Slimy Slug Sex in Your Own Backyard

IT IS A LASCIVIOUS BOUT OF FOREPLAY AND COPULATION that might have made the authors of the Kama Sutra blush. Its well-lubricated gyrations are featured in an uncharacteristically erotic nature video from the BBC (stay tuned for that). And it can happen in your own backyard, as it did here in Montpelier this past weekend.

During our neighborhood party in Vermont’s capital city, a pair of Leopard Slugs (Limax maximus, rhymes with Climax Maximus), uh, well, did it on a sugar maple late Saturday night. Right next to our four-square court!

I’ve witnessed some crazy courtship and mating in nature — some of it not too pretty. I’ve watched a male Least Tern hop onto the back of a female and rub a dead fish back and forth slowly (lovingly?) across the nape of her neck. (Don’t try this at home.) Dragonflies engage in some of the most elegant yet ruthless sex ever evolved. And duck sex is literally twisted.

Slug sex is slow and slimy — and requires some gravity. The spectacle begins when the slugs ascend a meter or so up a tree or other vegetation. After some tentative rubbing and nudging (which is when we found them), the slugs lower themselves from a strand of mucous about a foot-and-a-half long. They entwine and spun freely in a position we might call “The Double Helix.” And from here the kink begins.

Leopard Slugs are hermaphrodites, with supple, translucent male organs that emerge (“evert” is the biological term) from an opening at the side of head (pictured below). Their penises begin to entwine, sort of like a big, external French kiss. And when fully engaged, they blossom into a kind of slimy florette that glows a soft blue, during which the slugs exchange sperm (which is what you’re seeing here). Yeah, right here in Montpelier, a lovely prelude to leaf-peeping season.

After 15 minutes or so on our maple, each slug slowly retracted its penis (no apophallation here, thank goodness), unentwined, lowered itself back to earth, and went off to lay hundreds of eggs. There is no long-term pair bonding in slugs — probably not even a morning phone call. I’m told these copulations happen on warm, humid nights. We’ve got a few more on the way, and the Perseids are all but over. So head out with a flashlight and a camera these next few nights.

Oh, here’s that BBC video, which is amazing (but a bit over the top, if you ask me — okay, like this blog post). By the way, the Leopard Slug is an invader — native to Europe, North Africa, and Asia Minor rather than North America. I guess it gets around in transplanted soil. Finally, here are some great images from a guy, apparently in Australia, who was “called away for dinner” before the cheap thrills ended.