fabulous fakes

While hiking at the Baxter Conservation Area on Saturday, I photographed these two bee mimic flies (click on all images for larger view). I had hoped to have an ID for the fly in the top image, but so far, I haven’t found anything quite the same. However, I decided to post the photo in case anyone happens to recognize the species, or even the genus. I thought it might be a species of Mallota or Volucella, but I don’t see anything similar. One thing that was very conspicuous about this insect is that it was quite the performance artist. When I moved in to take some photos, it held its front pair of legs up and out in front of its head, and waved them around so that they looked like bee antennae. In fact, that’s what it’s doing in this photo. When that didn’t work to scare me away, it shimmied its body rapidly from side to side in a reasonable imitation of a bee’s typical vibrating movement as it buzzes its wings while walking over a flower. If one were less knowledgeable about insects, I think this fly would easily pass as a small bumblebee. In any case, if any of you have suggestions of a possible ID, post a note in the comments and I’ll take a look.

The fly in the photos above and below, is a member of the Asilidae Family — the Robber Flies. They are so named for their behaviour of grabbing other insects and carrying them off to consume in a rather morbid variation of purse-snatching. Their appearance has something of a Darth Vader aspect — dark and ominous creatures poised on favourite perches along woodland trails, waiting for an unsuspecting moth or other insect to fly within range. At lightning speed, they will shoot out and seize the insect with their very powerful front pair of legs, then return to their perch to feed. I believe the fly in these two photos is Laphria sacrator, which is has very densely furry legs. Other than the yellow and black fur, it doesn’t strike me as being too bumblebee-like in appearance. There’s something decidedly weird about its shape and its punk rock hairstyle, so it didn’t have me fooled for a second.

Wayne at Niches recently posted photos of a couple of different Robber Flies in the same genus here and here.

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9 Responses to “fabulous fakes”

  1. Larry Ayers Says:

    That robber fly… it looks like a hoodlum of the insect world! Your site has given me great mental images to retain in the hope I may stumble across some similar species.

    How long were the two species you photographed, BTW?

  2. bev Says:

    Larry – Yes, doesn’t it look sort of…uhm… sinister?!! I’m glad to hear that these kinds of photos may help you with your study of insects. I think it’s wonderful that digital photography seems to be inspiring many people to get out in the field learning about insects. The robber fly was the larger of those insects — probably close to an inch in length. The fly in the top photo was probably somewhere between a half and three-quarters of an inch in length.

  3. Leslie Says:

    The little “waving my antennae” trick is amazing. Great post.

  4. Wayne Says:

    I agree with Leslie – that performance art is amazing. I wonder if it’s species specific?

    One of the interesting things about robber flies to me is how photogenic they are. Somehow the little tarsi always come out in focus, the fur and beards always stand out so well. Maybe it’s because they’re a good bit larger than many flies.

    As I was looking through the Laphria I noticed how furry the legs on that species was. They’re amazing critters.

  5. bev Says:

    Leslie – The leg waving thing is really quite convincing until you get in close for a good look. To me, these kinds of behavioural adaptations show just how complex the whole mimicry thing as appearance and behaviour work together.

    Wayne – I’ve seen similar behaviour in some other bee and wasp mimic flies, so I think it’s part of the whole package. However, this mimic was particularly convincing. You’re right about the robber flies being very photogenic and I expect it has a lot to do with their size. Also, I find that when they’re in a cooperative mood, they will remain very still while I get the camera in close for a few shots, so that helps. That particular species of Laphria is particularly furry — yellow fur too, so it’s even more striking.

  6. Duncan Says:

    Love those inscet photos Bev. :-)

  7. Duncan Says:

    I meant insect of course, this toothache must have taken my mind off the job for a moment :-(

  8. robin andrea Says:

    Really fantastic photos, Bev. That top one is just something I can’t take my eyes off of. What a great-looking fake. Beautiful.

  9. Jenn Says:

    That fly at the top is really fab! Hard to id though – once I posted what turned out to be a Mallota at bugguide and they went through two other genera (Criorhina and Merodon) before settling on that. Apparently wing venation is important…if you are lucky enough to have captured that in the photos!

    Often I do not realize I’ve photographed a bee mimic until I get home and get the photos up on the computer monitor. Some of them are quite impressive. What a great post!