they make ’em big out west

I haven’t posted much about insects seen during my recent trip out west, but I’ll eventually get around to that. No doubt, you’ll see more about them when I begin scrounging around looking for things to write about in another few weeks after the snow flies. I do have some insect sightings from the past week here at the farm, but I’ll save them for another day when I have a little more time and energy. In the meantime, here’s something interesting that I came across one sunny afternoon while wandering along the rocky shoreline of a quiet river in central Oregon. It’s some species of Robber Fly (Family Asilidae), of proportions unlike anything I’ve ever seen before. As you can see from the photo, it has captured a good-sized wasp and is gripping it with its center pair of legs while biting and feeding on the underside. What amazed me was the *size* of the fly. It was huge. At first, I thought it was some species of small to medium-sized dragonfly. However, when I moved in closer, I realized that I was looking at a Robber fly that was probably close to 2 inches in length. I’ve never seen anything like it up here in eastern Canada. About a week later, I found another of similar size along a river down in the Humboldt Redwoods region. It seems they make ’em big out west — and I’m not just talking about the Redwood trees and the Banana slugs!

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12 Responses to “they make ’em big out west”

  1. Wayne Says:

    The wasp looks like a yellowjacket – is that possible? If so, good riddance! At any rate, yes, the robber fly is enormous and I haven’t seen any nearly that size here. (FC probably has.) It can’t be the extra oxygen that all the paleontologists attribute meter-wide wingspans of dragonflies to in the Carboniferous.

  2. burning silo Says:

    Wayne – I’m not sure, but it looked like a yellowjacket to me too. I don’t know what explanation there could be for the size of this insect, but it certainly was large. Seemed “in scale” with some of the other things I saw out there.

  3. Duncan Says:

    That is a beauty Bev, don’t know that we’ve got them that big over here, an inch and a half would probably be the biggest I’ve seen. Great picture of it with the wasp.

  4. Pamela Says:

    Great shot, Bev. Maybe they’re big to keep up with the redwoods and banana slugs….but it was in Alberta (Spruce Grove) that I saw the biggest dragonflies I’ve ever seen.

  5. burning silo Says:

    Duncan – Yes, it sure was an impressive Robber fly. The body was so large and furry. Quite a sight!

    Pamela – Thanks! I’d like to see more dragonflies from other ranges and hope to next summer. When Don was down in Arizona last summer, he saw some real jumbo-sized species along the banks of a small river.

  6. robin andrea Says:

    Bev– My reading seems to be a day behind your posting! Great photograph. That is a huge Robber Fly, but I guess they have to be big if they’re going to make a meal out of a wasp! Yum.

  7. burning silo Says:

    Robin – I’ve been posting later in the day than usual, so I’m not at all surprised. I seem to be finding it a little difficult to settle back into any kind of routine here at home. Maybe with the time change, I’ll be back to posting in the morning!

  8. Tussock Mirth Says:

    If you’ve ever drunk a yellow jacket out of a luminum can, you feel – – cheer, in seeing one “git what’s commin to him.”

    But he looks like he’s gonna sting that robber fly IN THE EYE.


    Come to think of it, I got stung on the EYELID, once, too.


  9. burning silo Says:

    TM – I was thinkng just the same while looking at several photos that I shot of the Robber Fly. It looked a little perilous for the Robber Fly. Being stung on the eyelid (or your compound eye) is no fun at all!

  10. Jace Stansbury Says:


    What an excellent photo of the Robber Fly! I see these all the time near out camp but not quite that large. I one time spotted one as it attacked a large saddlebag dragonfly. It drove it to the ground, fed on its juices and then left the hollow remnants. They’re like the wolves of the insect world!


  11. burning silo Says:

    Jace – Thanks! And yes, you’re right, Robber flies are such quick and powerful fliers that most are a match for almost any winged insect. I’m sure this one would have been capable of capturing quite a large dragonfly.

  12. Drhoz! Says:

    they make ’em even bigger here in Western Australia