1. Introduction
Silk, from both domesticated and wild silkworms and spiders, represents a unique and important class of polymeric composite materials in nature providing a wide range of evolutionary and ecological functions with optimum microstructures and properties [1] and [2]. Larvae of silkmoths spin silk threads and form cocoon shells to enwrap themselves completely prior to metamorphosis. These cocoon shells are non-woven structures majorly composed of two proteins, fibroin and sericin. They exhibit extensive variation in structure, property and composition which imposes direct influence on their adaptive function. The functional significance of these proteinaceous structures includes crypsis, provision of barricade from predators, pathogens and parasitoids and assisting the pupae to complete their metamorphosis by improving thermal and/or moisture conditions [3]. The multitude of variations in diet, breed and climate resulted in considerable diversity in the type and properties of the cocoons and fibers produced by silk producing insects of different origins and within the same type. Thus, species-specific fiber mechanical, chemical and physical properties reflect the ecology and behaviour of cocoon-spinning insects [4] and [5] and can significantly influence the quality, quantity and efficiency of the reeling process in commercial varieties [6].