1
|
Bian X, Pinilla A, Chandler T, Peters R. Simulations with Australian dragon lizards suggest movement-based signal effectiveness is dependent on display structure and environmental conditions. Sci Rep 2021; 11:6383. [PMID: 33737677 PMCID: PMC7973430 DOI: 10.1038/s41598-021-85793-3] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2020] [Accepted: 03/04/2021] [Indexed: 11/09/2022] Open
Abstract
Habitat-specific characteristics can affect signal transmission such that different habitats dictate the optimal signal. One way to examine how the environment influences signals is by comparing changes in signal effectiveness in different habitats. Examinations of signal effectiveness between different habitats has helped to explain signal divergence/convergence between populations and species using acoustic and colour signals. Although previous research has provided evidence for local adaptations and signal divergence in many species of lizards, comparative studies in movement-based signals are rare due to technical difficulties in quantifying movements in nature and ethical restrictions in translocating animals between habitats. We demonstrate herein that these issues can be addressed using 3D animations, and compared the relative performance of the displays of four Australian lizard species in the habitats of each species under varying environmental conditions. Our simulations show that habitats differentially affect signal performance, and an interaction between display and habitat structure. Interestingly, our results are consistent with the hypothesis that the signal adapted to the noisier environment does not show an advantage in signal effectiveness, but the noisy habitat was detrimental to the performance of all displays. Our study is one of the first studies for movement-based signals that directly compares signal performance in multiple habitats, and our approach has laid the foundation for future investigations in motion ecology that have been intractable to conventional research methods.
Collapse
Affiliation(s)
- Xue Bian
- Animal Behaviour Group, Department of Ecology, Environment and Evolution, La Trobe University, Melbourne, VIC, Australia
| | - Angela Pinilla
- Faculty of Information Technology, Monash University, Caulfield East, VIC, Australia
| | - Tom Chandler
- Faculty of Information Technology, Monash University, Caulfield East, VIC, Australia
| | - Richard Peters
- Animal Behaviour Group, Department of Ecology, Environment and Evolution, La Trobe University, Melbourne, VIC, Australia.
| |
Collapse
|
2
|
Abstract
Reptile behavior varies widely among the approximately 11,000 species of this class. The authors' objective is to allow practitioners to discriminate between normal and abnormal behaviors in reptiles. Some of the most common reasons for presentation of behavioral issues are discussed, including hyperactivity, self-mutilation, biting, repetitive behaviors, and postural abnormalities. Medical problems and suboptimal husbandry causing abnormal behaviors should be ruled out by attending veterinarians. Addressing behavior issues involves determining a differential diagnosis through a systematic approach, which then allows implementation of necessary environmental changes including enrichment, developing plans for behavior modification and biomedical training, and medication when appropriate.
Collapse
|
3
|
López Juri G, Rossi N, Chiaraviglio M, Cardozo G. Phenotypic diversity and its relationship to reproductive potential in changing social contexts in a lizard model. Biol J Linn Soc Lond 2020. [DOI: 10.1093/biolinnean/blaa101] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Abstract
Phenotype in lizards is related to reproductive function, and hence to reproductive output. Besides the intraspecific diversity in phenotypes, their temporal variation throughout the reproductive season in relation to the variation of social contexts builds extra complexity into sexual selection scenarios. One useful model for understanding phenotypic diversity dynamics is Tropidurus spinulosus because it presents sexual dimorphism in different phenotypic traits, dichromatism in regions related to reproductive behaviour, and it has intense social reproductive interactions. We aimed to evaluate how the reproductive and phenotypic traits of individuals vary with changing social contexts, and how intrasexual phenotypic diversity and reproductive potential are explained by the phenotypic traits. In this study, we used data obtained during four consecutive breeding seasons (2015–2018) in a wild population. The social context, characterized according to the operational sex ratio, varied between months and, therefore, some phenotypic and reproductive traits also varied. We found that body robustness and chromatic diversity were the main sources of phenotypic diversity and were related to reproductive traits in both sexes. Our results help to understand the dynamics and reproductive implications of phenotypic diversity in changing social contexts in a lizard social model.
Collapse
Affiliation(s)
- Guadalupe López Juri
- Universidad Nacional de Córdoba, Facultad de Ciencias Exactas, Físicas y Naturales. Laboratorio de Biología del Comportamiento, Córdoba, Argentina
- Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Instituto de Diversidad y Ecología Animal (IDEA), Córdoba, Argentina
| | - Nicola Rossi
- Universidad Nacional de Córdoba, Facultad de Ciencias Exactas, Físicas y Naturales. Laboratorio de Biología del Comportamiento, Córdoba, Argentina
- Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Instituto de Diversidad y Ecología Animal (IDEA), Córdoba, Argentina
| | - Margarita Chiaraviglio
- Universidad Nacional de Córdoba, Facultad de Ciencias Exactas, Físicas y Naturales. Laboratorio de Biología del Comportamiento, Córdoba, Argentina
- Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Instituto de Diversidad y Ecología Animal (IDEA), Córdoba, Argentina
| | - Gabriela Cardozo
- Universidad Nacional de Córdoba, Facultad de Ciencias Exactas, Físicas y Naturales. Laboratorio de Biología del Comportamiento, Córdoba, Argentina
- Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Instituto de Diversidad y Ecología Animal (IDEA), Córdoba, Argentina
| |
Collapse
|
4
|
Ultraviolet imaging in dermatology. Photodiagnosis Photodyn Ther 2020; 30:101743. [DOI: 10.1016/j.pdpdt.2020.101743] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2019] [Revised: 03/09/2020] [Accepted: 03/13/2020] [Indexed: 01/05/2023]
|
5
|
Vergneau-Grosset C, Péron F. Effect of ultraviolet radiation on vertebrate animals: update from ethological and medical perspectives. Photochem Photobiol Sci 2020; 19:752-762. [PMID: 33856678 DOI: 10.1039/c9pp00488b] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2019] [Accepted: 03/31/2020] [Indexed: 11/21/2022]
Abstract
Many animals under human care are kept indoors to prevent infectious diseases vectored by wildlife, facilitate environment control, or due to the lifestyle of their owners. However, ultraviolet radiation has documented effects on animal vision, vitamin synthesis, immunity, behavior, psychogenic disorders and on their environment. Ultraviolet-emitting lights are commercially available and the documentation of their effect on indoor-housed animals is increasing. This article reviews published information about ultraviolet effects in vertebrate animals from veterinary and ethological perspectives, and techniques used to assess ultraviolet exposure across animal taxa.
