As the light gradually improved, I saw that many of them were occupied by their builders - the 8-legged arachnid architects of these marvelous food-catching nets of silk. Most striking among them were the giant so-called "Garden" or "Banana" spiders, who presided over webs of great size and diversity of parts, including a curious "zig-zag" pattern of thick silk knitted into the center of their otherwise simple concentric design. One hypothesis for this adornment is that it is readily noticeable by large creatures like birds or deer that might otherwise blunder into the web: as a kind of warning, advertising the presence of a spider web which might otherwise not be seen by birds and mammals which could easily damage or destroy it, the "insignia" is potentially quite effective. It is certainly most often the first thing I notice that instructs me to the presence of a garden spider web on the trail.

How the insignia evolved invites contemplation: perhaps those spiders that possessed some 'nervous' tendency to incorporate random patterns which were significantly visible to large creatures would be more likely to preserve their webs and increase the likelihood that their 'nervous genes' would survive. Eventually such patterns might become systematically stylized by selection pressures that place a premium on efficiency - the patterns evolve toward maximum effectiveness in warning large animals in combination with a minimum of silk and weaving time. (Even spiders are constrained by a "budget" on their construction projects and materials - not consciously, of course, but by the necessities of a finite world of resources and time which circumstance and Nature imposes; economic thrift certainly isn't an invention by human beings, who are more apt to regard themselves as "inventors" rather than "discoverers"). The zig-zag pattern may be a design which specifically enhances the chance of detection by large animals and birds while consisting of a minimal amount of silk. Moreover, it may be considerably simpler and quicker, in terms of energy expenditure, to weave the zig-zag pattern as part of a relatively easily programmed set of repetitive motions. However the final design that we see was finally arrived at, random experiments in pattern-making would inevitably produce a range of efficiencies that are tested by the environment. The best designs would be those which required a minimal amount of silk and effort to weave in order to capture the eye of a bird or mammal, and those would be the designs which would most likely be selected.