Prey and predators perceive orb-web spider conspicuousness differently: evaluating alternative hypotheses for color polymorphism evolution

Color polymorphisms have been traditionally attributed to apostatic selection.The perception of color depends on the visual system of the observer.Theoretical models predict that differently perceived degrees of conspicuousness by two predator and prey species may cause the evolution of polymorphisms in the presence of anti-apostatic and apostatic selection.The spider Gasteracantha cancriformis(Araneidae)possesses several conspicuous color morphs.In orb-web spiders,the prey attraction hypothesis states that conspicuous colors are prey lures that increase spider foraging success via flower mimicry.Therefore,polymorphism could be maintained if each morph attracted a different prey species(multiple prey hypothesis)and each spider mimicked a different flower color(flower mimicry hypothesis).Conspicuous colors could be a warning signal to predators because of the spider's hard abdomen and spines.Multiple predators could perceive morphs differently and exert different degrees of selective pressures(multiple predator hypothesis).We explored these 3 hypotheses using reflectance data and color vision modeling to estimate the chromatic and achromatic contrast of G.cancriformis morphs as perceived by several potential prey and predator taxa.Our results revealed that individual taxa perceive the conspicuousness of morphs differently.Therefore,the multiple prey hypothesis and,in part,the multiple predator hypothesis may explain the evolution of color polymorphism in G.cancriformis,even in the presence of anti-apostatic selection.The flower mimicry hypothesis received support by color metrics,but not by color vision models.Other parameters not evaluated by color vision models could also affect the perception of morphs and influence morph survival and polymorphism stability.

中国棘腹蛛属一新种及一新纪录种记述(蜘蛛目,园蛛科)(英文)

记述了采自云南高黎贡山的园蛛科棘腹蛛属1新种和1新纪录种,华丽棘腹蛛Gasteracantha aureola sp.nov.和北棘腹蛛Gasteracantha unguifera Simon,1889。模式标本保存在湖南师范大学。