The Bug Geek

Insects. Doing Science. Other awesome, geeky stuff.

Photo Friday – Whitespotted Sawyer Beetle, Monochamus scutellatus

A few days ago, it seemed as though my yard was teeming with really cool, very photogenic beetles.

Naturally, I stuck them all in vials and made them hang around for a bit while I did some portrait sessions (yeah, I’m mean to bugs like that). I’ll be dishing out the photos over the next few weeks, but here’s the first to kick things off: a male longhorned beetle (Family Cerambycidae), Monochamus scutellatus – the whitespotted sawyer. This is a very widespread and common species that feeds on conifers, but it’s one of the larger longhorns in my region so I’m always a little tickled to find one.

Monochamus scutellatus (male)

Now, longhorned beetles are very good at one thing: chewing wood (i.e., trees). They lay their eggs in wood, the larvae bore into and feed on wood, then the adult bores OUT of the wood after it ecloses from its pupa.

As such, these beetles tend to have very impressive chompers. I was fairly cautiously holding this fellow at the thorax as he made repeated futile attempts to bite me.  Naturally, I was curious as to how much this might hurt should he actually make contact, so I deliberately let him bite my thumb.

Mmmm, foolish Geek digits. Om nom.

“Ha-ha to you, stupid beetle,” I thought. “Doesn’t hurt.” But, since I was drawing that conclusion with a sample size of n=1, I repeated the experiment. At about n=6 I realized that allowing the beetle to bite me anywhere other than the fairly callused tips of my digits was, in fact, very painful.

So I put him down.

Apparently satisfied that he had proved his point, he sat nicely for the next five minutes or so as I snapped a bunch of pictures, even allowing me to adjust one antennae mid-way through the photo shoot (the darn things are so long they kept getting cut off the edges of the image).

One other thing I noticed (you may have spotted them in the first shot) was that this beetle had some little red hitchhikers hanging on to the sides of his pronotum. I knew they were mites (and I’ve seen these on other specimens of M. scutellatus), but did not know that they were Uropodoid mites until a friend (a mite specialist working at the CNC) tagged them on Facebook (I can honestly say I’ve never seen mites subjected to FB tagging before – it was pretty awesome) – thanks Wayne!

Monochamus’ hitchhikers – Uropodoid mites

5 responses to “Photo Friday – Whitespotted Sawyer Beetle, Monochamus scutellatus

  1. Morgan Jackson June 1, 2012 at 10:46 PM

    I can see a new paper in your future Geek, along the lines of the Schmidt Sting Pain Index!

  2. jason June 3, 2012 at 11:34 AM

    LOL! I can imagine the pain becomes evident once you move to less worked skin. And Morgan has a great idea, so I’ll be looking forward to that when you finally publish.

    Great photos, BTW! What a handsome devil, mites included.

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  4. Dawn September 30, 2012 at 8:53 PM

    I was recently bitten or stung by a bug very similar to this bug (white spotted sawyer beetle) was curious if you may be able to identify. The bug had almost exact body but was all black with tiny white spots on its under belly. It’s outer shell was hard and instead of “pinchers” at mouth had a 1/8 in stinger. At the end of its tail was fluorescent orange that disappeared after a day in a bottle. Kept it to show dr. in case of allergic reaction. Unfortunately didn’t take a picture. It looked like a cross between a beetle, and
    amosquito or wasp. If you could identify would be appreciated. The mark left by it’s sting resembled mark that would be left by bee sting. Red, swollen, and very itch

    • TGIQ September 30, 2012 at 9:21 PM

      Hi Dawn, can you give me more info about where you live? Send an email to tgiq at hotmail dot com if you don’t want to post publicly. I’ll see what I can think of, but locality helps to narrow things down! 🙂 Also, what were you doing when you got bitten/stung? Holding it? Swatting it? Putting pressure on it? Just curious about the behavior.

      In the meantime, based on your description of the mouthpart, I’m guessing it was some kind of True Bug. There are many that are known to bite (more of a “pierce/puncture”) humans when handled. Was it anything like this?

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