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Moreno VM, Schweikert LE. Visual acuity of the summer flounder (Paralichthys dentatus) captures spatial information relevant to dynamic camouflage at close range. Anat Rec (Hoboken) 2024. [PMID: 39096041 DOI: 10.1002/ar.25543] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2024] [Revised: 06/21/2024] [Accepted: 07/08/2024] [Indexed: 08/04/2024]
Abstract
Dynamic camouflage is the capacity to rapidly change skin color and pattern, often for the purpose of background-matching camouflage. Summer flounder (Paralichthys dentatus) are demersal fish with an exceptional capacity for dynamic camouflage, but with eyes that face away from the substrate, it is unknown if this behavior is mediated by vision. Past studies have shown that summer flounder skin can match the pattern (i.e., spatial detail) of substrate with a high degree of precision, and for that to be achieved using sight, one testable assumption is that the resolution of vision must match the degree of detail produced in color-change performance. To test this, approaches in morphology and behavior were used to estimate visual acuity, which is the capacity of the visual system to resolve static spatial detail. Using image processing techniques, we then compared the degree of spatial detail from a relevant substrate with what may be detectable by summer flounder spatial vision. The morphological and behavioral estimates of visual acuity were calculated as 3.62 cycles per degree (CPD) ± 0.8 (s.d.) and 4.06 CPD ± 0.4 (s.d.), respectively. These estimates fall within a range of acuities known among other flatfishes and appear adequate for detecting the spatial information needed for background-matching camouflage, though only at close distances. These data provide new knowledge about summer flounder visual acuity and suggest the capacity of flounder vision to support dynamic camouflage of the skin.
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Affiliation(s)
- Vanessa M Moreno
- Department of Biology and Marine Biology, University of North Carolina Wilmington, Wilmington, North Carolina, USA
| | - Lorian E Schweikert
- Department of Biology and Marine Biology, University of North Carolina Wilmington, Wilmington, North Carolina, USA
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2
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Zhang J, Zhang Y, Yang J, Wang X. Beyond Color Boundaries: Pioneering Developments in Cholesteric Liquid Crystal Photonic Actuators. MICROMACHINES 2024; 15:808. [PMID: 38930778 PMCID: PMC11205596 DOI: 10.3390/mi15060808] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/17/2024] [Revised: 06/09/2024] [Accepted: 06/17/2024] [Indexed: 06/28/2024]
Abstract
Creatures in nature make extensive use of structural color adaptive camouflage to survive. Cholesteric liquid crystals, with nanostructures similar to those of natural organisms, can be combined with actuators to produce bright structural colors in response to a wide range of stimuli. Structural colors modulated by nano-helical structures can continuously and selectively reflect specific wavelengths of light, breaking the limit of colors recognizable by the human eye. In this review, the current state of research on cholesteric liquid crystal photonic actuators and their technological applications is presented. First, the basic concepts of cholesteric liquid crystals and their nanostructural modulation are outlined. Then, the cholesteric liquid crystal photonic actuators responding to different stimuli (mechanical, thermal, electrical, light, humidity, magnetic, pneumatic) are presented. This review describes the practical applications of cholesteric liquid crystal photonic actuators and summarizes the prospects for the development of these advanced structures as well as the challenges and their promising applications.
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Affiliation(s)
- Jinying Zhang
- Beijing Key Laboratory for Precision Optoelectronic Measurement Instrument and Technology, School of Optics and Photonics, Beijing Institute of Technology, Beijing 100081, China; (Y.Z.); (J.Y.); (X.W.)
