In Bavaria, hatching begins in some years as early as the second half of May and lasts well into August. The main flight time is from the end of July to mid-August. Observations are possible until the beginning of October. Adult males typically inhabit sunny, exposed sitting areas above running water, including stalks, branches protruding over the water, stones, and sandbanks. These areas are often characterized by agitated water flowing over shallow, sandy bottoms. Males defend these sitting areas against others of the same species, though conflicts are typically brief and non-violent. Territorial boundaries are not established, and males may frequent the same stretch of river for several days. They avoid shaded areas. Areas bordered by wooded banks are usually flown around. Even after they have reached maturity, the adults sometimes move far away from their breeding waters. Males can be detected at distances of up to two kilometres from the inhabited rivers in sun-exposed hillside forests on the edge of a valley. Individuals caught there could be found along the river later. When sexually mature animals were marked, the ratio of males to females was between 16:1 (
Rezat) and 67:1 (
Aurach). This is to explain the secret behaviour of the females when laying eggs. They usually press the egg balls in the cover of dense vegetation, the eggs are laid in seconds by repeatedly dipping the end of the abdomen into the water. They then immediately disappear from the water. There are also indications that the females also visit the breeding waters separately from the males in terms of space and time. The larvae can reach relatively high densities. Up to ten larvae per square meter were found on a stream in the northern Upper Palatinate. Larvae hunt both burrowing and on the substrate surface. In addition, hide hunting is known, in which only the front part of the head capsule and the anal pyramid protrude from the substrate. The larval development usually takes three or four, possibly only two years.The hatch occurs close to the water's edge. The gender ratio in the exuvia is balanced. Hatching and flight areas do not necessarily have to be identical, exuvia can also be found in places where adult animals are only sporadically sighted. ==Etymology==