More Drama by the Back Door

This spring I wrote about a feather-legged orbweaver that subdued a jumping spider in the stone wall by my back door.  Around the same time, while I was watching the sweat bees digging their burrows in the soil between the stones, I saw one land right next to a wolf spider, which pounced on her and tried in vain to subdue her as she busily dug away without the slightest acknowledgment of her would-be predator.  Yesterday, I stepped out for a moment while waiting for my lunch to heat up, and I saw another little drama unfold there.

A spider wasp (Pompilidae) was carrying a wolf spider (Lycosidae) she had stung and paralyzed, heading to her nest, into which she would stuff the spider and lay an egg before sealing it up.  This is a common sight, but I recently discovered (while putting together a slide show about spiders) that I don’t have any good pictures of it.  My camera was far away and the wasp was moving quickly, so I just stood and watched, but then the wasp started climbing the stone wall, and the spider got caught in a stray strand of spider silk.  The wasp fell to the ground and began running around frantically, occasionally darting at the spider but failing to get it free.  This bought me some time, so I ran upstairs to get my camera, and when I got back down the spider was still dangling there.

The wasp continued her frantic running around, occasionally pausing to rest long enough for me to get a photo.

After about ten minutes of this, the wasp finally made contact with the spider and hung on. She seemed to be trying to get the spider free, but in the next several shots I took, she is clearly working on chewing off the spider’s right front leg at the base (note that the leg behind this one is already missing in the first photo).

Suddenly, another spider arrived on the scene–apparently this wasn’t just a stray strand of silk after all.  Unfortunately I only managed to get this one out-of-focus shot:

The much larger wasp’s struggling sent the spider back up the web pretty quickly.  It looks to me like it was a Steatoda borealis (Theridiidae)–a cobweb spider closely related to the black widows.

Moments later, the wasp was on the ground, dragging the wolf spider, some webbing, and a bunch of debris by her hind leg.

For the next few minutes, she was alternately dragging the spider and wrestling with it, apparently stinging it, and presumably trying to get it unstuck from her leg.

Eventually she got it free and resumed carrying it in her jaws as she had been doing when I first spotted her.  I remembered that the reason I don’t have any good pictures of a spider wasp doing this is that they’re moving all fast and jerkily while they do it.

She carried the spider to a more secluded spot, where I thought she was working on cleaning it off.  But in reviewing the photos, she doesn’t seem to be concerned with the debris attached to the spider, and again appears to be chewing the bases of its legs.

This went on for a couple of minutes, and then she stepped away and preened herself for a few moments…

…before taking off, leaving the spider lying there–where it still lies this morning.  It still has seven legs, so if the wasp was trying to chew any of them off, she didn’t succeed. Spider wasps in the tribe Auplopodini (the ones that make cylindrical mud nests, of which there are many by my back door) habitually remove several of a spider’s legs before carrying it to their nest.  I’m not sure if this is to make it less awkward to carry, or maybe to prevent the spider from escaping if it’s not fully paralyzed (this one was still moving its legs a little), or for some other reason.  And I have no idea why a wasp would go to all this trouble to secure its prey only to abandon it.

About Charley Eiseman

I am a freelance naturalist, endlessly fascinated by the interconnections of all the living and nonliving things around me. I am the lead author of Tracks & Sign of Insects and Other Invertebrates (Stackpole Books, 2010), and continue to collect photographs and information on this subject. These days I am especially drawn to galls, leaf mines, and other plant-insect interactions.
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