Q: I have a bed of double zinnias in red, yellow, and white colors. Butterflies love the white and avoid the red and yellow flowers – why?
A: Different butterflies are attracted to different colors and nectars. They do not see the color red as well as we do, which might explain why they are not visiting the red zinnias. Butterflies can see light that is invisible to animals, including humans. Petals of many flowers reflect ultraviolet light that we cannot see. Flower colors evolved for the benefit of insects. They are created by light reflecting from pigments rather than minerals or nutrients in the plants and flowers.
Butterflies are more attracted to mass plantings than single specimens, which is another reason why they are visiting your zinnias.