A loveless left-handed snail can’t find a mate

September 21, 2017 • 2:30 pm

Is there a Match.com for gastropods? Because if there is, “Jeremy,” a rare left-handed variant of what the Torygraph says is a garden snail (Cornu aspersa) needs to put up his profile pronto:

Left-handed garden snail seeks mate for companionable dinners (no garlic butter!), long crawls on the beach, and, above all, mating. No right-handed snails need apply.

Most land snails have right-handed coiling, but the Torygraph reports that researchers at Nottingham University found a rare, left-handed variant: a one in a million find. Naming it “Jeremy” (these are hemaphrodites), they started a worldwide search for another left-handed snail, because, for reasons shown just below, lefties can only mate with lefties, and righties with righties:

Alas, poor Jeremy was a big-time loser. As the Washington Post reports:

And just weeks later, after drawing international attention, Jeremy’s love story appeared to reach a fairytale ending. Not one, but two left-coiling mates came forward: “Lefty,” a snail owned by a collector in England, and “Tomeu,” a snail rescued at a restaurant while awaiting a fate as a menu item.

As winter hibernation came to a close, Davison hoped the heat would turn up for Jeremy and one of his two possible mates.

“But in a tragic twist, Jeremy has been left shellshocked after being given the cold shoulder by both of his suitors,” Davison said.

That’s right, Jeremy was thrust into a love triangle. The other two snails took a liking to each other, leaving Jeremy a bachelor once more. Lefty and Tomeu began copulating, and now have produced about 170 eggs between them, Davison announced Wednesday.

“We liken it to when you’re interested in someone romantically and you end up introducing that person to your best friend,” Davison said. This first batch of eggs to hatch were “fathered” by Lefty and laid by Tomeu in April. (Snails are hermaphrodites so they can take on the role of either mother or father.) Two more batches of eggs — another laid by Tomeu and one laid by Lefty and fathered by Tomeu — will soon be hatching.

The curious thing is that all the offspring of Lefty and Tomeu have right-handed coiling! How could that be? Well, it’s an interesting story of snail genetics and how the genes for coiling are inherited and activated, but I’ll let a reader fill in that part.

Here’s Jeremy along with a snail of opposite coiling:

Photo by Angus Davidson

And Lefty and Tomeu mating (TRIGGER WARNING: SEX: NSFW!) Poor Jeremy!

“Lefty” and “Tomeu” are pictured mating. (Courtesy of Angus Davison).

As of last May, the aging Jeremy was still a virgin. Lefty went back to hir owner (these are rarities), but the researchers still hope that Jeremy and Tomeu will mate. With further judicious crosses, they could produce an entire race of left-handed snails, and they’d in effect be producing a new species, since members of that group couldn’t mate with the right-handed type.

36 thoughts on “A loveless left-handed snail can’t find a mate

  1. Snails mate face-to-face with their sex organ protruding from the right hand side.

    Leaving aside the fact that snails have no hands, the diagram seems to show the genitalia protruding from the snails’ left sides.

    1. I was going to suggest rotation through the fourth dimension. That way the sex organs would be compatible (though the biochemistry would not be).

        1. I think I see Jeremy’s problem – see the top photo
          (“Here’s Jeremy along with a snail of opposite coiling:”)

          That’s not how you do it, Jeremy!


      1. Why don’t the snails face the same direction, with Jeremy on the right?

        That doesn’t solve the problem that Jeremy appears to be sexually unattractive to other snails.

        1. Excellent idea. Now, how do we tell Jeremy, I assume he doesn’t speak English. Sign language, maybe? 😉


  2. Brilliant story! Would whatever determines the handedness of snails be one of those vaunted magic gene(s) example that leads to instant reproductive isolation and eventually perhaps speciation? Are there any instances of sister species with different handedness?

    1. Good point. At least one general biology textbook that I am familiar with (Campbell Biology) suggests that the direction of coiling is often affected by just one or a few genes, and there indeed are sister species with different handedness (e.g., in the genus Bradybaena). The inference here is that, just as you suggest, this sort of mechanical, pre-zygotic isolation is a potential mechanism of speciation. One usually thinks of different forms of local natural selection in geographically isolated (allopatric) populations causing speciation (and PCC,E is an expert on the topic). But in this case one wonders whether genetic drift at one or a few genes could cause fixation of different handedness alleles and hence mediate speciation.

  3. It’s honeysuckle rather than snails, but nevertheless, you might enjoy the Flanders & Swann song Misalliance, available in YouTube.

  4. Could someone please define “right” and “left” “handedness” (or “coilingness”, I suppose) for snails. If it is a side view which way should the snail be oriented – relative to my onlookers “right” or “left”.

    1. I assume a right-handed snail shell is one that coils in the same direction as a right-handed screw.

      A right-handed screw is one that you screw in by gripping the screwdriver in your right fist and turning in the direction your fingertips point.

  5. Perhaps Jeremy could mate with a regular right-handed snail if one were upside down. You never know if you will like it unless you try!

    1. I’m thinking this could actually work. Stick them to opposite faces of a sheet of glass and have them approach a hole in the glass from opposite sides. One veers left and the other veers right and the corresponding parts come together in the middle.

  6. This is appalling. The social construct of right-handedness obviously privileges members of the dominant chirality over the oppressed minority. We must right this by making the right-handed oppressors acknowledge their guilt.

    Left-handed good! Right-handed bad!


  7. This is appalling. The social construct of right-handedness obviously privileges members of the dominant chirality over the oppressed minority. We must right this by making the right-handed oppressors acknowledge their guilt.

    Left-handed good! Right-handed bad!


  8. I spent a summer working on a strawberry trial, myself and another field worker collected all the snails into a bucket. I felt like a pimp for the snail orgy that ensued.

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