Why don’t spiders get stuck in their own webs?
Orb webs are one of the most admired structures in the natural world – both for their ingenuity and architectural beauty. Attached to the supporting radial structure at more than a thousand points, the spiral ‘catching’ thread has a coating of tiny gluey beads that make the web lethally effective in intercepting prey.
How the spiders themselves avoid falling foul of their own sticky snare is complex, with three different antiadhesion mechanisms thought to be at work. First, although a spider’s legs have to touch the spirals many hundreds of times during web construction, their area of contact with the glue is minimised by dense arrays of branched bristles (setae); second, careful engagement and withdrawal of the legs helps to minimise contact with the sticky line; and third, the legs appear to have a non-stick, chemical coating, perhaps applied from glands in the mouthparts during grooming. This latter idea was widely regarded as a myth until recent research gave it credence.