Wasps: artists or robots?

by Matthew Cobb

[Continuing my lazy practice of re-posting material from elsewhere in the blogosphere and bringing it to the attention of WEIT readers, here’s one I posted last week over at Pestival (the insect arts festival – yes, honest!  Go look!)]

In case you weren’t listening to BBC Radio 4 at 06:15 am the other Sunday morning, I thought I would present to you the case of one of nature’s artists, the potter wasp. This small solitary wasp was the subject of the excellent Radio 4 programme The Living World. Anyone, anywhere in the world, can listen to it again here:

The female wasp makes a little clay pot about 1cm across, with a small hole in the end. She lays an egg in the pot, and then crams it full of living, semi-paralysed caterpillars which her offspring can eat. You can see quite how small the pot is in this photo from the BBC website, by Andrew Dawes. The “pot” is the tiny white thing underneath the middle finger!

[EDIT: The following (clearer) picture was taken by WEIT reader TrineBM (see comment 2 below)]:

According to Wikipedia (so it must be true, no?) the great entomologist Karl von Frisch, who was the first to study the honey bee’s waggle dance, claimed that the shape of the potter wasps’s pot inspired native American pottery designs. Quite how one could know that was true (or not) is hard to say – and what about other pots from round the world that look pretty much the same?

But is the wasp really an artist? Does it know what the pot should look like? John Walters, who’s been studying the potter wasps on this Devon heath for the last four years, says that he thinks each wasp has a different style – some pots are symmetrical, others have distinct twists. That doesn’t mean to say they know what they’re doing. Indeed, it seems certain they do not.

One of my favourite studies of animal behaviour was carried out on a potter wasp in 1978 by Andrew P. Smith, then of the University of Sydney. On the other hand, I seem to be one of very few people who rate this work – it has only been cited 13 times in the last 32 years. I feel your pain Dr Smith!

Andrew’s wasp – Paralastor – makes a rather more elaborate nest than the Devon potter wasp, a kind of odd umbrella shape, made up of a mud column and a bell-shaped entrance, leading to an underground chamber where the larva can munch its way through its living lunch, as seen here:

This picture shows the female wasp in action:

So how does she know what to build? Construction takes place in stages:

But does she have an image of what the final nest should look like? Or does she simply know that she’s carried out a series of behaviours and simply do them in sequence? The answer to both these questions is “No”.

Through a series of experiments involving changing the ground level, or altering the angle of the column, or making holes at various points, Smith was able to show that the wasp in fact proceeds by a series of steps, each of which is induced by a particular stimulus. If she sees a hole, she makes a column – even if this ends up with a bizarre double-umbrella nest:

The conclusion of the paper – apart from a lot of very tired and confused wasps – is this rather neat flow diagram, showing how the wasp decides what to do next:

So the wasp is not an artist, it’s more like a simple robot, carrying out a task when the appropriate conditions are provided. Less romantic, but still amazing!

Andrew P. Smith (1978) An investigation of the mechanisms underlying nest construction in the mud wasp Paralastor sp. (Hymenoptera: Eumenidae). Animal Behaviour 26:232-240.


  1. whyevolutionistrue
    Posted November 15, 2010 at 5:28 am | Permalink

    I haven’t read the paper, but what’s her stimulus to stop building the straight column and then curve it around, ultimately producing the “umbrella”?

    • Matthew Cobb
      Posted November 15, 2010 at 5:59 am | Permalink

      It would appear to be the height of the column above the ground. If you put a load of mud around the column, she then builds a column of the same height again, and then starts putting the curve on it. This shows that it’s a visual signal and not an “I’ve put all this effort in” signal.

      • Dominic
        Posted November 15, 2010 at 6:12 am | Permalink

        Why the wide entrance? Presumably it helps stop rain water clogging up a smaller entrance, allowing it to drip off?

        • Dominic
          Posted November 15, 2010 at 7:52 am | Permalink

          Oh I see – read it – they are to deter parasitic Chrysidid wasps – but only during construction. They level it off then so the umbrella construction is wrecked – a sort of destruam et aedificabo.

      • Peter Carlton
        Posted November 15, 2010 at 7:18 am | Permalink

        Probably what matters is the height of the column above its own base, and not above the ground, right? Since in the double-funnel nest (Figure 4), the upper column extends even farther above the ground…

        • Matthew Cobb
          Posted November 15, 2010 at 7:20 am | Permalink

          Yes, good point!

  2. TrineBM
    Posted November 15, 2010 at 6:40 am | Permalink

    Ohhh – how timely! I found two potter wasp nests this summer, and knowing nothing of potter wasps, I had to ask our local entomological society “what’s this”? before I got my iPhone ca´mera ready I’d already sliced one of them open revealing two biggish, green larvae. The other one looked like this:

    Sorry if this doesn’t work – It should be a link ???

  3. TrineBM
    Posted November 15, 2010 at 6:41 am | Permalink

    Oh – I should have gone for this maybe?