Collapse
Affiliation(s)
- Claire Vergneau-Grosset
- Department of Clinical sciences, Faculté de médecine vétérinaire, Université de Montréal, 3200 rue Sicotte, J2S 2 M2, Saint-Hyacinthe, QC, Canada.
| | - Franck Péron
- 15 Rue de la Johardière, 44 800, Saint-Herblain, France
| |
Collapse
|
6
|
Rossi N, Benitez-Vieyra S, Cocucci A, Chiaraviglio M, Cardozo G. Sexual dichromatism and color diversity in the spiny lava lizard Tropidurus spinulosus using lizard visual modelling. Sci Rep 2019; 9:14270. [PMID: 31582783 PMCID: PMC6776660 DOI: 10.1038/s41598-019-50712-0] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2018] [Accepted: 09/17/2019] [Indexed: 12/04/2022] Open
Abstract
Colors are important vehicles for social signals in many taxa. In Squamata, previous studies have linked color characteristics and chromatic diversity to sexual selection and, particularly, species showing male-biased body size dimorphism also showed male-biased dichromatism and color diversity. Sexual dichromatism may occur in body regions used for conspecific communication and it may be expressed at wavelengths, such as ultraviolet, easily perceivable by conspecifics. We tested this prediction in a social lizard model, Tropidurus spinulosus, using spectrophotometry and visual modelling which enable colors to be interpreted as the individuals of the same taxon see them. Our results indicate that sexual dichromatism occurs in the ventral regions and the flanks, which are the body regions involved in sexual displays. Males show greater color diversity, having larger color volumes and more contrasting colors. These findings reinforce the idea that sexual selection towards males is coupled with the evolution of male-biased, diverse, coloration which could act as a signal in social reproductive contexts.
Collapse
Affiliation(s)
- N Rossi
- Universidad Nacional de Córdoba, Facultad de Ciencias Exactas Físicas y Naturales. Laboratorio de Biología del Comportamiento, Córdoba, Argentina. .,Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Instituto de Diversidad y Ecología Animal (IDEA), Córdoba, Argentina.
| | - S Benitez-Vieyra
- Laboratorio de Ecología Evolutiva y Biología Floral, IMBIV-CONICET, FCEFyN, Universidad Nacional de Córdoba, Córdoba, Argentina
| | - A Cocucci
- Laboratorio de Ecología Evolutiva y Biología Floral, IMBIV-CONICET, FCEFyN, Universidad Nacional de Córdoba, Córdoba, Argentina
| | - M Chiaraviglio
- Universidad Nacional de Córdoba, Facultad de Ciencias Exactas Físicas y Naturales. Laboratorio de Biología del Comportamiento, Córdoba, Argentina.,Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Instituto de Diversidad y Ecología Animal (IDEA), Córdoba, Argentina
| | - G Cardozo
- Universidad Nacional de Córdoba, Facultad de Ciencias Exactas Físicas y Naturales. Laboratorio de Biología del Comportamiento, Córdoba, Argentina.,Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Instituto de Diversidad y Ecología Animal (IDEA), Córdoba, Argentina
| |
Collapse
|
7
|
Garcia JE, Shrestha M, Howard SR, Petersen P, Dyer AG. Signal or cue: the role of structural colors in flower pollination. Curr Zool 2019; 65:467-481. [PMID: 31413719 PMCID: PMC6688579 DOI: 10.1093/cz/zoy096] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Revised: 09/27/2017] [Accepted: 12/11/2018] [Indexed: 11/13/2022] Open
Abstract
Angle dependent colors, such as iridescence, are produced by structures present on flower petals changing their visual appearance. These colors have been proposed to act as signals for plant-insect communication. However, there is a paucity of behavioral data to allow for interpretations of how to classify these colors either as a signal or a cue when considering the natural conditions under which pollination occurs. We sampled flowers from 6 plant species across various viewpoints looking for changes in the visual appearance of the petals. Spectral characteristics were measured with different instruments to simulate both the spectral and spatial characteristics of honeybee's vision. We show the presence of color patches produced by angle dependent effects on the petals and the calyx of various species; however, the appearance of the angle dependent color patches significantly varies with viewpoint and would only be resolved by the insect eye at close distances. Behavior experiments with honeybees revealed that pollinators did not use angle dependent colors to drive behavior when presented with novel flower presentations. Results show that angle dependent colors do not comply with the requirements of a signal for plant-pollinator communication since the information transmitted by these colors would be unreliable for potential, free-flying pollination vectors. We thus classify angle dependent colors produced by micro- and ultra-structures as being a cue (a feature which has not evolved for communication), and observe no evidence supporting claims of these angle dependent colors having evolved as visual signal.
