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Science & Environment
Mon September 9, 2013
Husband-Wife Team Takes New Approach to Cracking the Mystery of Camouflage
How squids turn what they see into complex, sometimes three-dimensional, camouflage patterns has been a persistent mystery. A husband-and-wife team is applying their diverse experience – with dragonflies and biodiversity – to the difficult problem.
Take a look around you. What would you have to do to make yourself invisible? Would you change your posture? The color of your skin? Could you do it in less than a second?
Cephalopods – squid, cuttlefish, and octopuses - are masters of camouflage. In a quarter of a second, they can adjust their posture, and change the color and even texture of their skin to make themselves indistinguishable from their surroundings. They can also make themselves impossible to miss.
Scientists know some of how they do this. There are chromatophores – special skin cells like sacs full of color that grow or shrink under the control of nerves. There's a second layer of iridescence cells that produce different shimmering effects by building special subcellular structures. Last year, scientists in MBL's Program in Sensory Physiology and Biology demonstrated that iridescence is also controlled by the nervous system.
Changes in color and iridescence are combined with different postures (tentacles, for example, held horizontally or vertically) and skin textures to produce a range of patterns and effects. Researchers can classify all camouflage displays into four general categories, but there are countless variations on those themes.
In the laboratory, scientists can use electrodes to stimulate color and iridescence cells. A squid's s0-called electric skin can even 'dance' to the baseline of music played through electrodes.
The situation in nature is rather more complex, though. How does a squid decide what patterns and textures to deploy at any given moment? They don’t seem to use touch, only sight. And they don’t even have color vision. Somehow, these animals translate a black and white image into full-color, three-dimensional camouflage in the blink of an eye, literally.
MBL Senior Scientist Dr. Roger Hanlon is fond of saying that camouflage is the least studied phenomenon in biology that we think we already know about. Drs. Paloma Gonzalez-Bellido and Trevor Wardhill - a husband-and-wife team working in Hanlon's laboratory - are trying to unlock the secrets of cephalopods' electric skin by putting aside all assumptions.
This is a relatively new area of research for both Gonzalez-Bellido and Wardhill; she previously studied dragonflies, while he has tackled a handful of questions in insect biology and ecology. The two say their experience with other species and different subject matter gives them a fresh perspective on difficult problems.
Of course, their passion and dedication don't hurt either. Gonzalez-Bellido and Wardhill revel in the experience of making a discovery or breakthrough. The pair often works late into the night and through the weekend. They even use their vacations to document interesting behaviors by insects, using the photo sharing website, Flickr, to find possible targets and locations.
Gonzalez-Bellido and Wardhill are expecting their first child in a few months. They say they waited to have a family until their careers felt secure. They still worry some about being able to continue the intense, science-centric lifestyle they've developed, but say they're looking forward to sharing the responsibilities and joys of parenthood ... while still cracking nature's mysteries.