Class: Insects
Size: 0.7 to 12mm
Weight: Variable
Age: Unknown
Appearance: Brown-black coloured
Food: Bast, bark, wood
Distribution: Worldwide, 6’000 species; in Europe approx. 250 to 300 species
Original location: Unknown
Habitat: Forests, trees
Natural enemies: Birds (woodpeckers, titmice, treecreepers and nuthatches), ant beetles
Threatened with extinction: No

• Bark beetles are very species-rich, mostly brown or black beetles, many of which reproduce under the bark or in the wood of trees in self-drilled tunnels, sometimes causing enormous economic losses.
• As a primary pest/forest pest, they play an important role in the material cycle of forest ecosystems. However, the reason why bark beetles are known to the public is mainly because some of them have already caused severe forest damage as forest pests after multiplying over large areas.
• Most bark beetles develop in the living tissue of the bark, the bast of trees and other woody plants. Many of them begin their development there, but then later switch to the lying further out bark, which actually gives the insect’s name.
• Wood is a very nutrient-poor substrate and lacks a variety of nutrients that are important for herbivores. To compensate for this deficiency, many bark beetles use the decomposition power provided by fungi and live in close symbiosis with them.
• Most bark beetles use the wood and bark of tree species. Many species, feed on the nutrient-rich phloem (bast, bark). They sometimes occur only on one group/genus of related tree species (oligophagous) or even only on one tree species (monophagous). However, most wood-feeding species are polyphagous, i.e. on very different wood species, some even overlapping hardwoods and softwoods. Although most species attack living trees, there are also bark beetles that specialise in deadwood. There are also specialists for twigs, branches and roots.
• Of the numerous bark beetle species, only a few settle on living trees (mainly conifers) and can then even cause them to die completely. On the other hand, most species are weak parasites (secondary pests) and can only settle on dying or diseased trees whose resistance is greatly reduced. Overall, only about 15 to 20 species tend to reproduce on a large scale and can then cause entire forests to die in a high-growth year.
• In Europe, bark beetles caused an average of 2.9 million cubic metres of damaged wood per year from 1950 to 2’000, which is 0.7 % of the European logging volume and about half of the damage caused by all biological pests.