Golden eye in UV light. Coloured photograph of golden eye (Bidens ferulifolia) flower in ultraviolet (UV) light. The bull's-eye UV pattern is a result of the flower either reflecting UV (yellow) or absorbing UV (dark). This pattern is known as a 'nectar guide' and is thought to attract insect pollinators that can see in UV light. This image was taken on a digital camera adapted to filter and detect UV light. The resulting monochrome image was coloured on a computer. See image B802/1169 for the same flower seen in daylight.