Genus Speyeria Fritillary Butterfly Wing Posters
The genus Speyeria belong to a group of butterflies known as Fritillaries. Some species exhibit sexual dimorphism where female and male adults have strikingly different coloration. The patterns in this poster are from the dorsal (upper) wing surfaces and illustrate how a pattern element is repeated but varied from wing cell to wing cell.
If we take a closer look at the individual scale cells, we notice they vary considerably in size, shape and structure. Scale cells are generally held at a 45 degree angle to the wing membrane. The exposed top surface of these scale cells have an elaborate extra cellular structural architecture known as fenestration. These micro structures play an important roll in the iridescent color characteristics of various butterflies. The tiny structures interfere with light wavelengths and usually result in brilliant shimmering blues and greens. The multitude of other colors found on the scales of butterflies and moths comes from pigmentation. Each scale cell holds a single color pigment that include melanins, ommochromes, pterins, and flavonoids derived from plants.
Observing patterns as a whole, we notice that the left and right wing designs are generally symmetrically along the axis of the body. The dorsal (top) forewing, dorsal hindwing, ventral (underside) forewing and ventral hindwing represent the four wing surfaces that carry a unique pattern on each butterfly species. The dorsal wing surfaces typically display bold, simple and colorful designs, whereas the ventral surfaces are notably more detailed. This phenomenon corresponds with the fact that the dorsal surfaces are generally visible during the rapid undulating wing beats of flight compared to the detailed and often cryptic ventral surfaces which are encountered in plain view as the stationary butterfly assumes a resting position. (continued…)