Stilt-legged fly

A group of stilt-legged flies (Rainieria antennaepes), apparently all females, was walking about and ovipositing on a large fallen log. They stop periodically to wave their forelegs, which are marked with white. I think this might be a defensive display, as it resembles the waving antennae of a wasp, but I can find no references on that--it appears to be my own idea. (Well, of course, Thomas Say named this species antennaepes in 1823, and that means "antennae-foot"! I can't find where anyone has mentioned that this is mimicry, specifically.)

 

-BugGuide account--Rainieria antennaepes

  • Ludi 6y

    Hi, I'm an admin for a group called Macros de Naturaleza - Macros of Nature (Post 1, comment 3), and we'd love to have this added to the group!
  • Ludi 6y

    Hi, I'm an admin for a group called Spectacular Insects - invited images only, and we'd love to have this added to the group!
  • oakum 6y

    She looks pretty stuffed with eggs to me.
  • Ash 6y

    Neat find!
  • jciv 6y

    Really weird looking fly.
  • antoni targarona 6y

    I give you a FROM CITRIT,BEST OF YOURS
    Citrit, best of yours!
  • Bob In North Carolina 6y

    I give you a FROM CITRIT,BEST OF YOURS
    Citrit, best of yours!
  • JMDN 3y

    I don't understand very well your hypothesis but in any case the fly itself is mindblowing... not to mention the detail of the eggs visible through the skin! A very sharp, detailed and interesting shot, thanks for sharing.
  • cotinis 3y

    JMDN, I'm suggesting that the upraised, white-tipped forelegs might serve to mimic the antennae of certain wasps. Many ichneumons, for instance, have white-tipped antennae, and they can at least poke at a predator with their sharp ovipositor. That's one reason the hypothesis is rather uncertain. However these flies spend an awful lot of time with a foreleg or two in the air--seems like there's got to be something going on.
  • JMDN 3y

    OK, thanks. I would rather expect that the white tip of the legs is equipped with sensory organs, so they spend the time "smelling" the air in search of food, predators or pheromones. This means we agree on that they use their front legs as antennae. Maybe both hypothesis are true!
  • cotinis 3y

    Oh, I had not thought of that. Great idea! Seems like a microscopic examination would reveal if there are lots of sensory organs (chemoreceoptors?). The white color, to me, suggests some mimicry is going on, but there certainly could be other explanations. As you note, both hypotheses could be true.
  • Ashley Perkins 3y

    Fantastic shot HFDF
  • afterforty‽ 3y

    One heck of a fly!
  • cotinis 1y

    I note (May 2014) that the default view on the page for this photo is small. If you click on the "* * *" menu I believe you can see the full size. Flickr seems to default to the small size for older photos--perhaps an understandable way to save bandwidth.
  • jciv 1y

    I hadn't seen a photo this small, my old ones are stuck at 1024 pixels wide, the old Flickr Large size. Now there are Large 1024, 1600, and 2048 created for new uploads. Converting all the billions of old photos to the new sizes would take forever so it wouldn't surprise me if they never do them all. Hopefully they will do popular photos that still get traffic. Lets see what happens with this one now that its got a new comment and favorite.
  • Ash 1y

    Wait, J, are they "upsizing" old photos, then? Or just bringing back original upload sizes that got hidden in in-between iterations?

    Nice to see this photo again, anyway. :-)
  • jciv 1y

    Neither at the moment. I am hoping they will use the original uploaded images to create the new large resolutions for needed for Flickr's new "full screen" display. I think the reason they haven't done it yet is because going back and resizing every old original resolution image to create two new Large resolution versions would take tons of processor power. And since they don't seem to care much about the past, I don't really see that happening.
  • cotinis 1y

    Hmm. I may stand corrected on this. It is displaying onscreen at 640 pixel width--probably what was used on the old layout. The original upload was 1024, and this is available, just not displayed inline by default, as it would be now, I think. Comments above now make me understand what is going on, sort-of!
  • jciv 1y

    Its still about 640x480 for me on a larger screen. Maybe it is because your original image was slightly less than 1024x768 in height. Maybe that throws off their sizing algorithm.
  • Ash 1y

    I have a monster Cinemascreen, but even if I maximize my browser window, this image only displays here on this page at 640x420.
29,783 views
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24 comments
Taken on June 13, 2009
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