Why is the colour blue so rare in nature?
Blue is a very prominent and beautiful colour on planet Earth. Our sky and oceans are all blue! Don’t you feel a sense of peace and warmth just by looking at this colour? But have never heard of a blue plant or animal. Ever wondered why? This is due to the rarity of the colour blue in nature! However, there is one insect that is an exception. We will tell you more about the colour blue, the reason behind its rarity, and the exception too!
A rare mineral that produces blue pigment
The colour blue is rarely found in nature because only a few organisms can create the true-blue pigment. Also, no naturally occurring compound can colour things blue. This is why you often won’t see blue rocks and minerals. Lapis lazuli, mined in Afghanistan, is the only mineral that produces a rare blue pigment called ultramarine. Owing to its uniqueness, lapis lazuli was considered sacred in the olden days!
Why do plants not have blue leaves?
Now that you know of rocks, let’s find out why blue is so rare among plants. Blue pigments are not found in any plant. It’s true! Some plants have a blue appearance, but this is not their true colour. Some of the blue flowers you may see at florists are artificially grown with their DNA altered or pH levels altered. But what about leaves? Are there blue leaves? When certain plants reflect high-energy light, their leaves appear blue. However, high energy light is harmful to their health. You’d be surprised to know that only 10% of all flowering plants on the planet appear blue!
Why are animals not blue?
The colour of animals is usually determined by their diet. Flamingos, for example, are pink due to the dye found in shrimp. Goldfish get their golden colour from their aquatic diet. Can you think of any blue-coloured food in nature? No, right? That is why there are no blue animals. However, there is one exception: the Blue Jay bird! They get their blue colour through a different process. Their feathers contain microscopic beads that scatter light. Every wavelength is cancelled out when light is reflected from their feathers, with the exception of one. Yes, you guessed it right, blue! So, their feathers appear blue when they are flying across the sky.
The Obrina Olivewing butterfly, an exception
The only species of animal known to produce the true-blue pigment is the Obrina Olivewing butterfly! It gets its characteristic blue from a pigment called pterobilin. Other butterflies produce bluish colours too, but these are not from true blue pigments. For example, the blue–green wings of the common Bluebottle butterfly found in Southeast Asia and Eastern Australia are caused by a bile pigment and a blue-absorbing carotenoid called lutein. The Morpho butterfly found in South America also has blue wings, but this blue is the result of light reflection.