Insects are featured by presence of exoskeleton or cuticular body wall which specifies it’s Arthropoda character.
BODY WALL STRUCTURE
The body wall provides with two distinct layers of cuticle:
EPICUTICLE = present externally lacks chitin component. It is of variable types among different orders of insects.
PROCUTICLE = present next to epicuticle. Incorporated of chitinous exocuticle and endocuticle.
COMPOSITION OF CUTICLE
About 50-80% Proteins such as Resilin, Arthropodin, Sclerotin forms cross linkage with 20-50% of Chitin [A polysaccharide chain of Acetoglucosamine (C8H13O6N) x] which gives rigidity to the cuticle.
It forms the living part of body wall. Columnar cells are incorporated with gland cells that secrets cuticle under the influence of moulting hormone. Thus it also referred as chitogenous epithelium.
Trichogen cell i.e. cell that forms seta outer side of body wall and Dermal Gland cells also found in this layer.
It is composed of flattened cells and forms the base of body wall.
FUNCTIONS OF BODY WALL
1. It protects and maintain the body form.
2. Get rides of dehydration of body.
3. Allow diffusion of CO2 and promotes respiration.
4. Outer modifications of cuticle forms sensory , defensive, feeding, locomotory and copulatory organs.