A pigment is a substance that adds color
More is brighter, less is duller.
Of these two flowers, chicory has less
Than Lechenaultia seems to possess.
Of Nature’s colors, blue is a little weird. There are plenty of blue pigments in the plant kingdom, but not so much among the animals. This is where we encounter structural colors. Most structural colors tend to be sparkly or metallic. More about that on the iridescence page.
Even within plants, blue is not that common, less than 10% of the plant species make blue pigments. The one above, Lechenaultia (sometimes spelled Leschenaultia), has an especially vibrant blue color. This is mostly caused by a pigment with the glorious name: delphinidin 3-O-[6-O-(malonyl)-beta-D-glucopyranoside]-7-O-[6-O-(4-O-(6-O-(4-O-(beta-D-glucopyranosyl)-trans-caffeoyl)-beta-D-glucopyranosyl)-trans-caffeoyl)-beta-D-glucopyranoside.
Some of the plants that have purple colored flowers or leaves combine red and blue pigments. The most common blue pigment is anthocyanin. It is a little unusual because it can cause different colors – especially in response to the acidity of the soil. The picture below is of hydrangeas, and these plants have blue or pink flowers depending on the chemical nature of the soil.
The chicory plant has a much softer color than the Lechenaultia. It has common names like blue daisy, blue dandelion, blue sailors, and blue weed. Roasted roots have been used to make a coffee-like drink. Bluefield in West Virginia got its name from the abundance of chicory flowers that used to grow there and which were used not only for the ‘coffee’, but as feed for animals. It was a useful feedstuff because the chemicals in the plant helped to reduce the number of parasites living in the cattle.
Chicory contains four anthocyanins: delphinidin 3,5-di-O-(6-O-malonyl-beta-D-glucoside); delphinidin 3-O-(6-O-malonyl-beta-D-glucoside)-5-O-beta-D-glucoside; delphinidin 3-O-beta-D-glucoside-5-O-(6-O-malonyl-beta-D-glucoside); and delphinidin 3,5-di-O-beta-D-glucoside.
Blue in animals is a different story.
Blue pigment is rare in their inventory.
Blue pigments are rare in animals. Blue eyes, as in our friendly husky, or blue colors in soft bodies molluscs and amphibia such as the blue poison-dart frog, involve pigments. However, blue is much more likely to result from how hardened parts of animals are structured to cause blue light to be refllected more than any other colors. There are plenty of examples with the skeletons of insects and the feathers of birds,
The Gould’s or Gouldian finch is an Australian seed-eating finch. The short tapered beak is common in finches and seed-eaters. Because of its pretty colors, it was exported around the world to be kept as caged birds. These days, their numbers in the wild have greatly diminished. Originally, they lived in places without predators, but with the expansion of European civilization, cats and foxes now roam the land. These brightly colored birds are especially likely to be seen and caught.
So, how come blue is on show
By the rainbow lorikeet below?
It’s how the feathers are constructed
So that only some colors are reflected.
That creates the nice blue sheen
Then add some yellow to get green.
If you ever find a feather of a blue bird, look at it with light in front and light behind. When the light is behind the feather, you will not see any blue color – only brown or black. This is one way to show that the blueness does not come from pigment. Rather the color is caused by the way that the feather reflects and refracts the incoming light. The detailed structure of often miniscule elements within the feather cause some colors to be reflected and some not so. Often such feathers have a dark component to help absorb other wavelengths (colors). This makes the structural blue color seem stronger. Especially in parrots, the feathers may contain other pigments, such as the reds and yellows. When feathers with yellow pigments also have blue structural features, then we see green.
More information about colors in birds here.