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Blary CLM, Duriez O, Bonadonna F, Mitkus M, Caro SP, Besnard A, Potier S. Low achromatic contrast sensitivity in birds: a common attribute shared by many phylogenetic orders. J Exp Biol 2024; 227:jeb246342. [PMID: 38099472 DOI: 10.1242/jeb.246342] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2023] [Accepted: 12/06/2023] [Indexed: 02/10/2024]
Abstract
Vision is an important sensory modality in birds, which can outperform other vertebrates in some visual abilities. However, sensitivity to achromatic contrasts - the ability to discern luminance difference between two objects or an object and its background - has been shown to be lower in birds compared with other vertebrates. We conducted a comparative study to evaluate the achromatic contrast sensitivity of 32 bird species from 12 orders using the optocollic reflex technique. We then performed an analysis to test for potential variability in contrast sensitivity depending on the corneal diameter to the axial length ratio, a proxy of the retinal image brightness. To account for potential influences of evolutionary relatedness, we included phylogeny in our analyses. We found a low achromatic contrast sensitivity for all avian species studied compared with other vertebrates (except small mammals), with high variability between species. This variability is partly related to phylogeny but appears to be independent of image brightness.
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Affiliation(s)
- Constance L M Blary
- CEFE, Univ Montpellier, CNRS, EPHE, IRD, 34293 Montpellier, France
- Agence de l'environnement et de la Maîtrise de l'Energie 20, 49004 Angers Cedex 01, France
| | - Olivier Duriez
- CEFE, Univ Montpellier, CNRS, EPHE, IRD, 34293 Montpellier, France
| | | | - Mindaugas Mitkus
- Institute of Biosciences, Life Sciences Center, Vilnius University, 10257 Vilnius, Lithuania
| | - Samuel P Caro
- CEFE, Univ Montpellier, CNRS, EPHE, IRD, 34293 Montpellier, France
| | - Aurélien Besnard
- CEFE, Univ Montpellier, CNRS, EPHE PSL University, IRD, 34293 Montpellier, France
| | - Simon Potier
- Lund Vision Group, Department of Biology, Lund University, Lund 22362, Sweden
- Les Ailes de l'Urga, 27320 Marcilly la Campagne, France
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2
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Cantlay JC, Martin GR, McClelland SC, Potier S, O'Brien MF, Fernández-Juricic E, Bond AL, Portugal SJ. Binocular vision and foraging in ducks, geese and swans (Anatidae). Proc Biol Sci 2023; 290:20231213. [PMID: 37670586 PMCID: PMC10510447 DOI: 10.1098/rspb.2023.1213] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2023] [Accepted: 08/02/2023] [Indexed: 09/07/2023] Open
Abstract
Wide variation in visual field configuration across avian species is hypothesized to be driven primarily by foraging ecology and predator detection. While some studies of selected taxa have identified relationships between foraging ecology and binocular field characteristics in particular species, few have accounted for the relevance of shared ancestry. We conducted a large-scale, comparative analysis across 39 Anatidae species to investigate the relationship between the foraging ecology traits of diet or behaviour and binocular field parameters, while controlling for phylogeny. We used phylogenetic models to examine correlations between traits and binocular field characteristics, using unidimensional and morphometric approaches. We found that foraging behaviour influenced three parameters of binocular field size: maximum binocular field width, vertical binocular field extent, and angular separation between the eye-bill projection and the direction of maximum binocular field width. Foraging behaviour and body mass each influenced two descriptors of binocular field shape. Phylogenetic relatedness had minimal influence on binocular field size and shape, apart from vertical binocular field extent. Binocular field differences are associated with specific foraging behaviours, as related to the perceptual challenges of obtaining different food items from aquatic and terrestrial environments.
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Affiliation(s)
- Jennifer C. Cantlay
- Department of Biological Sciences, School of Life and Environmental Sciences, Royal Holloway University of London, Egham, Surrey TW20 0EX, UK
| | - Graham R. Martin
- School of Biosciences, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK
| | - Stephanie C. McClelland
- Department of Biological Sciences, School of Life and Environmental Sciences, Royal Holloway University of London, Egham, Surrey TW20 0EX, UK
| | - Simon Potier
- Department of Biology, Faculty of Science, Lund University, Sölvegatan 35, 223 62 Lund, Sweden
| | | | | | - Alexander L. Bond
- Bird Group, Department of Life Sciences, The Natural History Museum, Akeman Street, Tring, Hertfordshire HP23 6AP, UK
| | - Steven J. Portugal
- Department of Biological Sciences, School of Life and Environmental Sciences, Royal Holloway University of London, Egham, Surrey TW20 0EX, UK
- Bird Group, Department of Life Sciences, The Natural History Museum, Akeman Street, Tring, Hertfordshire HP23 6AP, UK
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3
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Ramirez L. Trade-off between coding efficiency and color space in outer retinal circuits with colored oil droplets. Vision Res 2023; 208:108224. [PMID: 37011508 DOI: 10.1016/j.visres.2023.108224] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2022] [Revised: 03/10/2023] [Accepted: 03/22/2023] [Indexed: 04/03/2023]
Abstract
To enhance color vision, animals adapt diverse strategies according to their environmental conditions. For instance, zebrafish use clever retinal circuits to encode spectral information in aquatic environments. Other species, such as birds, develop colored oil droplets to expand their plethora of distinguishable colors. Studies on these species provide insights into each strategy. Nevertheless, there is no data on retinas using both strategies simultaneously. In this work, we combine our knowledge of colored oil droplets and circuits for efficient spectral coding in different species to explore the outcome of retinas exhibiting both strategies simultaneously. Our findings suggest the existence of a trade-off between coding efficiency and color-space area in zebrafish-like retinal circuits. More specifically, we find that spectral encoding becomes compromised with the presence of colored oil droplets while the accessible color space expands significantly.
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4
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Nolazco S, Delhey K, Fan M, Hall ML, Kingma SA, Roast MJ, Teunissen N, Peters A. Which plumage patches provide information about condition and success in a female fairy-wren? Behav Ecol 2022. [DOI: 10.1093/beheco/arac096] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Abstract
Recent evidence suggests that female ornaments can commonly act as signals. However, how signaling functions might be affected by the tendency for reduced ornament elaboration in relation to males is less well-understood. We address this in mutually ornamented purple-crowned fairy-wrens. We investigated putatively ornamental (tail, ear coverts, crown) and non-ornamental (throat, back) plumage patches in females and compared our findings to previous studies in males. Both sexes have brown backs, buff-white throats, and turquoise-blue tails (bluer in males), while ear coverts are rufous in females and black in males. Both sexes also have a seasonal crown (slate-gray in females, black-and-purple in males). Dominant (breeder) females expressed more complete and grayer (more ornamented) crowns, although variation in coloration should not be discriminable by individuals. Unexpectedly, subordinates showed more colorful (saturated) rufous ear coverts, which should be discriminable. Condition-dependence was only evident for crown completeness (% slate-gray cover). Females with more reddish-brown backs were more reproductively successful. Variation in plumage characteristics did not explain differential allocation by mates or chances of gaining dominance. Our outcomes were not entirely consistent with findings in males. The most notable disparity was for the crown, a signal used in male-male competition that in females seems to be expressed as an incomplete version of the male crown that is not associated with fitness benefits. Our study shows that in a species, multiple traits can vary in their information content and that female ornaments can sometimes be less informative than in males, even those that are produced seasonally.
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Affiliation(s)
- Sergio Nolazco
- School of Biological Sciences, Monash University , 25 Rainforest Walk, Clayton, Victoria 3800 , Australia
| | - Kaspar Delhey
- School of Biological Sciences, Monash University , 25 Rainforest Walk, Clayton, Victoria 3800 , Australia
- Max Planck Institute for Ornithology , Seewiesen , Germany
| | - Marie Fan
- School of Biological Sciences, Monash University , 25 Rainforest Walk, Clayton, Victoria 3800 , Australia
| | - Michelle L Hall
- Max Planck Institute for Ornithology , Seewiesen , Germany
- School of Biological Sciences, University of Western Australia , 35 Stirling Highway, Perth, Western Australia 6009 , Australia
| | - Sjouke A Kingma
- Max Planck Institute for Ornithology , Seewiesen , Germany
- Behavioural Ecology Group, Department of Animal Sciences, Wageningen University and Research , De Elst 1, 6708 WD Wageningen , The Netherlands
| | - Michael J Roast
- School of Biological Sciences, Monash University , 25 Rainforest Walk, Clayton, Victoria 3800 , Australia
| | - Niki Teunissen
- School of Biological Sciences, Monash University , 25 Rainforest Walk, Clayton, Victoria 3800 , Australia
| | - Anne Peters
- School of Biological Sciences, Monash University , 25 Rainforest Walk, Clayton, Victoria 3800 , Australia
- Max Planck Institute for Ornithology , Seewiesen , Germany
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5
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Romero-Diaz C, Silva PA, Soares MC, Cardoso GC, Trigo S. Oestradiol reduces female bill colour in a mutually ornamented bird. Proc Biol Sci 2022; 289:20221677. [PMID: 36476006 PMCID: PMC9554724 DOI: 10.1098/rspb.2022.1677] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2022] [Accepted: 09/20/2022] [Indexed: 12/14/2022] Open
Abstract
Carotenoid-based colour signals can be costly to produce and maintain, and trade-offs between signalling and other fitness traits are expected. In mutually ornamented species, trade-offs with reproduction may be stronger for females than males, because females often dedicate more resources to offspring production, which may lead to plastic investment in colour signals and plastic sexual dichromatism. Oestradiol is a candidate mediator of this trade-off because it regulates reproductive physiology and may also influence the expression of coloration. We tested this hypothesis by giving female common waxbills (Estrilda astrild) either oestradiol (17β-oestradiol) or empty implants during the early breeding season and measured spectral reflectance of carotenoid-based bill coloration weekly for two months. Using a model of avian vision, we found that bill colour in oestradiol-implanted females became less saturated, less red in hue and brighter, compared with control females and with unimplanted males. This resulted in a change in bill sexual dichromatism from imperceptible to perceptible. Results support the hypothesis that female reproductive physiology influences investment in coloration through changes in oestradiol and show a form of female-driven plastic sexual dichromatism. Greater sensitivity of female colour to physiological and/or environmental conditions helps explain why differences in sexual dichromatism among species differing in ecology often evolve owing to changes in female rather than male phenotype.
