There exist several <A HREF="https://en.wikipedia.org/wiki/Spider_web#Types">distinct types</A> of spider webs, one type that has been extensively studied is the orb web, see <A HREF="https://www.researchgate.net/publication/43021747_Simple_Model_for_the_Mechanics_of_Spider_Webs">Simple Model for the Mechanics of Spider Webs</A>. A key property of the orb web model is that the web is free of stress concentrations even when a few spiral threads are broken. According to the model, spiders can increase the number of spiral threads to make a dense web (to catch small insects) or adjust the number of radial threads (to adapt to environmental conditions or reduce the cost of making the web) without reducing the damage tolerance of the web.