Signal polymorphism in the web-decorating spider Argiope argentata is correlated with reduced survivorship and the presence of stingless bees, its primary prey

Many spiders, and in particular those in the genus Argiope, spin highly vis ible web decorations whose function and significance are the subject of spi rited debate. In this work, we present data to address two of the competing hypotheses that fuel this controversy. In particular, we examine the relat ionship between the presence of web decorations and spider survivorship (pr edator-protection hypothesis) and the relationship between the presence of prey and spider decorating behavior (the prey-attraction hypothesis). Our l aboratory studies reveal that tile decorating behavior of the spider A. arg entata has a genetic component hut that the expression elf decorating behav ior tends to be elicited only when a spider is well fed. Furthermore, our f ield studies show th;lt in the presence of abundant stingless bees, spider decorating behavior is induced. Nevertheless, our field surveys also sugges t that spiders that decorate their webs show reduced survivorship. We propo se that the high correlation between web decorating in the presence of stin gless bees supports the hypothesis that A. argentata engage in decorating b ehavior when attracting or targeting specific prey types. However, we also propose that web decorations attract the: predators of A. argentata because high-frequency decorators suffer lower survivorship than spiders that deco rate moderately or rarely. These findings suggest that spider web decoratin g behavior is affected by conflicting selection pressures: the positive eff ect of prey attraction versus the negative effect of predator attraction. D ue to the heritable component of decorating behavior, web decorating among A. argentata is likely to be particularly sensitive to the spider's local e cology as well as local patterns of gene flow.