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Affiliation(s)
- Cristina Romero-Diaz
- CIBIO, Centro de Investigação em Biodiversidade e Recursos Genéticos, Universidade do Porto, InBIO Laboratório Associado, Biodiversity and Land Planning, CIBIO, Campus de Vairão, Vairão 4485-661, Portugal
- BIOPOLIS Program in Genomics, Biodiversity and Land Planning, CIBIO, Campus de Vairão, Vairão 4485-661, Portugal
| | - Paulo A. Silva
- CIBIO, Centro de Investigação em Biodiversidade e Recursos Genéticos, Universidade do Porto, InBIO Laboratório Associado, Biodiversity and Land Planning, CIBIO, Campus de Vairão, Vairão 4485-661, Portugal
- BIOPOLIS Program in Genomics, Biodiversity and Land Planning, CIBIO, Campus de Vairão, Vairão 4485-661, Portugal
| | - Marta C. Soares
- CIBIO, Centro de Investigação em Biodiversidade e Recursos Genéticos, Universidade do Porto, InBIO Laboratório Associado, Biodiversity and Land Planning, CIBIO, Campus de Vairão, Vairão 4485-661, Portugal
- BIOPOLIS Program in Genomics, Biodiversity and Land Planning, CIBIO, Campus de Vairão, Vairão 4485-661, Portugal
| | - Gonçalo C. Cardoso
- CIBIO, Centro de Investigação em Biodiversidade e Recursos Genéticos, Universidade do Porto, InBIO Laboratório Associado, Biodiversity and Land Planning, CIBIO, Campus de Vairão, Vairão 4485-661, Portugal
- BIOPOLIS Program in Genomics, Biodiversity and Land Planning, CIBIO, Campus de Vairão, Vairão 4485-661, Portugal
| | - Sandra Trigo
- CIBIO, Centro de Investigação em Biodiversidade e Recursos Genéticos, Universidade do Porto, InBIO Laboratório Associado, Biodiversity and Land Planning, CIBIO, Campus de Vairão, Vairão 4485-661, Portugal
- BIOPOLIS Program in Genomics, Biodiversity and Land Planning, CIBIO, Campus de Vairão, Vairão 4485-661, Portugal
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6
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Avian vision. Curr Biol 2022; 32:R1079-R1085. [DOI: 10.1016/j.cub.2022.06.065] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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7
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Tedore C, Tedore K, Westcott D, Suttner C, Nilsson DE. The role of detectability in the evolution of avian-dispersed fruit color. Vision Res 2022; 196:108046. [DOI: 10.1016/j.visres.2022.108046] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2021] [Revised: 03/18/2022] [Accepted: 03/21/2022] [Indexed: 11/26/2022]
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8
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Nagloo N, Mountford JK, Gundry BJ, Hart NS, Davies WIL, Collin SP, Hemmi JM. Enhanced short-wavelength sensitivity in the blue-tongued skink, Tiliqua rugosa. J Exp Biol 2022; 225:275680. [PMID: 35582824 PMCID: PMC9234500 DOI: 10.1242/jeb.244317] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2022] [Accepted: 05/11/2022] [Indexed: 11/20/2022]
Abstract
Despite lizards using a wide range of color signals, the limited variation in photoreceptor spectral sensitivities across lizards suggests only weak selection for species-specific, spectral tuning of photoreceptors. Some species, however, have enhanced short wavelength sensitivity, which likely helps with the detection of signals rich in ultraviolet and short wavelengths. In this study, we examined the visual system of Tiliqua rugosa, which has a UV/blue tongue, to gain insight into this species' visual ecology. We used electroretinograms, opsin sequencing and immunohistochemical labelling to characterize whole eye spectral sensitivity and the elements that shape it. Our findings reveal that T. rugosa expresses all five opsins typically found in lizards (SWS1, SWS2, RH1, RH2 and LWS) but possesses greatly enhanced short wavelength sensitivity compared to other diurnal lizards. This enhanced short wavelength sensitivity is characterized by a broadening of the spectral sensitivity curve of the eye towards shorter wavelengths while the peak sensitivity of the eye at longer wavelengths (560 nm) remains similar to other diurnal lizards. While an increased abundance of SWS1 photoreceptors is thought to mediate elevated ultraviolet sensitivity in a couple of other lizard species, SWS1 photoreceptor abundance remains low in our species. Instead, our findings suggest that short-wavelength sensitivity is driven by multiple factors which include a potentially red-shifted SWS1 photoreceptor and the absence of short-wavelength absorbing oil droplets. Examining the coincidence of enhanced short-wavelength sensitivity with blue tongues among lizards of this genus will provide further insight into the co-evolution of conspecific signals and whole-eye spectral sensitivity.
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Affiliation(s)
- Nicolas Nagloo
- School of Biological Sciences, The University of Western Australia, 6009 WA, Australia.,Department of Biology, Lund University, Lund, S-212263, Sweden.,The UWA Oceans Institute, The University of Western Australia, 6009 WA, Australia
| | - Jessica K Mountford
- School of Biological Sciences, The University of Western Australia, 6009 WA, Australia.,The UWA Oceans Institute, The University of Western Australia, 6009 WA, Australia.,Oceans Graduate School, The University of Western Australia, 6009 WA, Australia.,Clinical Genetics and Epidemiology, and Centre for Ophthalmology and Visual Science incorporating the Lions Eye Institute, The University of Western Australia, 6009 WA, Australia
| | - Ben J Gundry
- School of Biological Sciences, The University of Western Australia, 6009 WA, Australia
| | - Nathan S Hart
- School of Biological Sciences, The University of Western Australia, 6009 WA, Australia.,School of Natural Sciences, Macquarie University, 2109 NSW, Australia
| | - Wayne I L Davies
- School of Biological Sciences, The University of Western Australia, 6009 WA, Australia.,The UWA Oceans Institute, The University of Western Australia, 6009 WA, Australia.,Oceans Graduate School, The University of Western Australia, 6009 WA, Australia.,Clinical Genetics and Epidemiology, and Centre for Ophthalmology and Visual Science incorporating the Lions Eye Institute, The University of Western Australia, 6009 WA, Australia.,Umeå Centre for Molecular Medicine (UCMM), Umeå University, Umeå, S-90187, Sweden.,School of Agriculture, Biomedicine and Environment, La Trobe University Bundoora, Victoria 3086, Australia
| | - Shaun P Collin
- School of Biological Sciences, The University of Western Australia, 6009 WA, Australia.,The UWA Oceans Institute, The University of Western Australia, 6009 WA, Australia.,Oceans Graduate School, The University of Western Australia, 6009 WA, Australia.,Clinical Genetics and Epidemiology, and Centre for Ophthalmology and Visual Science incorporating the Lions Eye Institute, The University of Western Australia, 6009 WA, Australia.,School of Agriculture, Biomedicine and Environment, La Trobe University Bundoora, Victoria 3086, Australia
| | - Jan M Hemmi
- School of Biological Sciences, The University of Western Australia, 6009 WA, Australia.,The UWA Oceans Institute, The University of Western Australia, 6009 WA, Australia
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9
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Whiting MJ, Holland BS, Keogh JS, Noble DWA, Rankin KJ, Stuart-Fox D. Invasive chameleons released from predation display more conspicuous colors. SCIENCE ADVANCES 2022; 8:eabn2415. [PMID: 35544573 PMCID: PMC9094656 DOI: 10.1126/sciadv.abn2415] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/12/2021] [Accepted: 03/25/2022] [Indexed: 06/15/2023]
Abstract
Conspicuous social and sexual signals are predicted to experience pronounced character release when natural selection via predation is relaxed. However, we have few good examples of this phenomenon in the wild and none in species with dynamic color change. Here, we show that Jackson's chameleons inadvertently introduced from Kenya to Hawaii (Oahu), where there are no coevolved, native lizard predators, experienced pronounced character release of color signals. Hawaiian chameleons displayed more conspicuous social color signals than Kenyan chameleons during male contests and courtship, were less cryptic in response to bird and snake predators, and showed greater change between display and antipredator color states. Hawaiian chameleon display colors were also more conspicuous in their local than ancestral habitats, consistent with local adaptation of social signals. These results demonstrate that relaxed predation pressure can result in character release of dynamic social signals in introduced species experiencing strong sexual selection.
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Affiliation(s)
- Martin J. Whiting
- School of Natural Sciences, Macquarie University, Sydney, NSW 2109, Australia
- School of Animal, Plant and Environmental Sciences, University of the Witwatersrand, Wits 2050, South Africa
| | - Brenden S. Holland
- Department of Natural Science, Hawaii Pacific University, Honolulu, HI, USA
| | - J. Scott Keogh
- Division of Ecology and Evolution, Research School of Biology, The Australian National University, Canberra, ACT 2602, Australia
| | - Daniel W. A. Noble
- Division of Ecology and Evolution, Research School of Biology, The Australian National University, Canberra, ACT 2602, Australia
| | - Katrina J. Rankin
- School of BioSciences, The University of Melbourne, Parkville, Victoria 3010, Australia
| | - Devi Stuart-Fox
- School of BioSciences, The University of Melbourne, Parkville, Victoria 3010, Australia
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10
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11
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Nokelainen O, Galarza JA, Kirvesoja J, Suisto K, Mappes J. Genetic colour variation visible for predators and conspecifics is concealed from humans in a polymorphic moth. J Evol Biol 2022; 35:467-478. [PMID: 35239231 PMCID: PMC9314616 DOI: 10.1111/jeb.13994] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2021] [Revised: 01/31/2022] [Accepted: 02/06/2022] [Indexed: 11/29/2022]
Abstract
The definition of colour polymorphism is intuitive: genetic variants express discretely coloured phenotypes. This classification is, however, elusive as humans form subjective categories or ignore differences that cannot be seen by human eyes. We demonstrate an example of a ‘cryptic morph’ in a polymorphic wood tiger moth (Arctia plantaginis), a phenomenon that may be common among well‐studied species. We used pedigree data from nearly 20,000 individuals to infer the inheritance of hindwing colouration. The evidence supports a single Mendelian locus with two alleles in males: WW and Wy produce the white and yy the yellow hindwing colour. The inheritance could not be resolved in females as their hindwing colour varies continuously with no clear link with male genotypes. Next, we investigated if the male genotype can be predicted from their phenotype by machine learning algorithms and by human observers. Linear discriminant analysis grouped male genotypes with 97% accuracy, whereas humans could only group the yy genotype. Using vision modelling, we also tested whether the genotypes have differential discriminability to humans, moth conspecifics and their bird predators. The human perception was poor separating the genotypes, but avian and moth vision models with ultraviolet sensitivity could separate white WW and Wy males. We emphasize the importance of objective methodology when studying colour polymorphism. Our findings indicate that by‐eye categorization methods may be problematic, because humans fail to see differences that can be visible for relevant receivers. Ultimately, receivers equipped with different perception than ours may impose selection to morphs hidden from human sight.
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Affiliation(s)
- Ossi Nokelainen
- Department of Biological and Environmental Science, University of Jyväskylä, Jyväskylä, Finland.,Organismal and Evolutionary Biology Research Program, Faculty of Biological and Environmental Sciences, University of Helsinki, Helsinki University, Helsinki, Finland
| | - Juan A Galarza
- Department of Biological and Environmental Science, University of Jyväskylä, Jyväskylä, Finland.,Organismal and Evolutionary Biology Research Program, Faculty of Biological and Environmental Sciences, University of Helsinki, Helsinki University, Helsinki, Finland
| | - Jimi Kirvesoja
- Department of Biological and Environmental Science, University of Jyväskylä, Jyväskylä, Finland
| | - Kaisa Suisto
- Department of Biological and Environmental Science, University of Jyväskylä, Jyväskylä, Finland
| | - Johanna Mappes
- Department of Biological and Environmental Science, University of Jyväskylä, Jyväskylä, Finland.,Organismal and Evolutionary Biology Research Program, Faculty of Biological and Environmental Sciences, University of Helsinki, Helsinki University, Helsinki, Finland
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12
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Effect of pre-hatch incubator lights on the ontogeny of CNS opsins and photoreceptors in the Pekin duck. Poult Sci 2022; 101:101699. [PMID: 35176701 PMCID: PMC8857459 DOI: 10.1016/j.psj.2022.101699] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2021] [Revised: 11/30/2021] [Accepted: 01/03/2022] [Indexed: 02/02/2023] Open
Abstract
Incubated eggs with and without light had no effect on post-hatch production. Light does not influence the ontogeny of retinal rod and cone photoreceptors. Brain OPN4 mRNA is increased the later stages of embryonic development.
The Pekin duck is a valuable agricultural commodity globally and in the United States. Pekin ducks are seasonal breeders; they are sensitive to light and thus, research on the neuroendocrine and behavioral responses are needed to maximize production and to improve their welfare. There is compelling evidence that specific wavelengths of light may adversely alter the growth and welfare of meat (grow out) ducks. However, despite a birds’ dependence upon light, in commercial poultry hatcheries, incubators almost exclusively hold eggs in the dark. Therefore, our objective was to determine the effects of lighting on the expression of retina photoreceptors (RPs) and deep brain photoreceptors (DBPs) during duck embryological development. Two groups of ducks were raised with and without light over 21 d from egg laying, embryonic day 0. Brain and retinal tissues were collected at embryonic days 3, 7, 11, 16, and 21 of a 24 d incubation period. qRT-PCR was performed on RPs (OPN1LW, OPN2SW, OPN1SW, MAFA, RHO, and RBP3) and the DBP OPN4M from retinal and brain samples, respectively. We find that the presence and absence of light during pre-hatch incubation, had no influence on the expression of any retinal photoreceptor. However, a late embryological increase in DBP OPN4M expression was observed. Taken together, the impact of light during pre-hatch incubation does not impact the overall post-hatch production. However, future directions should explore how OPN4M pre-hatch activation impacts Pekin duck post-hatch development and growth.
