A Spectrophotometric Study of Plumage Color in the Eared Dove (Zenaida auriculata), the Most Abundant South American Columbiforme

Valdez, Diego J.; Benitez‐Vieyra, Santiago

doi:10.1371/journal.pone.0155501

Cited by 9 publications

(11 citation statements)

References 44 publications

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“…Differences in colour saturation were mostly driven by an opposing relationship between reflectance values in the UV (300–400 nm) and red (600–700 nm) ranges, which had more pronounced sexual dimorphism in the continental population. Previous studies also show a pattern of male columbids displaying higher UV reflectance than females, especially in plumage patches linked to sexual courtship (Mahler & Kempenaers, 2002; Valdez & Benitez‐Vieyra, 2016). This difference is more pronounced in the mainland than in the Azores, matching the recognized trend in reduced sexual dimorphism on islands in plumage characters (Badyaev & Hill, 2003; Doutrelant et al., 2016; Roulin & Salamin, 2010).…”

Section: Discussionmentioning

confidence: 69%

Selection underlies phenotypic divergence in the insular Azores woodpigeon

et al. 2020

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The study of phenotypic evolution in island birds following colonization is a classic topic in island biogeography. However, few studies explicitly test for the role of selection in shaping trait evolution in these taxa. Here, we studied the Azores woodpigeon (Columba palumbus azorica) to investigate differences between island and mainland populations, between females and males, and interactions between geographical origin and sex, by using spectrophotometry to quantify plumage colour and linear measurements to examine external and skeletal morphology. We further tested if selection explains the observed patterns by comparing phenotypic differentiation to genome‐wide neutral differentiation. Our findings are consistent with several predictions of morphological evolution in island birds, namely differences in bill, flight and leg morphology and coloration differences between island and mainland birds. Interestingly, some plumage and morphological traits that differ between females and males respond differently according to geographical origin. Sexual dimorphism in colour saturation is more pronounced in the mainland, but this is driven by selection on female plumage coloration. Differences in flight morphology between females and males are also more pronounced in the mainland, possibly to accommodate contrasting pressures between migration and flight displays. Overall, our results suggest that phenotypic differentiation between mainland and island populations leading to divergent sexual dimorphism patterns can arise from selection acting on both females and males on traits that are likely under the influence of natural and sexual selection.

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Section: Discussionmentioning

confidence: 69%

Selection underlies phenotypic divergence in the insular Azores woodpigeon

et al. 2020

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“…As such, Yuma Ridgway's Rails may differ in color at locations on the body or in wavelengths that we did not measure. For example, juvenile Brown-headed Cowbirds Molothrus ater show sexual differences in the underwing coverts (Farmer and Holmgren 2000) and many apparently monomorphic avian species show strong sexual differences when evaluated at wavelengths across the full range of avian visual capabilities (Eaton 2005;Valdez and Benitez-Vieyra 2016). Variable light conditions during field measurements may have influenced our results.…”

Section: Discussionmentioning

confidence: 93%

“…The resulting canonical classification function can then be applied to predict the sex of unknown individuals (Alarcos et al 2007;Dechaume-Moncharmont et al 2011). In addition to morphometric measurements, subtle differences in the color of plumage and bare parts (e.g., mandibles, tarsi) can help determine sex in otherwise monomorphic species (Farmer and Holmgren 2000;Valdez and Benitez-Vieyra 2016). For example, electronic devices have been used to quantify inter-sexual differences in the plumage color of birds (Eaton 2005;Valdez and Benitez-Vieyra 2016).…”

Section: Introductionmentioning

confidence: 99%

Sexual Dimorphism in Morphology and Plumage of Endangered Yuma Ridgway's Rails: A Model for Documenting Sex

