Just-so stories: why spiders don’t have necks

Commenter Marella asked a question based on the post about scorpions just below:

Marella

What I’d like explained is why arachnids don’t have necks. Everyone else has one and finds it useful, but arachnids have to move their entire bodies to look around.

While having my walk, the answer suddenly came to me—in the form of a limerick. Or rather, the answer came to me as it would be given by a molecular biologist who denies the ubiquity of natural selection (e.g., two posts down). So:

An anti-selectionist lout
Was asked why all spiders are stout:
“Why, the gene for the neck
Is deleted, by heck,
And that’s why they can’t look about!”

And a related one just came to me in the shower (I swear: soon I’ll start dreaming about monkeys holding each other’s tails):

“The giraffe,” said this colleague last fall,
“Causes me no amazement at all;
“Why the gene for the neck
“Is repeated, by heck:
“And that’s why the damn thing’s so tall!”

35 Comments

  1. Posted December 2, 2012 at 3:21 pm | Permalink

    Lol.

    Jerry, you’re a poet and you didn’t even figure it out!

    • Posted December 2, 2012 at 5:37 pm | Permalink

      + 0.5 (not quite a +1 IMHO, but still pretty funny)

  2. Grania Spingies
    Posted December 2, 2012 at 3:39 pm | Permalink

    Very good 🙂

    If the biology thing doesn’t work out, you can maybe try your hand at becoming National Poet or something.

  3. aldoleopold
    Posted December 2, 2012 at 3:55 pm | Permalink

    Love it!! Can we expect a WEIT limerick book out by spring 2013? 🙂

  4. Diane G.
    Posted December 2, 2012 at 3:56 pm | Permalink

    Ha, ha! Brilliant!

    As a pro-selectionist, non-lout (if I say so myself), I was gonna reply much more dully…

  5. Linda Grilli Calhoun
    Posted December 2, 2012 at 4:00 pm | Permalink

    I think you should challenge the Digital Cuttlefish to a poetry slam. L

    • Torbjörn Larsson, OM
      Posted December 2, 2012 at 4:04 pm | Permalink

      Kitteh against cuttlefish?

      Poor fishie.

      • Ichthyic
        Posted December 2, 2012 at 8:46 pm | Permalink

        oh noes, in the world of poetry, cuttlefish is more like Architeuthis!

  6. Posted December 2, 2012 at 4:02 pm | Permalink

    Except assassin spiders, which have evolved to hunt other spiders. They have necks, long ones. And are extremely creepy.

    • Dominic
      Posted December 3, 2012 at 4:42 am | Permalink

      Technically it is still a part of the head! Amazing creatures!

  7. Torbjörn Larsson, OM
    Posted December 2, 2012 at 4:03 pm | Permalink

    A limerick by estimable Jerry,
    is making us laughing and merry.
    Why, no post on boots!
    Instead it’s a hoot.
    And that’s why the damn things so eerie.

    • Occam
      Posted December 2, 2012 at 5:22 pm | Permalink

      There was this bright chap in Chicago
      Who figured speciation long ago:
      Selection of genes
      Gave nature its means —
      And PuffHo their mental lumbago.

      • chascpeterson
        Posted December 3, 2012 at 9:49 am | Permalink

        keep the day jobs

  8. Matthew Cobb
    Posted December 2, 2012 at 4:16 pm | Permalink

    Crabs don’t have necks either.

  9. Scott near Berkeley
    Posted December 2, 2012 at 4:16 pm | Permalink

    I speculate that no one from Ukiah is posting or reading, or a spate of haikU would have broken out by now.

    • Diane G.
      Posted December 2, 2012 at 4:26 pm | Permalink

      ( o _ o )

      Wow; I shall no longer believe in coincidence!

    • Posted December 2, 2012 at 8:37 pm | Permalink

      Spiders have no necks.
      This is why they are so stiff
      even in Springtime.

      b&

    • Jim Sweeney
      Posted December 2, 2012 at 11:46 pm | Permalink

      I used to have friends in Ukiah, and now my brother lives in Haiku (on Maui).

  10. Marella
    Posted December 2, 2012 at 4:58 pm | Permalink

    For me? You shouldn’t have, *blushes*, but thanks! Finally it all makes sense.