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13
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Victory N, Segovia Y, García M. Cone distribution and visual resolution of the yellow-legged gull, Larus michahellis (Naumann, 1840). Anat Histol Embryol 2021; 51:197-214. [PMID: 34939688 DOI: 10.1111/ahe.12779] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2021] [Revised: 10/21/2021] [Accepted: 11/27/2021] [Indexed: 01/21/2023]
Abstract
The morphological characteristics of the yellow-legged gull's photoreceptors and cone distribution were studied using light and electron microscopy. In wholemount fresh retinas, five different coloured oil droplets located in the cone inner segments could be seen and characterized by colour, diameter and stratification. The photoreceptors were classified by comparing the fresh and fixed vertical sections under a light and electron microscope. Rods were easily distinguished from cones based on the outer segment morphology and the absence of oil droplets in their inner segments. Four types of single cones were associated with red, yellow, colourless and transparent oil droplets. Unequal double cones comprised a long principal member with a green oil droplet and an accessory short member containing a green microdroplet which was highly electron-dense under electron microscopy. The different types of oil droplets were counted from microphotographs of fresh retinal samples in 20 regions. The density, percentage and diameter of the oil droplets were determined. The results showed that central regions had the highest oil droplet density which decreased towards the retinal periphery in all quadrants. Moreover, the oil droplet density was higher in the dorsotemporal quadrant than in other retinal regions. The average density of the red oil droplets was highest in the central areas, whereas colourless oil droplets had the highest density throughout the retina. In contrast, transparent oil droplets had the lowest density across all the regions of the retina. Finally, the retinal resolution was 52.61 cycles/degree. It was calculated using the posterior nodal distance and the oil droplet diameter. The work concludes by discussing the significance of the relative proportion of different cone types across the retina.
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Affiliation(s)
- Noemi Victory
- Department of Biotechnology, Faculty of Science, University of Alicante, Alicante, Spain
| | - Yolanda Segovia
- Department of Biotechnology, Faculty of Science, University of Alicante, Alicante, Spain
| | - Magdalena García
- Department of Biotechnology, Faculty of Science, University of Alicante, Alicante, Spain
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14
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House GM, Sobotik EB, Nelson JR, Archer GS. Experimental monochromatic light-emitting diode fixture impacts Pekin duck stress and eye development. Poult Sci 2021; 100:101507. [PMID: 34715544 PMCID: PMC8564677 DOI: 10.1016/j.psj.2021.101507] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2021] [Revised: 09/16/2021] [Accepted: 09/22/2021] [Indexed: 11/26/2022] Open
Abstract
Poultry color perception of artificial light-emitting diode (LED) lighting mediates bird physiology and behavior; however, very limited research has focused on how changes in LED light color affect these same parameters in Pekin ducks. Therefore, the objective of this investigation was to determine how four LED bulbs emitting various portions of the visible light spectrum – monochromatic blue (BLUE), monochromatic green (GREEN), monochromatic red (RED), and white (WHITE) - impact the stress, fear responses, eye development, and growth of 768 straight run Pekin ducks. Elevated plasma corticosterone concentration and heterophil to lymphocyte ratio was observed in BLUE and RED ducks compared to WHITE and GREEN ducks (P = 0.005 and P = 0.001, respectively), and asymmetry scores were highest in BLUE ducks (P < 0.001), indicating BLUE and RED lighting increase the stress susceptibility of Pekin ducks. Eye weight was lowest in BLUE and RED ducks compared to GREEN and WHITE ducks (P < 0.01). No differences were observed in d 35 body weight, FCR, gait score, or fear response parameters (P > 0.05). These results indicate BLUE and RED lighting may not be adequate for Pekin duck growout, and Pekin ducks may require artificial light sources containing a broad range of wavelengths, as seen with WHITE and GREEN lights, rather than lights containing more concentrated ranges such as in RED and BLUE lights, but further investigation is needed to understand how eye weight affects duck light perception and welfare. The current findings emphasize that although Pekin ducks and chickens are both sensitive to light color, species-specific nuances in light perception may cause distinct differences in Pekin duck versus broiler physiological responses and must be considered when selecting artificial light color in Pekin duck growout facilities.
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Affiliation(s)
- Gabrielle M House
- Department of Poultry Science, Texas A&M University, College Station, TX 77843, USA
| | - Eric B Sobotik
- Department of Poultry Science, Texas A&M University, College Station, TX 77843, USA
| | - Jill R Nelson
- Department of Poultry Science, Texas A&M University, College Station, TX 77843, USA
| | - Gregory S Archer
- Department of Poultry Science, Texas A&M University, College Station, TX 77843, USA.
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15
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White ND, Batz ZA, Braun EL, Braun MJ, Carleton KL, Kimball RT, Swaroop A. A novel exome probe set captures phototransduction genes across birds (Aves) enabling efficient analysis of vision evolution. Mol Ecol Resour 2021; 22:587-601. [PMID: 34652059 DOI: 10.1111/1755-0998.13496] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2021] [Revised: 08/17/2021] [Accepted: 08/20/2021] [Indexed: 11/27/2022]
Abstract
The diversity of avian visual phenotypes provides a framework for studying mechanisms of trait diversification generally, and the evolution of vertebrate vision, specifically. Previous research has focused on opsins, but to fully understand visual adaptation, we must study the complete phototransduction cascade (PTC). Here, we developed a probe set that captures exonic regions of 46 genes representing the PTC and other light responses. For a subset of species, we directly compared gene capture between our probe set and low-coverage whole genome sequencing (WGS), and we discuss considerations for choosing between these methods. Finally, we developed a unique strategy to avoid chimeric assembly by using "decoy" reference sequences. We successfully captured an average of 64% of our targeted exome in 46 species across 14 orders using the probe set and had similar recovery using the WGS data. Compared to WGS or transcriptomes, our probe set: (1) reduces sequencing requirements by efficiently capturing vision genes, (2) employs a simpler bioinformatic pipeline by limiting required assembly and negating annotation, and (3) eliminates the need for fresh tissues, enabling researchers to leverage existing museum collections. We then utilized our vision exome data to identify positively selected genes in two evolutionary scenarios-evolution of night vision in nocturnal birds and evolution of high-speed vision specific to manakins (Pipridae). We found parallel positive selection of SLC24A1 in both scenarios, implicating the alteration of rod response kinetics, which could improve color discrimination in dim light conditions and/or facilitate higher temporal resolution.
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Affiliation(s)
- Noor D White
- Neurobiology Neurodegeneration and Repair Laboratory, National Eye Institute, National Institutes of Health, Bethesda, Maryland, USA.,Department of Vertebrate Zoology, National Museum of Natural History, Smithsonian Institution, Washington, District of Columbia, USA.,Behavior, Ecology, Evolution and Systematics Program, University of Maryland, College Park, Maryland, USA
| | - Zachary A Batz
- Neurobiology Neurodegeneration and Repair Laboratory, National Eye Institute, National Institutes of Health, Bethesda, Maryland, USA
| | - Edward L Braun
- Department of Biology, University of Florida, Gainesville, Florida, USA
| | - Michael J Braun
- Department of Vertebrate Zoology, National Museum of Natural History, Smithsonian Institution, Washington, District of Columbia, USA.,Behavior, Ecology, Evolution and Systematics Program, University of Maryland, College Park, Maryland, USA.,Department of Biology, University of Maryland, College Park, Maryland, USA
| | - Karen L Carleton
- Behavior, Ecology, Evolution and Systematics Program, University of Maryland, College Park, Maryland, USA.,Department of Biology, University of Maryland, College Park, Maryland, USA
| | - Rebecca T Kimball
- Department of Biology, University of Florida, Gainesville, Florida, USA
| | - Anand Swaroop
- Neurobiology Neurodegeneration and Repair Laboratory, National Eye Institute, National Institutes of Health, Bethesda, Maryland, USA
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16
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Arias M, Leroy L, Madec C, Matos L, Tedore C, Elias M, Gomez D. Partial wing transparency works better when disrupting wing edges: Evidence from a field experiment. J Evol Biol 2021; 34:1840-1846. [PMID: 34601773 DOI: 10.1111/jeb.13943] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2021] [Revised: 09/04/2021] [Accepted: 09/19/2021] [Indexed: 11/28/2022]
Abstract
Lepidoptera-a group of insects in which wing transparency has arisen multiple times-exhibits much variation in the size and position of transparent wing zones. However, little is known as to how this variability affects detectability. Here, we test how the size and position of transparent elements affect the predation of artificial moths by wild birds in the field. Morphs with transparent elements touching wing borders showed a reduced predation risk, with the effect being the same regardless of the number of wing borders being touched. By contrast, transparent element size had little to no effect on predation risk. Overall, this experiment shows for the first time that transparency offers higher protection when it disrupts prey contour in terrestrial habitats.
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Affiliation(s)
- Mónica Arias
- CEFE, CNRS, Univ. Montpellier, EPHE, IRD, Montpellier, France.,ISYEB, CNRS, MNHN, Sorbonne Univ, EPHE, Univ. Antilles, 45 rue Buffon CP50, Paris, France
| | - Lucie Leroy
- CEFE, CNRS, Univ. Montpellier, EPHE, IRD, Montpellier, France
| | - Clément Madec
- CEFE, CNRS, Univ. Montpellier, EPHE, IRD, Montpellier, France
| | - Louane Matos
- CEFE, CNRS, Univ. Montpellier, EPHE, IRD, Montpellier, France
| | - Cynthia Tedore
- CEFE, CNRS, Univ. Montpellier, EPHE, IRD, Montpellier, France.,Faculty of Mathematics, Informatics and Natural Sciences, Institute of Zoology, Univ. Hamburg, Hamburg, Germany
| | - Marianne Elias
- ISYEB, CNRS, MNHN, Sorbonne Univ, EPHE, Univ. Antilles, 45 rue Buffon CP50, Paris, France
| | - Doris Gomez
- CEFE, CNRS, Univ. Montpellier, EPHE, IRD, Montpellier, France.,INSP, CNRS, Sorbonne Univ., Paris, France
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17
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18
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Ausprey IJ, Hauber ME. Host and brood parasite coevolutionary interactions covary with comparative patterns of the avian visual system. Biol Lett 2021; 17:20210309. [PMID: 34582733 PMCID: PMC8478515 DOI: 10.1098/rsbl.2021.0309] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/04/2022] Open
Abstract
In coevolutionary arms-races, reciprocal ecological interactions and their fitness impacts shape the course of phenotypic evolution. The classic example of avian host–brood parasite interactions selects for host recognition and rejection of increasingly mimetic foreign eggs. An essential component of perceptual mimicry is that parasitic eggs escape detection by host sensory systems, yet there is no direct evidence that the avian visual system covaries with parasitic egg recognition or mimicry. Here, we used eye size measurements collected from preserved museum specimens as a metric of the avian visual system for species involved in host–brood parasite interactions. We discovered that (i) hosts had smaller eyes compared with non-hosts, (ii) parasites had larger eyes compared with hosts before but not after phylogenetic corrections, perhaps owing to the limited number of independent evolutionary origins of obligate brood parasitism, (iii) egg rejection in hosts with non-mimetic parasitic eggs positively correlated with eye size, and (iv) eye size was positively associated with increased avian-perceived host–parasite eggshell similarity. These results imply that both host-use by parasites and anti-parasitic responses by hosts covary with a metric of the visual system across relevant bird species, providing comparative evidence for coevolutionary patterns of host and brood parasite sensory systems.