- Yangtze Delta Region Academy of Beijing Institute of Technology, Jiaxing 314001, China
| | - Yexiaotong Zhang
- Beijing Key Laboratory for Precision Optoelectronic Measurement Instrument and Technology, School of Optics and Photonics, Beijing Institute of Technology, Beijing 100081, China; (Y.Z.); (J.Y.); (X.W.)
| | - Jiaxing Yang
- Beijing Key Laboratory for Precision Optoelectronic Measurement Instrument and Technology, School of Optics and Photonics, Beijing Institute of Technology, Beijing 100081, China; (Y.Z.); (J.Y.); (X.W.)
| | - Xinye Wang
- Beijing Key Laboratory for Precision Optoelectronic Measurement Instrument and Technology, School of Optics and Photonics, Beijing Institute of Technology, Beijing 100081, China; (Y.Z.); (J.Y.); (X.W.)
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Keren-Rotem T, Main DC, Barocas A, Donaire-Barroso D, Haddas-Sasson M, Vila C, Shaharabany T, Wolf L, Tolley KA, Geffen E. Genetic and behavioural factors affecting interpopulation colour pattern variation in two congeneric chameleon species. ROYAL SOCIETY OPEN SCIENCE 2024; 11:231554. [PMID: 38234439 PMCID: PMC10792394 DOI: 10.1098/rsos.231554] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/13/2023] [Accepted: 12/19/2023] [Indexed: 01/19/2024]
Abstract
We conducted a study on interpopulation variation of colour patterns in two congeneric chameleon species, which have an analogous life history. Both species are able to rapidly change colour pattern, and their context-dependent colour patterns often vary across a wide geographical range. Specifically, we tested four hypotheses that can explain the observed interpopulation variation of colour patterns by a series of behavioural field trials where the colour patterns of individuals were recorded and later analysed by a deep neural network algorithm. We used redundancy analysis to relate genetic, spectral and behavioural predictors to interpopulation colour pattern distance. Our results showed that both isolation by distance (IBD) and alternative mating tactics were significant predictors for interpopulation colour pattern variation in Chamaeleo chamaeleon males. By contrast, in Chamaeleo dilepis, the interpopulation colour pattern variation was largely explained by IBD, and evidence for alternative mating tactics was absent. In both chameleon species, the environmental colours showed no evidence of influencing chameleon interpopulation colour pattern variation, regardless of sex or behavioural context. This contrasting finding suggests that interpopulation context-dependent colour pattern variations in each species are maintained under a different set of selective pressures or circumstances.
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Affiliation(s)
- Tammy Keren-Rotem
- Ecology Department, Israel Nature and Parks Authority, Jerusalem, Israel
| | - Devon C. Main
- Centre for Ecological Genomics and Wildlife Conservation, University of Johannesburg, Auckland Park Campus, Johannesburg, South Africa
| | - Adi Barocas
- San Diego Zoo Wildlife Alliance, Escondido, CA, USA
- Wildlife Conservation Research Unit, University of Oxford, Oxford, UK
| | | | | | - Carles Vila
- Doñana Biological Station (EBD-CSIC), Seville, Spain
| | - Tal Shaharabany
- The Faculty of Engineering, Tel Aviv University, Tel Aviv, Israel
| | - Lior Wolf
- School of Computer Science, Tel Aviv University, Tel Aviv, Israel
| | - Krystal A. Tolley
- Centre for Ecological Genomics and Wildlife Conservation, University of Johannesburg, Auckland Park Campus, Johannesburg, South Africa
- Kirstenbosch Research Centre, South African National Biodiversity Institute, Cape Town, South Africa
| | - Eli Geffen
- School of Zoology, Tel Aviv University, Tel Aviv, Israel
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de Alcantara Viana JV, Campos Duarte R, Vieira C, Augusto Poleto Antiqueira P, Bach A, de Mello G, Silva L, Rabelo Oliveira Leal C, Quevedo Romero G. Crypsis by background matching and disruptive coloration as drivers of substrate occupation in sympatric Amazonian bark praying mantises. Sci Rep 2023; 13:19985. [PMID: 37968331 PMCID: PMC10652001 DOI: 10.1038/s41598-023-46204-x] [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: 08/02/2023] [Accepted: 10/29/2023] [Indexed: 11/17/2023] Open
Abstract
Background matching and disruptive coloration are common camouflage strategies in nature, but few studies have accurately measured their protective value in living organisms. Amazon's Bark praying mantises exhibit colour patterns matching whitish and greenish-brown tree trunks. We tested the functional significance of background matching and disruptive coloration of different praying mantis morphospecies (white, grey and green) detected by DNA barcoding. Through image analysis, avian visual models and field experiments using humans as potential predators, we explored whether the background occupation of mantises provides camouflage against predation. Data were obtained for individuals against their occupied tree trunks (whitish or greenish-brown) and microhabitats (lichen or bryophyte patches), compared to non-occupied trunks. White and grey mantises showed lower colour contrasts against occupied trunks at the scale of tree trunk, with no differences in luminance contrasts. Conversely, green mantises showed lower colour and luminance contrasts against microhabitats and also exhibited high edge disruption against greenish-brown trunks. The camouflage of white and green mantis models against colour-matching trunks increased search time and reduced encounter distance of human predators. We highlight the importance of camouflage strategies at different spatial scales to enhance individual survival against predators. Specifically, we present a stunning study system to investigate the relationship of phylogenetically related species that use camouflage in sympatry.
