Cerambyx longicorn (Cerambyx cerdo)

Also known as: Great oak longhorn beetle
GenusCerambyx (1)
SizeLength: 24 -55 mm (2)

The Cerambyx longicorn is classified as Vulnerable (VU) on the IUCN Red List (1). Extinct in the UK, this species is listed on Appendix II of the Bern Convention as a strictly protected fauna species, on Annex II of the European Habitats and Species Directive as a non-priority species and on Annex IV of the European Habitats and Species Directive (3).

This large and beautiful beetle is among the largest of the European beetle species (2). It has an elongated, robust body and, like all members of the longhorn family, it has long antennae. In males, these thread-like antennae are longer than the body, but in females they are only as long as the hard wing cases (the elytra) (4). The legs and body are black, except for the elytra which are reddish-brown towards the tips (5) (6).

The Cerambyx longicorn is found throughout Europe and also occurs in northern Africa, the Near East and Caucasia (5) (6). In spite of fossil records (7), it is no longer found in the UK (1) (3).

This species develops in fresh wood of broadleaf trees. In Central Europe, only trees of the genus Quercus (the oaks) are used (5), while in more southern parts of Europe it is also able to develop in Castanea (the chestnuts) and some other trees, including Ceratonia species (5).

The Cerambyx longicorn inhabits large trees with sun-exposed stems, such as large, solitary oaks situated in fairly open landscape, or old pasture-woodlands (8).

The life cycle of the Cerambyx longicorn takes two to five years, dependent on the climatic conditions within the area. The females lay up between 100 and 400 eggs into deep slits in the tree bark, and the first larvae hatch after 8 to 12 days (14). In northern Africa, there are five larval stages over a period of 28 months, followed by the pupal stage which lasts 32 days (15). The larvae begin feeding just underneath the bark, but later the larvae penetrate deeper into the woody parts of the trunk (10). This beetle is only able to develop in fresh wood, but the larvae impacts on the tree as it feeds, creating dead wood structures (13). Pupation takes place in the outer wood parts of the tree. After emerging from the pupa, this beetle will remain inactive in the wood for several months before leaving the tree. Within 13 days of becoming a sexually mature adult, the Cerambyx longicorn will mate (10).

This beetle possesses specialised structures for producing sound: a hard edge is rubbed against a row of toughened ridges on the abdomen, making a chirping noise called stridulation (10).

Despite the Cerambyx longicorn existing in many national parks, suitable habitats may still be lost as dead and dying wood is often removed due to health and safety measures to prevent accidents. This is to the detriment of many species that exist only on dead or dying matter (11). Development in modern agriculture followed by changes in landscape structure in Central Europe has lead to a substantial decrease in suitable habitats for species dependent on large, sun-exposed oaks. Fragmentation of remaining populations may be a threat for this species as small populations are much more vulnerable to the detrimental impacts of chance events. Small and fragmented populations may also be affected by the low dispersal ability of this beetle, as it hinders its ability to colonise new, suitable habitats (8).

The removal of deadwood has been recognised recently as an important and unnecessary habitat damaging process that occurs even within protected areas. Since this kind of habitat loss is not economically beneficial, it should not be hard to prevent. WWF issued a report in October 2004 to encourage landowners and managers to leave veteran trees and deadwood in place, as they provide a habitat for many species of insect, fungus and lichen, as well as playing a role in forest productivity and environmental stabilisation, such as carbon storage (12). It is not only important that old oak trees are protected, but establishing new suitable habitats to connect existing populations may also be beneficial to the Cerambyx longicorn. Such measures require a long-term conservation plan, to ensure the long-term survival of this vulnerable beetle (13).

For further information on the conservation of beetles see:

For further information on deadwood see:

Authenticated (15/09/08) by Dr. Jörn Buse, Department of Ecology, Institute of Zoology, Johannes Gutenberg-University Mainz.

  1. IUCN Red List (July, 2014)