Asian Callipogon longhorn beetle
- Latin: Callipogon relictus Semenov
- English: Asian Callipogon longhorn beetle
- French: Xylophage vestige
- Synonym(s): Eoxenus relictus Semenov, 1898 , Eoxenus relictus Semenov, 1898 , Eoxenus relictus Semenov, 1898
This species is not found in Canada
Damage, symptoms and biology
This very large shiny black beetle with convex-shaped, reddish brown to dark brown elytra (front wings) lives in deciduous and mixed forests in eastern Asia, but is rare. Its folded-back antennae are almost as long as its body. Callipogon relictus is xylophagous (chews on or bores into wood) and its larvae feed on the sapwood, a part of the wood containing starch.
The adults emerge from mid-July to mid-September, with the females typically emerging about 2 weeks after the males. The females, which have impressive jaws, bore holes in the bark in which they deposit clusters of 20 to 30 eggs. They choose large trees with a diameter between 30 and 100 cm. They usually lay eggs in the thickest part of the trunk. Since this insect lives in symbiosis with the tree on which it becomes established and forms small colonies of 3 to 4 individuals, successive egg-laying phases can be observed and the same parts of the tree are reinfested year after year. Because larval development is slow (some authors say it takes the beetles 3 to 6 years to become adults), larvae of a wide range of ages can be found under the bark concommitantly. Newly hatched larvae bore into the cortical layer of wood and create galleries as large as 40 cm long and 2 cm wide. Through their tunnelling activity, they produce open scars up to 5 cm long on the bark surface along the trunk axis. They later tunnel deeper into the wood and, while feeding, create a dense and extensive network of galleries running in almost every direction which are filled with tightly packed sawdust. The larvae overwinter there at least 5 times until they construct a huge chamber in which they pupate with their heads oriented toward the surface of the bark. The pupal stage lasts from 4 to 5 weeks, and the newly formed adults emerge in July and August. They leave the tree through oval exit holes measuring up to 3 cm by 4.5 cm. Larvae this size obviously cause considerable physiological and structural damage to the host tree. They also transport a wood decay fungus (Pleurotus citrinopileatus) that can eventually cause a tree to split or fall down. When this happens, it may be possible to see some live larvae in the tree.
This species is an entomological oddity: its attested presence in the Amazon Valley as well as in Southeast Asia supports the hypothesis that the continents concerned were once joined.
Callipogon relictus is one of the largest existing beetles and certainly the largest in Russia, where it is, moreover, the only representative of the genus Callipogon. Although the female is smaller, the male can reach a length of 10 to 13 cm. This species is now rare, even threatened, owing to forest harvesting (including sanitation cutting), which selectively removes the mature trees (particularly Japanese elm) that the beetle clearly prefers. Avid collectors have also contributed to the decline in populations of this remarkable species.
Callipogon relictus is an undesirable species for many countries, including Canada, where it is a quarantine species.
[Anonymous]. [N.D.]. Callipogon Longhorn. Insects on stamps. http://www.asahi-net.or.jp/~CH2M-NITU/usurye.htm. Consulté en mai 2007.
[Anonymous]. [N.D.]. Distribution map of Callipogon relictus in Russia: http://www.sevin.ru/redbook/content/88mpbig.html. Consulté en mai 2007.
Cherepanov, A. I. 1988. Cerambycidae of Northern Asia. Volume 1. [Usachi Severnoi Azii (Prioninae, Disteniinae, Lepturinae, Aseminae)]. Ed. S. Otdelenie. Traduit du russe. Amerind Publishing Co. Pvt. Ltd., New Delhi. 642 p.
Cultural Heritage Administration. [N.D.]. Long-horned beetles (Callipogon relictus Semenov). Republic of Korea. http://www.cha.go.kr/english/search_plaza/ECulresult_Db_View.jsp?VdkVgwKey=16,02180000,ZZ&queryText=V_EKDCD='16'&requery=0. Consulté en mai 2007.
European and Mediterranean Plant Protection Organization (EPPO). [N.D.] Forest pests on the territories of the former USSR. O5/12249. 117 pp. http://www.eppo.org/QUARANTINE/forestry_project/EPPOforestry_project.pdf. Consulté en février 2011.
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