Sad, doomed little spider

Don’t worry, no photos of the pathetic creature here. Yesterday, I found one of my little friends in mid-molt — but there was a problem, and she had failed to extract her left legs, and so her limbs were immobilized and trapped in her old cuticle. I left her alone, hoping that today she’d have managed to complete the molt.

She didn’t.

I put her under the microscope, grabbed some watchmaker’s forceps, and delicately peeled away the stuff that had her legs bound. The operation was a success, in that all was removed without doing any further harm to the spider. But now her legs are deformed, and permanently, I think. They’re elongated, and locked together around the patella. She can’t move them. She drags herself around with her right legs, dragging the unmoving mass of the left with her.

I don’t think she’ll make it. This seems to be a common cause of mortality, general failures during molting. I’m suddenly grateful to have squishy stretchy skin that doesn’t need to be periodically replaced wholesale.

<shakes fist at sky> How could a benevolent deity allow such tragedies?


  1. birgerjohansson says

    God made a design error during creation, not making the molting process more reliable. Come to think of it, he flubbed the embryogenesis process too, making a big chunk of fetuses fail and be rejected at the earliest stage of pregnancy.
    The only organism that is nearly indestructible is the cockroach. And, of course, the “water bear”.

  2. moarscienceplz says

    Oh PZ,
    At long last, don’t you realize this is all part of omnicient God’s plan to (mumble, mumble, cough, gasp)!
    Jeebus saves!!!

  3. nomdeplume says

    What’s that hymn something about “he knows when a sparrow falls”? I guess he’s just not aware of invertebrates.

  4. Jean says

    If it had access to enough food, would another molt correct this or would the damage be permanent?

  5. Dago Red says

    Similar problem among young snakes, who lose their desire to feed while molting….and then inadvertently starve to death before they can get the hang of molting during their first or second molt. Very sad (if you like baby snakes).

  6. StevoR says

    Pardon my aboslute ignorance but do arachnid limbs regrow? I wonder if the deformed ones were amputated and the spider nursed through this cycle – perhaps quickly encouraged to moult again whether that might save it and allow it to survive and take its normal shape again?

    Or do spiders not work like that?

    Or a set of tiny arachnid prosthethes or invertebrate crutches?

  7. StevoR says

    Would more delicate spider surgery to separate the limbs and reduce their length be worth a try?

  8. John Morales says

    … well, there’s the popular conception of Darwinian evolution.

    (The culling of the weak)

  9. StevoR says

    @ ^ John Morales : Popular perhaps but a misunderstanding of it tho’ – “survival of fittest” and specifically more reproduction over time by the fittest, yes.

    Death by moulting failure, (Which seems here to be more bad luck rather than “unfitness” as such?) not-so-much.

    “Fittest” needing considerable defining and varying on specifics and context.