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Headless sea slugs, or bodiless sea slug heads, take your pick | CellPress & N.Y. Times

March 17, 2021

[Posted by Chuck Almdale]

People sent me four links to this slugfest. I’ll pass on two of them.

Their severed heads get around just fine until they regenerate perfectly functioning, parasite-free new bodies, scientists say.
New York Times | Annie Roth | 8 March 2021

A few years ago, Sayaka Mitoh, a Ph.D. candidate at Nara Women’s University in Japan, was perusing her lab’s vast collection of sea slugs when she stumbled upon a gruesome sight. One of the lab’s captive-raised sea slugs, an Elysia marginata, had somehow been decapitated.

When Ms. Mitoh peered into its tank to get a better look, she noticed something even more shocking: The severed head of the creature was moving around the tank, munching algae as if there was nothing unusual about being a bodiless slug. More…

Now if you really want the details, here’s the original article published in Cell Press: Current Biology. This includes more photographs and a 2:46 minute film of the day-by-day progression of the process of losing one’s head…that is, losing one’s body.

Extreme autotomy and whole-body regeneration in photosynthetic sea slugs

Current Biology | Sayaka Mitoh & Yoichi Yusa | 14 January 2021

Summary of Paper
Autotomy, the voluntary shedding of a body part, is common to distantly-related animals such as arthropods, gastropods, asteroids, amphibians, and lizards. Autotomy is generally followed by regeneration of shed terminal body parts, such as appendages or tails. Here, we identify a new type of extreme autotomy in two species of sacoglossan sea slug (Mollusca: Gastropoda). Surprisingly, they shed the main body, including the whole heart, and regenerated a new body. In contrast, the shed body did not regenerate the head. These sacoglossans can incorporate chloroplasts from algal food into their cells to utilise for photosynthesis (kleptoplasty), and we propose that this unique characteristic may facilitate survival after autotomy and subsequent regeneration.

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