The Wild Sex Life of Slugs

March 27, 2010
The wild sex lives of slugs
These sexual athletes are not just something to throw into your neighbour’s garden — they deserve far more attention
Simon Barnes

Warning: the following piece contains some of the most extraordinary information about sex that you will ever read. If you find sex dull, then please seek out the sports pages and look for the golf. What I have to tell you will make the doings of Zeus, Messalina and the figures carved on the Konark Temple seem like the tame experiments of the undersexed and the unimaginative.

Because I’m talking about slugs. Gardeners don’t like slugs, and fight a war with them throughout the summer months, seeing them as the incarnation of an evil and hostile nature. Slugs are poisoned as if it were a moral crusade, or pursued with all kinds of ingenious use of beer and crushed eggshells.

But even as the war continues, slugs are pursuing their own mysterious lives, and they do so with wild exoticism, remarkable athleticism, astonishing stamina, amazing virtuosity and a conclusion that would daunt the boldest of us.

Slugs are many and various. There are more than species in this country, where the cold limits the things that a slug can get up to. There are about 5,000 species worldwide: slugs are emblems of the great life-principle of biodiversity, just like everything else. Only a few of them run counter to the interests of gardeners. As Matt Shardlow, of the invertebrate charity Buglife, says: “It’s rather like finding one species of monkey that causes problems and damning all the primates.”

Slugs are molluscs, shell-less snails — save that some slugs, confusingly, have reduced or internal shells, and there are three shelled slugs in this country. That’s not confusing, that’s just glorious biodiversity. As molluscs, slugs are related to squids and octopuses, so let that add a little prestige to the nocturnal garden-creepers.

They have two pairs of tentacles; the front ones sense light and the back ones sense smells. These are retractable, and they can be regrown. And yes, they do slime. Two sorts of slime: watery stuff, and thick, sticky stuff. They get about by gliding gracefully along this self-created carpet. It’s hard for human beings to get excited about mucus — though it is life and death to the slugs — so let’s move on to sex.

For a start, slugs are hermaphrodites. Both halves of a pair have penises, both halves present sperm to the partner, and both halves go off and lay eggs. Slugs have the best of both worlds. But they are not just wham-bammers. They believe in courtship. Perhaps, being female as well as male, they are devoted, to the point of mania, to the concept of foreplay.

It can go on for hours, circling, nibbling and lunging at each other. Sometimes they will savour each other’s mucus, perhaps to get genetic information, perhaps just as a light sustaining snack. Anointed in mucus, they engage in a slimy and sensual ballet. Some species will do this suspended from long ropes of mucus: acrobatic, gravity-defiant, and no doubt as thrilling as doing it on a trapeze.

The pace is slow, the rhythm sensuous, as if each nuance is savoured. And some species have the most colossal penises: half as long as their own bodies. You can find copulatory rituals in which the pair dance about each other, each partner waving a giant penis overhead.

The act continues with a mutual entering and a prolonged and slimy embrace. But then, how to break it off? The phrase, I fear, is no metaphor. With some species, a long and corkscrew-shaped penis doesn’t always emerge too easily. In these circumstances — gentlemen are invited to cross their legs at this point — one slug chews off the penis of the other. Sometimes both slugs will perform this feat. It is called apophallation. The slug, hermaphrodite no longer, goes away. Alas, he can’t grow another penis. So she carries on as a female for ever after.

And you thought slugs were just something to throw into your neighbour’s garden. Don’t poison them: that kills plenty of things other than slugs. You can, if you are truly good, lure them with potato halves and then dump them somewhere wilder.

Perhaps we should consider our gardens as a corner of the wild: a place that doesn’t require total control freakery, a place where frogs and toads, hedgehogs and birds can drop by to snack on slugs.

If you savour your garden as a place that has something to do with nature, then accept that slugs play their part. They deserve your consideration for their gladiatorial sex lives.