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of the University of Puget Sound slug penises, which are as long as, if not longer, than their body, are everted, wrapping around each other and continually expanding until they form a translucent, orb-like penis flower. Be sure to watch out for that while walking through the woods! After copulation, the sex organs are retracted safely within the mantle and one slug falls to the ground, while the other eats its way up the mucus rope, recovering the precious water lost to its costly production.
of withdrawal: apophallation, or the oral amputation of one or both of the partner’s penises in order to separate postcopulation. This behavior is not uncommon in the Ariolimax genus to which the banana slug belongs. Interestingly, this rather unfortunate end doesn’t seem to discourage banana slugs from jumping back on the sex wagon. They are able to continue the mating season as females and can re-grow a penis for the next annual apophallation.
The genus Deroceras includes most generic small garden slugs, some of which have made some amusing additions to the courtship stage and some cutbacks in copulation. Specifically, Deroceras gorgonium, a common grey slug you might see on a Puget Sound sidewalk at night, has the most branched and largest penial gland of the genus, which they like to wave around, literally. Courtship for these slimers includes about 9-15 hours of circling each other, penises erect and waving, occasionally trashing violently toward each other. Partners are often struck in the face, either by the tail or the erect organ. These blows to the face are followed by periods of inaction, prolonging courtship. Finally, after this unique foreplay, the sarcobela at the base of their genital complex make contact and sperm is excreted. Copulation usually lasts 1-5 seconds. The branch-like top of the penial gland is then used to distribute the secreted material over the partner’s body surface—like a nice slimy pat on the back.
Banana Banging: Apophallation
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The Next Generation
Uncommon Copulation: You will get hit in the face
Have you ever wondered where tapioca balls come from? I’ll give you a hint: they don’t grow on trees...
The genetic material so carefully exchanged in these imaginative methods of intercourse will be packaged into eggs and laid in a cool, moist place to mature. As little as two weeks later, anywhere from tens to hundreds of baby slugs will emerge, ready to continue their parents’ legacy of creative coition, as the orally fixated acrobatic deviants they were meant to be.
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Banana slugs are a popular favorite in the Pacific Northwest, known for their alarmingly good impersonation of snot and their anesthetic effects when licked by daring hikers (though I caution that they can carry salmonella). Banana slugs are also known for their particular practice
*This is not altogether true. In fact, mating leopard slugs were observed by students Kyle Wenholz and Evan Arkin on the University of Puget Sound campus, outside the Thompson science building, on a structure that was only about three feet tall.
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Leonard, J. (2006) Sexual selection: lessons from hermaphrodite mating
Banana Slug foreplay usually involves hours of tender nibbling. I wonder if their radula get numb...
systems. Integrative and Comparative Biology 46 (4): 349–367 Reise, H. (2007) A review of mating behavior in slugs of the genus Deroceras (Pulmonata: Agriolimacidae). American Malacologist Bulletin 23: 137-156 Reise, H., S. Visser, J. M. C. Hutchinson (2007) Mating behaviour in the terrestrial slug Deroceras gorgonium: is extreme morphology associated with extreme behaviour? Animal Biology 57 (2): 197-215