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Affiliation(s)
- João Vitor de Alcantara Viana
- Programa de Pós-Graduação em Ecologia, Instituto de Biologia, Universidade Estadual de Campinas, Campinas, São Paulo, Brazil.
- Laboratório de Interações Multitróficas e Biodiversidade, Departamento de Biologia Animal, Instituto de Biologia, Universidade Estadual de Campinas (UNICAMP), CP 6109, Campinas, São Paulo, CEP 13083-970, Brazil.
| | - Rafael Campos Duarte
- Universidade Federal Do ABC, São Bernardo Do Campo, São Paulo, CEP 09606-045, Brazil
- Centre for Ecology and Conservation, College of Life and Environmental Sciences, University of Exeter, Penryn Campus, Penryn, TR10 9FE, UK
| | - Camila Vieira
- Departamento de Ciências Básicas, Universidade de São Paulo (USP), Campus de Pirassununga, Pirassununga, São Paulo, CEP 13635-900, Brazil
| | - Pablo Augusto Poleto Antiqueira
- Laboratório de Interações Multitróficas e Biodiversidade, Departamento de Biologia Animal, Instituto de Biologia, Universidade Estadual de Campinas (UNICAMP), CP 6109, Campinas, São Paulo, CEP 13083-970, Brazil
| | - Andressa Bach
- Programa de Pós-Graduação Em Ecologia E Conservação da Biodiversidade, Instituto de Biociências, Universidade Federal de Mato Grosso, Avenida Fernando Corrêa da Costa, N° 2367, Boa Esperança, Cuiabá, 78060900, Brazil
| | - Gabriel de Mello
- Programa de Pós-Graduação Em Ecologia E Conservação da Biodiversidade, Instituto de Biociências, Universidade Federal de Mato Grosso, Avenida Fernando Corrêa da Costa, N° 2367, Boa Esperança, Cuiabá, 78060900, Brazil
| | - Lorhaine Silva
- Programa de Pós-Graduação Em Ecologia E Conservação da Biodiversidade, Instituto de Biociências, Universidade Federal de Mato Grosso, Avenida Fernando Corrêa da Costa, N° 2367, Boa Esperança, Cuiabá, 78060900, Brazil
| | - Camila Rabelo Oliveira Leal
- Laboratório de Interações Multitróficas e Biodiversidade, Departamento de Biologia Animal, Instituto de Biologia, Universidade Estadual de Campinas (UNICAMP), CP 6109, Campinas, São Paulo, CEP 13083-970, Brazil
| | - Gustavo Quevedo Romero
- Laboratório de Interações Multitróficas e Biodiversidade, Departamento de Biologia Animal, Instituto de Biologia, Universidade Estadual de Campinas (UNICAMP), CP 6109, Campinas, São Paulo, CEP 13083-970, Brazil
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Liedtke HC, Lopez-Hervas K, Galván I, Polo-Cavia N, Gomez-Mestre I. Background matching through fast and reversible melanin-based pigmentation plasticity in tadpoles comes with morphological and antioxidant changes. Sci Rep 2023; 13:12064. [PMID: 37495600 PMCID: PMC10371988 DOI: 10.1038/s41598-023-39107-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2023] [Accepted: 07/20/2023] [Indexed: 07/28/2023] Open
Abstract
Facultative colour change is widespread in the animal kingdom, and has been documented in many distantly related amphibians. However, experimental data testing the extent of facultative colour change, and associated physiological and morphological implications are comparatively scarce. Background matching in the face of spatial and temporal environmental variation is thought to be an important proximate function of colour change in aquatic amphibian larvae. This is particularly relevant for