Cuticle: Ecological Significance

Abstract

The morphological and chemical complexity of the arthropod cuticle reflects the many diverse and important functions performed by this multilayered external covering. As noted by Beament (1976), the arthropod integument is an integral part of such physiological processes as locomotion, respiration, feeding, excretion, and osmoregulation. It serves as an interface between the organism and the environment and, in so doing, helps resist the influx of disease-causing microorganisms, insecticides, and other potentially harmful external contaminants in addition to providing mechanical protection. In many species, the cuticle also effectively deters predators, either as a result of its being a physical barrier or because of camouflage and/or mimicry created by elaborate surface structures or colours. The latter can also protect the arthropod against harmful ultraviolet radiation and provide limited thermal benefits for some terrestrial species through increased absorption or increased reflection of solar insolation. Chemical compounds associated with the cuticle also produce signals or form surface patterns which act as visual cues to enhance species recognition and location. No cuticular function, however, is perhaps more important from both an immediate and evolutionary standpoint than its role in restricting water loss. It is the one feature that was essential for the transition of arthropods from an aquatic to a terrestrial existence, and is largely responsible for the various forms and structures observed in the general arthropod integument today.