  11. hexag1
    Posted December 2, 2012 at 5:24 pm | Permalink

    Jerry,
    While we’e doing biology poetry, you should share Walter Garstang’s amazing poem “The Axolotl and the Ammocoete”

    The Axolotl and the Ammocoete
    by Walter Garstang
    from “Larval Forms, and other Zoological verses”, 1966

    Ambystoma’s a giant newt who rears in swampy waters,
    as other newts are wont to do, a lot of fishy daughters:
    These Axolotls, having gills, pursue a life aquatic,
    But, when they should transform to newts, are naughty and erratic.

    They change upon compulsion, if the water grows too foul,
    for then they have to use their lungs, and go ashore to prowl:
    but when a lake’s attractive, nicely aired, and full of food,
    they cling to youth perpetual, and rear a tadpole brood.

    And newts Perrenibranchiate have gone from bad to worse:
    They think aquatic life is bliss, terrestrial a curse.
    They do not even contemplate a change to suit the weather,
    But live as tadpoles, breed as tadpoles, tadpoles all together!

    Now look at Ammocoetes there, reclining in the mud,
    Preparing thyroid-extract to secure his tiny food:
    If just a touch of sunshine more should make his gonads grow,
    The lancelet’s claims to ancestry would get a nasty blow!

  12. Steven Obrebski
    Posted December 2, 2012 at 6:00 pm | Permalink

    With reference to some spidery
    mating habits where the females
    eat up the males after reproduction:

    A spider said “What the heck?”
    And asked his lady to neck.
    She declared “My sweet treasure,
    we’re not made for such pleasure.”
    And ate him, not leaving a speck.

  13. abrotherhoodofman
    Posted December 2, 2012 at 6:38 pm | Permalink

    “Gene selection is not the king!”
    Shapiro was likely to sing.
    “Some bits don’t code!”
    “And others erode!”
    — Essentially not saying a thing.

  14. Posted December 2, 2012 at 7:44 pm | Permalink

    Necks are derived; necklessness is a derived condition. Animals are neckless unless they evolve necks.

  15. Posted December 2, 2012 at 7:44 pm | Permalink

    Edit: necklessness is the *ancestral* condition.

  16. Posted December 2, 2012 at 7:49 pm | Permalink

    So fish are neckless: necks evolve in Devonian tetrapodomorphs with the separation of the pectoral girdle from the skull, and allowed for feeding on land.

    Most crustaceans are neckless; insects (derived within Pancrustacea) evolve the neck by the loss of the carapace and division of the cephalothorax. Again, associated with feeding on land.

    Arachnids, however, feed by shoving food in their mouth with their chelicerae, and don’t have to move their heads up and down.

    • Diane G.
      Posted December 2, 2012 at 8:20 pm | Permalink

      I was also thinking that many of them don’t use their eyes as much for foraging/hunting as they do other senses, so they wouldn’t have such a need for moving their heads? (Excluding things like jumping spiders!)

  17. Steven Obrebski
    Posted December 2, 2012 at 11:12 pm | Permalink

    With respect to comments by Dianne G. concerning jumping spider vision:

    A jumping spider tried to increase its chances
    Of spotting flies behind it with sidelong glances
    But it found it easier to see more flies
    With median and posterior lateral eyes

    • Diane G.
      Posted December 3, 2012 at 5:18 pm | Permalink

      Nicely done. 🙂

  18. Jim Sweeney
    Posted December 2, 2012 at 11:59 pm | Permalink

    Hate to nitpick, but doesn’t a giraffe have seven cervical vertebrae, like pretty much every other mammal?

  19. joe3eagles
    Posted December 3, 2012 at 1:01 am | Permalink

    American football linebackers have also have no neck. Must be a dormant gene.

    • joe3eagles
      Posted December 3, 2012 at 1:02 am | Permalink

      Oops, that post has a repeating “have” gene.

  20. Posted December 3, 2012 at 3:17 am | Permalink

    I first looked at my mission with dread,
    when the earlier verses were read
    then I conceded
    than no neck is needed
    with eyes on the side of your head.

    • Diane G.
      Posted December 3, 2012 at 5:19 pm | Permalink

      While that may be often the case
      For critters that mainly are chased
      Most spiders that hunt
      Have their eyes out in front;
      And must move their entire carapace.

  21. Roo
    Posted December 3, 2012 at 8:13 am | Permalink

    Love it. I want to see a Where The Side Walk Ends-esque book of Jerry Coyne evolutionary poetry for kids. It could be a classroom aid for science curriculum…


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