Non-protein chemical compounds from lepidopteran insect cocoons

Abstract

Cocoons are the specialized naturally engineered structures constructed by lepidopteran insect silkworms. They are natural protein composites of fibroin and sericin as a nonwoven biological structural material. This complex structure is presumed to be optimized through evolution over millions of years. It provides the prime protection for the silkworm pupae from biotic and abiotic factors and facilitates the thermal insulation to the inactive pupa stage of the insects, during metamorphosis. In present chapter chemical compounds other than silk proteins in commercially valuable lepidopteran insect cocoons which are responsible for sustained protection of the insect pupae inside the cocoon which is predicted to be the key factors to achieve the unique structural and chemical barriers to protect the pupa within the cocoons are described. Biophysical analysis of the various ingredients in the cocoons was performed. The role of host plants in the biosynthesis or the sequestration of the phytochemicals or the active compounds was evaluated qualitatively to understand the interaction of the host plants and non- protein chemical constituents from lepidopteran insect cocoons specifically the domesticated and wild silkworms.