Exocutícula

Exocutícula is a term used in biology, primarily in the study of insects and other arthropods, to refer to the outermost layer of the cuticle. The cuticle itself is a protective, non-cellular outer covering that provides structural support and defense against environmental factors. The exocuticle is characterized by its hardness and rigidity, due to the presence of sclerotizing agents like proteins and chitin, and often phenolic compounds.

This hardened layer is distinct from the endocuticle, which lies beneath it and is more flexible. The exocuticle plays a crucial role in protecting the organism from desiccation, physical damage, and predation. It is also the primary component of exoskeletons, which are shed periodically during molting (ecdysis) to allow for growth. The precise composition and thickness of the exocuticle can vary significantly between different arthropod species and even within different body parts of the same organism, reflecting adaptations to specific ecological niches and lifestyles. In some insects, the exocuticle may also bear decorative or sensory structures.