Butterfly adaptations to blend in, show off and shimmer
The phenomenal variety of colors on butterfly wings are sorted into patterns that repeat from right to left wing. But they vary from the top sides of wings to the bottom sides. To our eyes, a single butterfly may boast practically the entire color spectrum. That ranges from red to violet. The colors can be in patterns. The patterns include circles, dashes, and splashes. It is challenging to figure out how natural selection has shaped this wild riot of colors.
If you look across butterfly species, you can see trends. Many butterflies have bright colors on top. But they have duller colors on the bottom. Lots of butterflies have repeating large, round spots along the edges of their wings. These look like eyes painted on. The surfaces of butterfly wings are shimmery. Their colors shift when viewed from different angles.
Scientists observe how animals behave in relation to their habitats. This is how scientists explain body patterns. A fluttering butterfly is easy to see. But it is hard to catch. In flight, bright butterfly wings create a flashing effect that may alarm predators. Or it may make zeroing in on a butterfly harder. A perched butterfly often shows the duller side of its wings. This may be to conceal it from hungry birds or snakes.
Butterfly colors may also play a role in mate attraction. Every butterfly species has a unique set of color patterns. Some female butterflies vibrate their wings in a way that displays patterns. This may announce their species to males. For colors to work in courtship, they must be visible to the eyes of the viewer. It turns out that butterfly eyes have large visual fields and extra color photoreceptors. They support a rich, panoramic color vision.
Pigments are compounds that absorb certain light wavelengths and reflect others. They are responsible for most of the colors humans and other animals see. But blues in nature do not often come from pigments. Animals that look blue are reflecting blue light in other, unique ways. Such animals are Blue Jays or Peacocks or Blue Morpho Butterflies. This has less to do with chemistry and more with structure.
Learn more about structural butterfly colors and how they relate to butterfly adaptations in a "Smithsonian Science How" webcast on Thursday, May 24, 2018. It airs at 11 a.m. and 2 p.m. EDT on the Q?rius website. During Butterfly Adaptations – How They Come By Their Colors, Butterfly Pavilion Manager Eric Wenzel and Microscopy Educator Juan Pablo Hurtado Padilla will take you behind the scenes with butterflies. They will answer your questions live. You can also get teaching resources to use with the webcast.