As winter weather descends on the Chicago area, we are well-past the butterfly season at the Chicago Botanic Garden. The Butterflies and Blooms exhibit closed in early September and the Garden has already moved the mesh enclosure to its new location for next summer. While construction is going on at the Children's Learning Campus, the butterfly exhibit will be temporarily located in an open area along the east road of the Garden, just east of of the parking lots and south of McDonald Woods. Eventually a new, more permanent butterfly structure will be incorporated into the new Children's Learning Campus. I am thankful the Garden is keeping this wonderful exhibit going in its new location while the transition occurs. It is a highlight of summer for this butterfly enthusiast.
This morning I came across a fascinating article on NPR's website by Rae Ellen Bichell about the color blue in nature: How Animals Hacked the Rainbow and Got Stumped on Blue. In the article Bichell talks about one of the most magnificent examples of blue in nature, the Blue Morpho butterfly. The Blue Morpho is probably the most popular butterfly for visitors to the Butterflies and Blooms exhibit and it's easy to see why. Watching the Morpho fly about the enclosure one can see the shimmering blue of the Morpho's inner wings. As soon as the butterfly lands, she closes her wings and all one sees are the brown outer wings, which are beautifully patterned, but much less of a show-stopper as the glimmering blue. It's hard for us photographers to capture the resting Blue Morpho with wings open since they almost always rest with wings closed.
Most colors in nature - red, yellow, green - are chemical, or derived from pigment. Many animals take these pigments from the foods they eat and incorporate them into their outer structure, hence the pink color of flamingos (shrimp, crabs and algae) and the red breast of the robin (berries). Blue is the exception; it is actually rare for an animal to contain blue pigment. Bichell states, "of all Earth's inhabitants with backbones, not one is known to harbor blue pigment. Even some of the most brilliantly blue things in nature — a peacock feather, or a blue eye, for example — don't contain a single speck of blue pigment." Wait a minute...how do we explain the blue of the Morpho, the blue of a scarab beetle or the peacock feather? According to the article, it's a kind of a trick of nature, a structure or optical technology that has evolved that makes the butterfly or other creatures appear blue. The butterflies have "tiny transparent prism structures" on their wings that reflect light to make them appear blue. If you were to grind up the wings of a Blue Morpho butterfly, it would lose its reflective structure and the dust would be brown.
So next summer, when you see these beautiful creatures of nature fluttering about the enclosure, think of the science behind that blue. The evolution of color and the way animals incorporate it is a fascinating thing!
If you enjoy reading about the Butterflies and Blooms exhibit, read another recent post here.
Link to podcast about Summer at The Chicago Botanic Garden and Butterflies and Blooms exhibit here.