Collapse
Affiliation(s)
- Jair E Garcia
- School of Media and Communication, RMIT University, Melbourne, Victoria 3001, Australia
| | - Mani Shrestha
- School of Media and Communication, RMIT University, Melbourne, Victoria 3001, Australia
- Faculty of Information Technology, Monash University, Clayton, Victoria 3800, Australia
| | - Scarlett R Howard
- School of Media and Communication, RMIT University, Melbourne, Victoria 3001, Australia
| | - Phred Petersen
- School of Media and Communication, RMIT University, Melbourne, Victoria 3001, Australia
| | - Adrian G Dyer
- School of Media and Communication, RMIT University, Melbourne, Victoria 3001, Australia
| |
Collapse
|
8
|
Bruinjé AC, Moura MO, Maggi BS, São-Pedro VA, Pessoa DM, Costa GC. Conspecifics of the Striped Lava Lizard are able to distinguish sex and male colour morphs in apparently homogeneous dull dorsal colouration. AMPHIBIA-REPTILIA 2019. [DOI: 10.1163/15685381-20181048] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Abstract
Animal colouration plays a key role in inter and intraspecific interactions, pre-eminently in mate signalling. When multiple types of colouration occur within sexes it is possible that they show alternative reproductive strategies. In lizards, most colouration studies do not incorporate how colour is perceived by conspecifics. Here, we used unbiased colour analysis methods (spectrophotometry and visual modelling) to test for sexual dimorphism and within male dichromatism in the Striped Lava Lizard. We found that males express two distinct colourations that are different from females in several dorsal and ventral body regions. Our results showed UV reflection at the throat, an important body region for signalling. Ventral patches, the coloured badge seen in adult males of Tropidurus spp., have two distinct colour classes within males (Y and B males). Morphs are best discriminated by blue and yellow chroma, and brightness. Body size had little influence on colouration, suggesting that colour may be linked to inheritance rather than growth. Our study clearly shows sexual dichromatism and the existence of colour morphs in this species. Moreover, morph differences in colouration are perceptible by conspecifics. These differences are not only between ventral patches, but also in other body parts such as the dorsum, previously considered as cryptic by human observers. We suggest that colouration at the ventral patches and throat might play a role in intraspecific interactions. Patches increase colour intensity during breeding season and are likely to be costly by pigment-based expression, whereas throat’s UV reflection might have a cost infringed by conspicuousness.
Collapse
Affiliation(s)
- Andre C. Bruinjé
- 1Graduate Program in Ecology and Conservation Biology, Department of Zoology, Universidade Federal do Paraná, Curitiba, Paraná, Brazil
- 2Laboratory of Biogeography, Macroecology and Evolutionary Biology, Universidade Federal do Rio Grande do Norte, Natal, Rio Grande do Norte, Brazil
| | - Mauricio O. Moura
- 1Graduate Program in Ecology and Conservation Biology, Department of Zoology, Universidade Federal do Paraná, Curitiba, Paraná, Brazil
| | - Bruno S. Maggi
- 2Laboratory of Biogeography, Macroecology and Evolutionary Biology, Universidade Federal do Rio Grande do Norte, Natal, Rio Grande do Norte, Brazil
| | - Vinicius A. São-Pedro
- 3Laboratory of Sensory Ecology, Department of Physiology, Universidade Federal do Rio Grande do Norte, Natal, Rio Grande do Norte, Brazil
- 4Centro de Ciências da Natureza, Universidade Federal de São Carlos, Campus Lagoa do Sino, Buri, São Paulo, Brazil
| | - Daniel M.A. Pessoa
- 3Laboratory of Sensory Ecology, Department of Physiology, Universidade Federal do Rio Grande do Norte, Natal, Rio Grande do Norte, Brazil
| | - Gabriel C. Costa
- 5Department of Biology, Auburn University at Montgomery, Montgomery, AL 36124, USA
| |
Collapse
|
9
|
Rodríguez-Morales D, Rico-Gray V, García-Franco JG, Ajuria-Ibarra H, Hernández-Salazar LT, Robledo-Ospina LE, Rao D. Context-dependent crypsis: a prey's perspective of a color polymorphic predator. Naturwissenschaften 2018; 105:36. [PMID: 29754205 DOI: 10.1007/s00114-018-1562-0] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2018] [Revised: 05/04/2018] [Accepted: 05/07/2018] [Indexed: 12/11/2022]
Abstract
Many animals use body coloration as a strategy to communicate with conspecifics, prey, and predators. Color is a trade-off for some species, since they should be visible to conspecifics but cryptic to predators and prey. Some flower-dwelling predators, such as crab spiders, are capable of choosing the color of flowers where they ambush flower visitors and pollinators. In order to avoid being captured, visitors evaluate flowers visually before landing. The crab spider Mecaphesa dubia is a polymorphic species (white/purple color morphs), which inhabits the flower heads of a dune plant, Palafoxia lindenii. Using full-spectrum photography of spiders and flowers, we evaluated how honeybees perceived the spiders at different distances. Using visual modeling, we obtained the chromatic and achromatic contrasts of the spiders on flower heads as perceived by honeybees. Purple morphs were found mainly on the receptacle area and white morphs were equally likely to be found in the flowers and receptacle. According to theoretical modeling, white morphs were visible to honeybees from a distance of 10 cm in receptacle area but appeared to be cryptic in the flower area. Purple morphs were cryptic on the receptacle and less so when they were on the flowers. Spiders on flower heads are predicted to be more easily detected by honeybees using chromatic contrast. Our study shows that the conspicuousness of flower dwelling spiders to honeybees depends on the color morph, the distance of observation, and the position of spider on the flower head.
