By Trying It All, Predatory Sea Slug Learns What Not to Eat

June 6, 2013 — Researchers have found that a type of predatory sea slug that usually isn't picky when it comes to what it eats has more complex cognitive abilities than previously thought, allowing it to learn the warning cues of dangerous prey and thereby avoid them in the future.

The research appears in the Journal of Experimental Biology.

Pleurobranchaea californica is a deep-water species of sea slug found off the west coast of the United States. It has a relatively simple neural circuitry and set of behaviors. It is a generalist feeder, meaning, as University of Illinois professor of molecular and integrative physiology and leader of the study Rhanor Gillette put it, that members of this species "seem to try anything once."

Another sea slug species, Flabellina iodinea, commonly known as the Spanish shawl because of the orange outgrowths called cerata that cover its purple back, also lives off the west coast. Unlike Pleurobranchaea, however, the Spanish shawl eats only one type of food, an animal called Eudendrium ramosum. According to Gillette, the Spanish shawl digests the Eudendrium's entire body except for its embryonic, developing stinging cells. The Spanish shawl instead transports these stinging cells to its own cerata where they mature, thereby co-opting its victim's body parts for its own defense.

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