小蠹亚科亚科

树皮甲虫在树木的内皮中繁殖，一些树皮甲虫，如山松甲虫会啃食完好的树木导致其死亡，但大多数树皮甲虫只是寄生在将死或死去的树中。

A bark beetle is the common name for the subfamily of beetles Scolytinae. Previously, this was considered a distinct family (Scolytidae), but is now understood to be a specialized clade of the "true weevil" family (Curculionidae). Although the term "bark beetle" refers to the fact that many species feed in the inner bark (phloem) layer of trees, the subfamily also has many species with other lifestyles, including some that bore into wood, feed in fruit and seeds, or tunnel into herbaceous plants. Well-known species are members of the type genus Scolytus, namely the European elm bark beetle S. multistriatus and the large elm bark beetle S. scolytus, which like the American elm bark beetle Hylurgopinus rufipes, transmit Dutch elm disease fungi (Ophiostoma). The mountain pine beetle Dendroctonus ponderosae, southern pine beetle Dendroctonus frontalis, and their near relatives are major pests of conifer forests in North America. A similarly aggressive species in Europe is the spruce ips Ips typographus. A tiny bark beetle, the coffee berry borer, Hypothenemus hampei is a major pest on coffee plantations around the world.

Life cycle and morphology

Bark beetles go through four stages of life: egg, larvae, pupae, and adult, with the time to develop often relying on the species as well as the current temperature. While there is variation among species, generally adults first bore into a tree and lay their eggs in the phloem of the tree. This usually occurs in mid to late summer. Once the eggs hatch, the larvae then live in the tree, feeding on the living tissues below the bark, often leading to death of the tree if enough larvae are present.

Description and ecology

Bark beetles feed and breed between the bark and the wood of various tree species. While some species, such as the mountain pine beetle (Dendroctonus ponderosae), do attack living trees, many bark beetle species feed on weakened, dying, or dead spruce, fir, and hemlock. Most restrict their breeding area to one part of the tree: twig, branch, stem, or root collar. Some breed in trees of only one species, while others in numerous species of tree. In undisturbed forests, bark beetles serve the purpose of hastening the recycling and decomposition of dead and dying wood and renewing the forest.

Biochemistry

The bark beetle's pheromones, including kairomones, can attract other insects. The pheromones distinguished as kairomones are hormones, pheromones, or allomones of bark beetles, which in turn are used as a locator by insects that are attracted by it, such as flies, which may intend to harm the bark beetle itself. These chemicals interact with pine trees as the bark beetle's host, based on the behavioral, physiological, and biochemical effects of monoterpenes.

Monoterpenes are a chemical fragrance that plays a significant role in tree-insect interactions, specifically within pine trees.

Taxonomy

There are around 6,000 described species of bark beetles in 246 genera, placed into 26 distinct tribes.

As invasive species

Bark beetles are most commonly recognized by their impact on the lumber industry. Massive outbreaks of mountain pine beetles in western North America after about 2005 have killed millions of acres of forest from New Mexico to British Columbia. Bark beetles enter trees by boring holes in the bark of the tree, sometimes using the lenticels, or the pores plants use for gas exchange, to pass through the bark of the tree. As the larvae consume the inner tissues of the tree, they often consume enough of the phloem to girdle the tree, cutting off the spread of water and nutrients.

Hazard in Europe

According to a BBC article in August 2025, the spruce bark beetle has already devastated millions of spruce trees across Europe. The beetle has reached the UK by being blown over the English Channel, posing a threat to its forests. In order to face the threat, UK scientists are using drones, sniffer dogs, and even nuclear waste models, claiming to have eradicated it in vulnerable regions of the south and southeast. But as climate change continues and weakened trees, it’s getting harder to control the beetle.

External links and further reading

American and Mexican Bark and Ambrosia beetles

Nordhaus, Hannah. Bark Beetle Outbreaks in Western North America: Causes and Consequences. University of Utah Press: Salt Lake City, 2009. ISBN 978-0-87480-965-7