Collapse
Affiliation(s)
- D Rodríguez-Morales
- Instituto de Neuroetología, Universidad Veracruzana, Av. Luis Castelazo, Col. Industrial Animas, Xalapa, 91190, Veracruz, Mexico.
| | - V Rico-Gray
- Instituto de Neuroetología, Universidad Veracruzana, Av. Luis Castelazo, Col. Industrial Animas, Xalapa, 91190, Veracruz, Mexico
| | - J G García-Franco
- Red de Ecología Funcional, Instituto de Ecología, A.C. Carretera Antigua a Coatepec 351, El Haya, Xalapa, 91070, Veracruz, Mexico
| | - H Ajuria-Ibarra
- Instituto de Biotecnologia y Ecologia Aplicada, Universidad Veracruzana, Av. Culturas Veracruzanas No. 101, Xalapa, 91090, Veracruz, Mexico
| | - L T Hernández-Salazar
- Instituto de Neuroetología, Universidad Veracruzana, Av. Luis Castelazo, Col. Industrial Animas, Xalapa, 91190, Veracruz, Mexico
| | - L E Robledo-Ospina
- Red de Ecoetología, Instituto de Ecología, A.C. Carretera antigua a Coatepec No. 351, Xalapa, 91070, Veracruz, Mexico.,Grupo de Aracnología, Universidad de Caldas, Calle 65 No. 26-10, Manizales, Colombia
| | - D Rao
- Instituto de Biotecnologia y Ecologia Aplicada, Universidad Veracruzana, Av. Culturas Veracruzanas No. 101, Xalapa, 91090, Veracruz, Mexico
| |
Collapse
|
10
|
Somveille M, Marshall KL, Gluckman TL. A global analysis of bird plumage patterns reveals no association between habitat and camouflage. PeerJ 2016; 4:e2658. [PMID: 27867762 PMCID: PMC5111890 DOI: 10.7717/peerj.2658] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2016] [Accepted: 10/05/2016] [Indexed: 12/03/2022] Open
Abstract
Evidence suggests that animal patterns (motifs) function in camouflage. Irregular mottled patterns can facilitate concealment when stationary in cluttered habitats, whereas regular patterns typically prevent capture during movement in open habitats. Bird plumage patterns have predominantly converged on just four types-mottled (irregular), scales, bars and spots (regular)-and habitat could be driving convergent evolution in avian patterning. Based on sensory ecology, we therefore predict that irregular patterns would be associated with visually noisy closed habitats and that regular patterns would be associated with open habitats. Regular patterns have also been shown to function in communication for sexually competing males to stand-out and attract females, so we predict that male breeding plumage patterns evolved in both open and closed habitats. Here, taking phylogenetic relatedness into account, we investigate ecological selection for bird plumage patterns across the class Aves. We surveyed plumage patterns in 80% of all avian species worldwide. Of these, 2,756 bird species have regular and irregular plumage patterns as well as habitat information. In this subset, we tested whether adult breeding/non-breeding plumages in each sex, and juvenile plumages, were associated with the habitat types found within the species' geographical distributions. We found no evidence for an association between habitat and plumage patterns across the world's birds and little phylogenetic signal. We also found that species with regular and irregular plumage patterns were distributed randomly across the world's eco-regions without being affected by habitat type. These results indicate that at the global spatial and taxonomic scale, habitat does not predict convergent evolution in bird plumage patterns, contrary to the camouflage hypothesis.
Collapse
Affiliation(s)
- Marius Somveille
- Department of Zoology, University of Cambridge, Cambridge, United Kingdom
- The Edward Grey Institute, Department of Zoology, University of Oxford, Oxford, United Kingdom
| | - Kate L.A. Marshall
- Department of Zoology, University of Cambridge, Cambridge, United Kingdom
| | - Thanh-Lan Gluckman
- Department of Zoology, University of Cambridge, Cambridge, United Kingdom
- Department of Animal and Plant Sciences, University of Sheffield, Sheffield, United Kingdom
- Center for Interdisciplinary Research in Biology, College de France, Paris, France
| |
Collapse
|
11
|
Outomuro D, Söderquist L, Johansson F, Ödeen A, Nordström K. The price of looking sexy: visual ecology of a three‐level predator–prey system. Funct Ecol 2016. [DOI: 10.1111/1365-2435.12769] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Affiliation(s)
- David Outomuro
- Section for Animal Ecology Department of Ecology and Genetics Evolutionary Biology Centre Uppsala University Norbyvägen 18D 75236 Uppsala Sweden
| | - Linus Söderquist
- Section for Animal Ecology Department of Ecology and Genetics Evolutionary Biology Centre Uppsala University Norbyvägen 18D 75236 Uppsala Sweden
| | - Frank Johansson
- Section for Animal Ecology Department of Ecology and Genetics Evolutionary Biology Centre Uppsala University Norbyvägen 18D 75236 Uppsala Sweden
| | - Anders Ödeen
- Section for Animal Ecology Department of Ecology and Genetics Evolutionary Biology Centre Uppsala University Norbyvägen 18D 75236 Uppsala Sweden
| | - Karin Nordström
- Department of Neuroscience Uppsala University Box 593 75124 Uppsala Sweden
- Anatomy and Histology Centre for Neuroscience Flinders University GPO Box 2100 Adelaide South Australia5001 Australia
| |
Collapse
|
12
|
Pérez I de Lanuza G, Font E. The evolution of colour pattern complexity: selection for conspicuousness favours contrasting within-body colour combinations in lizards. J Evol Biol 2016; 29:942-51. [PMID: 26801820 DOI: 10.1111/jeb.12835] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2015] [Revised: 01/11/2016] [Accepted: 01/15/2016] [Indexed: 02/04/2023]
Abstract
Many animals display complex colour patterns that comprise several adjacent, often contrasting colour patches. Combining patches of complementary colours increases the overall conspicuousness of the complex pattern, enhancing signal detection. Therefore, selection for conspicuousness may act not only on the design of single colour patches, but also on their combination. Contrasting long- and short-wavelength colour patches are located on the ventral and lateral surfaces of many lacertid lizards. As the combination of long- and short-wavelength-based colours generates local chromatic contrast, we hypothesized that selection may favour the co-occurrence of lateral and ventral contrasting patches, resulting in complex colour patterns that maximize the overall conspicuousness of the signal. To test this hypothesis, we performed a comparative phylogenetic study using a categorical colour classification based on spectral data and descriptive information on lacertid coloration collected from the literature. Our results demonstrate that conspicuous ventral (long-wavelength-based) and lateral (short-wavelength-based) colour patches co-occur throughout the lacertid phylogeny more often than expected by chance, especially in the subfamily Lacertini. These results suggest that selection promotes the evolution of the complex pattern rather than the acquisition of a single conspicuous colour patch, possibly due to the increased conspicuousness caused by the combination of colours with contrasting spectral properties.
