Perceptual distance between colored stimuli in the lizard Anolis sagrei: comparing visual system models to empirical results

Fleishman, Leo J.; Perez, Carley W.; Yeo, Anna I.; Cummings, Kailee J.; Dick, Stephanie; Almonte, Elizabeth

doi:10.1007/s00265-016-2072-8

Cited by 57 publications

(56 citation statements)

References 36 publications

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“…Other study systems have also investigated warning signal evolution and utilized vision modelling such as in Anolis lizards (Fleishman et al. ), ladybirds (Arenas and Stevens ), and tiger moths (Henze et al. ).…”

Section: Discussionmentioning

confidence: 99%

The appearance of mimetic Heliconius butterflies to predators and conspecifics

et al. 2018

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Adaptive coloration is under conflicting selection pressures: choosing potential mates and warning signaling against visually guided predators. Different elements of the color signal may therefore be tuned by evolution for different functions. We investigated how mimicry in four pairs of Heliconius comimics is potentially seen both from the perspective of butterflies and birds. Visual sensitivities of eight candidate avian predators were predicted through genetic analysis of their opsin genes. Using digital image color analysis, combined with bird and butterfly visual system models, we explored how predators and conspecifics may visualize mimetic patterns. Ultraviolet vision (UVS) birds are able to discriminate between the yellow and white colors of comimics better than violet vision (VS) birds. For Heliconius vision, males and females differ in their ability to discriminate comimics. Female vision and red filtering pigments have a significant effect on the perception of the yellow forewing band and the red ventral forewing pattern. A behavioral experiment showed that UV cues are used in mating behavior; removal of such cues was associated with an increased tendency to approach comimics as compared to conspecifics. We have therefore shown that visual signals can act to both reduce the cost of confusion in courtship and maintain the advantages of mimicry.

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Section: Discussionmentioning

confidence: 99%

The appearance of mimetic Heliconius butterflies to predators and conspecifics

et al. 2018

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“…Following Fechner’s assumption of additivity, large colorspace should be possible to model (discussed in [95, 96] among others). Furthermore, the only study investigating a behavioral response (in this case the visual attention reflex) in relation to perceptually large color distances found that just-noticeable-differences, as calculated by the receptor noise model, are effective in describing colors separated by large distances in visual space [97]. Nevertheless, because the evidence is sparse, very large differences in units of JND should be interpreted with prudence.…”

Section: Discussionmentioning

confidence: 99%

Assessing Sexual Dicromatism: The Importance of Proper Parameterization in Tetrachromatic Visual Models

2017

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Perceptual models of animal vision have greatly contributed to our understanding of animal-animal and plant-animal communication. The receptor-noise model of color contrasts has been central to this research as it quantifies the difference between two colors for any visual system of interest. However, if the properties of the visual system are unknown, assumptions regarding parameter values must be made, generally with unknown consequences. In this study, we conduct a sensitivity analysis of the receptor-noise model using avian visual system parameters to systematically investigate the influence of variation in light environment, photoreceptor sensitivities, photoreceptor densities, and light transmission properties of the ocular media and the oil droplets. We calculated the chromatic contrast of 15 plumage patches to quantify a dichromatism score for 70 species of Galliformes, a group of birds that display a wide range of sexual dimorphism. We found that the photoreceptor densities and the wavelength of maximum sensitivity of the short-wavelength-sensitive photoreceptor 1 (SWS1) can change dichromatism scores by 50% to 100%. In contrast, the light environment, transmission properties of the oil droplets, transmission properties of the ocular media, and the peak sensitivities of the cone photoreceptors had a smaller impact on the scores. By investigating the effect of varying two or more parameters simultaneously, we further demonstrate that improper parameterization could lead to differences between calculated and actual contrasts of more than 650%. Our findings demonstrate that improper parameterization of tetrachromatic visual models can have very large effects on measures of dichromatism scores, potentially leading to erroneous inferences. We urge more complete characterization of avian retinal properties and recommend that researchers either determine whether their species of interest possess an ultraviolet or near-ultraviolet sensitive SWS1 photoreceptor, or present models for both.

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“…Endler's [22] early insights into the importance of using objective measures of colour are now routinely coupled with Vorobyev & Osorio's [23] visual model, which effectively estimates the contrast between an animal and its habitat while taking into account the sensory system of the receiver (see also [24]). Incorporating objective measures of the habitat has led to several important findings.…”

Section: Introductionmentioning

confidence: 99%

Shaping communicative colour signals over evolutionary time

et al. 2016

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Many evolutionary forces can shape the evolution of communicative signals, and the long-term impact of each force may depend on relative timing and magnitude. We use a phylogenetic analysis to infer the history of blue belly patches of Sceloporus lizards, and a detailed spectrophotometric analysis of four species to explore the specific forces shaping evolutionary change. We find that the ancestor of Sceloporus had blue patches. We then focus on four species; the first evolutionary shift (captured by comparison of S. merriami and S. siniferus) represents an ancient loss of the belly patch by S. siniferus, and the second evolutionary shift, bounded by S. undulatus and S. virgatus, represents a more recent loss of blue belly patch by S. virgatus. Conspicuousness measurements suggest that the species with the recent loss (S. virgatus) is the least conspicuous. Results for two other species (S. siniferus and S. merriami) suggest that over longer periods of evolutionary time, new signal colours have arisen which minimize absolute contrast with the habitat while maximizing conspicuousness to a lizard receiver. Specifically, males of the species representing an ancient loss of blue patch (S. siniferus) are more conspicuous than are females in the UV, whereas S. merriami males have evolved a green element that makes their belly patches highly sexually dimorphic but no more conspicuous than the white bellies of S. merriami females. Thus, our results suggest that natural selection may act more immediately to reduce conspicuousness, whereas sexual selection may have a more complex impact on communicative signals through the introduction of new colours.

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Perceptual distance between colored stimuli in the lizard Anolis sagrei: comparing visual system models to empirical results

Cited by 57 publications

References 36 publications

The appearance of mimetic Heliconius butterflies to predators and conspecifics

The appearance of mimetic Heliconius butterflies to predators and conspecifics

Assessing Sexual Dicromatism: The Importance of Proper Parameterization in Tetrachromatic Visual Models

Shaping communicative colour signals over evolutionary time

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