Secrets of the shiny yellow buttercup

When it comes to attracting pollinators, buttercup petals hold all the aces. They even provide their guests with heating

Do you like butter? Hold a buttercup under your chin and folklore says if there is a yellow reflection on your skin it means you do. But the real reason the flowers seem to shine with an intense glittering yellow is nothing to do with butter but about advertising the plants to insect pollinators from a great distance.

Buttercups get their bright colour from yellow pigments in the petals' surface layer, and their shiny gloss is thanks to layers of air just beneath the surface reflecting the light like mirrors. The glowing phenomenon is unique in plants, although something similar happens with some butterfly and bird wings.