Octopus are really amazing and of all the inverts, they are smarter than others. They can camouflage themselves, they can open jars, solve puzzles and are very efficient escape artists. Now, researchers with the University of California, at Santa Barbara have discovered another unique aspect of the octopus, the capability for its skin to change color without a central nervous system. That is, the California two-spot octopus can sense light without the use of its eyes.
Researchers Todd Oakley and Desmond Ramirez discovered the skin of the California two-spot octopus (Octopus bimaculoides) can sense light due to opsins in its skin that are of the same family found in its eyes. These light sensitive proteins enable the skin to detect brightness, but not contrast or edge, according to Desmond Ramirez , lead author of the study and a doctoral student in the Department of Ecology, Evolution and Marine Biology at the university. Ramirez exposed white light to the skin tissues and this caused the chromatophores to expand and change their color. When he turned the light off, the chromatophores relaxed and the skin resumed its original coloration. They dubbed this process Light-Activated Chromatophore Expansion, or LACE.
“Octopus skin doesn’t sense light in the same amount of detail as the animal does when it uses its eyes and brain,” Ramirez said. “But it can sense an increase or change in light.”
Upon further examination, Ramirez found rhodopsins, which is usually produced in the eye, in the sensory neuron’s of the tissue sample’s surface. The presence of rhodopsins in the skin suggests an evolutionary adaptation of octopus camouflage.
“It looks like the existing cellular mechanism for light detection in octopus eyes, which has been around for quite some time, has been co-opted for light sensing in the animal’s skin and used for LACE,” Oakley said. “So instead of completely inventing new things, LACE puts parts together in new ways and combinations.”