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.
The story of Gillette’s Pleurobranchaea-Flabellina research began with a happy accident that involved showing a lab visitor Pleurobranchaea’s penchant for predation.
“I had a Pleurobranchaea in a small aquarium that we were about to do a physiological experiment with, and my supplier from Monterey had just sent me these beautiful Spanish shawls,” Gillette said. “So I said to the visitor, ‘Would you like to see Pleurobranchaea eat another animal?’”
Gillette placed the Spanish shawl into the aquarium. The Pleurobranchaea approached, smelled, and bit the purple and orange newcomer. However, the Flabellina’s cerata stung the Pleurobranchaea, the Spanish shawl was rejected and left to do its typical “flamenco dance of escape,” and Pleurobranchaea also managed to escape with an avoidance turn.
Some minutes later, his curiosity piqued, Gillette placed the Spanish shawl back into the aquarium with the Pleurobranchaea. Rather than try to eat the Spanish shawl a second time, the Pleurobranchaea immediately started its avoidance turn. (Watch a video of this interaction.)
“I had never seen that before! We began testing them and found that they were learning the odor of the Spanish shawl very specifically and selectively,” Gillette said.
Gillette and his team later replicated that day’s events by placing a Pleurobranchaea in a training arena 12-15 centimeters from a Spanish shawl, then recorded the Pleurobranchaea’s behavior. They returned the Pleurobranchaea to the arena for four more trials in 20-minute intervals, then repeated the procedure 24 and 72 hours later.
In the experiments, those Pleurobranchaea whose feeding thresholds were too high (meaning they were already full) or too low (they were extremely hungry) would either not participate or completely consume the Spanish shawl, respectively. Those that were hungry, but not ravenously so, continued to exhibit the avoidance-turn behavior when placed with the Spanish shawl even 72 hours later.
This showed that Pleurobranchaea was selective in its food choices, but only on a case-by-case basis; the sea slugs already trained to avoid the Spanish shawl would readily eat a species closely related to Flabellina called Hermissenda crassicornis.
Such behaviors come in handy in Pleurobranchaea’s natural environment, Gillette said.
“If you’re a generalist like Pleurobranchaea, it’s highly strategic and advantageous to learn what’s good and what’s not good so you can decide whether or not to take the risk or of attacking certain types of prey,” he said.
These findings show that the “simple” Pleurobranchaea is much more complex than originally thought.
“We already knew the neuronal circuitry that mediates this kind of decision,” Gillette said. “Finding this highly selective type of learning enlarges our perspective of function, in terms of the animal’s ability to make cost-benefit decisions that place it on a rather higher plane of cognitive ability than previously thought for many sea slugs.”
Chelsey B. Coombs | University of Illinois
Cryo-electron microscopy achieves unprecedented resolution using new computational methods
24.03.2017 | DOE/Lawrence Berkeley National Laboratory
How cheetahs stay fit and healthy
24.03.2017 | Forschungsverbund Berlin e.V.
Astronomers from Bonn and Tautenburg in Thuringia (Germany) used the 100-m radio telescope at Effelsberg to observe several galaxy clusters. At the edges of these large accumulations of dark matter, stellar systems (galaxies), hot gas, and charged particles, they found magnetic fields that are exceptionally ordered over distances of many million light years. This makes them the most extended magnetic fields in the universe known so far.
The results will be published on March 22 in the journal „Astronomy & Astrophysics“.
Galaxy clusters are the largest gravitationally bound structures in the universe. With a typical extent of about 10 million light years, i.e. 100 times the...
Researchers at the Goethe University Frankfurt, together with partners from the University of Tübingen in Germany and Queen Mary University as well as Francis Crick Institute from London (UK) have developed a novel technology to decipher the secret ubiquitin code.
Ubiquitin is a small protein that can be linked to other cellular proteins, thereby controlling and modulating their functions. The attachment occurs in many...
In the eternal search for next generation high-efficiency solar cells and LEDs, scientists at Los Alamos National Laboratory and their partners are creating...
Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are less stable. Now researchers at the Technical University of Munich (TUM) have, for the first time ever, produced a composite material combining silicon nanosheets and a polymer that is both UV-resistant and easy to process. This brings the scientists a significant step closer to industrial applications like flexible displays and photosensors.
Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are...
Enzymes behave differently in a test tube compared with the molecular scrum of a living cell. Chemists from the University of Basel have now been able to simulate these confined natural conditions in artificial vesicles for the first time. As reported in the academic journal Small, the results are offering better insight into the development of nanoreactors and artificial organelles.
Enzymes behave differently in a test tube compared with the molecular scrum of a living cell. Chemists from the University of Basel have now been able to...
20.03.2017 | Event News
14.03.2017 | Event News
07.03.2017 | Event News
24.03.2017 | Materials Sciences
24.03.2017 | Physics and Astronomy
24.03.2017 | Physics and Astronomy