Fluorescent labeling with dual probes (green and red) reveals both cellular nuclei and wing scales in the digital image presented below. Taken with a confocal laser scanning microscope, the wing tissue shows nuclei in green and developing scales in red.

Butterfly Wing Scales and Nuclei Specimen: Butterfly Pupal Wing Epithelium Technique: Fluorescence (Double Label)

A network of scales covers most of the butterfly wing, giving it a beautiful array of colors produced either by pigmentation or through optical interference. The iridescent colors usually associated with butterfly wings arise from the small ridges on the scales, which interact with light causing constructive and destructive interference, much like that produced by a soap bubble. Other coloration in the wing is caused by clusters of dehydrated blood cells, leading to a wide spectrum of colors that we see as distinct patterns in the wings.