EVOLUTION AND ECOLOGY OF SPIDER COLORATION

Genetic color variation provides a tangible link between the external phenotype of an organism and its underlying genetic determination and thus furnishes a tractable system with which to explore fundamental ev olutionary phenomena. Here we examine the basis of color variation in spiders and its evolutionary and ecological implications. Reversible c olor changes, resulting from several mechanisms, are surprisingly wide spread in the group and must be distinguished from true genetic variat ion for color to be used as an evolutionary tool. Genetic polymorphism occurs in a large number of families and is frequently sex limited: S ex linkage has not yet been demonstrated, nor have the forces promotin g sex limitation been elucidated. It is argued that the production of color is metabolically costly and is principally maintained by the act ion of sight-hunting predators. Key avenues for future research are su ggested.