European regional assessment: listed as Near Threatened although this species is on the borderline between Least Concern and Near Threatened; better information is needed. This species is entirely dependent upon veteran trees as it inhabits decaying heartwood. This is a very specific habitat type which is already highly fragmented and subject to continuing significant decline. Although this species has a relatively wide distribution, its Area of Occupancy is small as it is only found in veteran trees which are scattered across the landscape at very low densities. The Area of Occupancy of this species has not been quantified, but it may not be much greater than 2,000 km². The rate of loss of veteran trees has not been quantified, but it is significant, and it may potentially exceed 20% in the next ten years (= three generations). Moreover, there is very little regeneration of suitable habitat across the species' range. Once the existing veteran trees have died, there will be no replacements in many areas. Even if efforts are made now to re-plant appropriate tree species, there may still be a 'gap' during which time there would be very little suitable habitat available. Action is urgently needed to protect and appropriately manage existing veteran trees, as well as to ensure that suitable habitat continues to be available in future.

EU 27 regional assessment: listed as Near Threatened because this species is entirely dependent upon veteran trees as it inhabits decaying heartwood. This is a very specific habitat type which is already highly fragmented and subject to continuing significant decline. Although this species has a relatively wide distribution, its Area of Occupancy is small as it is only found in veteran trees which are scattered across the landscape at very low densities. The Area of Occupancy of this species has not been quantified, but it may not be much greater than 2,000 km². The rate of loss of veteran trees has not been quantified, but it is significant, and it may potentially exceed 20% in the next ten years (= three generations). Moreover, there is very little regeneration of suitable habitat across the species' range. Once the existing veteran trees have died, there will be no replacements in many areas. Even if efforts are made now to re-plant appropriate tree species, there may still be a 'gap' during which time there would be very little suitable habitat available. Action is urgently needed to protect and appropriately manage existing veteran trees, as well as to ensure that suitable habitat continues to be available in future.

This western Palaearctic species (Laibner 2000) is known from Spain across to the east of Europe, and from Italy to Sweden (Tolasch et al. 2007). It is also found in the Caucasus. In Ukraine it occurs in the western part of the forest-steppe zone. In Britain it is only known from small areas in the south-east. It is absent from Ireland (Mendel and Clarke 1996).

It is a rare species and somewhat patchily distributed throughout its European range. Suspected to be declining, as its habitat is declining. Threatened throughout entire range (Tolasch et al. 2007).

It is widespread but not abundant in France, more localised in north (Brustel 2005). In the UK it has a very fragmented range in the south-east, with just a few isolated populations remaining (Mendel and Clarke 1996); six small sites are known plus one large one, Windsor Great Park and Forest; it has been lost from 50% of its known sites due to habitat destruction (K.N.A. Alexander pers. comm. 2009). In Ukraine it is not common and occurs very locally. In Hungary it is sporadic in the hilly and mountain regions and along the Danube River; its populations are patchy and small (O. Merkl pers. comm. 2009). In Denmark it is rare and local and it is only in Zealand and Lolland (National Environmental Research Institute 2007). In Spain the concentration of known sites is in northern Navarra (Sánchez-Ruiz et al. 2001).

This is an obligate saproxylic species. A specialist of large, hollow veteran trees. It is an old growth species - an indicator species for undamaged natural forests (Tolasch et al. 2007).

The larvae develop in black wood mould in the interior of old hollow trunks and boughs of broad-leaved trees, generally live trees; mainly in elm Ulmus, beech Fagus, willow Salix, ash Fraxinus and horse-chestnut Aesculus, very occasionally in oak Quercus (Allen 1966); may prefer white-rot over red-rot; often associated with bird nest material in Britain. The larvae overwinter and pupate in late May or early June; the life cycle is normally 3-4 years but may last up to 6 years. An individual tree can potentially sustain a population of the beetle for several decades. The larvae feed on other invertebrates in the wood mould, especially chafer larvae (Alexander 2002); the adults are active at midsummer V-VIII and are attracted to hollow trees with Osmoderma pheromones (Svensson et al. 2004); the adult is short-lived and often said to be crepuscular, attracted to lights, but males also known to swarm around midday; females attract males by pheromone (Tolasch et al. 2007).  The adult beetles occasionally feed at sap of some trees (Acer, Castaneus).

In the Czech Republic and Slovakia it lives in deciduous forests and groves, also in isolated groups of old trees (limes, willows, poplars, oaks, maples) from lowlands to foothills; frequently along water courses (Laibner 2000). In Hungary it is known from old growth forests or wood pastures with ancient trees, but the most records are from riverine willow galleries (O. Merkl pers. comm. 2009). UK sites are in the cultural landscape - historic parklands and wood pastures - and also old willows along floodplains (K.N.A. Alexander pers. comm. 2009).

This species is restricted to veteran trees, so any activities which destroy these trees (e.g. cutting down avenues) is strongly detrimental to the species. The main overall threat is likely to be degradation or loss of habitat quality, involving structural changes in the tree populations arising from changing land use – affecting age structures and tree density. Exploitation from forestry is often a key immediate issue, but equally damaging can be long-term changes towards canopy closure and loss of ancient trees as a result of non- or minimum-intervention management systems which all too often exclude grazing by large herbivores. Fragmentation and increasing isolation of beetle populations are also key factors.

In Hungary very old trees are threatened all over the country - also true of most European states - and the known localities are threatened by over-collecting and destruction of microhabitats.

Saproxylic Coleoptera tend to be popular with beetle collectors although trade is rarely an issue, the only exceptions being a few larger species of more dramatic form or colour.

Generally, the most important conservation measure to be recommended is the protection of large old trees of appropriate species, and habitat management to ensure that there is a constant or increasing supply of such veteran trees in future. The species occurs in protected areas (e.g. UK, Ukraine, Hungary).

In the UK it is a priority species under the UK Biodiversity Action Plan; also the Ancient Tree Hunt project aims to document all ancient trees across the UK and promote their protection (K.N.A. Alexander pers. comm. 2009).

This species is listed in the British Red Data Book as Endangered (Shirt 1987), Endangered in Germany and Sweden, as Vulnerable in Denmark (2005) and as Critically Endangered in the Czech Republic.