Insects · Coleoptera · Scolytidae

Eight-toothed Spruce Bark Beetle

Ips typographus

Not Evaluated

It has not yet been assessed against the IUCN criteria. See full glossary

A bark beetle barely half a centimetre long that excavates beneath the bark of Norway spruce a system of galleries so regular that it looks engraved, which is where its name of typographer comes from. Healthy trees repel it with resin, but those weakened by drought or blown down by the wind succumb in numbers.

Size

up to 0.6 cm

Diet

Herbivore

Feeds mainly on plants.

Social structure

Colony

Lives in large concentrations, often for breeding reasons.

Sighting difficulty

Unknown

Temperate forestHerbivore Colonial Insect Temperate forest

58countries

Fun facts

The males give off aggregation pheromones that recruit thousands of beetles onto the same tree: only a massive, simultaneous attack can overcome the resin defence of a healthy spruce.
It carries blue-stain fungi that colonise the wood and block the transport of water, helping to kill the tree.
The major storms and droughts of recent decades have triggered outbreaks in central Europe that have destroyed hundreds of thousands of hectares of spruce forest.
It does not kill trees on its own: it inoculates blue-stain fungi, above all Endoconidiophora polonica, which overcome the tree's defences and make the attack lethal.
It coordinates mass attacks with aggregation pheromones produced by the males; once the population passes a certain threshold, those collective attacks bring down healthy trees.
The symbiotic fungi themselves give off volatile compounds that attract more beetles, an unusual case of chemical convergence across kingdoms.
It has killed millions of hectares of spruce in Europe, and the outbreaks are put down to warming, drought and forest management that leaves stands vulnerable.
In natural forests it is not a pest but a driver of forest succession.

Life cycle & biology

Habitat & environment: Weakened, wind-thrown or freshly felled Norway spruce

Sources consulted: Forest Research (Reino Unido); Jirošová et al. (2022), Frontiers in Microbiology; Kandasamy et al. (2023), PLOS Biology; Wermelinger (2004)