Class: Insects
Size: 10 to 28mm
Weight: Variable
Age: 3 to 12 years
Appearance: Brown-black, grey-white hairs
Food: Sapwood (larvae)
Distribution: Worldwide
Original location: Unknown
Habitat: Forest, obstructed wood outdoors
Natural enemies: Woodpecker
Threatened with extinction: No

• The house longhorn beetle is widespread, from North Africa to Europe and far into Asia. The natural habitat of the beetle is the forest, where it lays its eggs in dead undergrowth.
• As a wood pest, the longhorned beetle prefers to attack coniferous wood of spruce, pine, larch and Douglas fir. The larvae concentrate on the sapwood. Furniture or doors on the lower floors of the house are rarely infested. The beetle often colonises obstructed wood outdoors, such as trusses, poles and posts. Even the upper part of harbour pilings installed in fresh or sea water can be infested.
• The optimal wood moisture content for house longhorn beetle larvae is 10% to 30%, the lower limit for their development is 8% to 10%. Relatively fresh installed wood is more susceptible than old dry wood, as it still contains a lot of scent (oils and resins) and attracts the female beetle when looking for a suitable place to lay eggs. But even with old wood, damage by the beetles has to be expected. The larvae then compensate for the low-quality sapwood by taking in more food, which accelerates the destruction of the wood.
• House longhorn beetle males select suitable wood based on the specific scent of the coniferous wood and then attract the females with their sexual scent. Two to three days after mating, the female with the long and flexible ovipositor lays about 300 eggs in suitable cracks and crevices of pines, spruces, larches or Douglas firs. When the larvae hatch after 2 to 3 weeks, they immediately eat into the sapwood. During their life of several years, the larvae can consume a lot of wood. After pupation, the hatched beetles leave the wood from June to August through an oval exit hole approx. 3×7 mm and look for a sexual partner for the next reproductive cycle.
• In order to assess the infestation of hardwood longhorn beetles, it is usually necessary to break open the infested wood to see the extent of the destruction. In contrast to the woodworm (Anobium punctatum), no traces of wood flour are visible externally. The larvae close the feeding tunnels, so that the wood flour does not penetrate. An infestation can be recognised by the characteristic rasping eating sound of the larvae, but this is not always noticed, so that the infestation with house longhorn beetle remains unnoticed for a long time. The damage is already considerable when the oval holes (4 to 7mm) are visible in the wood. If the remaining wood skin is removed, the feeding tunnels underneath become visible and the full extent of the damage is revealed.
• Due to its considerable feeding capacity, the house longhorn beetle can cause considerable damage to the installed coniferous wood in a relatively short time. The infested sapwood can be completely destroyed during the long-term development of the larvae.