Spiders can tell from the vibrations what sort of insect they have caught, and home in on it. There is a reason why the webs are radial, and the spider plants itself at the convergence of the radii. The strands are an extension of its nervous system. Information propagates down the gossamer and into the spider, where it is processed by some kind of internal Turing machine. Waterhouse has tried many different tricks, but he has never been able to spoof a spider. Not a good omen!