species with long larval periods such as the western spadefoot toad, Pelobates cultripes, whose tadpoles spend up to six months developing in temporary waterbodies with temporally variable vegetation. By rearing tadpoles on different coloured backgrounds, we show that P. cultripes larvae can regulate pigmentation to track fine-grained differences in background brightness, but not hue or saturation. We found that colour change is rapid, reversible, and primarily achieved through changes in the quantity of eumelanin in the skin. We show that this increased eumelanin production and/or maintenance is also correlated with changes in morphology and oxidative stress, with more pigmented tadpoles growing larger tail fins and having an improved redox status.
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Affiliation(s)
- H Christoph Liedtke
- Ecology Evolution and Development Group. Biological Station of Doñana - CSIC, 41092, Seville, Spain.
| | - Karem Lopez-Hervas
- Max Planck Institute for Evolutionary Biology, August-Thienemann Str. 2, 24306, Plön, Germany
| | - Ismael Galván
- Department of Evolutionary Ecology, National Museum of Natural Sciences, CSIC, 28006, Madrid, Spain
| | - Nuria Polo-Cavia
- Department of Biology, Universidad Autónoma de Madrid, Ciudad Universitaria de Cantoblanco, 28049, Madrid, Spain
| | - Ivan Gomez-Mestre
- Ecology Evolution and Development Group. Biological Station of Doñana - CSIC, 41092, Seville, Spain
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Batabyal A, Zambre A, Mclaren T, Rankin KJ, Somaweera R, Stuart‐Fox D, Thaker M. The extent of rapid colour change in male agamid lizards is unrelated to overall sexual dichromatism. Ecol Evol 2023; 13:e10293. [PMID: 37435020 PMCID: PMC10329938 DOI: 10.1002/ece3.10293] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2023] [Revised: 06/12/2023] [Accepted: 06/21/2023] [Indexed: 07/13/2023] Open
Abstract
Dynamic colour change is widespread in ectothermic animals, but has primarily been studied in the context of background matching. For most species, we lack quantitative data on the extent of colour change across different contexts. It is also unclear whether and how colour change varies across body regions, and how overall sexual dichromatism relates to the extent of individual colour change. In this study, we obtained reflectance measures in response to different stimuli for males and females of six species of agamid lizards (Agamidae, sister family to Chameleonidae) comprising three closely related species pairs. We computed the colour volume in a lizard-vision colour space occupied by males and females of each species and estimated overall sexual dichromatism based on the area of non-overlapping male and female colour volumes. As expected, males had larger colour volumes than females, but the extent of colour change in males differed between species and between body regions. Notably, species that were most sexually dichromatic were not necessarily those in which males showed the greatest individual colour change. Our results indicate that the extent of colour change is independent of the degree of sexual dichromatism and demonstrate that colour change on different body regions can vary substantially even between pairs of closely related species.