Harrity

Michael

Conway

2021

Journal of Fish and Wildlife Management

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Many applications in wildlife management require knowledge of the sex of individual animals. The Yuma Ridgway’s Rail Rallus obsoletus yumanensis is an endangered marsh bird with monomorphic plumage and secretive behaviors, thereby complicating sex determination in field studies. We collected morphometric measurements from 270 adult Yuma Ridgway’s Rails and quantified the plumage and mandible color of 91 of those individuals throughout their geographic range to evaluate inter-sexual differences in morphology and coloration. We genetically sexed a subset of adult Yuma Ridgway’s Rails ( N =101) and used these individuals to determine the optimal combination of measurements (based on discriminant function analyses) to distinguish between sexes. Males averaged significantly larger than females in all measurements and the optimal discriminant function contained whole-leg, culmen, and tail measurements and classified correctly 97.8% (95% CI: 92.5-100.0%) of genetically sexed individuals. We used two additional functions that correctly classified ≥95.5% of genetically sexed Yuma Ridgway’s Rails to assign sex to individuals with missing measurements. These simple models provide managers and researchers with a practical tool to determine the sex of Yuma Ridgway’s Rails based on morphometric measurements. Although color measurements were not in the most accurate discriminant functions, we quantified subtle inter-sexual differences in the color of mandibles and greater coverts of Yuma Ridgway’s Rails. These results document sex-specific patterns in coloration that allow future researchers to test hypotheses to determine the mechanisms underlying sex-based differences in plumage coloration.

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“…Photographs were processed and analyzed in ImageJ. 39 We took color measurements from three representative barbule patches per feather and used the straight-line tool in ImageJ to measure the width of each barbule patch (Figure 2). Because we could not include a color standard in the microscope photographs, the brightness and contrast of these images were standardized in ImageJ, using photos of a Tiffen (Hauppauge, NY) color standard, which were taken with the same microscope camera immediately before feather photos were taken.…”

Section: Methodsmentioning

confidence: 99%

Feather morphological predictors of angle-dependent color changes in parrot plumage

Reed

Simpson

McGraw

2020

Avian Biology Research

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Among the most ornate animal traits in nature are the angle-dependent (e.g. iridescent) structural colors of many fishes, damselflies, birds, beetles, and butterflies. Though we now have a solid understanding of the mechanisms that create angle-dependent coloration in several groups, we know little about whether pigmentary colors reflect light in an angle-dependent fashion or if similar or different mechanisms govern angle-dependent reflectance from pigmentary versus structural colors. Here for the first time we describe non-iridescent angle-dependent coloration from the tail and wing feathers of several parrot species (Aves: Psittaciformes). We employed a novel approach—by calculating chromatic and achromatic contrasts (in just noticeable differences, JNDs) of straight and angled measurements of the same feather patch—to test for perceptually relevant angle-dependent changes in coloration on dorsal and ventral feather surfaces. We found, among the 15 parrot species studied, significant angle dependence for seven of our eight feather JND parameters. We then measured micro-scale features on each side of feathers, including size and color of barbs and barbules, to attempt to predict interspecific variation in degree of angle-dependent reflectance. We found that barb height, plumage-color type (e.g. melanin, structural), and differences between barb-barbule coloration (measured using Euclidean distances) were the strongest predictors of angle-dependent coloration. Interestingly, there was no significant phylogenetic signal in any of the angle-dependence models tested. These findings deepen our views on the importance of microscopic feather features in the production of directional animal coloration, especially in tissues that are colored predominantly by pigments and appear to be statically colored.

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A Spectrophotometric Study of Plumage Color in the Eared Dove (Zenaida auriculata), the Most Abundant South American Columbiforme

Cited by 9 publications

References 44 publications

Selection underlies phenotypic divergence in the insular Azores woodpigeon

Selection underlies phenotypic divergence in the insular Azores woodpigeon

Sexual Dimorphism in Morphology and Plumage of Endangered Yuma Ridgway's Rails: A Model for Documenting Sex

Feather morphological predictors of angle-dependent color changes in parrot plumage

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