Scientists have long wondered about the purpose of the pyramid-like conical cells that cover the petal surfaces of 80 per cent of flowers.

They were not thought to attract pollinators, since bees and other insects can spot nectar-rich flowers from their colour, shape and smell.

A new study has now revealed how the cells make life easier for bees.

Without the conical cells, the insects would be like climbers struggling to find a foothold on an ice-covered cliff.

They provide a "Velcro-like" surface the bees can hook their feet onto, said the researchers reporting their findings today in the journal Current Biology.

To test the role of the cells, scientists created lollipop-like artificial flowers cast from epoxy resin. Half had surface projections similar to conical cells and half did not.