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Question: What are butterfly wings made of?
The butterfly wing: an amazing structure that seems so delicate and yet it carries Monarch butterflies over hundreds of miles of migration and to high mountain peaks. The butterfly wing can shimmer with hypnotic light on one side and hide the butterfly from predators with the other side. The butterfly wing seems so simple, like a piece of colored paper, but its structure is complicated.
Butterfly wings are made out of chitin, the same substance as the insect's exoskeleton. Along with insects, chitin is found in other arthropods, such as crabs and lobsters, as well as the cells of mushrooms. To chemists, it is a polymer (many long chain molecules) of sugars and amino groups (protein) called N-acetylglucosamine. To most of us non-chemists chitin looks like a semi-transparent, armor-like skin. Butterfly wings contact two layers of chitin with tubes or veins that provide blood and oxygen. After changing from a caterpillar, when a butterfly first breaks out of its chrysalis, the wings look like wadded paper, but soon they are straightened by fluid pumping through the veins.
The scientific name of the order to which butterflies belong is "lepidoptera" or "scale wing." Chitin scales and hairs of various colors cover the clean membrane of butterfly wings. The scales are loose so that when a butterfly flaps its wings it may look like dust swirls around them. The scales are mostly harmless, but some peopel may be allergic to them. Even the colors of a butterfly wing are complicated. Some of the scales contain pigments that reflect certain colors and other scales create color by bending light. Hidden to our eyes, some butterflies shine ultraviolet colors. All these colors may serve different function in different species. Bright colors may signal that a butterly tastes bad or is even toxic to predators, but attract their own species. Since many species of butterflies are declining, when I see one flash its colorful wings, I appreciate it that much more.
Almost fifty species of butterflies have been spotted in the Binghamton University Nature Preserve, including Monarchs and Tiger Swallowtails. To view the Nature Preserve's butterfly list, as well as lists of other animals, visit http://naturepreserve.binghamton.edu/FloraFauna.html.
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