Genus Danaus Monarch Butterfly Wing Posters
This very familiar Danaus plexippus species is also known as the Monarch Butterfly. Notice the striking venous stripes represented by a darkened region on either side of each wing vein. This bold pattern is the model for other species to mimic as predators are well aware of the distasteful glycosides this species stored up from eating poisonous Milkweed plants as a caterpillar.
Characteristic patterns on a wing are the result of the wing shape, the mapping of the wing venation, and the actual shape size and coloration of pattern elements formed by the scale cells. There are several studied processes that are responsible for modifying the generic pattern elements found in the Nymphalid ground plan into the spectacular diversity we have come to expect from these inspirational insect designers. Each individual wing cell (the space between the wing veins) are capable of customizing the pattern elements found within. This kind of cell-by-cell customization gives the freedom to resize, shape and color individual elements.
An additional mechanism worth noting is known as pierellization where pattern elements become so dislocated from their expected neighboring wing cell element that they align to other elements. This freedom of pattern manipulation has allowed species like the Indian Leaf Butterfly to simulate a very convincing leaf pattern on the ventral wing surfaces, complete with venation that mimics a leaf rather that a butterfly wing.