That rainbow you see on the ground when oil sits on a wet sidewalk, that captivating swirl of color shimmering on the outer surface of that bubble, or the reflections of color on the back of your favorite CD; its iridescence and is displayed in many creatures of the animal kingdom. Iridescence is basically the ability of an object to show different colors when viewed from different angles. When you look at the animal kingdom you see this property in many species of animals, insect exoskeletons as well as bird feathers are the most common iridescence exhibit, but fish scales and shells Oysters also display an impressive range of colors. For the purposes of this article, I will specifically look at the iridescence of the exoskeletons of the most diverse group of insects on the planet, beetles (Order Cleopatra), and how this eye-catching pattern evolved to help them survive and thrive while throughout evolution. If you want to find the origin of this beautiful metallic assortment of light, you just need to look deep into these beetles, so to speak. Epidermal cells and more particularly the smoother ER of these cells seem to be responsible. The smooth ER synthesizes proteins that then overlap to form a complex network pattern. The differentiation of coloration in many animals arises from a phenomenon known as thin layer interference, by layer on layer structures with a lattice-like formation that interferes with visible light. Researchers know where these proteins come from, but they seem to assemble into this complex structure that offers a wide range of iridescent colorations without any rhyme or reason. Furthermore, why did iridescence ever arise and thrive in the gene pool? All animals...... middle of paper ......the for beetles, the beautiful iridescence is these are diffreaction gratings. Diffraction is the propagation of light around an object or barrier. Diffraction gratings are parallel slits on the outside of the beetle's cuticle and when white light hits these grooves it is reflected. Arrangements, spacings and thickness of gratings can produce a range of colors. For this reason, Driffaction networks can create the most remarkable display of “rainbow colors”. The physics of light determines the order of colors that will be visible on the beetle, as this is the same order in which the spectra of light fall due to wavelengths, much like a rainbow . First red with the longest wavelength passing to orange, yellow, green, until arriving at shorter wavelengths like blue, then finally to violet. Unlike three-dimensional photonic crystals, diffraction