ABSTRACT
The sensory drive theory predicts that signals, sensory systems, and signaling behavior should coevolve. Variation in the sensory systems of prey and predators may explain the diversity of color signals, such as color polymorphism. The spider Gasteracantha cancriformis (Araneidae) possesses several conspicuous color morphs. The aim of the present study was to assess whether the color polymorphism of G. cancriformis may be maintained by pressure from multiple signal receivers, such as prey and predators with distinct color vision systems. In orb-web spiders, the prey attraction hypothesis states that conspicuous colors are prey lures that increase spider foraging success via flower mimicry. However, in highly defended species, conspicuous colors could also be a warning signal to predators. We used color vision modelling to estimate chromatic and achromatic contrast of G. cancriformis morphs as perceived by potential prey and predators taxa. The results revealed that individual prey and predator taxa perceive the conspicuousness of morphs differently. Therefore, the multiple prey and multiple predator hypotheses may explain the evolution of color polymorphism in G. cancriformis. However, the spider’s coloration did not resemble flower coloration, which suggests that the species’ conspicuousness is not the result of flower mimicry. Other parameters that are not evaluated by color vision models, such as distance, shape, angle, pattern geometry, and contour, could also affect the perception of color morphs by both prey and predators and thereby influence morph survival.
Summary statement We assessed the role of both prey and predator vision on the evolution and maintenance of color polymorphism and color conspicuousness of the orb-web spider Gasteracantha cancriformis (Araneidae).