A common house spider uses two different types of silk structure, or attachment disc, to anchor its cobwebs — one for webs that ensnare walking insects and another for those intended to trap flying prey.
'Gumfoot' silk threads are connected to the ground and can easily release and yank walking prey into silk nets; 'scaffolding' silk is more securely attached to substrates and is used to catch flying insects. Ali Dhinojwala and his team at the University of Akron, Ohio, used electron microscopy to examine cobwebs made by the spider Achaearanea tepidariorum, and found that each of these webs is anchored using a different type of attachment disc. Gumfoot discs (pictured right) consist of thin arms, whereas scaffolding discs (left) have thicker fibres with many more attachment points, and stick to surfaces 10 times more strongly than gumfoot discs.
Synthetic discs made from nylon strands and tape strips displayed similar properties to their natural counterparts.
Nature Commun. htp://dx.doi.org/10.1038/ncomms2099 (2012)