Strengthening of Draglines by UV Rays

UV rays from sunlight are harmful to a variety of living organisms including animals and humans, as well as to biomaterials such as silkworm silk. Spiders fre- 

Compared to the MBS at the starting point of UV-irradiation, the BS was larger by ca. 60% for UV-A and ca. 40% for UV-B irradiation. Thus, irradiation with UV-A showed better improvement of BS. The peaks in the MBS may come about as a consequence of two factors, an increase in molecular weight due to cross-linking of protein molecules and a decrease in molecular weight due to decomposition. 

Consequently, spiders effectively utilize the UV-A rays to mechanically strengthen the orb-web. The study of spider silk provides valuable information regarding the benefits of UV-rays upon essential activities of living organisms, the characteristics of biomaterials and development of industrial materials. 

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