All insects live within a dead shell called the cuticle, an armour, that surrounds the organism, protecting and equipping it to suit its environment as best as possible. The insects are not the only organisms bearing cuticular exoskeleton, sharing the exoskeleton with arthropods in general. The phylum arthropoda includes crustacea, myriapods, arachnida and insecta. In this blog I will talk only about the cuticle of the insects.
The insects account for more than 60% of the living organism on earth. With such a vast amount of species it is amazing that all insects have a cuticle that in its general composition does not vary significantly. The insect cuticle is formed on and by the organism’s epidermis and is divided into three main layers, the endocuticle, exocuticle and the epicuticle (see figure in sidebar).
The cuticle as a whole has a variety of functions such as a water barrier between the living organism and the environment it lives in, a defensive barrier from pathogens as well as a mechanical barrier that can ward off physical and chemical damage. Outwardly the cuticle creates structures that allow the insect to sense tactile and chemical cues of the environment, or that allow the insect to camouflage it self either through mechanical or photonic camouflage. Inwardly the cuticle serves as an exoskeleton allowing muscles and tendons to work.
Common to all insects is that the cuticle is a water barrier between the living tissue and that of the environment as well as a barrier that can respond and manipulate the environment to allow the owner to have a greater survivability . It is specifically the diversity and ingenuity of the insect cuticle that in so many ways fascinates and boggles me. However to understand the evolutionary powers behind and the physical properties and limitations of the insect cuticle it is necessary to know how the cuticle is made and in what ways it can be moulded.
