Scientists discover how metallic blue fruits produce iridescent colour

The Viburnum tinus plant does not solely rely on pigment for its colour.

The iridescent blue colour of the fruit produced by Viburnum tinus, an evergreen shrub widespread across the UK, is down to the fat that lines the cell walls of the outer skin, according to scientists.

In a study which included experts from Cambridge University, researchers have found that this metallic blue fruit, which serves as a nutritious treat for birds, does not solely rely on pigment for its colour.