What is chitin in butterflies?

Chitin is a tough polysaccharide that forms the external skeleton (exoskeleton) of insects. In butterflies it makes up the wings, legs, head, wing veins, and scales that create coloration.

What are butterfly wings made of?

Butterfly wings are thin chitinous plates traversed by hollow veins (also chitin). The wing surface is covered with tiny chitinous scales — they create color and pattern.

Butterfly Atlas

Chitin

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Chitin is the main structural polymer of insect integument. The hard external skeleton of butterflies, wing scales, and caterpillar armor are made of chitin.

What is chitin

Chitin is a natural polymer from the polysaccharide group, the main building material of the external skeleton (exoskeleton) of insects, crustaceans, and fungi. Structurally it is close to cellulose but contains nitrogen — making it strong and light at the same time.

In butterflies, chitin is the main structural material of the body.

What a butterfly is made of

Exoskeleton — head, thorax, abdomen, legs: all hard body parts
Wings — thin double chitinous plates with hollow veins inside
Scales — modified chitinous hairs covering the wings (hence the order name Lepidoptera — scale-winged)
Proboscis — a spirally coiled chitinous tube

Chitin and wing coloration

Some wing pigments (melanins, flavonoids) are embedded directly in chitin of the scales. Other colors — especially blue and green — arise from nanostructures on the surface of chitinous scales that refract light (structural coloration).

Chitin and caterpillar molting

The chitinous armor does not stretch. To grow, the caterpillar periodically molts — sheds the old chitinous layer and grows a new, larger one. Most caterpillars molt 4–5 times in life.

More on structure — in the article what are butterflies.