Beautiful Demoiselle is her name, and she is beautiful. This insect is a kind of dragonfly, widespread in Europe but recorded only three places in Hordaland. The upper part of the Sjøbøelva river has the highest abundance in the municipality. As many as 100 individuals at a time have been seen on several occasions.
The beautiful demoiselle is not alone, however; seven species of damselfly have been observed in the Sjøbøelva river/Endelausmarka, in addition to eleven different species of Libellulidae (the other main group of dragonfly). Some of these species are not found any other places in western Norway. Many groups of insects are still poorly documented in this part of the country. For an amateur entomologist the dragonflies can be a good group to start with. There are not too many species, and it is fairly easy to distinguish them from one another using binoculars.
- Greve, L.; Overvoll, O.; Sætersdal, M 1992. Vann-nymfen Calopteryx virgo i Hordaland. Fauna 45:150–156.
- Johnsen, G. H. 1997. Forekomst av «blåvingevannymfe» Calopteryx virgo ved Sjøbøelva i Os kommune. Rådgivende Biologer rapport 293.