Biological relevance of host plant-derived terpenoid in the cocoons of the tropical tasar silkworm Antheraea mylitta

We have characterized and studied the biological functions of a terpenoid derivative in the Indian tropical tasar silkworm, Antheraea mylitta reared on the primary host plant Arjun, Terminalia arjuna. The compound from insect cocoon turned out to be a terpenoid derivative which resembled oleanane type triterpene (Arjunolic acid) present in the host plant. The plant and cocoon compounds were anti-oxidative as determined by bleaching of beta carotene in vitro. UV-exposure is the major form of peroxidative insult encountered by this wild tropical silkworm. The life cycle comprising five larval stages and the cocoon stage lasts for about 30–45 days. Hence the sequestration of antioxidant and UV-protectant molecule from the host plant commands great biological significance.