It is believed that it is mainly used for communication, it also supports the ventilation in the thorax and accordingly probably also plays a role in thermoregulation of the animals Mating and egg laying Mating takes place in a way that for the genus Calopteryx and is typical of an eye-catching advertising behavior precedes. The females fly over the water, always in search of suitable nesting places and fly it through the territories of males. The males who recognize the females to the reflections of the moving wings, fly towards it, once they have crossed the border area. They use a striking Schwirrflug that only in the courtship will be shown, and demonstrate the underside of its abdomen raised high. The last three segments of it are much brighter and are referred to as a "lantern" that will be presented. The male leads in this way, the female to the nesting sites ("Show flight") and circled it on the water once it has settled out. Then in turn followed by a period of hovering flight and only if the female is sitting there and so his willingness to mate signaled it comes to mating. In return, the male is on the wings of the female and begins copulation, which can last between 40 seconds and 5 minutes, the animals themselves in the "mating wheel" can rely on the vegetation. After mating, the male releases the female again and again shows this is the nesting place, the female abdomen with drooping sit for a few seconds ("post-copulatory rest") and then follows the male. The eggs are laid in the stems of aquatic plants in the water level and below, where the female can submerge up to 90 minutes. It climbs here (unlike almost all other species of dragonflies) upside down on the stem down and stabs the eggs with the egg-laying apparatus ( ovipositor ) almost vertically into the stems. During the nesting above the water surface while the female is the male defended against other males. Both sexes mate several times a day for several weeks until her death. Larval development and life of larvae The eggs, in which the embryos develop, are on average about 1.2 millimeters long and have a spindle-shaped structure with approximately 0.2 millimeters wide. At the pointed end are, as with other demoiselles also a hole structure ( Mikropylenapparat ) with four holes to enable