Collapse
Affiliation(s)
- G Pérez I de Lanuza
- CIBIO Research Centre in Biodiversity and Genetic Resources, InBIO, Universidade do Porto, Campus Agrário de Vairão, Vairão, Vila do Conde, Portugal
| | - E Font
- Ethology Lab, Cavanilles Institute of Biodiversity and Evolutionary Biology, University of Valencia, Paterna, Spain
| |
Collapse
|
13
|
Domínguez-López ME, Diego-Rasilla FJ, Ortega-León Á. Effects of sex and microhabitat structure on escape behaviour in the diurnal gecko Gonatodes albogularis. ANIM BIOL 2016. [DOI: 10.1163/15707563-00002485] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Flight initiation distance is defined as the distance between a prey and an approaching predator when the prey starts to flee. Escape theory predicts that the optimal flight initiation distance is the distance where predation risk rises to the point at which it equals the cost of fleeing. Therefore, staying close to refuge and occupying microhabitats with more abundant shelters (i.e., crevices or shrubs) may allow lizards to have shorter flight initiation distance. By simulating an approaching predator, we studied the effect of microhabitat structural complexity on escape behaviour, in particular, the distance fled before stopping and final distance (predator-prey distance when the prey stops fleeing), of a small diurnal tropical gecko, the yellow-headed geckoGonatodes albogularisinhabiting a tropical dry forest. The findings indicate that refuge abundance and distance to the nearest potential refuge influence escape behaviour ofG. albogularis. In addition, we found sex differences in escape behaviour which are not explained by microhabitat use. Females had longer flight initiation distance but shorter distance fled, and longer final distances than males.
Collapse
Affiliation(s)
- Moisés E. Domínguez-López
- Fundación Ambiente Biodiverso, Carrera 7 #2-24 sur, Bogotá, Colombia
- Sección Herpetología, Departamento de Vertebrados, Museo de La Plata, Calle 122 y 60 s/n, La Plata (1900), Buenos Aires, Argentina
| | - Francisco J. Diego-Rasilla
- Departamento de Biología Animal, Universidad de Salamanca, Campus Miguel de Unamuno, Edificio de Farmacia 5 planta, 37007 Salamanca, Spain
| | - Ángela M. Ortega-León
- Grupo de Investigación en Biodiversidad, Universidad de Córdoba, Carrera 6 No. 76-103, Córdoba, Colombia
| |
Collapse
|
14
|
Marshall KLA, Philpot KE, Damas-Moreira I, Stevens M. Intraspecific Colour Variation among Lizards in Distinct Island Environments Enhances Local Camouflage. PLoS One 2015; 10:e0135241. [PMID: 26372454 PMCID: PMC4570707 DOI: 10.1371/journal.pone.0135241] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2015] [Accepted: 07/20/2015] [Indexed: 11/19/2022] Open
Abstract
Within-species colour variation is widespread among animals. Understanding how this arises can elucidate evolutionary mechanisms, such as those underlying reproductive isolation and speciation. Here, we investigated whether five island populations of Aegean wall lizards (Podarcis erhardii) have more effective camouflage against their own (local) island substrates than against other (non-local) island substrates to avian predators, and whether this was linked to island differences in substrate appearance. We also investigated whether degree of local substrate matching varied among island populations and between sexes. In most populations, both sexes were better matched against local backgrounds than against non-local backgrounds, particularly in terms of luminance (perceived lightness), which usually occurred when local and non-local backgrounds were different in appearance. This was found even between island populations that historically had a land connection and in populations that have been isolated relatively recently, suggesting that isolation in these distinct island environments has been sufficient to cause enhanced local background matching, sometimes on a rapid evolutionary time-scale. However, heightened local matching was poorer in populations inhabiting more variable and unstable environments with a prolonged history of volcanic activity. Overall, these results show that lizard coloration is tuned to provide camouflage in local environments, either due to genetic adaptation or changes during development. Yet, the occurrence and extent of selection for local matching may depend on specific conditions associated with local ecology and biogeographic history. These results emphasize how anti-predator adaptations to different environments can drive divergence within a species, which may contribute to reproductive isolation among populations and lead to ecological speciation.
