Britannica Sources used in this answer

What substance helps form an arthropod’s exoskeleton?

Created from Britannica articles using AI. AI can make mistakes, so verify using Britannica articles.

Illustration showing a variety of adult insects, each labeled with its common name and order, including walkingstick, earwig, stonefly, tree cricket, dragonfly, female scale, cat flea, thrips, sucking louse, thysanuran, ant, scarab beetle, stinkbug, mosquito, and cabbage butterfly, highlighting their diverse shapes and sizes. — insect An illustration of insect diversity.

The primary substance that forms an arthropod's exoskeleton is chitin, a high-molecular-weight polysaccharide.1

In arthropods, the epidermis secretes a tough cuticle composed of chitin fibers embedded in a matrix of protein. This structure is often reinforced through sclerotization, a process that stabilizes protein chains to create a natural plastic known as sclerotin. Additionally, the exoskeleton features an outer, water-resistant layer of wax that helps prevent dehydration in terrestrial environments. In some species, such as crustaceans, the cuticle may also be hardened by the incorporation of mineral substances like calcite or aragonite.123