Migrant Hawker

Autumn Hawker ( Aeshna mixta ), male

The Autumn Hawker ( Aeshna mixta ) is a species of dragonfly from the subordination of dragonflies ( Anisoptera ). Within her family, the noble Dragonfly ( Aeshnidae ), is one of the Autumn Hawker to the smaller representatives. Your German name refers to the seasonal late flight time out - it is the Central European occurring at the latest style of the noble dragonflies. The scientific epithet mixta means as much as " mixed ", which refers to the composite of several colors stain drawing.

Features

The Autumn Hawker reaches a wingspan of about 80 mm and a body length of 62 (females ) to 64 millimeters (male). The chest section (thorax ) of the animals is brown and has oberseits very small, yellowish Antehumeralstreifen. The thorax sides have wide green yellow page napkins. The abdomen (abdomen) of the males is black with a blue mottling; at its base, so the first widened segment, there is a yellowish- white triangle or "T". Since the blue Abdominalflecken are quite small, the males sometimes act a little " gloomy". This also helps to ensure that the blue can darken to a black violet depending on cooler ambient temperature. The abdomen of the female is furnished with small yellow and large brown spots; even with them you can discover the T-shaped to triangular sign. In addition to the brown -colored females and those can occur with so-called androchromer staining. These have a really typical for the males coloring.

The line of contact of the two complex eyes, dorsal considered relatively long Aeshna mixta at.

Dissemination

It is a European- Asian faunal element; the species is widespread, especially in central and southern Europe and North Africa. As the northernmost occurrence of southern Norway is called; in England, the South and since the mid- 20th century, the center will be populated. To the east, the area over Russia and China dates to Japan. In central Germany the fall Darner was still at the beginning of the 20th century as rare. She has since expanded her site here and now belongs locally to even the most Aeshniden. Distribution focus in the lowlands and river valleys of the south-central Europe.

Way of life

During the months of July / August to October, the very lively kind is to be found in plant -rich standing water - the Mediterranean, the emergence begins in June. Preference is given to pond with reeds or sedges in extensive siltation zones. Your flights can be quite extended, so that one also on meadows at some distance encounters this dragonfly on water. The animals make frequent rest breaks than about the brown or the hawker. Contact then sometimes almost horizontal attitude on exposed structures - similar to otherwise rather sail dragonflies and not really typical for precious dragonflies.

The males fly in search of a partner, the banks of the water body up and down. These patrols may include shore distances of over 100 meters in length. Mating takes place partly in the air and takes between 20 minutes and an hour. The pairing wheels, however, are also commonly seen in reed leaves or twigs in one to two meters in height. Immediately after copulation, the female stings the eggs primarily in floating dead plant one.

Males are already active at ambient temperatures from about 10 ° C, unless at the same time the sun shines. Female fly usually only at temperatures above 13 ° C. This is one of the Autumn Darner Dragonfly to the precious with the lowest activity threshold temperatures. With the onset of sustained period of fog or damp - cool weather in the fall ends the flight and lifetime of the adult bees.

Larval development

The eggs are laid relatively late and hibernate as such, the larvae hatch until the following year. For this reason, the Autumn Hawker also exist in ponds that dry out in winter and to be drained. Another winter is sometimes done as a nearly full-grown larva. Otherwise there, metamorphosis takes place to the imago still in the larval hatching year.

Endangering

After the fall Darner has extended its area in Central Europe in the last decades, it is not considered as in Germany according to the Red List as an endangered species, but occurs sometimes even very often. Regional and locally may be threatened stocks but quite. Since Aeshna mixta waters preferably with extensive reed beds and tall sedge vegetation, walking interventions and adverse effects of such bank structures ( for example, by high recreational use and boat traffic) at the expense of art Excessive fish population will lead to increased predation and competition for food in the larvae of the aquatic environment; especially through grass carp underwater flora is also destroyed. Have drainage measures and groundwater depletion accelerated siltation and reduced water holding period smaller surface waters result, which can prevent a successful larval development of fall - hawker.