Squid can switch up their color and patterning in a flash, using their skin to send signals or camouflage themselves. Researchers have now shown how the structure of certain cells and their pigment work together to manipulate light and create the cephalopods’ stunning patterns.
Cells in the color-producing chromatophore organs of the cephalopod’s skin hold sacs of pigment. When surrounding muscles contract, the pigment pockets stretch to produce circles of color with hues based on which wavelengths the pigment absorbs. Deeper within the squid skin, groups of cells called iridophores make the skin shimmer as they reflect all incoming light because of their structural properties.
The new study, published March 1 in Nature Communications, reveals that chromatophores in the squid Doryteuthis pealeii employ particular proteins called reflectins that also lend them iridescence.
T.L. Williams et al., “Dynamic pigmentary and structural coloration within cephalopod chromatophore organs,” Nat Comm, doi:10.1038/s41467-019-08891-x, 2019.