    • TrineBM
      Posted November 15, 2010 at 6:42 am | Permalink

      I’m sorry – link-fail. Epic link-fail. I’ll just fade myself out. But it was beautiful.

      • whyevolutionistrue
        Posted November 15, 2010 at 7:24 am | Permalink

        Have included photo in updated post. Did you get a photo of the pot with the larvae in it?

        • TrineBM
          Posted November 15, 2010 at 7:30 am | Permalink

          Unfortunately not! I kicked myself afterwards, but I’m not much of a photographer and only remembered to take a pic after I’d dissected and thrown away the whole thing. Made a description of it though while I “dissected” the nest. Will dig it up when I get home.

        • TrineBM
          Posted November 15, 2010 at 2:55 pm | Permalink

          OK – my notes on the “dissection” of the other nest:
          – the outside is like fine layers of mud, the place where it was attached (to a parasol made of cloth) has a perfect imprint of the cloth on it. Obviously built while wet.
          – the inside is much more smooth.
          – This nest has no lid on it, the opening is in fact open. (The one in the picture is closed, and it looked very much like it was closed from the inside).
          – two surprisingly big larvae inhabited the nest. They were between 1,5 an 2 cm.s long, bright green, with a lighter stripe down their sides. Almost full length. Nothing else inside.

          I don’t know if the larvae were in fact potter wasp larvae, intruders or if they were meant as food for potter wasps. I have not been able to find pictures of potter wasp larvae on the internet to compare.

          Well – that was my potter wasp adventure this summer! Potter wasps were rare, but they are becoming more and more common in Denmark.

  4. Sven DiMilo
    Posted November 15, 2010 at 7:06 am | Permalink

    So the wasp is not an artist, it’s more like a simple robot, carrying out a task when the appropriate conditions are provided.

    Amazing indeed, especially as the robot-programming is somehow transduced from nucleotide sequences! The mechanisms of genetically encoded behavior are a real puzzle.

    Trine, no problem to cut & paste the url, and it’s worth it–a much much better photo than the one supplied in the OP.

    • Dominic
      Posted November 15, 2010 at 7:59 am | Permalink

      And we are robots too, if slightly more complex. Just try telling that to religious folk though.

      • Mike from Ottawa
        Posted November 15, 2010 at 11:48 am | Permalink

        Of course, by your own profession, nobody cares what you say.

        • Torbjörn Larsson, OM
          Posted November 15, 2010 at 2:33 pm | Permalink

          Huh? It’s science, so people really *do* care about what is learned and communicated.

          The only thing that would make sense out of that utterance is if you were a godbot, I think.

          Which, considering the subject, is deliciously ironic.

  5. Richard Benton
    Posted November 15, 2010 at 8:12 am | Permalink

    I am reading Bees,Wasps,and Ants by Eric Grissell.It is a fascinating,and humorous look at hugely various,and indispensable Hymenoptera(the little thing that run the world.There is a certain species that can produce over a thousand twins from one egg.But wait,theres more-read it

  6. Dominic
    Posted November 15, 2010 at 8:37 am | Permalink

    This article sparks more questions for me. Smith said that oviposition can occur at any time after funnel construction has begun & before the food catapillars are deposited. I wonder how often chrysidids (cleptoparasites – a new word to me!) if ever, manage to steal a nest. Are they species specific or do they steal any parasitic wasp or tunnelling bee nest?

  7. astrokid.nj
    Posted November 15, 2010 at 11:04 am | Permalink

    Very fascinating, even with my limited knowledge of the life sciences. When I was studying Engineering in India about 20 years ago, these wasps would find their way into my hostel room and build their pot-nests on my clothes hanging in the closet!! I hated them then, the caterpillars were especially yucky, but am loving the science behind it now 🙂

    I wanted to read up similar posts on this site, using the ‘categories’, but you have left this one Uncategorized.
    Also, Is there any way to display the list of All categories (so that I can explore past posts)?

  8. bobby
    Posted November 15, 2010 at 11:15 am | Permalink

    From a previous pestival: the finest insect based stand up set ever.

  9. bobby
    Posted November 15, 2010 at 11:16 am | Permalink

    sorry, i didn’t know that would happen…

  10. Tim Harris
    Posted November 16, 2010 at 3:28 pm | Permalink

    re the alleged remark of Karl von Frisch (a hero of mine), certain species of potter wasps in areas other than the Americas construct nests that have much the same shape as the one that is said to have inspired Native American pottery…

  11. Posted November 16, 2010 at 5:48 pm | Permalink

    No intent in this case as with none behind natural forces per Lamberth’s atelic/teleonomic argument: selection had no foresight to have the bees decide which kind of pots to make!
    We need ever to invoke this argument against directed-evolution, which not only violates the Ockham and is parasitic on natural causes, but also contradicts natural causes and explanations. To aver intent rather than complementing science, contradicts it!
    No form of creation evolution- Behe or evolutionary creationism- Miller as You and Rossow implicitly note is valid- mere sophisticated obscurantism!
    Jerry, that is why you, PZ and I so vehemently denounce so-called theistic evolution! Please use this argument, my friend!

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