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Bug of the Week

Week of June 18th, 2018: Whitespotted Sawyer Beetle

A female Whitespotted sawyer beetle

A female Whitespotted Sawyer Beetle (June 17th, 2018; Etna, ME); Staff Photo

If you spend any time in a forested part of the state this week, you might spot one of these somewhat fearsome-looking beetles flying about. It is a Whitespotted sawyer beetle, and if you think of it as having a body like ours for a moment, you can see that there is a rather prominent white spot located between its ‘shoulder blades’ (on the beetle’s hard wing coverings). Many people mistake sawyer beetles for the dreaded Asian longhorned beetle (ALB). However, the ALB does not have the single distinctive white spot of the whitespotted sawyer. Instead, the ALB has about 20 white spots on each wing cover. The body of the ALB is also shiny and black, compared to our sawyer beetles, and has not been detected in Maine as yet. Additionally, the antennae of the ALB are very conspicuously banded black and white. [What ALB Looks Like] (USDA)

photo of pair of Whitespotted Sawyer beetles (male on left; female on right)

Whitespotted Sawyer Beetles

The Whitespotted Sawyer beetle is a mostly minor pest of coniferous trees, especially white pine, balsam fir, and species of spruce. Other than some of the feeding done to the bark on the undersides of twigs by the adult beetles, it is regarded as a secondary pest because it is trees that are already weakened, dying or dead that the beetles utilize for their larvae. Size: Not counting the antennae, the whitespotted sawyer adults average one inch to an inch and a quarter in ‘body’ length. For more information, take a look at our page on sawyer beetles.

Whitespotted Sawyer beetle (female) Whitespotted-Sawyer-Beetle-060416b

 


Week of June 11th, 2018: “Hairy Rove Beetle” — Creophilus maxillosus (Linnaeus)

Photo of a Hairy Rove beetle beside a U.S. dime for scale purposes

Hairy Rove Beetle; Etna, Maine, 6/9/2018; Photo by C. Armstrong.

The first “Bug of the Week” for the 2018 season is an interesting type of rove beetle called a hairy rove beetle.  Rove beetles are in the family Staphylinidae, which is part of the “Superfamily” known as Staphylinoidea which is comprised of rove, carrion and fungus beetles.  Rove beetles often go unnoticed, even though their family is the largest of all beetle families at over 63,000 species throughout the world and nearly 400 new species being described each year!  They make up the largest beetle family in North America as well, at approximately 4,360 known species.  One reason they often go unnoticed is likely due to the fact that many rove beetles are found around decaying plant and animal remains, which people generally prefer to avoid (for obvious reasons).  The specimen featured here was in fact discovered near a compost bin full of decaying leaves, fruit, and even some lobster remains, which also made an ideal habitat for its primary prey: carrion maggots and other fly larvae.  Most rove beetles, in fact, feed on other insects and invertebrates, and their habitats on the whole are extremely varied, depending on the species.  For the most part, rove beetles have trivial importance as pests, and are collectively very beneficial given their work as predators and decomposers. 

A "Hairy rove beetle" rolled up into a defensive ball-like posture

The same Hairy rove beetle pictured above displaying its defensive, ball-like posture. Photo by C. Armstrong.

Rove beetles are essentially harmless to humans but some of the larger ones like this one–including the hairy rove beetle, in fact–can inflict a painful bite if necessary for defending themselves.  The hairy rove beetle also employs a few other very interesting tactics for defending itself.  It can release a chemical liquid from the tip of its abdomen that it will try to wipe onto whatever might be bothering it, while at the same time rolling up into a protective ball of sorts (see photo) which has the additional effect of causing it to look dead — it superficially resembles a dead bumble bee when it is rolled up in this manner.

To read much more about the hairy rove beetle, visit the following University of Florida web page that features it in great detail: Hairy Rove Beetle


The Bug of the Week is something we like to do in order to put some lucky (or maybe unlucky) ‘bugs’ in the spotlight from time to time throughout the year.  If you have a good picture of a ‘bug’ that you’ve very recently found somewhere in Maine that you’d like to have identified and/or would be willing to have featured here as the next Bug of the Week, please email your photo to us and don’t forget to include a statement giving us permission to use your photo on our web site and how you would like to be credited for the photo.  Send your email to Jim Dill (IPM Specialist) at james.dill@maine.edu


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