Pigments, also known as biochromes, are colored substances produced by living organisms as a consequence of color absorption that is selective. Chlorophyll, which gives green color, and carotenoids, which offer orange, red, and yellow color, are well-known pigments, but what about the pigment that produces blue color?
Only a few species in nature are owing to the blue pigment generated in their bodies, but the majority of them rely on the physical phenomena known as light interference. The science behind the blue color in nature-
The color blue is created by the microscopic structure of the scales and a phenomenon known as light interference. When two rays of light collide, they cause interference. This produces either a brighter ray of light (Constructive Interference-CI) or no light at all (Destructive interference-DI). Because light is essentially a wave, it contains crests and troughs. When the crests or troughs of two rays meet and overlap, CI occurs, and the waves are said to be 'in phase.' When a crest crosses a trough, however, DI emerges, and the waves are said to be 'out of phase.'
A few examples from nature-
Plant's blue blossoms are caused by pH changes and the mixing of a common red plant pigment called anthocyanin with other pigments and polymers, rather than by blue pigments.
The blue jay's feathers contain a unique bead design that scatters light in such a way that only blue light exits, giving the bird its blue color.
The blue morpho butterfly's hue comes from the ridges in its wing scales, which enable sunlight to bend in such a way that blue light of the proper wavelength reaches our eyes. The blue would vanish if the scales were fashioned differently or if something other than air occupied the gaps between them.
Why blue pigments are so uncommon in the natural world? Based on a concept, it was easier for animals to adapt their structure to take advantage of the physics of light rather than synthesis a new blue pigment as being blue became more desirable for survival (to stand out to attract mates or warn predators). Furthermore, because blue light's wavelengths are shorter and greater in energy than most colors, most biological pigments absorb it.
Use of genetic engineering to turn a flower into blue color-
In 2017, Japanese researchers employed genetic engineering to transform the typical red, yellow, and pink chrysanthemum flower into a cool blue hue. They transferred genes from a blue Canterbury bells flower and a blue-flowering butterfly pea into the plant, which attached a sugar molecule to the anthocyanin and shifted the pH to give the plant its blue hue.
Despite the scarcity of blue pigments in nature, only a few creatures synthesize pure blue pigments. Only a few creatures, such as the olive wing butterfly and the mandarin fish, exhibit a pigment-based blue color.
Discoveries are taking place on daily basis and we might find out more organisms that are truly blue.