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Affiliation(s)
- Ian J Ausprey
- Florida Museum of Natural History and Department of Biology, University of Florida, Gainesville, FL 32611-7011, USA
| | - Mark E Hauber
- Department of Evolution, Ecology, and Behavior, School of Integrative Biology, University of Illinois at Urbana-Champaign, Champaign, IL, USA
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19
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Fan M, Hall ML, Roast M, Peters A, Delhey K. Variability, heritability and condition-dependence of the multidimensional male colour phenotype in a passerine bird. Heredity (Edinb) 2021; 127:300-311. [PMID: 34188194 PMCID: PMC8405751 DOI: 10.1038/s41437-021-00453-6] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2020] [Revised: 06/18/2021] [Accepted: 06/18/2021] [Indexed: 02/06/2023] Open
Abstract
Elaborate ornamental traits are commonly assumed to be honest signals of individual quality, owing to the presumed costs involved in their production and/or maintenance. Such traits are often highly variable, possibly because of condition-dependence and/or high underlying genetic variation, and it has been suggested that their expression should be more sensitive to condition and/or more heritable than non-ornamental traits. Many bird species display colourful plumage with multiple distinct patches of different developmental origins, forming complex colour phenotypes. Despite this complexity, colourful ornaments are often studied in isolation, without comparison to suitable non-ornamental controls. Based on plumage reflectance data collected over 8 years, we assessed the signalling potential of the multidimensional male colour phenotype in a tropical bird: the purple-crowned fairy-wren Malurus coronatus. Specifically, we tested the predictions that the expression of putative ornamental colours (purple and black - the breeding colours - and blue) is (1) more variable, (2) more heritable and (3) more condition-dependent compared to year-round non-ornamental colours (buff-white and brown). Our results show that ornamental colours exhibit greater levels of variability, and some chromatic components of purple and blue colouration appear slightly heritable (h² = 0.19-0.30). However, contrary to predictions of heightened condition-dependence in ornaments, only brightness of the buff-white and brown colouration increased with male body condition, although brightness of the purple colouration was related to male age as expected. Despite partial support for predictions, the lack of consistent patterns illustrates the complexity of visual signals and highlights the need to study colour phenotypes in their entirety.
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Affiliation(s)
- Marie Fan
- School of Biological Sciences, Monash University, Clayton, VIC, Australia.
| | - Michelle L Hall
- School of BioSciences, University of Melbourne, Melbourne, Parkville, VIC, Australia.,Max Planck Institute for Ornithology, Radolfzell, Germany
| | - Michael Roast
- School of Biological Sciences, Monash University, Clayton, VIC, Australia
| | - Anne Peters
- School of Biological Sciences, Monash University, Clayton, VIC, Australia.,Max Planck Institute for Ornithology, Radolfzell, Germany
| | - Kaspar Delhey
- School of Biological Sciences, Monash University, Clayton, VIC, Australia.,Max Planck Institute for Ornithology, Radolfzell, Germany.,Max Planck Institute for Ornithology, Seewiesen, Germany
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20
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Pinzon-Rodriguez A, Muheim R. Cryptochrome expression in avian UV cones: revisiting the role of CRY1 as magnetoreceptor. Sci Rep 2021; 11:12683. [PMID: 34135416 PMCID: PMC8209128 DOI: 10.1038/s41598-021-92056-8] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2020] [Accepted: 06/03/2021] [Indexed: 02/05/2023] Open
Abstract
Cryptochromes (CRY) have been proposed as putative magnetoreceptors in vertebrates. Localisation of CRY1 in the UV cones in the retinas of birds suggested that it could be the candidate magnetoreceptor. However, recent findings argue against this possibility. CRY1 is a type II cryptochrome, a subtype of cryptochromes that may not be inherently photosensitive, and it exhibits a clear circadian expression in the retinas of birds. Here, we reassessed the localisation and distribution of CRY1 in the retina of the zebra finch. Zebra finches have a light-dependent magnetic compass based on a radical-pair mechanism, similar to migratory birds. We found that CRY1 colocalised with the UV/V opsin (SWS1) in the outer segments of UV cones, but restricted to the tip of the segments. CRY1 was found in all UV cones across the entire retina, with the highest densities near the fovea. Pre-exposure of birds to different wavelengths of light did not result in any difference in CRY1 detection, suggesting that CRY1 did not undergo any detectable functional changes as result of light activation. Considering that CRY1 is likely not involved in magnetoreception, our findings open the possibility for an involvement in different, yet undetermined functions in the avian UV/V cones.
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Affiliation(s)
- Atticus Pinzon-Rodriguez
- grid.4514.40000 0001 0930 2361Department of Biology, Lund University, Biology Building B, 223 62 Lund, Sweden
| | - Rachel Muheim
- grid.4514.40000 0001 0930 2361Department of Biology, Lund University, Biology Building B, 223 62 Lund, Sweden
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21
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Detectability is in the eye of the beholder—the role of UV reflectance on tadpole detection and predation by a passerine bird. Behav Ecol Sociobiol 2021. [DOI: 10.1007/s00265-021-02983-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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22
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Tedore C, Nilsson DE. Ultraviolet vision aids the detection of nutrient-dense non-signaling plant foods. Vision Res 2021; 183:16-29. [PMID: 33639304 DOI: 10.1016/j.visres.2021.01.009] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2020] [Revised: 01/10/2021] [Accepted: 01/24/2021] [Indexed: 11/29/2022]
Abstract
To expand our understanding of what tasks are particularly helped by UV vision and may justify the costs of focusing high-energy light onto the retina, we used an avian-vision multispectral camera to image diverse vegetated habitats in search of UV contrasts that differ markedly from visible-light contrasts. One UV contrast that stood out as very different from visible-light contrasts was that of nutrient-dense non-signaling plant foods (such as young leaves and immature fruits) against their natural backgrounds. From our images, we calculated color contrasts between 62+ species of such foods and mature foliage for the two predominant color vision systems of birds, UVS and VS. We also computationally generated images of what a generalized tetrachromat, unfiltered by oil droplets, would see, by developing a new methodology that uses constrained linear least squares to solve for optimal weighted combinations of avian camera filters to mimic new spectral sensitivities. In all visual systems, we found that nutrient-dense non-signaling plant foods presented a lower, often negative figure-ground contrast in the UV channels, and a higher, often positive figure-ground contrast in the visible channels. Although a zero contrast may sound unhelpful, it can actually enhance color contrast when compared in a color opponent system to other channels with nonzero contrasts. Here, low or negative UV contrasts markedly enhanced color contrasts. We propose that plants may struggle to evolve better UV crypsis since UV reflectance from vegetation is largely specular and thus highly dependent on object orientation, shape, and texture.
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Affiliation(s)
- Cynthia Tedore
- Lund Vision Group, Lund University, Sölvegatan 35, 223 62 Lund, Sweden.
| | - Dan-Eric Nilsson
- Lund Vision Group, Lund University, Sölvegatan 35, 223 62 Lund, Sweden
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23
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McQueen A, Delhey K, Barzan FR, Naimo AC, Peters A. Male fairy-wrens produce and maintain vibrant breeding colors irrespective of individual quality. Behav Ecol 2020. [DOI: 10.1093/beheco/araa128] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Abstract
Conspicuous colors may signal individual quality if high-quality individuals produce more elaborate colors or have a greater capacity to invest in color maintenance. We investigate these hypotheses using repeated within-individual observations and experimentally induced color production in a wild bird, the superb fairy-wren (Malurus cyaneus). Male superb fairy-wrens undergo an annual molt from brown, nonbreeding plumage to an ultraviolet-blue and black breeding plumage. Color maintenance is especially relevant for this species because structural, ultraviolet-blue plumage colors are particularly susceptible to fading. Further, only the most sexually attractive males molt to breeding plumage early (before spring) and thereby keep their colors for an extended time before the breeding season. Our results show that (i) sexually attractive, early-molting males do not have higher quality breeding colors and (ii) breeding colors are not impacted by experimentally inducing males to molt early and while in low body condition. We found that (iii) breeding colors do not fade but remain consistent or become more saturated within individuals over time. Despite this, (iv) males do not spend more time preening while in breeding plumage. Instead, males keep their colors in pristine condition by re-molting parts of their breeding plumage throughout the breeding season, suggesting an alternative, potential cost of maintaining ornamental colors. We conclude that variation in structural breeding colors is unlikely to indicate individual quality in superb fairy-wrens.
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Affiliation(s)
- Alexandra McQueen
- School of Biological Sciences, Monash University, Wellington Road, Clayton, Victoria, Australia
- Centre for Integrative Ecology, School of Life and Environmental Sciences, Deakin University, Burwood Highway, Burwood, Victoria, Australia
| | - Kaspar Delhey
- School of Biological Sciences, Monash University, Wellington Road, Clayton, Victoria, Australia
- Max Planck Institute for Ornithology, Eberhard-Gwinner-Straße, Seewiesen, Germany
| | - Flavia R Barzan
- School of Biological Sciences, Monash University, Wellington Road, Clayton, Victoria, Australia
- Departamento de Recursos Naturales y Gestión Ambiental, Estación Experimental Agropecuaria Paraná, Instituto Nacional de Tecnología Agropecuaria (INTA) and CONICET, Oro Verde, Entre Ríos, Argentina
| | - Annalise C Naimo
- School of Biological Sciences, Monash University, Wellington Road, Clayton, Victoria, Australia
| | - Anne Peters
- School of Biological Sciences, Monash University, Wellington Road, Clayton, Victoria, Australia
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24
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Ausprey IJ, Newell FL, Robinson SK. Adaptations to light predict the foraging niche and disassembly of avian communities in tropical countrysides. Ecology 2020; 102:e03213. [PMID: 33002207 DOI: 10.1002/ecy.3213] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/20/2020] [Revised: 06/21/2020] [Accepted: 08/06/2020] [Indexed: 12/22/2022]
Abstract
The role of light in partitioning ecological niche space remains a frontier in understanding the assembly of terrestrial vertebrate communities and their response to global change. Leveraging recent advances in biologging technology and intensive field surveys of cloud forest bird communities across an agricultural land use gradient in the Peruvian Andes, we demonstrate that eye size predicts (1) the ambient light microenvironment used by free-ranging birds, (2) their foraging niche, and (3) species-specific sensitivity to agricultural land use change. For 15 species carrying light sensors (N = 71 individuals), light intensity levels were best explained by eye size and foraging behavior, with larger-eyed species using darker microenvironments. Across the cloud forest bird community (N = 240 species), hyperopic ("far-sighted") foragers, (e.g., flycatchers), had larger eyes compared to myopic ("near-sighted") species (e.g., gleaners and frugivores); eye size was also larger for myopic insectivores that foraged in the forest understory. Eye size strongly predicted sensitivity to brightly lit habitats across an agricultural land use gradient. Species that increased in abundance in mixed intensity agriculture, including fencerows, silvopasture, and pasture, had smaller eyes, suggesting that light acts as an environmental filter when communities disassemble in a human-disturbed landscape. We suggest that eye size represents a novel functional trait contributing to terrestrial vertebrate community assembly and sensitivity to habitat disturbance.
