Butterflies have colorful and intricate wing patterns. These patterns 1) protect from predators through camouflage, 2) attract potential mates, 3) warn predators that the butterfly is toxic or 4) mimic toxic butterfly species to discourage predators.
Butterfly wings have two sides. Generally the upper (dorsal) side is used to seduce mates while the lower (ventral) side communicates toxicity and provides camouflage.
There is a specific gene that creates the pattern differences between the dorsal and ventral wing surfaces. When this gene is mutated both wing surfaces have the ventral wing pattern.
California sister butterflies illustrate the pattern differences between the upper and under wing sides. The dorsal California sister (Adelpha californica) wing surface is dark brown to black with orange patches near the tips of the forewings and broken white bands across the center of both the front and hind wings. The ventral surface also shows the orange patches and white bands but also has blue bands along the edges and blue and brown markings near the body.
The dorsal butterfly surface was photographed along Fenders Ferry Road in the Shasta Trinity National Forest (Shasta County CA). The ventral view illustrated my earlier post, California Sister 09-03-14). More information on the California sister can be found in this post.