doing it: part 2

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"Birds do it, bees do it..." Again, we'll take our lead from Cole Porter.

With snails, the textbook description of reproduction goes something like,

“Some snails are hermaphrodites, producing both spermatozoa and ova. Others, such as apple snails, are either male or female. Prolific breeders, snails in pairs inseminate each other to internally fertilize their ova.

A garden snail, Helix aspersa, is a hermaphrodite, producing both male and female gametes. Reproduction is usually sexual, although self-fertilization can occur. During a mating session of several hours (Yes, hours. So, the next time you hear the phrase "slow as snail," you should smile knowingly.) During this tantric encounter the two snails exchange sperm. (So both become gravid, i.e. pregnant.) The garden snail uses love darts during mating.

Quoting from Indiana Media's “Moment of Science” by Don Glass, “Since only a small part of a snail’s body extends outside its shell, it carries both sets of genitals–male and female–up front near the head.

Now here’s the strange part. About once a week, as garden snails share caresses, pressure builds up in the area surrounding a sac near the genital region housing a calcium dart. Just before the moment of sexual penetration, the impregnating snail stabs its partner near the genitals with what scientists have dubbed the snail love dart.

But what might sound like a nasty sadomasochistic ritual does have a practical purpose. According to one study, the darts are tipped with a chemical preventing the snail on the receiving end from digesting most of its mate’s sperm. As in many species, the garden snail’s female reproductive tract is hostile to sperm, allowing only the toughest and most resilient to fertilize the egg. To increase its chances of passing on its genes, the impregnating snail fires a dart to give its sperm a fighting chance.

Although snails can and do successfully mate without stabbing each other, studies have shown that darted snails store one-hundred-sixteen percent more sperm than undarted snails.”


"After about two weeks approximately 80 spherical pearly-white eggs are laid into crevices in the topsoil, while the weather is warm and damp. After two to four weeks of favorable weather, these eggs hatch and the young emerge. Up to six batches of 80 eggs can be laid in a year.”

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