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Affiliation(s)
- Ian J Ausprey
- Florida Museum of Natural History and Department of Biology, University of Florida, Gainesville, Florida, 32611, USA
| | - Felicity L Newell
- Florida Museum of Natural History and Department of Biology, University of Florida, Gainesville, Florida, 32611, USA
| | - Scott K Robinson
- Florida Museum of Natural History and Department of Biology, University of Florida, Gainesville, Florida, 32611, USA
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25
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Chen Z, Niu Y, Liu CQ, Sun H. Red flowers differ in shades between pollination systems and across continents. ANNALS OF BOTANY 2020; 126:837-848. [PMID: 32478385 PMCID: PMC7539362 DOI: 10.1093/aob/mcaa103] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/11/2019] [Accepted: 05/26/2020] [Indexed: 05/14/2023]
Abstract
BACKGROUND AND AIMS Floral colour is a primary signal in plant-pollinator interactions. The association between red flowers and bird pollination is well known, explained by the 'bee avoidance' and 'bird attraction' hypotheses. Nevertheless, the relative importance of these two hypotheses has rarely been investigated on a large scale, even in terms of colour perception per se. METHODS We collected reflectance spectra for 130 red flower species from different continents and ascertained their pollination systems. The spectra were analysed using colour vision models for bees and (three types of) birds, to estimate colour perception by these pollinators. The differences in colour conspicuousness (chromatic and achromatic contrast, purity) and in spectral properties between pollination systems and across continents were analysed. KEY RESULTS Compared with other floral colours, red flowers are very conspicuous to birds and much less conspicuous to bees. The red flowers pollinated by bees and by birds are more conspicuous to their respective pollinators. Compared with the bird flowers in the Old World, the New World ones are less conspicuous to bees and may be more conspicuous not only to violet-sensitive but also to ultraviolet-sensitive birds. These differences can be explained by the different properties of the secondary reflectance peak (SP). SP intensity is higher in red flowers pollinated by bees than those pollinated by birds (especially New World bird flowers). A transition from high SP to low SP in red flowers can induce chromatic contrast changes, with a greater effect on reducing attraction to bees than enhancing attraction to birds. CONCLUSIONS Shades of red flowers differ between pollination systems. Moreover, red bird flowers are more specialized in the New World than in the Old World. The evolution towards colour specialization is more likely to result in higher efficiency of bee avoidance than bird attraction.
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Affiliation(s)
- Zhe Chen
- CAS Key Laboratory for Plant Diversity and Biogeography of East Asia, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, Yunnan, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Yang Niu
- CAS Key Laboratory for Plant Diversity and Biogeography of East Asia, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, Yunnan, China
| | - Chang-Qiu Liu
- Center for Gardens and Horticultural Studies, Guangxi Institute of Botany, Guangxi Zhuang Autonomous Region and Chinese Academy of Sciences, Guilin, Guangxi, China
| | - Hang Sun
- CAS Key Laboratory for Plant Diversity and Biogeography of East Asia, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, Yunnan, China
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26
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Visual adaptations of diurnal and nocturnal raptors. Semin Cell Dev Biol 2020; 106:116-126. [DOI: 10.1016/j.semcdb.2020.05.004] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2020] [Revised: 05/06/2020] [Accepted: 05/06/2020] [Indexed: 02/06/2023]
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27
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Wei Y, Zheng W, Li B, Tong Q, Shi H. Effects of a two-phase mixed color lighting program using light-emitting diode lights on layer chickens during brooding and rearing periods. Poult Sci 2020; 99:4695-4703. [PMID: 32988504 PMCID: PMC7598341 DOI: 10.1016/j.psj.2020.06.072] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2020] [Revised: 05/17/2020] [Accepted: 06/08/2020] [Indexed: 11/01/2022] Open
Abstract
The behavior, growth and development, and production performance of poultry are affected by the light environment. The influence of light results from a combination of light sources, light intensity, light color, and the photoperiod regimen. With light-emitting diode (LED) lamps applied in poultry housing systems, specific light colors are desired for each time period for layer chickens. The objective of this study was to investigate the effects of a 2-phase mixed color lighting program (phase 1: blue-green, 1 D-13 wk; phase 2: yellow-orange, 14-20 wk) using LED lights on the blood parameters, skeletal development parameters, and sexual development parameters of caged layer chickens during their brooding and rearing periods. Fifty-two chickens were raised from 1 D to 20 wk of age in each of the 4 treatment groups with 3 replicates, with white (400-700 nm) light at phase 1 and phase 2 (WL treatment as the control); blue-green (435-565 nm) light at phase 1 followed by yellow-orange (565-630 nm) light at phase 2 (BG-YOL treatment); yellow-orange LED (565-630 nm) light at phase 1 and phase 2 (YOL treatment); and blue-green (435-565 nm) light at phase 1 and phase 2 (BGL treatment). The results showed that the serum Ig concentrations of the layer chickens in the BG-YOL treatment and BGL treatment were higher than those in the WL treatment at 13 wk of age (P < 0.05). At the age of 20 wk, the serum glucose concentration levels of the pullets after the WL and BGL treatments were lower than those after the YOL treatment (P < 0.05). Compared with the WL treatment, the YOL treatment significantly increased the bone mineral density of the layer chickens (P < 0.05), and BG-YOL treatment promoted the development of the sexual organs (oviducts and ovaries) of the laying hens at the age of 20 wk (P < 0.05). For the 50% egg production age, the YOL treatment was earlier than the other 3 treatments. This study demonstrated that appropriately staged spectral control using LED lights could have positive effects on the immune performance, bone development, and production performance of caged layer chickens during their brooding and rearing periods.
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Affiliation(s)
- Yongxiang Wei
- Department of Agricultural Structure and Environmental Engineering, College of Water Resources & Civil Engineering, China Agricultural University, Beijing 100083, China; Key Laboratory of Agricultural Engineering in Structure and Environment, Ministry of Agriculture and Rural Affairs of China, Beijing 100083, China; Beijing Engineering Research Center on Animal Healthy Environment, China Agricultural University, Beijing 100083, China
| | - Weichao Zheng
- Department of Agricultural Structure and Environmental Engineering, College of Water Resources & Civil Engineering, China Agricultural University, Beijing 100083, China; Key Laboratory of Agricultural Engineering in Structure and Environment, Ministry of Agriculture and Rural Affairs of China, Beijing 100083, China; Beijing Engineering Research Center on Animal Healthy Environment, China Agricultural University, Beijing 100083, China.
| | - Baoming Li
- Department of Agricultural Structure and Environmental Engineering, College of Water Resources & Civil Engineering, China Agricultural University, Beijing 100083, China; Key Laboratory of Agricultural Engineering in Structure and Environment, Ministry of Agriculture and Rural Affairs of China, Beijing 100083, China; Beijing Engineering Research Center on Animal Healthy Environment, China Agricultural University, Beijing 100083, China
| | - Qin Tong
- Department of Agricultural Structure and Environmental Engineering, College of Water Resources & Civil Engineering, China Agricultural University, Beijing 100083, China; Key Laboratory of Agricultural Engineering in Structure and Environment, Ministry of Agriculture and Rural Affairs of China, Beijing 100083, China; Beijing Engineering Research Center on Animal Healthy Environment, China Agricultural University, Beijing 100083, China
| | - Haipeng Shi
- Department of Agricultural Structure and Environmental Engineering, College of Water Resources & Civil Engineering, China Agricultural University, Beijing 100083, China; Key Laboratory of Agricultural Engineering in Structure and Environment, Ministry of Agriculture and Rural Affairs of China, Beijing 100083, China; Beijing Engineering Research Center on Animal Healthy Environment, China Agricultural University, Beijing 100083, China
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Ketter-Katz H, Lev-Ari T, Katzir G. Vision in chameleons-A model for non-mammalian vertebrates. Semin Cell Dev Biol 2020; 106:94-105. [PMID: 32576499 DOI: 10.1016/j.semcdb.2020.05.009] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2020] [Revised: 05/12/2020] [Accepted: 05/12/2020] [Indexed: 11/29/2022]
Abstract
Chameleons (Chamaeleonidae, Reptilia) are known for their extreme sensory and motor adaptations to arboreal life and insectivoury. They show most distinct sequences of visuo-motor patterns in threat avoidance and in predation with prey capture being performed by tongue strikes that are unparalleled in vertebrates. Optical adaptations result in retinal image enlargement and the unique capacity to determine target distance by accommodation cues. Ocular adaptations result in complex eye movements that are context dependent, not independent, as observed in threat avoidance and predation. In predation, evidence from the chameleons' capacity to track multiple targets support the view that their eyes are under individual controls. Eye movements and body movements are lateralised, with lateralisation being a function of many factors at the population, individual, and specific-situation levels. Chameleons are considered a potentially important model for vision in non-mammalian vertebrates. They provide exceptional behavioural tools for studying eye movements as well as information gathering and analysis. They open the field of lateralisation, decision making, and context dependence. Finally, chameleons allow a deeper examination of the relationships between their unique visuo-motor capacities and the central nervous system of reptiles and ectotherms, in general, as compared with mammals.
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Affiliation(s)
- Hadas Ketter-Katz
- Goldschleger Eye Institute, Sheba Medical Center, Tel-Hashomer, 52621, Israel; Sackler Faculty of Medicine, Tel-Aviv University, Tel-Aviv, 69978, Israel
| | - Tidhar Lev-Ari
- Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, GA, 30332, USA
| | - Gadi Katzir
- Department of Evolutionary and Environmental Biology, University of Haifa, 199 Aba Khoushy Ave., Mount Carmel, Haifa, 3498838, Israel.
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Zhou B, Liang W. Avian escape responses to observers wearing clothing of different colors: A comparison of urban and rural populations. Glob Ecol Conserv 2020. [DOI: 10.1016/j.gecco.2020.e00921] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022] Open
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Carleton KL, Escobar-Camacho D, Stieb SM, Cortesi F, Marshall NJ. Seeing the rainbow: mechanisms underlying spectral sensitivity in teleost fishes. J Exp Biol 2020; 223:jeb193334. [PMID: 32327561 PMCID: PMC7188444 DOI: 10.1242/jeb.193334] [Citation(s) in RCA: 51] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Among vertebrates, teleost eye diversity exceeds that found in all other groups. Their spectral sensitivities range from ultraviolet to red, and the number of visual pigments varies from 1 to over 40. This variation is correlated with the different ecologies and life histories of fish species, including their variable aquatic habitats: murky lakes, clear oceans, deep seas and turbulent rivers. These ecotopes often change with the season, but fish may also migrate between ecotopes diurnally, seasonally or ontogenetically. To survive in these variable light habitats, fish visual systems have evolved a suite of mechanisms that modulate spectral sensitivities on a range of timescales. These mechanisms include: (1) optical media that filter light, (2) variations in photoreceptor type and size to vary absorbance and sensitivity, and (3) changes in photoreceptor visual pigments to optimize peak sensitivity. The visual pigment changes can result from changes in chromophore or changes to the opsin. Opsin variation results from changes in opsin sequence, opsin expression or co-expression, and opsin gene duplications and losses. Here, we review visual diversity in a number of teleost groups where the structural and molecular mechanisms underlying their spectral sensitivities have been relatively well determined. Although we document considerable variability, this alone does not imply functional difference per se. We therefore highlight the need for more studies that examine species with known sensitivity differences, emphasizing behavioral experiments to test whether such differences actually matter in the execution of visual tasks that are relevant to the fish.
