Wasp mimic beetle

2008 July 26

This one landed on me while I was out pushing Sam on her swing. At first, I thought it was a wasp, because that’s what it looked and acted like while it was flying, but as soon as it landed and closed its wings, it was clearly a rather attractive beetle.

Looking at the underside, we can see why it looks like a wasp when it flies: the abdomen is banded in yellow, just like a yellowjacket or most paper wasps.

It definitely has more of a beetle-like face. It also “stridulates”: when I held it, I could feel it vibrating as it moved its head up and down in a nodding motion, and if I held it next to my ear I could hear a faint “eeeeee-eeeeee-eeeeee-eeeee” noise.

I had to ask about this one on BugGuide, and they told me it was Clytus ruricola, a species of longhorned beetle. Longhorned beetle larvae in general eat wood – sometimes dead wood, and sometimes wood from living trees. The adults evidently eat (among other things) flower nectar and pollen. Since wasps hang out on flowers too, it makes sense for this species to be a wasp mimic so that its predators will think twice about taking a chance on being stung.

Some species of longhorned beetles are lumber pests, but this particular species is one of the ones that eat decaying wood (they like rotting hardwoods, particularly maple), so they don’t actually damage any wood that anyone wants. The tunnels that they bore through decaying wood helps other things like fungal spores to get into the wood, so they are a first step in wood decomposition.

6 Responses
  1. July 26, 2008

    That’s really awesome. I love bugs that mimic other bugs for protection. Very cool.

  2. July 28, 2008

    For those of us that are arthropodically-challenged, I’m wondering what visual cue tipped you off that this was a beetle? I’m comparing it to your pictures of other wasps (like the European paper wasps and the yellowjacket), and I can’t tell the difference. *

    * At least, not in the situation you described, where it was either “something landed on my arm. Oh, it’s a beetle,” or “aaaah!”, followed by running in circles and flailing.

    What about the appearance tipped you off to its being a beetle and not a wasp?

  3. July 28, 2008

    I’m actually running across a surprising number of mimics, to the point where I should probably make a special category for them. We just caught another type of mimic yesterday.

    As far as what tipped me off it was a beetle, I didn’t know until it settled down, folded its wings, and looked beetle-like. The thing is, I learned back when I was a kid that wasps or hornets that approach you slowly are almost never intent on stinging you – the ones that mean you harm come in like a bullet, and sound like they are in overdrive. So, if one flies up slowly and lands on you, the best bet is just to stop moving and have a look at it (and at this point, I said “Hey, it’s not a wasp, it’s a a beetle! I’ll catch it!”). Most of the time, a wasp or hornet will crawl around a bit, maybe lap up some of your sweat, and then be on its way.

    On the other hand, in my experience the instinctive “running in circles and flailing” response practically guarantees getting stung. The time when running and flailing makes a little sense is when you have knocked over a major nest and they are a-coming for you, but in that case you want to move away in a straight line, while preferentially flailing around your head and face to force them to go for your arms, legs, and torso instead. Once you get beyond their defense perimeter, they generally drop the chase and go back home. Distance is your friend. I don’t recommend running, though, because you usually only need to move away about 20-30 feet, which only takes about ten seconds. Trying to run, tripping, and falling down while you are still too close to the nest will make it so very, very much worse . . .

  4. becky T permalink
    September 11, 2008

    Hello Tim!

  5. August 22, 2009

    Clytus ruricola for sur . you can look on http://www.lesinsectesduquebec.com or on this link http://bugguide.net/node/view/190674 . this is one of the best website for bug info

  6. bill schauer permalink
    June 29, 2013

    Can I send you a picture of a beetle for identification?

Comments are closed.