Monochamus

Dejean, 1821

sawyer beetles, sawyers

Monochamus is a large of longhorn () distributed worldwide. Commonly known as sawyer beetles, in this genus are characterized by that bore into dead or dying coniferous trees, particularly pines. Several species serve as for the pine wood nematode (Bursaphelenchus xylophilus), the causative agent of . The genus exhibits strong in length, with males typically bearing antennae twice as long as their bodies.

Monochamus scutellatus by no rights reserved, uploaded by Johannes. Used under a CC0 license.

Monochamus scutellatus by (c) Alexis Tinker-Tsavalas, some rights reserved (CC BY), uploaded by Alexis Tinker-Tsavalas. Used under a CC-BY license.

Monochamus clamator by no rights reserved, uploaded by Robbie Hannawacker. Used under a CC0 license.

Pronunciation

How to pronounce Monochamus: //moʊˈnɒkəməs//

These audio files are automatically generated. While they are not always 100% accurate, they are a good starting point.

Identification

are black or mottled gray with vertically oriented and mouthparts typical of Lamiinae. The (first antennal ) bears a distinctive circatrix—a carinate ring or scar-like area near the tip. is pronounced: female are approximately body-length, while male antennae are twice as long or longer. are divergent. are wood-borers with typical .

Images

Habitat

Associated with coniferous forests, particularly pine stands. are found in forest and around dead or dying trees. develop within the wood of dead, dying, injured, fire-scorched, or recently-felled conifers including pines, true firs, Douglas fir, and spruce.

Distribution

Worldwide distribution with occurring across North America, Europe, Asia, and Africa. In North America, species range from Canada through the United States; M. notatus occurs east of the Rocky Mountains. European species include M. galloprovincialis in southwestern Europe.

Seasonality

typically emerge in spring and are active through summer months. duration ranges from one to two years depending on and environmental conditions.

Diet

feed on bark and cambium of healthy conifer trees, particularly within crowns. feed on wood of dead or dying conifers, tunneling under bark and deep into wood, sometimes reaching heartwood.

Life Cycle

are deposited in slits chewed into bark of dead or dying trees. hatch and develop through several while tunneling in wood. occurs in a constructed near the wood surface. emerge by chewing through remaining wood, with sometimes audible to humans. Newly emerged adults remain in pupal cavities while hardens.

Behavior

Males produce (monochamol) that attract both sexes to sites. Larger males with longer engage in combat using antennae and to establish dominance at optimal oviposition resources. Males exhibit mate guarding , remaining with females during and after copulation while females oviposit. are capable fliers; M. galloprovincialis can sustain of approximately 1 km individually and up to 16 km total, with flight capacity increasing through adult life.

Ecological Role

Primary of dead conifer wood, contributing to in forest . Serve as for woodpeckers and other . Several act as for pine wood nematode (Bursaphelenchus xylophilus), transmitting this forest during feeding and . Engage in intraguild and competition with , while also utilizing bark beetle as .

Human Relevance

can cause 30–40% value loss in freshly cut pine logs through tunneling damage; rapid processing or water of logs is recommended to minimize economic impact. Several are significant forest pests as of . Some species affect agricultural —M. leuconotus is known as the coffee in Africa. Subject to research using .