Ingenious squids
The Hindu
How do squids tune colour and brightness of iridescence of their skin?Squids adeptly change the colour and patterns on their skin for camouflage and communication. Like their cephalopod cousins the oc
Squids adeptly change the colour and patterns on their skin for camouflage and communication. Like their cephalopod cousins the octopus and cuttlefish, Squids have specialised pigment-filled cells called chromatophores that expand to expose them to light, resulting in various shades of pigmentary colour. Squids shimmer and flicker, reflecting different colours and breaking light over their skin. Researchers have found that proteins called reflectins are responsible for their iridescence. Now, researchers from the University of California, Santa Barbara, have found (Applied Physics Letters) what allows squids to tune the reflected light. Daniel Morse’s team from the University had already found that structures (subwavelength-wide grooves) and mechanisms by which light-reflecting cells (iridocytes) in the skin can take on virtually every colour of the rainbow. The grooves are formed by a cell membrane that folds into nanoscale accordion-like structures called lamellae. The colour reflected depends on the width of the groove, which corresponds to certain light wavelengths (colours). The width of the grooves can be changed – widened or narrowed – at will by the action of “osmotic motor” driven by reflectin proteins. The researchers then found that the reflectin proteins can not only tune the colour but can also tune the brightness using the same mechanism.More Related News