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Affiliation(s)
- Karen L Carleton
- Department of Biology, University of Maryland, College Park, MD 20742, USA
| | | | - Sara M Stieb
- Centre of Ecology, Evolution and Biogeochemistry, EAWAG Swiss Federal Institute of Aquatic Science and Technology, 6047 Kastanienbaum, Switzerland
- Institute of Ecology and Evolution, University of Bern, 3012 Bern, Switzerland
- Queensland Brain Institute, University of Queensland, Brisbane 4072 QLD, Australia
| | - Fabio Cortesi
- Queensland Brain Institute, University of Queensland, Brisbane 4072 QLD, Australia
| | - N Justin Marshall
- Queensland Brain Institute, University of Queensland, Brisbane 4072 QLD, Australia
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Arias M, Davey JW, Martin S, Jiggins C, Nadeau N, Joron M, Llaurens V. How do predators generalize warning signals in simple and complex prey communities? Insights from a videogame. Proc Biol Sci 2020; 287:20200014. [PMID: 32070260 DOI: 10.1098/rspb.2020.0014] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
The persistence of distinct warning signals within and between sympatric mimetic communities is a puzzling evolutionary question because selection favours convergence of colour patterns among toxic species. Such convergence is partly shaped by predators' reaction to similar but not identical stimulus (i.e. generalization behaviour), and generalization by predators is likely to be shaped by the diversity of local prey. However, studying generalization behaviour is generally limited to simple variations of prey colour patterns. Here, we used a computer game played by humans as surrogate predators to investigate generalization behaviours in simple (4 morphs) and complex (10 morphs) communities of unprofitable (associated with a penalty) and profitable butterflies. Colour patterns used in the game are observed in the natural populations of unprofitable butterfly species such as Heliconius numata. Analyses of 449 game participants' behaviours show that players avoided unprofitable prey more readily in simple than in complex communities. However, generalization was observed only in players that faced complex communities, enhancing the protection of profitable prey that looked similar to at least one unprofitable morph. Additionally, similarity among unprofitable prey also reduced attack rates only in complex communities. These results are consistent with previous studies using avian predators but artificial colour patterns and suggest that mimicry is more likely to evolve in complex communities where increases in similarity are more likely to be advantageous.
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Affiliation(s)
- Mónica Arias
- Institut de Systématique, Evolution, Biodiversité (ISYEB), Muséum national d'Histoire naturelle, CNRS, Sorbonne Université, EPHE, Université des Antilles CP 50, 57 rue Cuvier, 75005 Paris, France.,Centre d'Ecologie Fonctionnelle et Evolutive, UMR 5175 CNRS-Université de Montpellier, École Pratique des Hautes Études, Université Paul Valéry, 34293 Montpellier 5, France
| | - John W Davey
- Bioscience Technology Facility, Department of Biology, University of York, Wentworth Way, York YO10 5DD, UK.,Department of Zoology, University of Cambridge, Downing Street, Cambridge CB2 3EJ, UK
| | - Simon Martin
- Department of Zoology, University of Cambridge, Downing Street, Cambridge CB2 3EJ, UK
| | - Chris Jiggins
- Department of Zoology, University of Cambridge, Downing Street, Cambridge CB2 3EJ, UK
| | - Nicola Nadeau
- Molecular Ecology Lab, Department of Animal and Plant Sciences, University of Sheffield, Sheffield, UK
| | - Mathieu Joron
- Centre d'Ecologie Fonctionnelle et Evolutive, UMR 5175 CNRS-Université de Montpellier, École Pratique des Hautes Études, Université Paul Valéry, 34293 Montpellier 5, France
| | - Violaine Llaurens
- Institut de Systématique, Evolution, Biodiversité (ISYEB), Muséum national d'Histoire naturelle, CNRS, Sorbonne Université, EPHE, Université des Antilles CP 50, 57 rue Cuvier, 75005 Paris, France
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Ramírez‐Barrera SM, Velasco JA, Orozco‐Téllez TM, Vázquez‐López AM, Hernández‐Baños BE. What drives genetic and phenotypic divergence in the Red-crowned Ant tanager ( Habia rubica, Aves: Cardinalidae), a polytypic species? Ecol Evol 2019; 9:12339-12352. [PMID: 31832165 PMCID: PMC6854386 DOI: 10.1002/ece3.5742] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2019] [Revised: 08/07/2019] [Accepted: 09/15/2019] [Indexed: 01/28/2023] Open
Abstract
AIM The effects of geographic and environmental variables on patterns of genetic and phenotypic differentiation have been thoroughly studied. Ecological speciation involves reproductive isolation due to divergent natural selection that can result in a positive correlation between genetic divergence and adaptive phenotypic divergence (isolation by adaptation, IBA). If the phenotypic target of selection is unknown or not easily measured, environmental variation can be used as a proxy, expecting positive correlation between genetic and environmental distances, independent of geographic distances (isolation by environment, IBE). The null model is that the amount of gene flow between populations decreases as the geographic distance between them increases, and genetic divergence is due simply to the neutral effects of genetic drift (isolation by distance, IBD). However, since phenotypic differentiation in natural populations may be autocorrelated with geographic distance, it is often difficult to distinguish IBA from the neutral expectation of IBD. In this work, we test hypotheses of IBA, IBE, and IBD in the Red-crowned Ant tanager (Habia rubica). LOCATION Mesoamerica (Mexico-Central America) and South America. TAXON Habia rubica (Aves: Cardinalidae). METHODS We compiled genetic data, coloration, and morphometric data from specimens from collections in Mexico and the United States. We used the Multiple Matrix Regression with Randomization (MMRR) approach to evaluate the influence of geographic and environmental distances on genetic and phenotypic differentiation of H. rubica at both phylogroup and population levels. RESULTS Our results provide strong evidence that geographic distance is the main driver of genetic variation in H. rubica. We did not find evidence that climate variation is driving population differentiation in this species across a widespread geographic region. MAIN CONCLUSIONS Our data point to geographic isolation as the main factor structuring genetic variation within populations of H. rubica and suggest that climate is not playing a major role in genetic differentiation within this species.
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Affiliation(s)
- Sandra M. Ramírez‐Barrera
- Posgrado en Ciencias BiológicasUniversidad Nacional Autónoma de MéxicoCiudad de MéxicoMexico
- Departamento de Biología EvolutivaFacultad de CienciasMuseo de ZoologíaUniversidad Nacional Autónoma de MéxicoCiudad de MéxicoMexico
| | - Julián A. Velasco
- Centro de Ciencias de la AtmósferaUniversidad Nacional Autónoma de MéxicoCiudad de MéxicoMexico
| | - Tania M. Orozco‐Téllez
- Departamento de Biología EvolutivaFacultad de CienciasMuseo de ZoologíaUniversidad Nacional Autónoma de MéxicoCiudad de MéxicoMexico
| | - Alma M. Vázquez‐López
- Posgrado en Ciencias BiológicasUniversidad Nacional Autónoma de MéxicoCiudad de MéxicoMexico
- Departamento de Biología EvolutivaFacultad de CienciasMuseo de ZoologíaUniversidad Nacional Autónoma de MéxicoCiudad de MéxicoMexico
| | - Blanca E. Hernández‐Baños
- Departamento de Biología EvolutivaFacultad de CienciasMuseo de ZoologíaUniversidad Nacional Autónoma de MéxicoCiudad de MéxicoMexico
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A novel cellular structure in the retina of insectivorous birds. Sci Rep 2019; 9:15230. [PMID: 31645645 PMCID: PMC6811557 DOI: 10.1038/s41598-019-51774-w] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2018] [Accepted: 10/04/2019] [Indexed: 01/09/2023] Open
Abstract
The keen visual systems of birds have been relatively well-studied. The foundations of avian vision rest on their cone and rod photoreceptors. Most birds use four cone photoreceptor types for color vision, a fifth cone for achromatic tasks, and a rod for dim-light vision. The cones, along with their oil droplets, and rods are conserved across birds - with the exception of a few shifts in spectral sensitivity - despite taxonomic, behavioral and ecological differences. Here, however, we describe a novel photoreceptor organelle in a group of New World flycatchers (Empidonax spp.) in which the traditional oil droplet is replaced with a complex of electron-dense megamitochondria surrounded by hundreds of small, orange oil droplets. The photoreceptors with this organelle were unevenly distributed across the retina, being present in the central region (including in the fovea), but absent from the retinal periphery and the area temporalis of these insectivorous birds. Of the many bird species with their photoreceptors characterized, only the two flycatchers described here (E. virescens and E. minimus) possess this unusual retinal structure. We discuss the potential functional significance of this unique sub-cellular structure, which might provide an additional visual channel for these small predatory songbirds.
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Lindstedt C, Suisto K, Mappes J. Appearance before performance? Nutritional constraints on life-history traits, but not warning signal expression in aposematic moths. J Anim Ecol 2019; 89:494-505. [PMID: 31538333 PMCID: PMC7027542 DOI: 10.1111/1365-2656.13103] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2019] [Accepted: 07/21/2019] [Indexed: 11/26/2022]
Abstract
Trade-offs have been shown to play an important role in the divergence of mating strategies and sexual ornamentation, but their importance in explaining warning signal diversity has received less attention. In aposematic organisms, allocation costs of producing the conspicuous warning signal pigmentation under nutritional stress could potentially trade-off with life-history traits and maintain variation in warning coloration. We studied this with an aposematic herbivore Arctia plantaginis (Arctiidae), whose larvae and adults show extensive variation in aposematic coloration. In larvae, less melanic coloration (i.e. larger orange patterns) produces a more efficient warning signal against predators, whereas high amounts of melanism (smaller orange pattern) enhance thermoregulation, correlate with better immunity and make individuals harder to detect for naïve predators. We conducted a factorial rearing experiment with larvae originating from lines selected for either small or large orange signal size, which were reared on an artificial diet that had either low or high protein content. Protein content of the diet is critical for melanin production. We measured the effects of diet on individual coloration, life-history traits, immune defence and reproductive output. We also compared the responses to dietary conditions between the small and large larval signal genotypes. Protein content of the diet did not affect warning coloration in the larval stage, but larval signal sizes differed significantly among selection lines, confirming that its variation is mainly genetically determined. In adults, signal line or diet did not affect coloration in hindwings, but males' forewings had more melanin on the high than on low protein diet. Contrary to coloration, diet quality had a stronger impact on life-history traits: individuals developed for longer had smaller hindwing sizes in females and lower immune defence on the low protein content diet compared with the high. These costs were higher for more melanic larval signal genotypes in terms of development time and female hindwing size. We conclude that low plasticity in warning signal characteristics makes signal expression robust under varying dietary conditions. Therefore, variation in diet quality is not likely to constrain signal expression, but can have a bigger impact on performance.
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Affiliation(s)
- Carita Lindstedt
- Department of Biological and Environmental Sciences, University of Jyväskylä, Jyvaskyla, Finland
| | - Kaisa Suisto
- Department of Biological and Environmental Sciences, University of Jyväskylä, Jyvaskyla, Finland
| | - Johanna Mappes
- Department of Biological and Environmental Sciences, University of Jyväskylä, Jyvaskyla, Finland
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35
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Fan M, D’alba L, Shawkey MD, Peters A, Delhey K. Multiple components of feather microstructure contribute to structural plumage colour diversity in fairy-wrens. Biol J Linn Soc Lond 2019. [DOI: 10.1093/biolinnean/blz114] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
AbstractClosely related species often differ in coloration. Understanding the mechanistic bases of such differences can reveal whether evolutionary changes in colour are driven by single key mechanisms or changes in multiple pathways. Non-iridescent structural plumage colours in birds are a good model in which to test these questions. These colours result from light absorption by pigments, light scattering by the medullary spongy layer (a nanostructure found within barbs) and contributions from other structural elements. Fairy-wrens (Malurus spp.) are a small clade of closely related birds that display a large diversity of ornamental structural colours. Using spectrometry, electron microscopy and Fourier analysis, we show that 30 structural colours, varying from ultraviolet to blue and purple, share a similar barb morphology. Despite this similarity, we find that at the microscopic scale, variation across multiple structural elements, including the size and density of the keratin cortex, spongy layer and melanin, explains colour diversity. These independent axes of morphological variation together account for sizeable amounts of structural colour variability (R2 = 0.21–0.65). The coexistence of many independent, evolutionarily labile mechanisms that generate colour variation suggests that the diversity of structural colours in this clade could be mediated by many independent genetic and environmental factors.
