Fall maid of honor
| Fall maid of honor | ||||||||||||
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Autumn damsel ( Aeshna mixta ), adult male |
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| Systematics | ||||||||||||
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| Scientific name | ||||||||||||
| Aeshna mixta | ||||||||||||
| Latreille , 1805 |
The autumn damsel ( Aeshna mixta ) is a type of dragonfly from the suborder of the large dragonflies (Anisoptera). Within her family, the noble dragonflies (Aeshnidae), the autumn mosaic maiden is one of the smaller representatives. Its German name indicates the late flight time of the season - it is the latest species of noble dragonflies in Central Europe. The scientific epithet mixta means something like "mixed", which refers to the drawing of spots composed of several colors.
features
The autumn mosaic maiden reaches a wingspan of about 80 millimeters and a body length of 62 (females) to 64 millimeters (males). The chest section ( thorax ) of the animals is brown and has very small, yellowish ante-humeral stripes on top. The sides of the thorax have wide green-yellow side bands. The abdomen of the males is black with a bruise; at its base, i.e. the first, widened segment, there is a yellowish-white triangle or "T". Since the blue abdominal spots are quite small, the males sometimes appear a bit "gloomy". This is also due to the fact that, depending on the cooler ambient temperature, the blue can darken to a black-violet. The abdomen of the females is provided with small yellow and large brown spots; You can also see the T-shaped to triangular symbol in them. In addition to the brown-colored females, those with so-called androchromic coloring can also occur. These have a coloring that is actually typical for the males.
The line of contact between the two complex eyes is, viewed dorsally, relatively long in Aeshna mixta .
distribution
It is a European-Asian fauna element; the species is particularly widespread in Central and Southern Europe and North Africa. Southern Norway is named as the northernmost occurrence; in England the south and, since the middle of the 20th century, also the center are settled. To the east, the area extends over Russia and China to Japan. In central Germany, the autumn mosaic maiden was still considered rare at the beginning of the 20th century. In the meantime it has expanded its area here and is now even one of the most common Aeshnids locally. The main areas of distribution are in the plains and river valleys of southern Central Europe.
Way of life
In the months of July / August to October, the very lively species can be found in plant-rich standing waters - in the Mediterranean area the emergence begins as early as June. Ponds with reed belts or sedge beds in extensive silting areas are preferred. Their flights can be quite extended, so that these dragonflies can also be found in meadows at some distance from the water. The animals take more breaks than the brown or blue-green mosaic maiden . They then sometimes sit in an almost horizontal position on exposed structures - similar to otherwise more sail dragonflies and actually atypical for noble dragonflies.
The males fly up and down the banks of the water in search of a partner. These patrol flights can include stretches of shore over 100 meters in length. The mating occurs partially in the air and lasts between 20 minutes and an hour. The mating wheels can often be seen on reed leaves or twigs at a height of one to two meters. Immediately after copulation, the female pierces the eggs mainly into floating dead plant parts.
Males are already active at ambient temperatures of around 10 ° C, provided the sun is shining at the same time. Females usually only fly at temperatures above 13 ° C. This makes the autumn mosaic maiden one of the noble dragonflies with the lowest activity threshold temperatures. With the beginning of the phase of persistent fog or damp and cool weather in autumn, the flight and life time of the adults ends .
Larval development
The eggs are laid relatively late and overwinter as such, the larvae do not hatch until the following year. For this reason, the autumn mosaic maiden can also exist in ponds that fall dry or are drained in winter. Another hibernation sometimes occurs as an almost fully grown larva . Otherwise the metamorphosis to the imago takes place in the larvae hatch year.
Danger
After the Herbst-Mosaikjungfer has expanded its area in Central Europe in the last decades, it is not considered an endangered species according to the Red List in Germany , but occurs very often in places. However, stocks can be threatened regionally and locally. Since Aeshna mixta prefers waters with extensive reed and sedge vegetation, interventions and impairments of such bank structures (for example through high leisure activities and boat traffic) are at the expense of the species. Excessive fish stock leads to increased feeding pressure and food competition in the larval waters; The underwater flora is also destroyed by grass carp in particular . Drainage measures and lowering of the groundwater level result in accelerated silting up or shortened water retention times for smaller surface waters, which can prevent successful larvae development in the autumn damsel.
literature
- Heiko Bellmann: The Kosmos dragonfly guide . Franckh-Kosmos Verlags GmbH & Co., Stuttgart 2007, ISBN 978-3-440-10616-7
- Günther Peters: Europe's noble dragonflies . Die Neue Brehm-Bücherei Vol. 585, Wittenberg-Lutherstadt 1987, ISBN 3740300507
- Sternberg, Klaus & Bernd Höppner (2000): Aeshna affinis Vander Linden, 1820 - Southern mosaic maid. Pp. 82-92. in: Sternberg / Buchwald (ed.): Die Libellen Baden-Württemberg. Volume 2: Dragonflies (Anisoptera). Ulmer, Stuttgart, ISBN 3-8001-3514-0
Web links
- Aeshna mixta inthe IUCN Red List of Threatened Species 2013.2. Listed by: Dow, RA, 2010. Retrieved February 18, 2014.