The broad-sided yellow pink butterfly is a species of the pink butterfly family that has a wide distribution. The species exhibits a phenomenon known as seasonal polyphenism, where the appearance of the butterfly changes based on the season.

In fall and winter, the forewing markings are lost and there are more reverse markings. In contrast, the common type seen during spring and summer has a rounded front corner of the forewing and a more rounded bend at the 3rd vein on the hindwing.

The inner edge of the black edge of the front wing also points inward on the 3rd vein and is nearly equal in width within the 1st and 4th chamber, with two spots on the opposite side of the forewing in the middle chamber.

The butterfly's most distinctive feature is its two pairs of colorful wings, which are made up of numerous tiny scales. These scales are similar to bird feathers, with a long oval shape and a small short stalk at the base embedded in the wing membrane.

There are two main sources of scale color: chemical color, which is produced by the butterfly's own physiological metabolism, and structural color, which is caused by light scattering, interference, and diffraction by light acting on the microstructure of the scales.

Chemical colors include white, yellow, red, brown, and black and are mostly formed from pigment particles. For example, yellow and red arise from carotenoid pigments, while brown and black come from melanin.

These pigments can be produced by the butterfly through its own physiological metabolism. Flavonoid pigment granules, which form white and yellow, are derived from plant pigments that butterflies ingest as larvae.

Structural coloration is even more variable and is the result of light scattering, interference, and diffraction by light acting on the microstructure such as ridges and grooves on the surface of the scales. This is why we can see the blue-green wings of butterflies in the sunlight always shining with an iridescent metallic shine.

The unique optical and structural properties of butterfly wings have attracted the attention of scientists since 1938 when the growth of butterfly wings was first recorded. These beautiful structures can help inspire the design of new materials and devices.

In addition to their beauty, the structural coloration of butterfly wings also serves an important purpose in their survival. The scales on their wings act as a protective barrier, shielding them from harsh environments. The scales also help to camouflage the butterfly by mimicking the colors and patterns of their surroundings.

The structural coloration of butterfly wings is also highly reflective, which helps them to avoid predators by making it difficult for them to be seen. This is particularly important for butterflies that are active during the day, when they are more visible to predators.

Butterfly wings are also important for thermoregulation, as the scales help to reflect the sun's rays and keep the butterfly cool. This is especially important for butterflies that are active in hot environments.

Overall, the coloration of butterfly wings is a complex and fascinating phenomenon that is the result of a combination of chemical and structural factors. The unique properties of butterfly wings continue to inspire scientists and researchers, as they work to understand and replicate the beautiful colors and patterns found in nature.