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Affiliation(s)
- Marie Fan
- School of Biological Sciences, Monash University, Clayton, Victoria, Australia
| | - Liliana D’alba
- Evolution and Optics of Nanostructures Group, Department of Biology, University of Ghent, Ghent, Belgium
| | - Matthew D Shawkey
- Evolution and Optics of Nanostructures Group, Department of Biology, University of Ghent, Ghent, Belgium
| | - Anne Peters
- School of Biological Sciences, Monash University, Clayton, Victoria, Australia
| | - Kaspar Delhey
- School of Biological Sciences, Monash University, Clayton, Victoria, Australia
- Max Planck Institute for Ornithology, Vogelwarte Radolfzell, Radolfzell, Germany
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Price TD, Stoddard MC, Shevell SK, Bloch NI. Understanding how neural responses contribute to the diversity of avian colour vision. Anim Behav 2019. [DOI: 10.1016/j.anbehav.2019.05.009] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Sibeaux A, Keser ML, Cole GL, Kranz AM, Endler JA. How viewing objects with the dorsal or ventral retina affects colour-related behaviour in guppies (Poecilia reticulata). Vision Res 2019; 158:78-89. [DOI: 10.1016/j.visres.2019.02.007] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2018] [Revised: 02/15/2019] [Accepted: 02/24/2019] [Indexed: 10/27/2022]
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Kane SA, Wang Y, Fang R, Lu Y, Dakin R. How conspicuous are peacock eyespots and other colorful feathers in the eyes of mammalian predators? PLoS One 2019; 14:e0210924. [PMID: 31017903 PMCID: PMC6481771 DOI: 10.1371/journal.pone.0210924] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2019] [Accepted: 03/28/2019] [Indexed: 12/15/2022] Open
Abstract
Colorful feathers have long been assumed to be conspicuous to predators, and hence likely to incur costs due to enhanced predation risk. However, many mammals that prey on birds have dichromatic visual systems with only two types of color-sensitive visual receptors, rather than the three and four photoreceptors characteristic of humans and most birds, respectively. Here, we use a combination of multispectral imaging, reflectance spectroscopy, color vision modelling and visual texture analysis to compare the visual signals available to conspecifics and to mammalian predators from multicolored feathers from the Indian peacock (Pavo cristatus), as well as red and yellow parrot feathers. We also model the effects of distance-dependent blurring due to visual acuity. When viewed by birds against green vegetation, most of the feathers studied are estimated to have color and brightness contrasts similar to values previously found for ripe fruit. On the other hand, for dichromat mammalian predators, visual contrasts for these feathers were only weakly detectable and often below detection thresholds for typical viewing distances. We also show that for dichromat mammal vision models, the peacock's train has below-detection threshold color and brightness contrasts and visual textures that match various foliage backgrounds. These findings are consistent with many feathers of similar hue to those studied here being inconspicuous, and in some cases potentially cryptic, in the eyes of common mammalian predators of adult birds. Given that birds perform many conspicuous motions and behaviors, this study suggests that mammalian predators are more likely to use other sensory modalities (e.g., motion detection, hearing, and olfaction), rather than color vision, to detect avian prey. This suggests new directions for future behavioral studies and emphasizes the importance of understanding the influence of the sensory ecology of predators in the evolution of animal coloration.
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Affiliation(s)
- Suzanne Amador Kane
- Physics & Astronomy Department, Haverford College, Haverford, Pennsylvania, United States of America
- * E-mail:
| | - Yuchao Wang
- Physics & Astronomy Department, Haverford College, Haverford, Pennsylvania, United States of America
| | - Rui Fang
- Physics & Astronomy Department, Haverford College, Haverford, Pennsylvania, United States of America
| | - Yabin Lu
- Physics & Astronomy Department, Haverford College, Haverford, Pennsylvania, United States of America
| | - Roslyn Dakin
- Migratory Bird Center, Smithsonian Conservation Biology Institute, National Zoological Park, Washington DC, United States of America
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Ronald KL, Fernández-Juricic E, Lucas JR. Mate choice in the eye and ear of the beholder? Female multimodal sensory configuration influences her preferences. Proc Biol Sci 2019; 285:rspb.2018.0713. [PMID: 29769366 DOI: 10.1098/rspb.2018.0713] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2018] [Accepted: 04/16/2018] [Indexed: 01/27/2023] Open
Abstract
A common assumption in sexual selection studies is that receivers decode signal information similarly. However, receivers may vary in how they rank signallers if signal perception varies with an individual's sensory configuration. Furthermore, receivers may vary in their weighting of different elements of multimodal signals based on their sensory configuration. This could lead to complex levels of selection on signalling traits. We tested whether multimodal sensory configuration could affect preferences for multimodal signals. We used brown-headed cowbird (Molothrus ater) females to examine how auditory sensitivity and auditory filters, which influence auditory spectral and temporal resolution, affect song preferences, and how visual spatial resolution and visual temporal resolution, which influence resolution of a moving visual signal, affect visual display preferences. Our results show that multimodal sensory configuration significantly affects preferences for male displays: females with better auditory temporal resolution preferred songs that were shorter, with lower Wiener entropy, and higher frequency; and females with better visual temporal resolution preferred males with less intense visual displays. Our findings provide new insights into mate-choice decisions and receiver signal processing. Furthermore, our results challenge a long-standing assumption in animal communication which can affect how we address honest signalling, assortative mating and sensory drive.
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Affiliation(s)
- Kelly L Ronald
- Department of Biology, Indiana University, Jordan Hall, 1001 E 3rd Street, Bloomington, IN 47405, USA .,Department of Biological Sciences, Purdue University, Lilly Hall, 915 West State Street, West Lafayette, IN 47907, USA
| | - Esteban Fernández-Juricic
- Department of Biology, Indiana University, Jordan Hall, 1001 E 3rd Street, Bloomington, IN 47405, USA
| | - Jeffrey R Lucas
- Department of Biology, Indiana University, Jordan Hall, 1001 E 3rd Street, Bloomington, IN 47405, USA
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Leitão AV, Hall ML, Delhey K, Mulder RA. Female and male plumage colour signals aggression in a dichromatic tropical songbird. Anim Behav 2019. [DOI: 10.1016/j.anbehav.2019.01.025] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
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Owls lack UV-sensitive cone opsin and red oil droplets, but see UV light at night: Retinal transcriptomes and ocular media transmittance. Vision Res 2019; 158:109-119. [PMID: 30825468 DOI: 10.1016/j.visres.2019.02.005] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2018] [Revised: 02/04/2019] [Accepted: 02/24/2019] [Indexed: 12/19/2022]
Abstract
Most diurnal birds have cone-dominated retinae and tetrachromatic colour vision based on ultra-violet/violet-sensitive UV/V cones expressing short wavelength-sensitive opsin 1 (SWS1), S cones expressing short wavelength-sensitive opsin 2 (SWS2), M cones expressing medium wavelength-sensitive opsin (RH2) and L cones expressing long wavelength-sensitive opsin (LWS). Double cones (D) express LWS but do not contribute to colour vision. Each cone is equipped with an oil droplet, transparent in UV/V cones, but pigmented by carotenoids: galloxanthin in S, zeaxanthin in M, astaxanthin in L and a mixture in D cones. Owls (Strigiformes) are crepuscular or nocturnal birds with rod-dominated retinae and optical adaptations for high sensitivity. For eight species, the absence of functional SWS1 opsin has recently been documented, functional RH2 opsin was absent in three of these. Here we confirm the absence of SWS1 transcripts for the Long-eared owl (Asio otus) and demonstrate its absence for the Short-eared owl (Asio flammeus), Tawny owl (Strix aluco) and Boreal owl (Aegolius funereus). All four species had transcripts of RH2, albeit with low expression. All four species express all enzymes needed to produce galloxanthin, but lack CYP2J19 expression required to produce astaxanthin from dietary precursors. We also present ocular media transmittance of the Eurasian eagle owl (Bubo bubo) and Short-eared owl and predict spectral sensitivities of all photoreceptors of the Tawny owl. We conclude that owls, despite lacking UV/V cones, can detect UV light. This increases the sensitivity of their rod vision allowing them, for instance, to see UV-reflecting feathers as brighter signals at night.
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Discrete or indiscrete? Redefining the colour polymorphism of the land snail Cepaea nemoralis. Heredity (Edinb) 2019; 123:162-175. [PMID: 30804571 PMCID: PMC6629550 DOI: 10.1038/s41437-019-0189-z] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2018] [Revised: 01/08/2019] [Accepted: 01/13/2019] [Indexed: 01/09/2023] Open
Abstract
Biologists have long tried to describe and name the different phenotypes that make up the shell polymorphism of the land snail Cepaea nemoralis. Traditionally, the view is that the ground colour of the shell is one of a few major colour classes, either yellow, pink or brown, but in practise it is frequently difficult to distinguish the colours, and define different shades of the same colour. To understand whether colour variation is in reality continuous, and to investigate how the variation may be perceived by an avian predator, we applied psychophysical models of colour vision to shell reflectance measures. We found that both achromatic and chromatic variation are indiscrete in Cepaea nemoralis, being continuously distributed over many perceptual units. Nonetheless, clustering analysis based on the density of the distribution did reveal three groups, roughly corresponding to human-perceived yellow, pink and brown shells. We also found large-scale geographic variation in the frequency of these groups across Europe, and some covariance between shell colour and banding patterns. Although further studies are necessary, the observation of continuous variation in colour is intriguing because the traditional theory is that the underlying supergene that determines colour has evolved to prevent phenotypes from “dissolving” into continuous trait distributions. The findings thus have significance for understanding the Cepaea polymorphism, and the nature of the selection that acts upon it, as well as more generally highlighting the need to measure colour objectively in other systems.
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Cain KE, Hall ML, Medina I, Leitao AV, Delhey K, Brouwer L, Peters A, Pruett-Jones S, Webster MS, Langmore NE, Mulder RA. Conspicuous Plumage Does Not Increase Predation Risk: A Continent-Wide Test Using Model Songbirds. Am Nat 2019; 193:359-372. [PMID: 30794446 DOI: 10.1086/701632] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
The forces shaping female plumage color have long been debated but remain unresolved. Females may benefit from conspicuous colors but are also expected to suffer costs. Predation is one potential cost, but few studies have explicitly investigated the relationship between predation risk and coloration. The fairy-wrens show pronounced variation in female coloration and reside in a wide variety of habitats across Australasia. Species with more conspicuous females are found in denser habitats, suggesting that conspicuousness in open habitat increases vulnerability to predators. To test this, we measured attack rates on 3-D-printed models mimicking conspicuously colored males and females and dull females in eight different fairy-wren habitats across Australia. Attack rates were higher in open habitats and at higher latitudes. Contrary to our predictions, dull female models were attacked at similar rates to the conspicuous models. Further, the probability of attack in open habitats increased more for both types of female models than for the conspicuous male model. Across models, the degree of contrast (chromatic and achromatic) to environmental backgrounds was unrelated to predation rate. These findings do not support the long-standing hypothesis that conspicuous plumage, in isolation, is costly due to increased attraction of predators. Our results indicate that conspicuousness interacts with other factors in driving the evolution of plumage coloration.
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Tedore C, Nilsson DE. Avian UV vision enhances leaf surface contrasts in forest environments. Nat Commun 2019; 10:238. [PMID: 30670700 PMCID: PMC6342963 DOI: 10.1038/s41467-018-08142-5] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2018] [Accepted: 12/17/2018] [Indexed: 11/30/2022] Open
Abstract
UV vision is prevalent, but we know little about its utility in common general tasks, as in resolving habitat structure. Here we visualize vegetated habitats using a multispectral camera with channels mimicking bird photoreceptor sensitivities across the UV-visible spectrum. We find that the contrast between upper and lower leaf surfaces is higher in a UV channel than in any visible channel, and that this makes leaf position and orientation stand out clearly. This was unexpected since both leaf surfaces reflect similarly small proportions (1–2%) of incident UV light. The strong UV-contrast can be explained by downwelling light being brighter than upwelling, and leaves transmitting < 0.06% of incident UV light. We also find that mirror-like specular reflections of the sky and overlying canopy, from the waxy leaf cuticle, often dwarf diffuse reflections. Specular reflections shift leaf color, such that maximum leaf-contrast is seen at short UV wavelengths under open canopies, and at long UV wavelengths under closed canopies. The utility of UV vision for visualizing habitat structure is poorly known. Here, the authors use optical models and multispectral imaging to show that UV vision reveals sharp visual contrasts between leaf surfaces, potentially an advantage in navigating forest environments.
