Mechanical properties of cocoons constructed consecutively by a single silkworm caterpillar, Bombyx mori

• 来源期刊: 力学学报（英文版）
• 年，卷（期）: 2008,（2）
• 页码范围: 151-160
• 页数: 10页
• 语种: 英文
• DOI: 10.1007/s10409-008-0141-6

摘要

Most animals have the ability to adapt, to some extends and in different ways, the variation or disturbance of environment. In our experiments, we forced a silkworm cater-pillar to spin two, three or four thin cocoons by taking it out from the cocoon being constructed. The mechanical prop-erties of these cocoons were studied by static tensile tests and dynamic mechanical thermal analysis. Though exter-nal disturbances may cause the decrease in the total weight of silk spun by the silkworm, a gradual enhancement was interestingly found in the mechanical properties of these thin cocoons. Scanning electron microscopy observations of the fractured specimens of the cocoons showed that there exist several different energy dissipation mechanisms occurred simultaneously at macro-, meso-, and micro-scales, yield-ing a superior capacity of cocoons to adsorb the energy of possible attacks from the outside and to protect efficiently its pupa against damage. Through evolution of millions of years,therefore, the silkworm Bombyx mori seems to have gained the ability to adapt external disturbances and to redesign a new cocoon with optimized protective function when its first cocoon has been damaged for some reasons.