The film shows the spatial distribution and the behaviour of the Mediterranean demoiselle Calopteryx haemorrhoidalis on typical reproduction waters. The great importance of suitable perches becomes obvious. These perches, e. g. single rush stems, are used by immature, hunting individuals as well as by reproductive males that are controlling territories from these sites. The latter chase all other individuals, the result being a spatial segregation between immature and reproductive specimens during the day. Typical behaviour, such as threatening, courting, copulation, and oviposition is shown in different film speeds.