Attention Female Slugs: Beware Ninjas Bearing “Gifts”

by Jennifer Frazer on December 30, 2010

This is *not* the ninja slug, but if you imagine that seedpod is a katana, we're 90% of the way there. OK, maybe not. Creative Commons papalars. Click for link.

As the year rounds down, I wanted to point you in the direction of a nice gallery put together by the editors at National Geographic of 2010′s weirdest new animals.

My fave: the ninja slug of Borneo. Apparently these guys shoot calcium carbonate hormone-soaked “love darts” into their paramours. Somehow this increases reproductive fitness, though whether it does so by helping lady slugs make more eggs or by putting them more “in the mood”, if you know what I mean, Nat Geo does not say. The wikipedia page seems to imply love dart hormones increase sperm survival on the part of the shooter, and that the use of the darts is fairly widespread among land snails and slugs. As with so many invetebrate systems, I’m *really glad* this is not a part of human courtship. Do not miss the gallery of love dart photos and drawings at the bottom of the page — fascinating. On a related note, anyone who has not scene the epic snail love scene (complete with opera music) in “Microcosmos” is greatly missing out. The snails look like they’re having more fun than most humans. Run, do not walk.

Taxonomically, slugs are snails that lost their shells. Like lichenization, this turn of events has taken place many times in unrelated groups, so “slugs” are what taxonomists call “polyphyletic”, or not a true, valid taxonomic group (which should always be based on a single ancestor and its descendants — that is, a monophyletic group). There are even some slugs that are still in the process of losing their shells and carry a tiny shell too small to duck into on their back, rendering them “semi-slugs”. Slugs are gastropods, which are in turn molluscs. You can see how it all fits together and who else they’re related to here. That’s it for 2010! See you in the New Year!

{ 2 comments… read them below or add one }

Jo December 30, 2010 at 8:57 pm

I think in the Microcosmos slug-love scene, you can see one of those darts; that is if you can tear your eyes away from the rest of the slug embrace!

kati December 30, 2010 at 11:36 pm

must google slugs with tiny shells :)

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