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

2018 ◽  
Vol 65 (5) ◽  
pp. 559-570 ◽  
Author(s):  
Nathalia G Ximenes ◽  
Felipe M Gawryszewski
Keyword(s):  
Color Vision ◽  
Prey Species ◽  
Flower Color ◽  
Warning Signal ◽  
Theoretical Models ◽  
Color Polymorphism ◽  
Multiple Predators ◽  
Apostatic Selection ◽  
Alternative Hypotheses ◽  
Orb Web

Abstract 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.

scholarly journals Orb-web spider color polymorphism through the eyes of multiple prey and predators

2017 ◽  
Author(s):  
Nathalia Ximenes ◽  
Felipe M. Gawryszewski
Keyword(s):  
Color Vision ◽  
Warning Signal ◽  
Sensory Systems ◽  
Color Polymorphism ◽  
Avian Predators ◽  
Web Spider ◽  
Color Morphs ◽  
Orb Web ◽  
Distinct Color ◽  
Orb Web Spiders

ABSTRACTThe 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. Although, the multiple receivers world is a more realistic scenario, it has received little attention. 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 predator taxa. Our results revealed that individual prey and predator taxa perceive the conspicuousness of morphs differently. For instance, the red morph is perceived as quite conspicuous to lepidopteran prey and avian predators, but not by other insects. Therefore, the multiple prey and predator hypotheses may explain the evolution of color polymorphism in G. cancriformis. However, flower mimicry hypothesis was weakly corroborated. Other parameters that are not evaluated by color vision models, such as distance, shape, angle, and pattern geometry could also affect the perception of color morphs by both prey and predators and thereby influence morph survival.

scholarly journals Pollination Ecology and Breeding System of Delphinium Occidentale

1993 ◽  
Vol 17 ◽  
pp. 87-90
Author(s):  
Ron Scogin
Keyword(s):  
Flower Color ◽  
Pollination Ecology ◽  
Seed Collection ◽  
Local Populations ◽  
Balanced Polymorphism ◽  
Flower Color Polymorphism ◽  
Tall Larkspur ◽  
Alternative Hypotheses ◽  
Flower Form ◽  
Delphinium Occidentale

Delphinium occidentale Nutt. (Ranunculaceae), the tall larkspur, occurs sporatically as isolated local populations in moist locations at lower and middle elevations of Grand Teton National Park. Individual plants of this species exhibit flowers which occur as one of three distinct color morphs and which occur mixed in the local populations. The three floral morphs are 1) plants exhibiting the most familiar, uniformly dark purple pigmented flower form, 2) plants exhibiting an all white, nonpigmented, albino form, and 3) plants whose flowers are intermediate in form between the extremes of 1) and 2), a semi-albino form which exhibits normally pigmented petals, but white, nonpigmented sepals. The occurrence of mixed, polymorphic populations of D. occidentale floral morphs can be rationalized by two alternative hypotheses: 1. A stable, balanced polymorphism exists among the three morphs. This polymorphism is actively maintained by selective pressures, probably on some aspect of the reproductive biology (perhaps pollination ecology) of the floral morphs, or 2. The distribution of polymorphs is merely a founder effect, reflecting the distribution of morphs present in the seed collection which initially established the colonizing population. The research undertaken during 1993 represents an effort to discriminate between these alternative explanations of flower color polymorphism in D. occidentale.

scholarly journals Prey community structure affects how predators select for Müllerian mimicry

2012 ◽  
Vol 279 (1736) ◽  
pp. 2099-2105 ◽  
Author(s):  
Eira Ihalainen ◽  
Hannah M. Rowland ◽  
Michael P. Speed ◽  
Graeme D. Ruxton ◽  
Johanna Mappes
Keyword(s):  
Prey Species ◽  
Generalization Test ◽  
Parus Major ◽  
Warning Signal ◽  
Specific Model ◽  
Müllerian Mimicry ◽  
Effective Community ◽  
Mullerian Mimicry ◽  
Specialist Predators ◽  
Signal Accuracy

Müllerian mimicry describes the close resemblance between aposematic prey species; it is thought to be beneficial because sharing a warning signal decreases the mortality caused by sampling by inexperienced predators learning to avoid the signal. It has been hypothesized that selection for mimicry is strongest in multi-species prey communities where predators are more prone to misidentify the prey than in simple communities. In this study, wild great tits ( Parus major ) foraged from either simple (few prey appearances) or complex (several prey appearances) artificial prey communities where a specific model prey was always present. Owing to slower learning, the model did suffer higher mortality in complex communities when the birds were inexperienced. However, in a subsequent generalization test to potential mimics of the model prey (a continuum of signal accuracy), only birds that had foraged from simple communities selected against inaccurate mimics. Therefore, accurate mimicry is more likely to evolve in simple communities even though predator avoidance learning is slower in complex communities. For mimicry to evolve, prey species must have a common predator; the effective community consists of the predator's diet. In diverse environments, the limited diets of specialist predators could create ‘simple community pockets’ where accurate mimicry is selected for.

THE ROLE OF HERBIVORES IN THE MAINTENANCE OF A FLOWER COLOR POLYMORPHISM IN WILD RADISH

Ecology ◽  
2003 ◽  
Vol 84 (7) ◽  
pp. 1733-1743 ◽  
Author(s):  
Rebecca E. Irwin ◽  
Sharon Y. Strauss ◽  
Shonna Storz ◽  
Aimee Emerson ◽  
Genevieve Guibert
Keyword(s):  
Flower Color ◽  
Color Polymorphism ◽  
Wild Radish ◽  
Flower Color Polymorphism

Frequency-dependent selection by predators

1988 ◽  
Vol 319 (1196) ◽  
pp. 485-503 ◽  
Keyword(s):  
Prey Density ◽  
Prey Species ◽  
Colour Pattern ◽  
Supporting Evidence ◽  
Frequency Dependent ◽  
Frequency Dependent Selection ◽  
Apostatic Selection ◽  
High Selection ◽  
Very High

Sometimes predators tend to concentrate on common varieties of prey and overlook rare ones. Within prey species, this could result in the fitness of each variety being inversely related to its frequency in the population. Such frequency-dependent or ‘apostatic’ selection by predators hunting by sight could maintain polymorphism for colour pattern, and much of the supporting evidence for this idea has come from work on birds and artificial prey. These and other studies have shown that the strength of the observed selection is affected by prey density, palatability, coloration and conspicuousness. When the prey density is very high, selection becomes ‘antiapostatic’: predators preferentially remove rare prey. There is still much to be learned about frequency-dependent selection by predators on artificial prey: work on natural polymorphic prey has hardly begun.

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