Flower Color Evolution

Big history post here (big history meaning all of history, not just human), about the fabulousness of how evolution works. This is about the ways bees created the colors we see on flowers.

We know that bees are super-pollinators critical for much of earth’s plant life. And we observe how bees are drawn to sweet smells and colorful flowers, so it is easy to assume that the plants would have been the initiators to develop their alluring traits, but it turns out that the opposite is true.

Flowering plants or angiosperms evolved between 240-200 million years ago, and they initially were not colorful. They and the gymnosperms (like conifers) began to develop anthocyanins, molecular compounds that regulated their heat and protected them from herbivores. Initially, some of these anthocyanins were red.

But studies have shown that it wasn’t until bees came along that the rich color diversity developed. A study from Australia showed that, when the land mass separated 34 million years ago from other continents, its flowers were pretty boring and bland. But by examining how the color receptors in bees’ eyes operate, they could detect which flower colors would most stand out. These scientists were looking to compare the colors of flowers in Australia today with flowers across the world. They reasoned that if the flowers developed the same colorful anthocyanins independently across the globe after bees came on the scene, it would show that bee preference would have been the force pushing natural selection forward.

And so it was! And from the specific vision receptors in bees’ eyes has arisen the hues of flowers we get to see today. (At least, where it’s not winter.)