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Affiliation(s)
- Anuradha Batabyal
- Department of Physical and Natural SciencesFLAME UniversityPuneIndia
- Centre for Ecological SciencesIndian Institute of ScienceBengaluruIndia
| | - Amod Zambre
- Centre for Ecological SciencesIndian Institute of ScienceBengaluruIndia
- Department of Ecology, Evolution and BehaviorUniversity of MinnesotaMinneapolisMinnesotaUSA
| | - Tess Mclaren
- School of BioSciencesThe University of MelbourneParkvilleVictoriaAustralia
| | - Katrina J. Rankin
- School of BioSciencesThe University of MelbourneParkvilleVictoriaAustralia
| | - Ruchira Somaweera
- Stantec AustraliaPerthWestern AustraliaAustralia
- School of Biological SciencesUniversity of Western AustraliaPerthWestern AustraliaAustralia
| | - Devi Stuart‐Fox
- School of BioSciencesThe University of MelbourneParkvilleVictoriaAustralia
| | - Maria Thaker
- Centre for Ecological SciencesIndian Institute of ScienceBengaluruIndia
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7
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Park C, No S, Yoo S, Oh D, Hwang Y, Kim Y, Kang C. Testing multiple hypotheses on the colour change of treefrogs in response to various external conditions. Sci Rep 2023; 13:4203. [PMID: 36918652 PMCID: PMC10015036 DOI: 10.1038/s41598-023-31262-y] [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: 12/14/2022] [Accepted: 03/08/2023] [Indexed: 03/15/2023] Open
Abstract
Amphibians are famous for their ability to change colours. And a considerable number of studies have investigated the internal and external factors that affect the expression of this phenotypic plasticity. Evidence to date suggests that thermoregulation and camouflage are the main pressures that influence frogs' adaptive colour change responses. However, certain gaps in our knowledge of this phenomenon remain, namely: (i) how do frogs adjust their colour in response to continuously changing external conditions?; (ii) what is the direction of change when two different functions of colour (camouflage and thermoregulation) are in conflict?; (iii) does reflectance in the near-infrared region show thermally adaptive change?; and (iv) is the colour change ability of each frog an individual trait (i.e., consistent within an individual over time)? Using Dryophytes japonicus (Hylidae, Hyla), we performed a series of experiments to answer the above questions. We first showed that frogs' responses to continuously-changing external conditions (i.e., background colour and temperature) were not linear and limited to the range they experience under natural conditions. Second, when a functional conflict existed, camouflage constrained the adaptive response for thermoregulation and vice versa. Third, though both temperature and background colour induced a change in near-infrared reflectance, this change was largely explained by the high correlation between colour (reflectance in the visible spectrum) and near-infrared reflectance. Fourth, within-individual variation in colour change capacity (i.e., the degree of colour change an individual can display) was lower than inter-individual variation, suggesting individuality of colour change capacity; however, we also found that colour change capacity could change gradually with time within individuals. Our results collectively reveal several new aspects of how evolution shapes the colour change process and highlight how variation in external conditions restricts the extent of colour change in treefrogs.
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Affiliation(s)
- Chohee Park
- Department of Biosciences, Mokpo National University, Cheonggye, Muan, Jeollanamdo, 58554, South Korea.,Department of Agricultural Biotechnology, Seoul National University, Seoul, 08826, South Korea
| | - Seongsoo No
- Department of Biosciences, Mokpo National University, Cheonggye, Muan, Jeollanamdo, 58554, South Korea.,Department of Agricultural Biotechnology, Seoul National University, Seoul, 08826, South Korea
| | - Sohee Yoo
- Department of Biosciences, Mokpo National University, Cheonggye, Muan, Jeollanamdo, 58554, South Korea.,Department of Agricultural Biotechnology, Seoul National University, Seoul, 08826, South Korea
| | - Dogeun Oh
- Department of Biosciences, Mokpo National University, Cheonggye, Muan, Jeollanamdo, 58554, South Korea.,Department of Agricultural Biotechnology, Seoul National University, Seoul, 08826, South Korea
| | - Yerin Hwang
- Department of Biosciences, Mokpo National University, Cheonggye, Muan, Jeollanamdo, 58554, South Korea.,Department of Agricultural Biotechnology, Seoul National University, Seoul, 08826, South Korea
| | - Yongsu Kim
- Department of Agricultural Biotechnology, Seoul National University, Seoul, 08826, South Korea
| | - Changku Kang
- Department of Agricultural Biotechnology, Seoul National University, Seoul, 08826, South Korea. .,Research Institute of Agricultural and Life Sciences, Seoul National University, Seoul, 08826, South Korea.