Collapse
Affiliation(s)
- Kate L. A. Marshall
- Behavioural Ecology Group, Department of Zoology, University of Cambridge, Cambridge, United Kingdom
| | - Kate E. Philpot
- Centre for Ecology and Conservation, College of Life and Environmental Sciences, University of Exeter, Penryn Campus, Penryn, Cornwall, United Kingdom
| | - Isabel Damas-Moreira
- CIBIO Research Centre in Biodiversity and Genetic Resources, InBIO, Universidade do Porto, Campus Agrário de Vairão, Rua Padre Armando Quintas, Vairão, Vila do Conde, Portugal
| | - Martin Stevens
- Centre for Ecology and Conservation, College of Life and Environmental Sciences, University of Exeter, Penryn Campus, Penryn, Cornwall, United Kingdom
| |
Collapse
|
15
|
Marshall KLA, Philpot KE, Stevens M. Conspicuous male coloration impairs survival against avian predators in Aegean wall lizards, Podarcis erhardii. Ecol Evol 2015; 5:4115-31. [PMID: 26442582 PMCID: PMC4588654 DOI: 10.1002/ece3.1650] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2015] [Revised: 06/03/2015] [Accepted: 07/09/2015] [Indexed: 11/09/2022] Open
Abstract
Animal coloration is strikingly diverse in nature. Within-species color variation can arise through local adaptation for camouflage, sexual dimorphism and conspicuous sexual signals, which often have conflicting effects on survival. Here, we tested whether color variation between two island populations of Aegean wall lizards (Podarcis erhardii) is due to sexual dimorphism and differential survival of individuals varying in appearance. On both islands, we measured attack rates by wild avian predators on clay models matching the coloration of real male and female P. erhardii from each island population, modeled to avian predator vision. Avian predator attack rates differed among model treatments, although only on one island. Male-colored models, which were more conspicuous against their experimental backgrounds to avian predators, were accordingly detected and attacked more frequently by birds than less conspicuous female-colored models. This suggests that female coloration has evolved primarily under selection for camouflage, whereas sexually competing males exhibit costly conspicuous coloration. Unexpectedly, there was no difference in avian attack frequency between local and non-local model types. This may have arisen if the models did not resemble lizard coloration with sufficient precision, or if real lizards behaviorally choose backgrounds that improve camouflage. Overall, these results show that sexually dimorphic coloration can affect the risk of predator attacks, indicating that color variation within a species can be caused by interactions between natural and sexual selection. However, more work is needed to determine how these findings depend on the island environment that each population inhabits.
Collapse
Affiliation(s)
| | | | - Martin Stevens
- Centre for Ecology and Conservation University of Exeter Penryn Campus Penryn Cornwall TR10 9FE UK
| |
Collapse
|
16
|
Pérez i de Lanuza G, Font E. Differences in conspicuousness between alternative color morphs in a polychromatic lizard. Behav Ecol 2015. [DOI: 10.1093/beheco/arv075] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
|
17
|
Garcia JE, Girard MB, Kasumovic M, Petersen P, Wilksch PA, Dyer AG. Differentiating Biological Colours with Few and Many Sensors: Spectral Reconstruction with RGB and Hyperspectral Cameras. PLoS One 2015; 10:e0125817. [PMID: 25965264 PMCID: PMC4428825 DOI: 10.1371/journal.pone.0125817] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2014] [Accepted: 03/18/2015] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND The ability to discriminate between two similar or progressively dissimilar colours is important for many animals as it allows for accurately interpreting visual signals produced by key target stimuli or distractor information. Spectrophotometry objectively measures the spectral characteristics of these signals, but is often limited to point samples that could underestimate spectral variability within a single sample. Algorithms for RGB images and digital imaging devices with many more than three channels, hyperspectral cameras, have been recently developed to produce image spectrophotometers to recover reflectance spectra at individual pixel locations. We compare a linearised RGB and a hyperspectral camera in terms of their individual capacities to discriminate between colour targets of varying perceptual similarity for a human observer. MAIN FINDINGS (1) The colour discrimination power of the RGB device is dependent on colour similarity between the samples whilst the hyperspectral device enables the reconstruction of a unique spectrum for each sampled pixel location independently from their chromatic appearance. (2) Uncertainty associated with spectral reconstruction from RGB responses results from the joint effect of metamerism and spectral variability within a single sample. CONCLUSION (1) RGB devices give a valuable insight into the limitations of colour discrimination with a low number of photoreceptors, as the principles involved in the interpretation of photoreceptor signals in trichromatic animals also apply to RGB camera responses. (2) The hyperspectral camera architecture provides means to explore other important aspects of colour vision like the perception of certain types of camouflage and colour constancy where multiple, narrow-band sensors increase resolution.