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Affiliation(s)
- Cynthia Tedore
- Lund Vision Group, Lund University, Sölvegatan 35, Lund, 223 62, Sweden. .,Zoological Institute, University of Hamburg, Martin-Luther-King Platz 3, Hamburg, 20146, Germany.
| | - Dan-Eric Nilsson
- Lund Vision Group, Lund University, Sölvegatan 35, Lund, 223 62, Sweden
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Erritouni YR, Reinke BA, Calsbeek R. A novel body coloration phenotype in Anolis sagrei: Implications for physiology, fitness, and predation. PLoS One 2019; 13:e0209261. [PMID: 30596690 PMCID: PMC6312277 DOI: 10.1371/journal.pone.0209261] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2018] [Accepted: 12/03/2018] [Indexed: 11/19/2022] Open
Abstract
In animals, color signals that convey information about quality are often associated with costs linked to the expression of coloration and may therefore be honest signals of sender quality. Honest indicators are often seen in sexual signals that are used by males to advertise quality to females. Carotenoid and pterin pigments are responsible for yellow, orange, and red coloration in a variety of taxa, but can also serve important roles as antioxidants by reducing free radicals in the body. In this study, we test the effects of a novel full-bodied orange color phenotype of the brown anole, Anolis sagrei, on mate choice, physiology, and survival. We found no evidence that lizards expressing the orange phenotype were preferred by females. Additionally, they did not differ in immune function, running endurance, or maximum sprint speed from lizards that did not express the novel phenotype. Pigment extractions revealed that orange body coloration resulted from pterin pigments and not carotenoids. Visual models suggest that the orange phenotype is less conspicuous to bird predators than the brown phenotype and may provide an adaptive explanation for the persistence of this trait. Given its small, yet positive effect on fitness, we expect the orange color phenotype to increase in frequency in subsequent decades.
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Affiliation(s)
- Yasmeen R. Erritouni
- Department of Biological Sciences, Dartmouth College, Hanover, New Hampshire, United States of America
- * E-mail:
| | - Beth A. Reinke
- Department of Biological Sciences, Dartmouth College, Hanover, New Hampshire, United States of America
| | - Ryan Calsbeek
- Department of Biological Sciences, Dartmouth College, Hanover, New Hampshire, United States of America
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Lack of conspecific visual discrimination between second-year males and females in the Saffron Finch. PLoS One 2018; 13:e0209549. [PMID: 30589869 PMCID: PMC6307699 DOI: 10.1371/journal.pone.0209549] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2017] [Accepted: 12/09/2018] [Indexed: 12/02/2022] Open
Abstract
Sexually dichromatic birds often show delayed plumage maturation, but second-year (SY) males may or may not be distinguishable from females. In competitive contexts, SY males receive a reduced amount of adult males’ aggression, either by mimicking females or through signaling their sex and inexperience as subordinate males. To the human eye, reproductive dull SY male Saffron Finches are indistinguishable from females, whereas after second-year (ASY) males are golden yellow. Our aim is to establish whether SY males are sexually dichromatic with females to the eye of conspecifics. We describe plumage variation in females, SY and ASY males and, in particular, analyze assortative mating by color by comparing a previously disregarded yellow feather patch shared by the three groups. We measured plumage reflectance of the forehead, breast, belly, and axillaries, and used a two-step avian visual model analysis to estimate the ability of Saffron Finches to distinguish between SY males and females. We find that those groups are indistinguishable to conspecifics by color. Furthermore, we find non-significant evidence of assortative mating directly related to the coloration of comparable feather patches between females and each type of male, though body condition of SY males is associated to that of their mates. Our results are compatible with both the female-mimicry and the status signaling hypotheses of evolution and maintenance of delayed plumage maturation. However, the singing behavior of males reveals their presence within the breeding site; the combined effect of song and dull coloration suggest that SY males are honestly revealing their sex and status to conspecifics.
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Matthews G, Goulet CT, Delhey K, Atkins ZS, While GM, Gardner MG, Chapple DG. Avian predation intensity as a driver of clinal variation in colour morph frequency. J Anim Ecol 2018; 87:1667-1684. [PMID: 30098209 DOI: 10.1111/1365-2656.12894] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2018] [Accepted: 07/28/2018] [Indexed: 12/23/2022]
Abstract
Phenotypic variation provides the framework for natural selection to work upon, enabling adaptive evolution. One of the most discernible manifestations of phenotypic variability is colour variation. When this variation is discrete, genetically based colour pattern morphs occur simultaneously within a population. Why and how colour polymorphisms are maintained is an evolutionary puzzle. Several evolutionary drivers have been hypothesized as influencing clinal patterns of morph frequency, with spatial variation in climate and predation being considered especially important. Despite this, no study has examined both of their roles simultaneously. The aims of this study were to: (a) examine the covariation of physiology, environmental variables and colouration at a local scale; and (b) determine if these factors and their interplay explain broad clinal variation in morph frequency. We used the lizard Liopholis whitii as a model system, as this species displays a discrete, heritable polymorphism for colour pattern (plain-backed, patterned morphs) whose morph frequency varies latitudinally. We measured reflectance, field activity temperatures and microhabitat structure to test for differences in crypsis, thermal biology and microhabitat selection of patterned and plain-backed morphs within a single population where colour morphs occur sympatrically. We then used data from the literature to perform a broad-scale analysis to identify whether these factors also explained the latitudinal variation of morph frequency in this species. At the local scale, plain-backed morphs were found to be less cryptic than patterned morphs while no other differences were detected in terms of thermal biology, dorsal reflectance and microhabitat use. At a broader scale, predation was the most influential factor mediating morph frequency across latitudes. However, the observed pattern of morph frequency is opposite to what the modelling results suggest in that the incidence of the least cryptic morph is highest where predation pressure is most severe. Clinal variation in the level of background matching between morphs or the potential reproductive advantage by the plain-backed morph may, instead, be driving the observed morph frequency. Together, these results provide key insights into the evolution of local adaptation as well as the ecological forces involved in driving the dynamics of colour polymorphism.
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Affiliation(s)
- Genevieve Matthews
- School of Biological Sciences, Monash University, Clayton, Victoria, Australia
| | - Celine T Goulet
- School of Biological Sciences, Monash University, Clayton, Victoria, Australia
| | - Kaspar Delhey
- School of Biological Sciences, Monash University, Clayton, Victoria, Australia
| | - Zak S Atkins
- Department of Ecology, Environment and Evolution, La Trobe University, Melbourne, Victoria, Australia
| | - Geoffrey M While
- School of Biological Sciences, University of Tasmania, Hobart, Tasmania, Australia
| | - Michael G Gardner
- School of Biological Sciences, Flinders University of South Australia, Adelaide, South Australia, Australia.,The Evolutionary Biology Unit, South Australian Museum, Adelaide, South Australia, Australia
| | - David G Chapple
- School of Biological Sciences, Monash University, Clayton, Victoria, Australia
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Gawryszewski FM. Color vision models: Some simulations, a general n-dimensional model, and the colourvision R package. Ecol Evol 2018; 8:8159-8170. [PMID: 30250692 PMCID: PMC6144980 DOI: 10.1002/ece3.4288] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2018] [Revised: 04/23/2018] [Accepted: 05/19/2018] [Indexed: 11/19/2022] Open
Abstract
The development of color vision models has allowed the appraisal of color vision independent of the human experience. These models are now widely used in ecology and evolution studies. However, in common scenarios of color measurement, color vision models may generate spurious results. Here I present a guide to color vision modeling (Chittka (1992, Journal of Comparative Physiology A, 170, 545) color hexagon, Endler & Mielke (2005, Journal Of The Linnean Society, 86, 405) model, and the linear and log-linear receptor noise limited models (Vorobyev & Osorio 1998, Proceedings of the Royal Society B, 265, 351; Vorobyev et al. 1998, Journal of Comparative Physiology A, 183, 621)) using a series of simulations, present a unified framework that extends and generalize current models, and provide an R package to facilitate the use of color vision models. When the specific requirements of each model are met, between-model results are qualitatively and quantitatively similar. However, under many common scenarios of color measurements, models may generate spurious values. For instance, models that log-transform data and use relative photoreceptor outputs are prone to generate spurious outputs when the stimulus photon catch is smaller than the background photon catch; and models may generate unrealistic predictions when the background is chromatic (e.g. leaf reflectance) and the stimulus is an achromatic low reflectance spectrum. Nonetheless, despite differences, all three models are founded on a similar set of assumptions. Based on that, I provide a new formulation that accommodates and extends models to any number of photoreceptor types, offers flexibility to build user-defined models, and allows users to easily adjust chromaticity diagram sizes to account for changes when using different number of photoreceptors.
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Affiliation(s)
- Felipe M. Gawryszewski
- Departamento de ZoologiaInstituto de Ciências BiológicasUniversidade de BrasíliaBrasíliaBrazil
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Gisbert S, Schaeffel F. M to L cone ratios determine eye sizes and baseline refractions in chickens. Exp Eye Res 2018; 172:104-111. [PMID: 29608907 PMCID: PMC6013296 DOI: 10.1016/j.exer.2018.03.029] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2018] [Revised: 03/26/2018] [Accepted: 03/29/2018] [Indexed: 10/27/2022]
Abstract
Following a hypothesis raised by M. and J. Neitz, Seattle, we have tested whether the abundance and the ratio of Long wavelength-sensitive (L) to Middle wavelength-sensitive (M) cones may affect eye size and development of myopia in the chicken. Fourteen chickens were treated with frosted plastic diffusers in front of one eye on day 10 post-hatching for a period of 7 days to induce deprivation myopia. Ocular dimensions were measured by A-scan ultrasonography at the beginning and at the end of the treatment and development of refractive state was tracked using infrared photorefraction. At the end of the treatment period, L and M cone densities and ratios were analyzed in retinal flat mounts of both myopic and control eyes, using the red and yellow oil droplets as markers. Because large numbers of cones were counted (>10000), software was written in Visual C++ for automated cone detection and density analysis. (1) On average, 9.7 ± 1.7D of deprivation myopia was induced in 7 days (range from 6.8D to 13.7D) with an average increase in axial length by 0.65 ± 0.20 mm (range 0.42 mm-1.00 mm), (2) the increase in vitreous chamber depth was correlated with the increase in myopic refractive error, (3) average central M cone densities were 10,498 cells/mm2, and L cone densities 9574 cells/mm2. In the periphery, M cone densities were 6343 cells/mm2 and L cones 5735 cells/mm2 (4) M to L cone ratios were highly correlated in both eyes of each animal (p < 0.01 in all cases), (5) the most striking finding was that ratios of M to L cones were significantly correlated with vitreous chamber depths and refractive states in the control eyes with normal vision, both in the central and peripheral retinas (p < 0.05 to p < 0.01), (6) M to L cone ratios did however not predict the amount of deprivation myopia that could be induced. M and L cone ratios are most likely genetically determined in each animal. The more L cones, the deeper the vitreous chambers and the more myopic were the refractions in eyes. M to L cone ratios may determine the set point of emmetropization and thereby ultimately the probability of becoming myopic. Deprivation myopia was not determined by M to L cone ratios.
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Affiliation(s)
- Sandra Gisbert
- Section of Neurobiology of the Eye, Ophthalmic Research Institute, University of Tuebingen, Elfriede Aulhorn Strasse 7, 72076, Tuebingen, Germany
| | - Frank Schaeffel
- Section of Neurobiology of the Eye, Ophthalmic Research Institute, University of Tuebingen, Elfriede Aulhorn Strasse 7, 72076, Tuebingen, Germany.
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