Lungwort in UV light. Lungwort (Pulmonaria officinalis) flowers showing the bull's-eye pattern of absorbed (dark areas) and reflected (light areas) ultraviolet (UV) light on the flower heads. These patterns are known as 'nectar guides' and help to attract pollinating insects, which can see UV light. Humans are unable to see these patterns. This image was taken using a digital camera adapted to filter and detect UV light. The resulting image is monochrome as UV light is outside the visible spectrum and has no true colour. See image B830/3461 for daylight version.