Collapse
Affiliation(s)
- Jair E. Garcia
- School of Media and Communication, RMIT University, Melbourne, Victoria, Australia
| | - Madeline B. Girard
- Department of Environmental Science, Policy and Management, University of California, Berkeley, California, USA
| | - Michael Kasumovic
- Ecology & Evolution Research Centre, University of New South Wales, Sydney, New South Wales, Australia
| | - Phred Petersen
- School of Media and Communication, RMIT University, Melbourne, Victoria, Australia
| | - Philip A. Wilksch
- School of Applied Sciences, RMIT University, Melbourne, Victoria, Australia
| | - Adrian G. Dyer
- School of Media and Communication, RMIT University, Melbourne, Victoria, Australia
| |
Collapse
|
18
|
Marshall KLA, Gluckman TL. The evolution of pattern camouflage strategies in waterfowl and game birds. Ecol Evol 2015; 5:1981-91. [PMID: 26045950 PMCID: PMC4449753 DOI: 10.1002/ece3.1482] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2014] [Revised: 02/25/2015] [Accepted: 03/10/2015] [Indexed: 11/06/2022] Open
Abstract
Visual patterns are common in animals. A broad survey of the literature has revealed that different patterns have distinct functions. Irregular patterns (e.g., stipples) typically function in static camouflage, whereas regular patterns (e.g., stripes) have a dual function in both motion camouflage and communication. Moreover, irregular and regular patterns located on different body regions ("bimodal" patterning) can provide an effective compromise between camouflage and communication and/or enhanced concealment via both static and motion camouflage. Here, we compared the frequency of these three pattern types and traced their evolutionary history using Bayesian comparative modeling in aquatic waterfowl (Anseriformes: 118 spp.), which typically escape predators by flight, and terrestrial game birds (Galliformes: 170 spp.), which mainly use a "sit and hide" strategy to avoid predation. Given these life histories, we predicted that selection would favor regular patterning in Anseriformes and irregular or bimodal patterning in Galliformes and that pattern function complexity should increase over the course of evolution. Regular patterns were predominant in Anseriformes whereas regular and bimodal patterns were most frequent in Galliformes, suggesting that patterns with multiple functions are broadly favored by selection over patterns with a single function in static camouflage. We found that the first patterns to evolve were either regular or bimodal in Anseriformes and either irregular or regular in Galliformes. In both orders, irregular patterns could evolve into regular patterns but not the reverse. Our hypothesis of increasing complexity in pattern camouflage function was supported in Galliformes but not in Anseriformes. These results reveal a trajectory of pattern evolution linked to increasing function complexity in Galliformes although not in Anseriformes, suggesting that both ecology and function complexity can have a profound influence on pattern evolution.
Collapse
Affiliation(s)
- Kate L A Marshall
- Department of Zoology, University of Cambridge Cambridge, CB2 3EJ, UK
| | - Thanh-Lan Gluckman
- Department of Zoology, University of Cambridge Cambridge, CB2 3EJ, UK ; Department of Zoology, University of Melbourne Parkville, Victoria, 3010, Australia ; Department of Animal and Plant Sciences, University of Sheffield Western Bank, S10 2TN, UK
| |
Collapse
|
19
|
Fincke OM. Trade-offs in female signal apparency to males offer alternative anti-harassment strategies for colour polymorphic females. J Evol Biol 2015; 28:931-43. [PMID: 25786740 DOI: 10.1111/jeb.12623] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2014] [Revised: 03/10/2015] [Accepted: 03/12/2015] [Indexed: 01/22/2023]
Abstract
Colour polymorphisms are known to influence receiver behaviour, but how they affect a receiver's ability to detect and recognize individuals in nature is usually unknown. I hypothesized that polymorphic female damselflies represent an evolutionary stable strategy, maintained by trade-offs between the relative apparency of morphs to male receivers. Using field experiments on Enallagma hageni and focal studies of E. hageni and Enallagma boreale, I tested for the first time the predictions that (i) green heteromorphs and blue andromorphs gain differential protection from sexual harassment via background crypsis and sexual mimicry, respectively, and (ii) female morphs behaviourally optimize their signal apparency to mate-searching males. First, based on male reactions elicited by females, against a high-contrast background, the two morphs did not differ in being detected by males, and once detected, they did not differ in being recognized (eliciting sexual reactions). However, on green ferns, heteromorphs were less likely to be detected (elicited only fly-bys) than andromorphs, but once detected, the morphs did not differ in being recognized. In contrast, when perched on a dowel with two male signal distractors, andromorphs were detected less often, and once detected, they were recognized less often than heteromorphs. Second, in fields where females foraged, andromorphs perched higher on vegetation than heteromorphs and were more often in the vicinity of males. Neither harassment rates nor evasive behaviours differed between morphs. Males aggregated in high density near shore where solitary females were rare. Equilibrium frequencies of these and other colour morphs should reflect the relative ease with which receivers detect and recognize them in the context where they are encountered.
Collapse
Affiliation(s)
- O M Fincke
- Ecology and Evolutionary Biology Graduate Program, Department of Biology, University of Oklahoma Norman, Norman, OK, USA
| |
Collapse
|
20
|
Bohórquez-Alonso ML, Molina-Borja M. Reflectance of sexually dichromatic UV-blue patches varies during the breeding season and between two subspecies ofGallotia galloti(Squamata: Lacertidae). Biol J Linn Soc Lond 2014. [DOI: 10.1111/bij.12345] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Martha L. Bohórquez-Alonso
- Grupo de investigación ‘Etología y Ecología del Comportamiento’; Departamento de Biología Animal; Facultad de Biología; Universidad de La Laguna; Tenerife Canary Islands Spain
| | - Miguel Molina-Borja
- Grupo de investigación ‘Etología y Ecología del Comportamiento’; Departamento de Biología Animal; Facultad de Biología; Universidad de La Laguna; Tenerife Canary Islands Spain
| |
Collapse
|
21
|
Marshall KLA, Stevens M. Wall lizards display conspicuous signals to conspecifics and reduce detection by avian predators. ACTA ACUST UNITED AC 2014; 25:1325-1337. [PMID: 25419083 PMCID: PMC4235580 DOI: 10.1093/beheco/aru126] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2014] [Revised: 06/14/2014] [Accepted: 06/19/2014] [Indexed: 11/13/2022]
Abstract
Visual signals are often under conflicting selection to be hidden from predators while being conspicuous to mates and rivals. Here, we investigated whether 3 different island populations of Aegean wall lizards (Podarcis erhardii) with variable coloration among diverse island habitats exhibit simultaneous camouflage and sexual signals. We examined whether signals appear better tuned to conspecific vision as opposed to that of avian predators, and whether background-matching camouflage and sexual signals are partitioned to specific body regions. This could facilitate both covert sexual signaling and camouflage according to the viewing perspectives of predators and conspecifics. We found that lizards typically appeared twice as conspicuous to conspecifics than to avian predators against the same visual background, largely due to lizards’ enhanced sensitivity to ultraviolet, suggesting that P. erhardii signals are tuned to conspecific vision to reduce detection by predators. Males were more conspicuous than females to both predators and conspecifics. In 2 populations, male backs were relatively more camouflaged to predators compared to signaling flanks, whereas in females, exposed and concealed surfaces were camouflaged to predators and generally did not differ in background matching. These findings indicate that lizard coloration evolves under the competing demands of natural and sexual selection to promote signals that are visible to conspecifics while being less perceptible to avian predators. They also elucidate how interactions between natural and sexual selection influence signal detectability and partitioning to different body regions, highlighting the importance of considering receiver vision, viewing perspectives, and signaling environments in studies of signal evolution. Lizards and their predators see the world differently, allowing lizards (Podarcis erhardii) to display bright sexual signals that are less visible to hunting birds. Males are more conspicuous than females, but reduce their visibility to predators by having camouflaged backs and restricting brighter signals to their sides, which makes them less visible to birds hunting from above while still being highly visible to mates and rivals on the ground.
