Apterona helicoidella
Snail -shaped protective casing of the shell - bag carrier ( Apterona helicoidella ) parth.
The shell - bag carrier ( Apterona helicoidella ) is a butterfly of the family of the Real Sackträger ( Psychidae ), the north of the Alps in a parthenogenetic form. Than Apterona helicoidella parth is called, occurs and is used to focus below.
Features
The small, gray, flight-capable males occur in the existing one in southern Europe bisexual form, however, there is Apterona helicoidella parth. all-female individuals who have a made -like shape. They lack legs, feelers, eyes and mouthparts. They are gray in color yellow, have brownish breast shields, single on the abdomen whitish hairs that are about five millimeters long and show a slightly hunched posture. The caterpillars have a yellowish color. The head is black -brown with a yellowish drawing. Also, the light split shields are colored otherwise black brown. Each caterpillar spins itself into a snail- shaped burrow, which is formed on the outside mainly of earth and sand grains and has the up to two and a half spiral turns. The outer diameter of the turns is an average of two millimeters and tapers towards the upper end to a point. The entire housing has a diameter of approximately five millimeters. Depending on the color of the background and different colored materials are used, so the color can vary from light gray to reddish brown.
Distribution and occurrence
The parthenogenetic form of the shell - bag carrier is widely used in Europe, ranging from Portugal through most of Central Europe, including the Alpine region, the Urals, as well as on the Balkan Peninsula and Turkey. The species was introduced from Europe on wood transporting ships to America. With regard to the incidence in the Asian region, there is still a need for clarification. You lack in higher altitudes of the mountains. The animals are mostly found in warm or hot regions, as well as on heat islands with sheltered, south-facing rocks.
Way of life
The caterpillars have a one-year development period. The females emerge in June or July. The parthenogenetic animals found in Baden- Württemberg, among others, in the catchment area of the rivers Rhine, Main, Neckar and Danube, but also along the highways. A wider spread of the species is possible by procrastination. Occupied with living caterpillars sacks on Schwemmholzästen were observed floating in rivers, as well as in avalanches, so that despite the inability to fly quite new areas can also be developed. Furthermore, a transport of the bags in the plumage of birds or the fur of animals is known. However, the kind so some thousand pieces on a railway bridge in Sinsheim or in the middle of Berlin was even within cities in some very small areas, but there quite numerous, have been found. The same Verpuppungsplätze be chosen again and again, which is probably due to attractive micro-climatic conditions. Throughout the caterpillar stage, the caterpillar remains in their original cases and pupate there, too. Immediately after hatching it comes to increase and the durability of the parthenogenetic female is often only a few hours. The caterpillars feed on polyphagous of many different plants, one of which is mentioned here only a selection:
- Spring cinquefoil ( Potentilla neumanniana )
- Herons (Erodium cicutarium )
- Gamanderarten ( Teucrium )
- Mugwort (Artemisia vulgaris),
- Yellow Rockrose ( Helianthemum nummularium )
- Mountain alyssum ( Alyssum montanum )
And others. The larval case of animals is preferred pieced on rocks, walls, road barriers and strains. In foliage -free seasons but it can be found attached in some large number of branches and twigs.
Endangering
The species is detected in Germany only in some states, there but usually numerous, so that it is classified in the Red List of Threatened Species as not at risk.