How Spiders Fix Their Webs

Spider silk is light and delicate, while incredibly resilient and tear-resistant. Understanding the structure and way of construction of these threads is a challenge taken up by a research team of Kiel University. The scientists examined five different spider species regarding the adhesion and tensile strength of a particular silk they use to fix the main thread to a surface. As shown in their new study published online on July 16, 2014 in the international Journal of the Royal Society Interface, the scientists found out that the substrate has a particularly significant impact on the silk’s adhesion. The research group led by Professor Stanislav Gorb (Institute of Zoology, Kiel University) has attended to the functional analysis of animal surfaces. Why do a gecko’s feet adhere to a wall? Why does a snake’s skin not fray out while the snake is moving forward? The group’s most recent study object is spider silk: spiders use the so-called safety thread to prevent them from falling, to lower themselves and to build the web’s framework. The threads are fixed to the surface and other threads by means of so-called attachment discs generated by rotating motions of the silk glands and applied in the form of a special lattice pattern. The scientists of Dr. Gorb’s research team investigated how attachment discs adhere to various surfaces. “To this end, we placed the spiders on glass, Teflon, and the leaf of a sycamore maple, and they produced attachment discs on each surface. Subsequently, we performed tensile tests to measure the strength necessary to detach the discs from the substrate,” says the author of the current study, Jonas Wolff.