Lifeline of Draglines

The ES for draglines of N. clavata spider weighing more than 50 mg at a 

Stretching velocity of 3.3x10 m/s was plotted against spider weight W in Fig. 4.51. The ES, defined as the mechanical strength at the elastic limit point, increased linearly with increasing W. Experimentally, we may express ES as 

The relationship between BS and W was examined for N. clavata spider draglines at a stretching velocity of 3.3 x 10 m/s. The breaking strength also increased linearly with increasing weight, with the slope determined to be near 6. The relationship between the BS and W was found to be expressed by the following empirical equation  

Since spiders move, jump and fall rapidly, maximal efficiency is needed for the mechanical strength of draglines from the viewpoint of safety, and is likely the result of 400 million years of evolution. 

The safety coefficient should be based on scientific law from the mechanical 

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