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Sneak Attack! (Goldenrod crab spider, Misumena vatia)
Posted by on August 7, 2011
Our gardens provide an excellent close-by space for bug hunting. Most days I do a “tour of the grounds”, inspecting flowers and leaves for interesting critters. So the other day I was poking around a patch of purple coneflowers, when I saw this:
A bee head...upsidedown?
A little bit of bee peeking out from behind the pink petals. Something was all wrong, though. First, it wasn’t moving, and secondly, it was peeking out head-first. Very odd. Crouching down to get a better look beneath, the problem quickly became apparent:
Goldenrod crab spider with prey
A well-hidden goldenrod crab spider (Misumena vatia: Thomisidae) had snatched up the unsuspecting foraging bee and was now enjoying a well-deserved snack.
As I photographed the scene, I noticed a pair of very small flies circling nearby. They occasionally landed on the bee.
Little...Muscids? Doing...something?
I’m really not sure (little help, fly guy or other fly guy?) but I think they’re little Muscids of some kind. If I had to guess, I would say that they were feeding on the pollen grains clinging to the bee’s hairs…I can’t think of what else they’d be doing…does anyone else care to venture a guess? (Ooh, I’d take guesses on the ID of the prey, too!!!)
***Edited to add: read the comments (Dooooooo it. Do it now). Morgan from Biodiversity In Focus (aka “Fly Guy #1) has some great insights here!
***Edited to add #2: Micheal has offered another really interesting suggestion, and a nice pic to boot (in other words, if you haven’t read the comments already, you really should now).
Cool find Geek, especially the flies at the end! I don’t think that they’re muscids, but more likely kleptoparasitic Phoridae or Sphaeroceridae. I can’t make out the large maxillary palps indicative of Phoridae or the tiny hind basotarsomere of the Sphaeroceridae. There are tons of kleptoparasitic species in both families who swoop in to steal a meal for themselves or their offspring from larger predators.
I don’t think I have any shots that would be more helpful for the ID, unfortunately, but still…cool! Now, would they be trying to steal the bee itself (if so, how ambitious!), or the pollen, or???
If I had to guess, I’d say they are interested in the bee itself, although not in its entirety. There are several species which will suck the fluids from other’s prey for their own nourishment. I think (although this is a shadow of a memory from somewhere) that there are species which will target spider victims to steal some venom/digestive juices for their own uses. And of course there are species which will lay their eggs in disabled prey to give their offspring a big meal to grow up on. Of course, they could just be going for an easy pollen meal, but the fact that there are multiple individuals would make me think they are drawn to something other than relatively plentiful pollen!
Can’t offer expert opinion, but the little guys looks similar to these I posted on Bugguide: http://bugguide.net/node/view/301415
Michael, those look pretty darn close, if not exactly bang-on! Thanks so much for the link to your images (and for your comment)! Perhaps I should submit this pic to BugGuide too, just to be sure that Canada be representin’. Thanks again! 🙂
Oh, here’s a similar type of situation…http://bugguide.net/node/view/512989/bgimage