3/2/2024 0 Comments Orb weaver spider predatorsMany orb-web spiders exhibit conspicuous coloration. Although Endler’s model has been developed to predators’ perception of prey, it could be applied to selection forces arising from other observers (e.g., variation in perception by prey). Additionally, polymorphism might be stable in the presence of anti-apostatic selection from different predators, given that predators perceive prey conspicuousness differently and there is a covariance between the relative degree of crypsis and the degree of frequency-dependent selection by each predator ( Endler 1988). Endler’s model (1988), for instance, indicated that a stable polymorphism might evolve in the presence of anti-apostatic selection (positive frequency-dependent) and apostatic selection (negative frequency-dependent) from different predators. The role of multiple predators on the evolution of prey coloration has been approached by theoretical models ( Endler 1988 Endler and Mappes 2004). Thus, the diversity of signals is likely influenced by variation in the sensory systems of receivers.Ĭonsidering that the same “color” may be perceived as cryptic or conspicuous by different species ( Endler and Mappes 2004), each color morph of a polymorphic population may represent an adaptation to particular visual systems of prey or predator species ( Endler 1992 Ruxton et al. Any factors that affect these steps can influence signal efficiency and, as a result, affect the direction of communication evolution ( Endler 1993). ![]() Animal communication involves the generation, transmission, and processing of the signal by a receiver, in which an appropriate response is elicited ( Endler 1993). In the context of visual signaling, the distinct visual systems of prey and predators may play a role in the evolution and maintenance of color polymorphisms ( Ruxton et al. For instance, gene flow between populations with distinct phenotypes that are favored by natural selection could maintain polymorphism within populations ( Grey and McKinnon 2007 Farkas et al. Nonetheless, other adaptive and nonadaptive explanations for the evolution and maintenance of color polymorphisms have been proposed ( Grey and McKinnon 2007). Assuming that predators form a search image ( Tinbergen 1960), the advantage of rarity promotes the coexistence of multiple prey types and stabilizes polymorphisms ( Bond 2007). The evolution and maintenance of color polymorphisms have traditionally been attributed to apostatic selection ( Clarke 1979). Other parameters not evaluated by color vision models could also affect the perception of morphs and influence morph survival and polymorphism stability.Īposematism, Araneidae, Gasteracantha cancriformis, luring, prey attraction, visual communication ![]() The flower mimicry hypothesis received support by color metrics, but not by color vision models. ![]() cancriformis, even in the presence of anti-apostatic selection. Therefore, the multiple prey hypothesis and, in part, the multiple predator hypothesis may explain the evolution of color polymorphism in G. Our results revealed that individual taxa perceive the conspicuousness of morphs differently. cancriformis morphs as perceived by several potential prey and predator taxa. We explored these 3 hypotheses using reflectance data and color vision modeling to estimate the chromatic and achromatic contrast of G. Multiple predators could perceive morphs differently and exert different degrees of selective pressures (multiple predator hypothesis). ![]() Conspicuous colors could be a warning signal to predators because of the spider’s hard abdomen and spines. 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). In orb-web spiders, the prey attraction hypothesis states that conspicuous colors are prey lures that increase spider foraging success via flower mimicry. The spider Gasteracantha cancriformis (Araneidae) possesses several conspicuous color morphs. 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 perception of color depends on the visual system of the observer. Color polymorphisms have been traditionally attributed to apostatic selection.
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