I woke up in the middle of the night to the sound of rain. I like to sleep with the windows open whenever possible, but rain will come in the west window, which is never a good idea.  So, in that trance-like state that one does things in the middle of the night, I got up, closed the window and went back to bed.        The following afternoon I found that the rain from the previous night had been replaced with a wonderfully refreshing breeze. It was clearly time to open the window again so, in the clear light of day I walked over, grabbed the crank, looked up to the latch and found myself staring at a huge beetle that had been inadvertently captured the night before.  

The thing that impressed me most about this creature was the length of its antennae. Sweeping in graceful arcs out from the beetle’s head, its antennae were far longer than its body. This triggered a synapse that had been firmly established in my brain many years ago, while I was working for my friend Jeff Boettner. That synapse had a name associated with it: Asian longhorned beetle. I was alarmed.

I transferred the beetle into a plastic tub and quickly went to my computer. A quick search showed me that the Asian longhorned beetle is shiny black with large irregular splotches of white on its wing covers. This beetle was clearly “long-horned,” but it lacked the irregular white splotches.  Thankfully, I had not captured an Asian longhorn. Why was I thankful? Well, that’s a story for another time.

So what had I found?  

This beetle had a sheen of coppery bronze with a single, distinctive heart-shaped spot at the topmost junction of the two wing covers. This beetle does have white spots, but they are more like the fine, scattered spots that one might associate with sloppy spray painting.  

These field marks identified my beetle as a white-spotted sawyer (Monochamus scutellatus). As I read the species description, the long antennae of the males (or, “horns” if you will) were clearly a field mark for this particular species.

Also known as the pine sawyer or spruce sawyer, the white-spotted sawyer is a well-known native species. Found from Newfoundland to North Carolina and extending northwest to Minnesota and up into Canada and Alaska, this beetle is a conifer specialist.  

In our area, the beetle appears to prefer white pine over other trees, but it will also turn its attention to red pine, balsam fir and the spruces.  

The female white-spotted sawyer will seek out sick, dying or dead trees and settle on the bark. She will chew into the bark with her formidable jaws and lay a single egg into a little trench she has created.  

The eggs will hatch and the larvae will burrow down into the inner bark of the dead or dying tree. Once established in this manner, the growing larva will graze on the preferred wood until it has reached the appropriate size. In some habitats, this may take one year, whereas in others it can take up to four years.

The tunnels these larvae excavate become larger as the larvae grow, and this is where the worlds of insects and humans can sometimes clash.  

Humans like to cut down trees and use the wood for building things. White-spotted sawyers need dead logs to reproduce in. If humans cut down trees and then pile up the logs and allow them to sit for a while, they will undoubtedly be irresistible to the beetles, which in turn will damage the value of the wood in the eyes of the humans.  

Once “mature” the larvae will pupate and the magical transformation of the insects will commence.  

Organs are reorganized, new body parts appear and eventually an adult beetle will emerge. This is accomplished by chewing yet another hole in the wood. The adult will then spend a few weeks feeding on pine needles and fungi. All the while, the adults will also pursue the goal of breeding.

The interesting thing is that the white-spotted sawyer is actually a beneficial species to have in the environment. The breakdown and recycling of dead wood is an important step in the nutrient pathways of forests, and the activities of the sawyer beetle hasten the recycling process. As larvae grow and tunnel, they provide pathways through which bacteria and fungi can get at the wood. However, this (again) is something that humans sometimes take issue with.

The thing that I most like about an encounter with an animal like this is the learning associated with it. Had I taken just one photograph of this male white-spotted sawyer, I would have taken the wide-angle shot that showed the extremely long antennae that had originally grabbed my attention. But, I didn’t stop with that one shot.  

To make my job easier, I put the plastic container in the refrigerator for about an hour. When I finally retrieved the beetle from its chilly confinement, I was able to place it on my porch railing without having to worry about it flying away on me. This allowed me the time I needed to get some close-ups, and the close-ups are what led to all sorts of interesting details that might otherwise have gone unseen.

One detail that I found particularly fascinating was the fact that the beetle’s antennae seem to be growing out of the middle of each of its eyes. A front view of the face of this beetle shows the compound eyes that one expects to find on an insect. A side view, on the other hand, shows that the eyes appear to wrap around the antennae. This is a detail that requires a specialized lens to capture, and it only came to my attention while I was reviewing the photos.

Another even more fascinating detail was the fact that this particular beetle was carrying passengers. What appear to be shiny little red lentils are in fact mites that are hitching a ride.  

I did a little research and learned that there is a symbiotic relationship in which small mites attach themselves to larger insects specifically to get a ride from one place to another.  

Known as “phoresy,” a mite that does this is known as a “phoretic mite.” It doesn’t hurt the larger insect in any way. It just wants a free ride.

And here is where I inevitably run out of room every week.

I hope you take some comfort in knowing that the beetle was released back into the wild after his brief confinement. His passengers may have been a bit irritated, but mites are generally annoyed at one thing or another anyway, so what are you going to do?

Bill Danielson has worked for the National Park Service, the U.S. Forest Service and Massachusetts State Parks. He has been a professional writer and nature photographer for 19 years and also works as a high school biology and physics teacher. Visit www.speakingofnature.com for more information, or go to Speaking of Nature on Facebook.

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