Orthotomicus

Ferrari, J.A., 1867

Species Guides

4

Orthotomicus is a of bark beetles in the Curculionidae, Scolytinae, containing approximately nine described . The genus is primarily associated with coniferous trees, particularly pines (Pinus spp.) and cedars (Cedrus spp.). Several species, notably Orthotomicus erosus (Mediterranean pine engraver) and O. laricis, have become significant forest pests through native and range expansions. Species in this genus are known for their associations with ophiostomatoid fungi, which they and which contribute to tree decline.

Orthotomicus erosus by Jim Stimmel, Pennsylvania Department of Agriculture, Bugwood.org. Used under a CC BY 3.0 license.Orthotomicus erosus pine gallery by Francis Maugard, Département de la Santé des Forêts, Bugwood.org. Used under a CC BY 3.0 license.

Pronunciation

How to pronounce Orthotomicus: /ˌɔr.θoʊˈtoʊ.mɪ.kəs/

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Habitat

in this inhabit coniferous forests, primarily pine and cedar stands. Orthotomicus erosus occurs in Mediterranean pine forests, including Aleppo pine (Pinus halepensis) and Brutia pine (Pinus brutia) stands. Orthotomicus tridentatus is to cedar forests (Cedrus libani) in the Taurus Mountains of southern Turkey. The genus has been introduced to non-native pine plantations in South America, South Africa, and other regions through global trade.

Distribution

Native range includes Europe, the Mediterranean region, Asia, and North Africa. Orthotomicus erosus is widely distributed across the Mediterranean, southern Europe, Asia, and North Africa. Orthotomicus tridentatus is to Turkey. Introduced established in South America (Chile, Argentina, Uruguay), South Africa, and potentially other regions through human-mediated transport. GBIF records indicate presence in Denmark, Norway, Sweden, and the United States (Vermont).

Host Associations

  • Pinus halepensis - Aleppo pine; primary for O. erosus
  • Pinus brutia - Brutia pine; for O. erosus
  • Pinus sylvestris - Scots pine; for O. erosus
  • Pinus eldarica - Eldar pine; for O. erosus in urban Iran
  • Cedrus libani - Lebanon cedar; sole for O. tridentatus
  • Ophiostomatales fungi - mutualistOphiostomatoid fungi including Ophiostoma ips, O. piceae, O. minus, Leptographium wingfieldii; vectored by beetles and associated with blue-stain
  • Streptomyces bacteria - associateActinomycete bacteria producing antifungal compounds; isolated from O. erosus in South Africa

Behavior

are bark borers that construct galleries in phloem and inner bark. Orthotomicus tridentatus constructs characteristic 'S'-shaped main galleries. Orthotomicus erosus has high ability through active and can be transported in infested wood material. The species exhibits mediated by , with 2-methyl-3-buten-2-ol and ipsdienol identified as key compounds for O. erosus. are influenced by drought stress and temperature, with potential increasing under climate warming scenarios.

Ecological Role

As primary or secondary bark beetles, in this contribute to tree mortality in coniferous forests. Orthotomicus erosus acts as a for ophiostomatoid fungi that cause blue-stain in pine sapwood. The -fungus mutualism facilitates of trees and may accelerate tree decline. In ranges, O. erosus poses significant threats to plantation forestry. The genus participates in complex multipartite involving fungal mutualists and bacterial associates that may influence fungal composition in galleries.

Human Relevance

Several are economically important forest pests. Orthotomicus erosus caused the first recorded in Croatia in 2017-2018, affecting 23% of trees in Marjan Forest Park with at least five per year. The species has invaded South America, South Africa, and other regions, threatening pine plantations. Control efforts include trapping using lures such as Erosowit®. Domestic sea trade facilitates range expansion within countries, as demonstrated in Italy where abundance at ports correlated with trade volume. Correct identification is critical for management; O. laricis was misidentified as O. erosus in Chilean research.

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