These spiders are zombies

January 16, 2013 • 11:20 am

They’re paralyzed but still alive.

From Minibeast’s Wildlife Photos on Facebook, we have this amazing picture by Alan Henderson, which the caption explains:

Paralysed and waiting: We accidentally broke open a mud-dauber wasp nest under our house yesterday while moving some equipment. The mud cells were packed with paralysed jumping spiders of multiple species. The adult female wasp captures and paralyses the spiders and then packs them into the mud cells. She then lays an egg before closing the cell over with mud. The spiders are paralysed, but not killed so that they do not rot and the wasp larva can consume them over time. I rearranged the contents of one cell for this photograph. A wasp larva is in the centre in the process of consuming a spider.


A somewhat sketchy Wikipedia article reports describes these lovely, thin-waisted wasps:

Adults of both sexes frequently drink flower nectar, but they stock their nests with spiders, which serve as food for their offspring. Like connoisseurs, they prefer particular kinds of spiders, and particular sizes of spiders for their larders. Instead of stocking a nest cell with one or two large spiders, mud daubers cram as many as two dozen small spiders into a nest cell. They appear to know exactly what they are hunting for, and where to find it.

Black and yellow mud daubers primarily prey on relatively small, colorful spiders, such as crab spiders (and related groups), orb weavers and some jumping spiders. They usually find them in and around vegetation.

Blue mud daubers prefer immature black widow spiders and their relatives. They hunt them in dry areas, such as outbuildings, rocky areas and stone piles.

Pipe-organ mud daubers generally provision their nests with various kinds of orb weavers, but their diets includes other kinds of spiders, as well.

To capture a spider, the wasp grabs it and stings it into submission. The venom from the sting does not kill the spider, but paralyzes and preserves it so it can be transported and stored in the nest cell until consumed by the larva. A mud dauber usually lays its egg on the prey item and then seals it into the nest cell with a mud cap. It then builds another cell or nest. Missouri’s mud daubers generally have two generations per year. The young survive the winter inside the nest.

It also notes that mud daubers were responsible for at least one airplane crash.

Here’s a video of one species showing how the group got its name—they roll up balls of mud, carry them to their nest site, and then plaster the mud into a beautiful nest. They are skilled workmen—or, rather, workwomen! Quite an amazing behavior, and one coded, along with every other wasp-y behavior, within a brain the size of a pinhead!

h/t: Matthew Cobb, Alex Wild

26 thoughts on “These spiders are zombies

  1. Wasps get more spiders than any other predator does. There’s good evidence that the cobweb–the kind of web that, for example, widow spiders make–evolved in response to the selective pressure that the evolution of predatory wasps put on orb-weaving spiders. Orb weavers are relatively easy pickings on a flat web (although they can bail out on a major ampullate dragline), whereas cobweb weavers are sheltered in what I think of as a silk shark cage. These poor little jumping spiders don’t make any web at all, and a dragline may not help them too much if a wasp is after them. On the other hand, they’re obviously doing something right because they make up the largest family of spiders (more than 5,000 species).

  2. I presume this sort of parasitic strategy evolved in parallel between wasps and spiders. Or maybe it is so common a strategy that it was also used by way-back common ancestors?

    1. I don’t know that much about the wasps, but I know that different species parasitize spiders like this (especially Sphecid wasps) and also that a number of wasps parasitize different arthropods. The first wasps evolved long after the first spiders.

  3. Local old farmer guy had a story for me years ago. He took his weedwacker to the local small-engine fixer-guy because it wasn’t working. Fixer-guy (puts toothpick in mouth) looks the thing over, mumbles a couple of hmmmms and mmmms, then takes toothpick out of mouth, sticks toothpick in holes in weedwacker engine thingy, blows on it, hands weedwacker back to old farmer guy, says, “yup, those mud dauber wasps are pretty bad this year.”
    There was no charge.

  4. This is a case, I reason, where evolution might have made a small leap. When the wasp’s predecessor made the first mud cave it couldn’t have been too rudimentary to fulfill its purpose. There had to be (at least) four things in place: 1.the wasp collecting collecting spiders for its eggs/larva, 2. the wasp collecting mud for the rudimentary “cave”, 3. the wasp actually putting the mud where the larva was. 4. The wasp laying the eggs where the spiders are.

    Just collecting mud once and randomly releasing it around the larva could hardly have made it an survival advantage. There had to be several mud collecting trips. Also, the result had to be a better protection than just laying the eggs on the ground.

    Evolution is interesting to say the least.

