Trident Pfeileule ( Acronicta tridens )
The trident - Pfeileule ( Acronicta tridens ), also called Dreizackeule is a butterfly (moth ) from the family of cutworms ( Noctuidae ).
The moths have a wingspan from 36 to 44 millimeters. The ground color of the forewings is gray, mostly colored dark gray and relatively uniform. Root line and tornaler line are clearly developed, as are the inner and outer transverse line. These are drawn in black, and double. In contrast, the central shadow is clearly visible only at the leading and trailing edge of the hem line is indistinct. Ring spot or blemish kidneys are clearly visible in the region of the intermediate blemish stroke. The fringes are white with narrow interneuralen strokes. The hind wings of the males are usually completely white, in some forms a black Überstäubung the veining occurs in the distal portions of the veins. In females, the hind wings are gray at the base and darker towards the outer edge. The mean transverse line and the Diskalfleck are only dimly seen, however, the hem line is drawn clearly in black. The underside of the front and hind wings is gray, the underside of the forewing is slightly darker. Both bases have a mean cross- line and a Diskalfleck, the transverse line is formed on the underside of the rear vane weak. Head and thorax are gray.
The egg is very strongly flattened and conical. The surface is covered with strong longitudinal ribs. It is bright yellow in color with a reddish-brown spot in the middle and three other, equally colored spots.
The black- gray, relatively long and slender caterpillars are relatively little hairy. The red and yellow backing strip is divided by a center line of black. She has on the fourth segment on the back of a short, black pin. The 11th segment has a black, red and yellow dotted increase. The wide, yellow-white side lines are spotted red. The head is black gray.
The pupa is reddish brown with a bristled cremaster.
The moths of alder Pfeileule ( Acronicta cuspis ), the Pfeileule ( Acronicta psi ) and the moth - Pfeileule the trident ( tridens Acronicta ) are very similar and can be distinguished only by certain genital examinations. Be cited:
- The moths of A. cuspis and A. tridens are slightly bigger on average, but the absolute magnitude range is almost the same.
- The color shades of the base color differ slightly, A. cuspis often has a bluish tinge. The root line and the line tornale are very much developed. The hind wings of the male are dark gray with relatively clear center line and Diskalfleck. For the other two species, the hind wings are white, except for the hem line ( in A. tridens ) or black dusted along the veins in A. psi.
- The forewings of A. psi is by far the most variable what the base color is concerned; this varies from white to gray monochrome dark gray. The hindwing is blackish along the distal portions of the veins and the hem line. In very dark forms, the hind wings of A. psi be as dark as that of A. cuspis, but is less dusted.
- In contrast, in A. tridens forewing less variable, less marked and usually darker than in A. psi.
- A. tridens is more common in more moist, bog -like habitats.
In contrast to the Lepidoptera caterpillars of the above type can be easily distinguished.
Geographical distribution and habitat
The trident - Pfeileule is widely used in Europe. They lack only in small areas of Southern Spain and Ostportugal, Ireland and Scotland, in West Scandinavia (Norway, with the exception of a few occurrences in southern Norway ), northern Scandinavia and northern Russia ( approximately north of 65 ° latitude). Also in southern Greece and the Greek islands it is largely absent. The species occurs outside of Europe in North-West Africa, in Asia Minor, Cyprus, the Caucasus region, Israel, northern Iran, in Siberia to the Russian Far East, northern China, Korea and Japan.
It prefers rich shrubbery forest edges, clearings, glades, forest trails in warm oak mixed forests, but also moist lowland forests. In the Alps, it rises to 1500 m above sea level.
Way of life
The trident - Pfeileule forms in Central Europe two generations a year, flying the moth from early May to late June and mid -July to late August / early September. The moths are nocturnal and come to artificial light sources as well as the bait.
The caterpillars feed on the leaves of beech (Fagus ), oak (Quercus ), Roses (Rosa), apples (Malus ), Prunus, pear (Pyrus ), flour berries ( Sorbus ), birch (Betula ), willow ( Salix), alder ( Alnus ) and ash (Fraxinus ). Ebert et al. (1997) mention hawthorn (Crataegus ) as a food plant of the caterpillars. The caterpillar pupates in the fall in a dream. The pupa overwinters.
Threats and conservation
The trident - Pfeileule is in Germany a kind of early warning. However, the situation in individual German states looks very different. In Bavaria, Brandenburg, North Rhine -Westphalia, Saxony, Saxony -Anhalt and Thuringia, the species is classified as endangered ( category 2), in Mecklenburg- Vorpommern in category 3 (endangered ). In Baden-Württemberg, however, it is missing on the Red List.
Systematics and Nomenclature
The species is of Fibiger et al. (2009) in the subgenus Triaena Hübner, 1818 featured, along with Pfeileule ( Acronicta psi ) and the alder Pfeileule ( Acronicta cuspis ). It lists no subspecies. There are at least three synonyms.