Alpine bearded beetle (Rosalia alpina)
This very attractively colored beetle with a long mustache, from which its genus name is derived, can pleasantly surprise you while wandering through the mountains of the Veľká Fatra. The drawing on the roofs of the Alpine Flycatcher is very variable and we would hardly find two individuals of the same color. Based on its appearance, more than a hundred different color deviations (aberrations) have been described in the past, from individuals with pure blue bushes without spots to almost completely black bushes. The spot on the gable of the bushes is also variable. Adult beetles can currently be seen in the Veľká Fatra National Park and in its protection zone. It is a submontane to mountain species occurring mainly at an altitude of 600 to 1000 m n. They are active in the period from June to September, in the hottest part of the day. This is when they choose warm south-facing slopes and begin the mating ritual. They look for thick, fallen trunks, especially beeches, but we can also find them on other deciduous trees. Imaga (adults) lay their eggs in drying wood. The larvae are polyphagous, which means that they feed on several species of deciduous trees. In our conditions, they develop in dead, semi-dry to dry wood, mainly on old beeches and hornbeams, but the development of larvae on elm (Ulmus), hornbeam (Carpinus), linden (Tilia) and chestnut (Castanea) is also known. they often become food for woodpeckers or ants of the genus Camponotus.
Larval development lasts 2-3 years, the last larval instar pupates at the end of May just below the surface of the wood. The imago is gnawing at the excursion holes.
The species was once very abundant, classified as a technical pest of wood. Its gradual decline is mainly caused by the felling of the original stands of old beech forests. Leaving harvested beech wood in the forest during the summer also adversely affects the size of the population. The fertilized female is looking for some freshly cut or dying beech to lay eggs in the cracks in the bark. Its subsequent removal for processing leads to the destruction of significant parts of local populations of this species. But if the female chooses the trunk that will remain in the forest, the embryos have a chance to survive. However, they have a long way to go before they finally become little bugs.
Until recently, people considered them to be pests of wood, but you will surely admit that they do not harm dying or felled trees so much. Due to their attractive appearance, they are among the gems of our nature.
Text and photos: Ing. Juraj Žiak
