whitespotted sawyer

(Monochamus scutellatus scutellatus)

Conservation Status

IUCN Red List

not yet assessed

whitespotted sawyer


NNR - Unranked


not listed


Common and widespread


June to September


Fire-damaged coniferous and mixed forests


¾ to 11 16



This is a moderate-sized, shiny black, wood-boring, long-horned beetle.

The adult female body is robust, broad-shouldered, ¾ to 11 16 long, and 3 16 to ¼ wide. There is a large, blunt projection on each side of the hardened covering of the thorax (pronotum). The hardened forewings (elytra) are shiny black, have a metallic appearance, and have small patches of white hairs. The small triangular plate between the bases of the elytra (scutellum) is covered with white hairs.

The face is nearly flat. The antennae are black, are longer than the body, and project from a notch in the eyes. When they are held back along the body the last two or three segments extend beyond the elytra. Two segmented feeler-like structures (palps) are attached to the lower jaw-like structures (maxillae). The last segment of each maxillary palp is pointed.

The legs are reddish-black. The forward, middle, and back legs each have 5 end segments (tarsi). They appear as 4 segments because the minute 4th segment is concealed by the enlarged 3rd segment.

The male is similar to the female but smaller (not including the antennae). The elytra do not have patches of white hairs.


Asian longhorned beetle (Anoplophora glabripennis) scutellum is black, not covered with white hairs. The white markings on the elytra of the female are much more conspicuous. The female has conspicuous white markings on the antennae.

Larval Food

Wood of conifers, especially eastern white pine, but also red pine, jack pine, balsam fir, white spruce, and black spruce, and occasionally tamarack.

Adult Food

Needles and the tender bark of twigs of conifers.

Life Cycle

Adults emerge in June or later depending on the weather. After mating, the female chooses a suitable location away from direct sunlight on the side or bottom of a host tree or log. She then chews a slit into the bark and lays one or sometimes more eggs in the slit. Egg laying begins in early June and continues to early September.

The egg hatches in 9 to 14 days. Within three days the larva tunnels into the cambium where it feeds until mid- or late summer. It then tunnels into the wood where it overwinters. In the spring it continues tunnelling, usually turning back toward the surface and creating a U-shaped tunnel. When it nears the surface it creates a pupal cell and plugs the end of the tunnel. It overwinters as a prepupa. In late May or June of the following spring the larva pupates. Two weeks later the adult emerges.

In northern Minnesota this cycle requires two years. Farther south it may take only one year.



Distribution Distribution Map  

Sources: 7, 24, 29, 72.





Coleoptera (beetles)



Polyphaga (water, rove, scarab, longhorn, leaf and snout beetles)






Chrysomeloidea (long-horned and leaf beetles)



Cerambycidae (long-horned beetles)



Lamiinae (flat-faced longhorns)





Monochamus resutor


whitespotted sawyer









A layer of softer growing tissue, one to several cells thick, under the bark of trees.



The hardened forewings on an insect used to protect the fragile hindwings, which are used for flying, in beetles and true bugs.



Paired mouth structures of arthropods located immediately behind the mandible and used for tasting and manipulating food.



Short for pedipalp. A segmented, finger-like process of an arthropod; one is attached to each maxilla and two are attached to the labium. They function as sense organs in spiders and weapons in scorpions.



The saddle-shaped, exoskeletal plate on the upper side of the first segment of the thorax of an insect.



The exoskeletal plate covering the rearward (posterior) part of the middle segment of the thorax in some insects. In Coleoptera, Hemiptera, and Homoptera, the dorsal, often triangular plate behind the pronotum and between the bases of the front wings.



The last two to five sections of an insect’s leg, attached to the tibia; the foot.
























Visitor Photos

Share your photo of this insect.

Rick Freitag

  whitespotted sawyer    

Bill Reynolds

They bite!

  whitespotted sawyer    


MinnesotaSeasons.com Photos

  whitespotted sawyer   whitespotted sawyer





  Whitespotted Sawyer (Monochamus scutellatus)
Andree Reno Sanborn
  Whitespotted Sawyer (Monochamus scutellatus)  
  Monochamus scutellatus (White-spotted Sawyer)
Allen Chartier
  Monochamus scutellatus (White-spotted Sawyer)  




Visitor Videos

Share your video of this insect.


Other Videos

  White-spotted Sawyer Beetle (Cerambycidae: Monochamus scutellatus) on the Move!
Carl Barrentine

Uploaded on Jul 3, 2011

Photographed at Nisswa, Minnesota (01 July 2010). Thank you to 'v belov' (@Bugguide.net) for confirming the identity of this specimen!

  Whitespotted Sawyer Beetle female moving, Monochamus scutellatus
Radu RXS

Published on Dec 16, 2013

Whitespotted Sawyer Beetle female moving, Monochamus scutellatus #11298786

This video is available for purchase at http://stock.rxs.ro

  Monochamus scutellatus

Published on Dec 7, 2013

White-spotted Sawyer - A member of the Cerambicydae Family of Long-horned Beetles. Seen on a picnic table at Lightning Lakes in Manning Park, BC. I was sitting there when this critter came in for a landing.

  Profile of Whitespotted Sawyer Beetle female, Monochamus scutellatus
Radu RXS

Published on Dec 16, 2013

Profile of Whitespotted Sawyer Beetle female, Monochamus scutellatus #11298287

This video is available for purchase at http://stock.rxs.ro





Visitor Sightings

Share your sighting of this insect.

Rick Freitag

Location: Duluth MN

whitespotted sawyer



Bill Reynolds

Location: St Louis Co MN

They bite!

whitespotted sawyer




MinnesotaSeasons.com Sightings





Last Updated:

About Us | Privacy Policy | Contact Us | © 2018 MinnesotaSeasons.com. All rights reserved.