Natural and highly protective composite structures - Wild silkworm cocoons

•Wild silkworm cocoons are lightweight composite structures that provide excellent protection.•High toughness and thermal buffer, directional moisture transfer and UV resistance was found.•It inspires innovation in designing new lightweight and protective materials and structure.

Wild silkworm cocoons are thin and lightweight composite structures that provide silkworms with excellent protection against extreme temperature and other harsh weather conditions (e.g. UV, wind, rain). Understanding such natural composite structures will provide bio-inspiration for developing highly protective and light-weight fibrous materials and structures. This paper highlights our recent research on the mechanical and thermal properties, moisture transfer behaviour, and UV resistance of wild silkworm cocoons, in comparison with the domestic Bombyx mori silkworm cocoon. Wild silkworm cocoons such as Antheraea pernyi exhibit exceptionally high toughness, excellent thermal buffer, directional moisture transfer and strong UV resistance, all of which contribute to the high-level protection of the silkworm pupa in harsh outdoor environments.