Brown-angled dwarf tension

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Brown-angled dwarf tension
Brown-angled dwarf flyworm (Idaea dimidiata)

Brown-angled dwarf flyworm ( Idaea dimidiata )

Systematics
Order : Butterflies (Lepidoptera)
Family : Spanner (Geometridae)
Subfamily : Sterrhinae
Tribe : Sterrhini
Genre : Idaea
Type : Brown-angled dwarf tension
Scientific name
Idaea dimidiata
( Hufnagel , 1767)

The brown-angled dwarf spanner ( Idaea dimidiata ), also known as the black-dotted spider , is a butterfly ( moth ) from the spanner family (Geometridae). It belongs to the genus Idaea , which is rich in species in Europe and belongs to the subsericeata species group.

features

The moths reach a wingspan of 15 to 20 millimeters. The wings have a brownish-yellow, brownish-white to slightly reddish-white basic color. The drawing elements are dark gray to dark brown. The middle shadow and the two transverse lines can be incomplete or interrupted. They are marked on the forewing at the front edge by so-called Kostalflecke. In the border area there is a light wavy line, which is bordered on both sides by dark spots, especially towards the inner edge. The fore and hind wings have black discal spots, which are sometimes markedly weaker on the forewing. The seam spots are also usually clearly drawn and occasionally connected to one another by a thin line.

The coloration seems to be somewhat temperature dependent. Breeding at higher temperatures resulted in butterflies with a slightly reddish base tone. Butterflies with slightly pink wings are found mainly in Sardinia. Here, however, this trait should be inherited recessively. Populations in Sicily are lighter in color and the seam spots blend into one another.

The elongated egg is truncated at one end; the surface covered with fine dimples. It is initially whitish with brown speckles and later turns reddish in color.

The caterpillars reach a length of about 20 millimeters and have short bristles. They have transverse grooves, are pale brown in color and have a double blackish back line that converges towards the rear. On either side of the back line is a series of sloping lines, sometimes arrow-shaped. The stigmas are on a white line under which a series of black drawings can be found. The caterpillar head is gray and slightly notched.

The doll is yellowish in color with a shiny surface. The rear end is a little darker.

Similar species

Geographical distribution

The brown-angled dwarf moth occurs in the western Palearctic and in North America . The species is widespread in Western, Southern and Central Europe . In the north, the distribution area extends to southern Scandinavia and in the east to the Urals . Idaea dimidiata can be found on almost all Mediterranean islands.

Outside Europe, the species is distributed in Morocco and from northwest Turkey , the Caucasus and Transcaucasia via northern Iran to Afghanistan and Central Asia. In Cyprus , southern Turkey, and the Levant , the nominate subspecies Idaea dimidiata dimidiata is replaced by the subspecies Idaea dimidiata antitaurica , which is also found in Canada and most of the northern parts of the United States .

Habitat

The brown-angled dwarf spanner is described in Central Europe as a silvicole (forest-bound), mesophilic to hygrophilic species. It colonizes moist forests such as soft and hard wood meadows as well as moist mixed beech forests. The species was also found in creek and river valleys, at headwaters and moors. In the east of its range, the brown-angled dwarf moth lives xerophilously and often colonizes dry steppe habitats. It can be found north of the Alps from the plains to altitudes of around 700 meters, in the Alps and in southern Europe it reaches up to 1,200 meters and in Turkey and Afghanistan it rises to 2,000 meters. In cultivated land it can be found in gardens and orchards .

Phenology and way of life

The brown-angled dwarf tensioner usually forms two generations a year, which can be found from late May to late September. Under favorable conditions (southern Europe, Levant), three generations arise from May to October or new generations are formed throughout the year. In Central Europe there is usually only one generation and, in favorable years, an incomplete second. The moths are found here from late June to late August. The moths are sometimes also active during the day and are often found on artificial light sources or on bait . During the day the moths hide in hedges and bushes. If they are frightened, they usually only flee a short distance and then sit down again on leaves with outstretched wings. Moths were found sucking nectar on flowering pipe grass ( Molinia ) and thistle ( Cirsium ).

The caterpillars can be seen in September. They feed polyphagous on various herbaceous plants . Various authors report that the larvae eat dried, rotting or rotting leaves, for example from:

In captivity, the caterpillars also feed on dandelions ( Taraxacum ) and knotweed ( Polygonum ). They also eat meat. They overwinter and continue their development in May of the following year. They pupate in a loose web on the ground in June. The species acts as a K-strategist .

Systematics

The species was first scientifically described in 1767 by Johann Siegfried Hufnagel as Phalaena dimidiata . Two subspecies are currently distinguished: the nominotypical subspecies Idaea dimidiata dimidiata Hufnagel, 1767 (in the greater part of the distribution area) and Idaea dimidiata antitaurica (Wehrli, 1931). It is slightly smaller than the nominate subspecies and darker in color. It represents the nominate subspecies in southern Turkey, Cyprus, the Levant and in North America.

Danger

The species is not endangered in Germany.

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Individual evidence

  1. ↑ a b Red Lists at science4you
  2. ^ A b Arno Bergmann: The large butterflies of Central Germany. Volume 4/2: Owls. Distribution, forms and communities. Urania-Verlag, Jena 1954, DNB 450378381 .
  3. ↑ a b c d e f David J. Carter, Brian Hargreaves: Caterpillars and butterflies of Europe and their forage plants. Blackwell Wissenschaftsverlag 1987, ISBN 3-8263-8139-4
  4. ↑ a b c d e f g h i j k l m n o Axel Hausmann: The Geometrid moths of Europe, 2. Sterrhinae. In A. Hausmann (Ed.): The Geometrid Moths of Europe 2. Apollo Books, Stenstrup 2004, ISBN 87-88757-37-4
  5. ↑ Idaea belemiata in Fauna Europaea. Retrieved September 13, 2007
  6. ↑ Idaea palaestinensis in Fauna Europaea. Retrieved September 13, 2007
  7. ↑ Idaea elongaria in Fauna Europaea. Retrieved September 13, 2007
  8. ↑ Günter Ebert (Ed.): The butterflies of Baden-Württemberg Volume 8, Nachtfalter VI (Spanner (Geometridae) 1st part), Ulmer Verlag Stuttgart 2001. ISBN 3-8001-3497-7

literature

  • Günter Ebert (Ed.): The butterflies of Baden-Württemberg Volume 8, Nachtfalter VI (Spanner (Geometridae) 1st part), Ulmer Verlag Stuttgart 2001. ISBN 3-8001-3497-7
  • Walter Forster , Theodor A. Wohlfahrt : The butterflies of Central Europe. Volume 5: Spanner. (Geometridae). Franckh'sche Verlagshandlung, Stuttgart 1981, ISBN 3-440-04951-5 .
  • Axel Hausmann: The Geometrid moths of Europe, 2nd Sterrhinae. Apollo Books, Stenstrup 2004, ISBN 87-88757-37-4
  • Bernard Skinner: Color Identification Guide to Moths of the British Isles , Penguin UK 1999, ISBN 0-670-87978-9

Web links

Commons : Brown-angled Zwergspanner  - Album with pictures, videos and audio files