Why are spider nets elastic?

1993/12/01 Elhuyar Zientzia Iturria: Elhuyar aldizkaria

• Ekologia

As we have all been able to see their fingers crushed, spider nets are very elastic and their cause has been revealed by Fritz Vollrath and his co-workers at the University of Basel.

Expanded 1,500 times in the electron microscope, this spider silk thread features plenty of curves. For example, when an insect in flight crushes the thread, the curves are corrected in the pull and therefore the thread is stretched. When you stop pressing, the thread is removed and collected again.

The thread shown in the image is that of the spider Aradeus diadematus, which being a very competent engineer, can thread six other types of threads depending on the load that supports the thread.

To make the frame the net uses rigid or “dry” silk (with a stretch index of 25%) and takes its shape after a few hours.

Spiral silk for insect capture is double and sticky, with moisture in the air (hydrophilic) and a high stretch index (400%).

The most powerful type of thread is to make an egg bag. It must be said that if the spider web breaks, the spider eats to absorb proteins and water before making another.