    1. Actually it’s not that hard to imagine a sequence by which this behavior could have evolved incrementally. For instance:

      Wasp lays eggs on muddy ground.
      Wasp preferentially lays eggs in natural dimples on muddy ground.
      Wasp enhances natural dimples by excavating mud before laying eggs.
      Wasp uses excavated mud to build up the edges of the nest.
      Wasp excavates mud from elsewhere to build up the edges of the nest.
      Wasp builds mud nests on surfaces other than mud.
      Wasp begins to carry food as well as mud to nesting site.

      And so on. Of course I have no idea if it actually happened like this, but I don’t think we need to leap to the conclusion that this nest-building behavior is irreducibly complex.

      1. You have a good point but still. I dont think that evolution is that straight forward, always taking one small step after another. Chance also plays a role in evolution. Some very pontent individuals might die due to accidents and some that lack competitive edge might live. Mutations sometimes introduce completely new properties. As you say though, the chain of events leading to this behavior, we will never know.

        1. That is exactly how evolution works. Those events you mention are all, themselves, just little evolutionary steps. As Gregory Kusnick says… no irreducible complexity.

          1. Again, a good point and I dont say that you are wrong. However I dont believe we know everything about evolution yet. Leaps in evolution is in my opinion not only believable but inevitable. Sudden events that change the prerequisites of life or random mutations that takes evolution in a totally new direction has happened many times.

            1. You mean like an asteroid hits and wipes out vast amounts of life? That’s just another evolutionary event. Random mutations are just normal events that happen all the time.

              Nobody claims that everything about evolution is known. If it was we wouldn’t be talking about science. But there is no support for the idea of irreducible complexity which you seem to be advocating. And every time someone has offered an example of irreducible complexity it has been shown to be misguided, as Gregory did in principle with the wasp nest example.

              So unless you have examples of “leaps in evolution” you are just stating some sort of wish you have. (For what? The touch of a deity?)

              1. Certainly not the touch of a deity, I am a “hard core” atheist. I try to think for myself based on the knowledge have, not pretending to know it all. Still dont say you are wrong and still think that I am not wrong. So why the aggressive tone?

                Who is gbjames anyway behind the image of sun radiation.

  5. A delightful and informative book on wasps: “Wasp Farm” by Howard Ensign Evans. An excellent book for the layman.

    “The Hunting Wasp” by John Crompton did not make such a lasting impression on me.

  6. Quite an amazing behavior, and one coded, along with every other wasp-y behavior, within a brain the size of a pinhead!

    I feel uncomfortable with this. As in the case of genes, I would prefer describing this as a recipe ingrained in the brain. To predict these behaviors from coding is like predicting chemical behavior from quantum mechanics.

    We don’t have codes that can do anything like this. And seeing how an animal with these behaviors have to develop to fruition, we can assume any code of ours would have to as well.

    Worst case there is a direct analog to QM, and presumptive future AIs of ours can’t self-analyse what makes them tick. I.e. the behavior is truly emergent on the substrate. Trapdoor encryption shows that this is a possible outcome.

    The upshot of the alternate term is that the environmental complexity and contingency involved becomes more visible.

    1. Hopefully, this will cheer you up: That whole wasp-spider interaction, including the picture, makes for one heck of a dilemma for the creationists.

      1. [Self] “Dr Coyne, Dr Coyne, my creationist has stopped screaming! What can I do?”
        [CC, for it is his voice] “Apply the Dauber Wasps! If that doesn’t work, get a new Creationist, for they are hardly endangered.”
        Sorry, that’s a bit strident. I’ll stick to pecking them to distraction with finches.

  7. I love mud daubers…but they’re far too efficient at filling in every nook & cranny they can find. They seal up all the “hanging holes” on our tools, the stanchion adjustment holes on the goat milking stand…I’ve even had them come investigate my ears! 😀

    And then the mud dries to an almost cement-like hardness.

    1. The worst place that they nest is in my boat. And the worst of that is when they attach their nests to the wiring behind the instrument panel. You can’t yank the nest off, because that would likely pull a wire loose. I generally have to sponge water onto them and then clean up the mess.

      Are these creatures not common everywhere? Jerry’s comments, and the Wikipedia snippet that he quoted, explain their behavior as if there are people who didn’t already know all that. From building the nests with little balls of mud, to paralyzing spiders for their larvae to feed on, every country hick in Texas could explain to you! (Like me.)

  8. “These spiders are zombies,

    They are paralysed but still alive”.

    I hate to quibble about terminology, but isn’t “paralysed but still alive” the opposite of zombie which is usually moving about but dead?

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