Gray larch moth
| Gray larch moth | ||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
Caterpillar on a larch |
||||||||||||
| Systematics | ||||||||||||
|
||||||||||||
| Scientific name | ||||||||||||
| Zeiraphera griseana | ||||||||||||
| ( Huebner , 1799) |
The gray larch moth ( Zeiraphera griseana , Syn . : Zeiraphera diniana ) belongs to the family of moths . It is one of the forest pests that occurs at all ages of the spruce . But particularly heavy damage he causes in the spread in the Alps European larch out and go into mountain pine larch forest on the stone pine on which he also damaged heavily.
features
Imago
The gray larch moth has long, narrow forewings, which are usually marbled in light gray, light and dark brown. However, color variants are occasionally observed that have lighter to almost white forewings.
The back wings of the gray larch moth are wider than the front wings. Their color is a brown-gray; the wing tips are rounded to a point. On both pairs of wings, which have a wingspan of 18 to 20 millimeters, the winder has a pale gray fringe that is only missing on the front wing edge.
Caterpillar and pupa
The caterpillars of the gray larch moth are initially black. Your body color develops with increasing age to a dirty green, which is interrupted by dark green vertical stripes. The legs of the caterpillars, however, remain black during this development process. Shortly before pupation, the caterpillars take on a darker color again, with the previously green areas changing from brown to black. Shortly before pupation, the caterpillars have reached a length of 15 to 19 millimeters.
The pupa is about eight millimeters long and brown to red-brown in color.
Synonyms
- Zeiraphera diniana Guenée , 1845
distribution
In addition to northern Siberia, the main distribution area of the gray larch moth is in the Alps . It can be found there mainly at altitudes between 1600 m and 2100 m . Find reports are also available at altitudes above 500 m . There have been reports of feeding damage from the Pyrenees , England , Japan and Alaska . Very different trees are attacked. In addition to the European larch, Scots pine and spruce ( Piceus abies ) are also attacked.
Way of life
The crepuscular moths can be observed from July to September. During the day, the moths stay in the treetops with their wings folded like a roof, which is typical for moths.
ecology
Together with the Swiss stone pine , the European larch forms the Swiss stone pine -larch forest, the typical forest type of the upper tree line in extreme high mountain areas. However, there are also numerous mountain forests made up of pure larch stands. They are mainly located at the foot of the mountainside and on easily accessible slopes exposed to radiation. This current distribution picture of pure larch stands goes back to a large extent to the centuries-long influence of the mountain forests by humans. Without human intervention, the more shade-tolerant stone pine would have gradually displaced the light-hungry larch via the natural forest succession. However, where mountain areas offered themselves for pasture use, humans have deliberately cut out the stone pines and spruces. In this way, light-flooded forests were created, which, similar to the oak forests of the lowlands used for acorn fattening , are suitable for pasture farming.
The alpine pasture economy is only of secondary importance today; This means that the Swiss stone pine would have to regain a larger proportion of the tree population in the mountain forest through natural forest succession. In fact, in many regions, Swiss stone pines now form a second layer of trees under the light canopy of the larches. Investigations by Friedrich-Karl Holtmeier show, however, that a new ecosystem of a previously non-existent stability has emerged, which prevents the Swiss stone pine from dominating. This is mainly due to the influence of the gray larch moth. The gray larch moth shows a mass multiplication at several year intervals in which the larches are eaten bare. If larches are no longer available to them, the larch moth caterpillars switch to the Swiss stone pine population and also destroy its needles. While larches usually do not die off when they are attacked by larch buds, Swiss stone pines suffer very long-term from this attack. Weakened stone pines are then susceptible to attack by other pests such as the common pine weevil , the Swiss stone pine wool aphid or the bark beetle , and then die or develop into stunted trees.
swell
Individual evidence
- ^ Zeiraphera griseana (Hübner 1799). Fauna Europaea, Version 1.3, April 19, 2007 , accessed on January 10, 2008 .
literature
- Friedrich-Karl Holtmeier: Animal in the landscape - influence and ecological significance. Ulmer Verlag, Stuttgart 2002, ISBN 3-8001-2783-0 .
Web links
- Zeiraphera diniana larch bud moth ( Memento from August 8, 2008 in the Internet Archive )