Why spiders don’t stick to their webs
The legs of spiders are protected by a covering of branching hairs and a non-stick chemical coating due to which they do not stick to their own sticky webs, a new study has found.
For the study, conducted by researchers from the Smithsonian Tropical Research Institute and University of Costa Rica, the web-weaving behaviour of two tropical species, Nephila clavipes and Gasteracantha cancriformis, was recorded with a video camera equipped with close-up lenses.
Another video camera coupled with a dissecting microscope helped to determine that individual droplets of sticky glue slide along the leg’s bristly hair, and to estimate the forces of adhesion to the web.
By washing spider legs with hexane and water, they showed that spiders’ legs adhered more tenaciously when the non-stick coating was removed.
The researchers also found that spiders carefully move their legs in ways that minimize adhesive forces as they push against their sticky silk lines hundreds to thousands of times during the construction of each orb.
The study has been published online in the journal Naturwissenschaften.