Bryodemella tuberculata (Fabricius, 1775)


Bryodemella tuberculata: Male (Lech near Forchach, September 2010) [N] Bryodemella tuberculata: Male (Lech near Forchach, September 2010) [N] Bryodemella tuberculata: Male (Lech near Forchach, September 2010) [N] Bryodemella tuberculata: Female (Lechtal near Forchach/Tyrol, September 2010) [N] Bryodemella tuberculata: Female (Lechtal near Forchach/Tyrol, September 2010) [N] Bryodemella tuberculata: Female [N] Bryodemella tuberculata: Habitat in the Bavarian Alps [N] Bryodemella tuberculata: Habitat in the Lechtal near Forchach/Tyrol, September 2010. [N] Bryodemella tuberculata: Habitat in the Lechtal near Forchach/Tyrol, September 2010. elevated place with pine succession, but still some open ground. [N]

Nutrition:
Herbs and dwarf shrubs on gravel banks as Dryas octopetala etc.

Habitat:
In Central Europe Bryodemella tuberculata colonizes only gravel banks of Alpine rivers (open areas with tamarisk, single Salix eleagnos and Salix purpurea bushes and pines at higher places). This species needs large habitats which allow survival even during extreme floods.

Life cycle:
The adults usually appear from July to September/early October. The males are elegant fliers and are patrolling in long lasting flight up and down the gravel bars in hot weather. They produce a rather soft wing buzzing.

Endangerment: threatened with extinction

Endangerment factors:
The eastern species reaches in the Austrian and Bavarian Alps valleys its western border. It is already extinct in Switzerland (formerly in the Upper Inn Valley). The vast majority of occurrences are already extinct or melted back to paltry remnants due to the immense destruction of the Alpine rivers, especially by river regulation (channelization, power generation, etc.). Further threats are gravel extractions, recreational use of the last natural remnants and afforestation after disturbance of the natural river dynamics, so that Bryodemella tuberculata might die out in Central Europe in the long term. Currently, Bryodemella tuberculata still exists in the Upper Isar (Germany) or the Upper Lech Valley in Tyrol (Austria).

Remarks:
Bryodemella tuberculata is already extinct in northern Germany. It still occurs in addition to the few alpine locations and some other, vanishing remnant populations nowadays mainly on Íland (Sweden) and particularly in easternmost Europe and parts of Asia.