During a survey of the “Ogres ieleja” Nature Park, a beetle species new to the Latvian fauna was recorded – the dark polypore beetle (Eustrophus dermestoides). This discovery is a significant addition to what is known about the insect world and biological diversity not only in Latvia, but across the whole Baltic region.

In July this year, certified entomologist Dmitrijs Teļnovs, invertebrate expert at the environmental solutions company Ecosoul, carried out a survey of the natural values of the Ogre valley on behalf of the Nature Conservation Agency. During the survey, in an old broadleaf forest in the river valley, the dark polypore beetle was found beneath a sulphur polypore and later identified in the laboratory.

The find confirms the ecological richness of the “Ogres ieleja” Nature Park – the area holds a large amount of deadwood, a diverse polypore flora and well-preserved old forest habitats with high humidity and deep shade. Such conditions are particularly important for rare and specialised species such as the dark polypore beetle.

“The dark polypore beetle is like a living thermometer – it shows how well natural processes are working without human interference. A find like this in Latvia is genuinely significant,” says Dmitrijs Teļnovs.

A rare find on a European scale

The dark polypore beetle is small – 4-8 mm long – with a uniformly black or dark brown body, slightly paler limbs, a small and faintly punctured head, a broad, densely punctured pronotum and moderately long, rounded elytra.

It is a mycetobiont, that is, a fungus-dwelling species whose life cycle is closely tied to particular wood-decay fungi. Adult beetles are usually observed on sulphur polypores and stalked polypores, favouring fungi that grow on oaks and willows. The population in the “Ogres ieleja” Nature Park was found in an old broadleaf forest beneath a sulphur polypore.

The dark polypore beetle occurs across Europe from the Pyrenees to the Urals, but everywhere it is scattered and rare. In the Baltic region and Fennoscandia only a few historical records have been known so far – in Finland (more than 50 years ago), in Estonia (more than 135 years ago), and recently in Russia in the vicinity of Karaļauči. The species does not occur in Sweden, and in Finland it is considered extinct. The Latvian site is currently the furthest known point in this species' European range, which gives the discovery particular scientific and nature conservation importance.

The dark polypore beetle is an indicator species that helps to identify habitats of especially high value that are worth conserving. Its presence points to the continuity of the forest ecosystem, is evidence of a natural deadwood decomposition cycle and clearly reflects the biological diversity of the habitat.
Photograph by Dmitrijs Teļnovs