Cuticulan

Cuticulan is a term used in biology to describe features, materials, or processes related to the cuticle, the multilayered protective covering that forms the outer integument of many invertebrates, especially arthropods. The word derives from cuticula, Latin for “little skin.” In descriptive usage, cuticulan may refer to cuticular tissues, structures embedded in the cuticle, or products of epidermal secretion that contribute to the layer's properties.

An arthropod cuticle typically comprises several functional layers: the waxy epicuticle and the protein–chitin layers of the exocuticle and endocuticle. The cuticle is secreted by epidermal cells and can undergo tanning or sclerotization, which cross-links proteins to increase rigidity. Lipids and waxes in the epicuticle help reduce water loss and provide a hydrophobic barrier. In crustaceans, mineralization can yield a harder, more rigid exoskeleton.

Functions of the cuticle include protection against mechanical damage, regulation of water loss, and barrier formation against microbes. Its mechanical properties, such as stiffness and flexibility, can vary by layer, developmental stage, and species, influencing movement and habitat adaptation. Coloration and structural coloration can also arise from cuticular components.

Developmentally, many arthropods molt: a new cuticle forms beneath the old one, and after shedding, the new cuticle hardens through processes such as sclerotization.

Research usage of cuticulan appears in entomology and comparative physiology, focusing on cuticle composition, permeability, elasticity, and the molting process. See also cuticle, exoskeleton, chitin, sclerotization, and molting.