Collapse
Affiliation(s)
| | - Martin Stevens
- Centre for Ecology and Conservation, University of Exeter , Penryn Campus, Penryn, Cornwall, TR10 9FE , UK
| |
Collapse
|
22
|
Garcia JE, Greentree AD, Shrestha M, Dorin A, Dyer AG. Flower colours through the lens: quantitative measurement with visible and ultraviolet digital photography. PLoS One 2014; 9:e96646. [PMID: 24827828 PMCID: PMC4020805 DOI: 10.1371/journal.pone.0096646] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2014] [Accepted: 04/09/2014] [Indexed: 11/30/2022] Open
Abstract
Background The study of the signal-receiver relationship between flowering plants and pollinators requires a capacity to accurately map both the spectral and spatial components of a signal in relation to the perceptual abilities of potential pollinators. Spectrophotometers can typically recover high resolution spectral data, but the spatial component is difficult to record simultaneously. A technique allowing for an accurate measurement of the spatial component in addition to the spectral factor of the signal is highly desirable. Methodology/Principal findings Consumer-level digital cameras potentially provide access to both colour and spatial information, but they are constrained by their non-linear response. We present a robust methodology for recovering linear values from two different camera models: one sensitive to ultraviolet (UV) radiation and another to visible wavelengths. We test responses by imaging eight different plant species varying in shape, size and in the amount of energy reflected across the UV and visible regions of the spectrum, and compare the recovery of spectral data to spectrophotometer measurements. There is often a good agreement of spectral data, although when the pattern on a flower surface is complex a spectrophotometer may underestimate the variability of the signal as would be viewed by an animal visual system. Conclusion Digital imaging presents a significant new opportunity to reliably map flower colours to understand the complexity of these signals as perceived by potential pollinators. Compared to spectrophotometer measurements, digital images can better represent the spatio-chromatic signal variability that would likely be perceived by the visual system of an animal, and should expand the possibilities for data collection in complex, natural conditions. However, and in spite of its advantages, the accuracy of the spectral information recovered from camera responses is subject to variations in the uncertainty levels, with larger uncertainties associated with low radiance levels.
Collapse
Affiliation(s)
- Jair E. Garcia
- School of Media and Communication, RMIT University, Melbourne, Victoria, Australia
- * E-mail:
| | | | - Mani Shrestha
- Faculty of Information Technology, Monash University, Clayton, Victoria, Australia
| | - Alan Dorin
- Faculty of Information Technology, Monash University, Clayton, Victoria, Australia
| | - Adrian G. Dyer
- School of Media and Communication, RMIT University, Melbourne, Victoria, Australia
| |
Collapse
|
23
|
Garcia JE, Dyer AG, Greentree AD, Spring G, Wilksch PA. Linearisation of RGB camera responses for quantitative image analysis of visible and UV photography: a comparison of two techniques. PLoS One 2013; 8:e79534. [PMID: 24260244 PMCID: PMC3832603 DOI: 10.1371/journal.pone.0079534] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2013] [Accepted: 09/30/2013] [Indexed: 11/18/2022] Open
Abstract
Linear camera responses are required for recovering the total amount of incident irradiance, quantitative image analysis, spectral reconstruction from camera responses and characterisation of spectral sensitivity curves. Two commercially-available digital cameras equipped with Bayer filter arrays and sensitive to visible and near-UV radiation were characterised using biexponential and Bézier curves. Both methods successfully fitted the entire characteristic curve of the tested devices, allowing for an accurate recovery of linear camera responses, particularly those corresponding to the middle of the exposure range. Nevertheless the two methods differ in the nature of the required input parameters and the uncertainty associated with the recovered linear camera responses obtained at the extreme ends of the exposure range. Here we demonstrate the use of both methods for retrieving information about scene irradiance, describing and quantifying the uncertainty involved in the estimation of linear camera responses.
Collapse
Affiliation(s)
- Jair E. Garcia
- School of Applied Sciences, RMIT University, Melbourne, Victoria, Australia
- School of Media and Communication, RMIT University, Melbourne, Victoria, Australia
- * E-mail:
| | - Adrian G. Dyer
- School of Media and Communication, RMIT University, Melbourne, Victoria, Australia
| | | | - Gale Spring
- School of Applied Sciences, RMIT University, Melbourne, Victoria, Australia
| | - Philip A. Wilksch
- School of Applied Sciences, RMIT University, Melbourne, Victoria, Australia
| |
Collapse
|