Bernhard Klausnitzer, 2007, ISSN  0232-5535
  • Tom Schulte, Oliver Eller, Manfred Niehuis & Erwin Rennwald: The butterflies of the Palatinate in fauna and flora in Rhineland-Palatinate , Volume 1, Supplement 36, GNOR, 2007
  • Rudolf Thust, Gerd Kuna & Rolf-Peter Rommel: The butterfly fauna of Thuringia. Status from 1991 to 2002. Development tendencies and protection of habitats , Naurschutzreport 23, Thuringian State Institute for Environment and Geology, 2006, ISBN 978-3-9807669-2-0
  • Butterflies. 2. Special part: Satyridae, Libytheidae, Lycaenidae, Hesperiidae . In: Günter Ebert, Erwin Rennwald (eds.): The butterflies of Baden-Württemberg . 1st edition. tape 2 . Ulmer, Stuttgart (Hohenheim) 1991, ISBN 3-8001-3459-4 .
  • Ottokar Kudrna (Ed.): The Distribution Atlas of European Butterflies . 1st edition. Apollo Books, Stenstrup 2002, ISBN 87-88757-56-0 (English).
  • Lepidopterists working group: Butterflies and their habitats , Volume 1. Swiss Confederation for Nature Conservation, 1994. ISBN 3-85587-402-6
  • Michael Stoltze: Danske dagsommerfugle , Gyldendal 1996
  • HJ Henriksen, IB Kreutzer: The Butterflies of Scandinavia in Nature , Scandinavisk Bogforlag, 1982
  • Peter Huemer: Die Tagfalter Südtirols , Folioverlag, 2004, ISBN 3-85256-280-5
  • Jim Asher et al .: The Millennium Atlas of Butterflies in Britain and Ireland , OUP 2001
  • Dirk Maes, Hans Van Dyck: Dagvlinders in Vlaanderen. Ecologie, verspreiding en behoud , Stichting Leefmilieu, 1999
  • RW Akkermans, RAJ Pahlplatz, K. Veling: Dagvlinders in Limburg. Verspreiding en ecologie 1990-1999 Natuurhistorisch Genootschap in Limburg, De Vlinderstichting, 2001
  • Tristan Lafranchis: Les Papillons de jour de France, Belgique et Luxembourg et leurs chenilles , Collection Parthénope, 2000
  • Elizabeth Balmer: Butterflies: Recognizing and Identifying. Parragon Books Ltd., Cologne 2007 ISBN 978-1407512037

Special literature

  • M. Davies: The White-letter Hairstreak butterfly , Butterfly Conservation, Colchester, 1992
  • Gabriel Hermann: Habitat binding, endangerment and protection of the elm hairstreak in Baden-Württemberg with comments on the distribution , Jh. Ges. Naturkunde. Württemberg 150: 223-236, 1994
  • Gabriel Hermann: Butterflies search in winter. Zipfelfalter, Schillerfalter und Eisvögel / Searching for Butterflies in Winter. Hairstreaks, Purple Emperors, Poplar Admiral & White Admirals , Books on Demand, 2007, ISBN 978-3-8334-9643-1

Web links

Commons : Satyrium w-album  - collection of pictures, videos and audio files