A person can hear all kinds of sounds when out camping in the canoe country. The call of a loon, the howl of a wolf, the splash of a fish, the hoot of an owl and the unwelcome buzz of a swarm of mosquitoes can all be heard in the wild of the northwoods. But what about that other sound you can sometimes hear on a still day or night? It kind of sounds like someone grinding their teeth but more like a chewing sound because it actually is a beetle chewing bark. I’m sure there are a few varieties of this flying, well-endowed with antennae beetle that will sometimes bite you or land on you. It’s antennae can be one to three times the length of the body! Here’s some information about the White-Spotted Sawyer.
MN Department of Natural Resources
White-spotted Sawyers, Oh My!
A white-spotted sawyer adult. Note the white spot between its “shoulder blades.” (They technically aren’t called shoulder blades, but you see what I mean.) The location of this spot separates the white-spotted sawyer from the dreaded Asian longhorned beetle, not yet found in Minnesota.
(photo by Whitney Cranshaw, CO State University, Bugwood.org)
A plague not by biblical standards, but perhaps by longhorned beetle standards, is happening in far northwestern Minnesota and adjacent areas in Ontario. The white-spotted sawyer—that one-inch-long, mostly black beetle with antennae longer than its body—is really irritating people in those areas. They are busy landing on everything. They are also laying their eggs on dying and freshly cut conifers. There are other longhorned beetles that may be out and about, but from pictures and descriptions, the primary species being reported is the white-spotted sawyer.
The larvae of the white-spotted sawyer are roundheaded borers that feed on dying and dead conifer wood. They go from egg to adult in 1 or 2 years, so something in northwestern Minnesota likely happened in 2013 to make a bunch of dead conifers. Eastern larch beetle is certainly helping add to the dead tamarack total up there and could be aiding the longhorned beetle population. Our Canadian friends put the blame on the branch-busting snows they received in April 2013. We also had ample snows that damaged conifers in April 2013.
The adult white-spotted sawyers do some feeding on branches, but most trees will be able to withstand this minor irritation. The adults also can bite you if they land on you: again, a minor irritation relative to other human maladies. People should expect to hear the larvae chewing in newly-killed and dying conifers in 2016. Other than freshly-cut coniferous logs and dying trees, these beetles are not a concern for the health of our forests.