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John L, Santon M, Michiels NK. Scorpionfish rapidly change colour in response to their background. Front Zool 2023; 20:10. [PMID: 36864453 PMCID: PMC9983180 DOI: 10.1186/s12983-023-00488-x] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2023] [Accepted: 02/20/2023] [Indexed: 03/04/2023] Open
Abstract
BACKGROUND To facilitate background matching in heterogenous environments, some animals rapidly change body colouration. Marine predatory fishes might use this ability to hide from predators and prey. Here, we focus on scorpionfishes (Scorpaenidae), well-camouflaged, bottom-dwelling sit-and-wait predators. We tested whether Scorpaena maderensis and Scorpaena porcus adjust body luminance and hue in response to three artificial backgrounds and thereby achieve background matching. Both scorpionfish species are also red fluorescent, which could contribute to background matching at depth. Therefore, we tested whether red fluorescence is also regulated in response to different backgrounds. The darkest and the lightest backgrounds were grey, while the third background was orange of intermediate luminance. Scorpionfish were placed on all three backgrounds in a randomised repeated measures design. We documented changes in scorpionfish luminance and hue with image analysis and calculated contrast to the backgrounds. Changes were quantified from the visual perspective of two potential prey fishes, the triplefin Tripterygion delaisi and the goby Pomatoschistus flavescens. Additionally, we measured changes in the area of scorpionfish red fluorescence. Because scorpionfish changed quicker than initially expected, we measured luminance change at a higher temporal resolution in a second experiment. RESULTS Both scorpionfish species rapidly adjusted luminance and hue in response to a change of background. From prey visual perspective, scorpionfishes' body achromatic and chromatic contrasts against the background were high, indicating imperfect background matching. Chromatic contrasts differed considerably between the two observer species, highlighting the importance of choosing natural observers with care when studying camouflage. Scorpionfish displayed larger areas of red fluorescence with increasing luminance of the background. With the second experiment, we showed that about 50% of the total luminance change observed after one minute is achieved very rapidly, in five to ten seconds. CONCLUSION Both scorpionfish species change body luminance and hue in response to different backgrounds within seconds. While the achieved background matching was suboptimal for the artificial backgrounds, we propose that the observed changes were intended to reduce detectability, and are an essential strategy to camouflage in the natural environment.
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Affiliation(s)
- Leonie John
- Animal Evolutionary Ecology, Institute of Evolution and Ecology, University of Tübingen, Auf Der Morgenstelle 28, 72076, Tübingen, Germany.
| | - Matteo Santon
- grid.10392.390000 0001 2190 1447Animal Evolutionary Ecology, Institute of Evolution and Ecology, University of Tübingen, Auf Der Morgenstelle 28, 72076 Tübingen, Germany ,grid.5337.20000 0004 1936 7603Ecology of Vision Group, School of Biological Sciences, University of Bristol, 24 Tyndall Avenue, Bristol, BS8 1TQ UK
| | - Nico K. Michiels
- grid.10392.390000 0001 2190 1447Animal Evolutionary Ecology, Institute of Evolution and Ecology, University of Tübingen, Auf Der Morgenstelle 28, 72076 Tübingen, Germany
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Sexual dimorphism in dynamic body color in the green anole lizard. Behav Ecol Sociobiol 2023. [DOI: 10.1007/s00265-023-03308-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/13/2023]
Abstract
Abstract
Animals capable of rapid (i.e., physiological) body color change may use color to respond quickly to changing social or physical environments. Because males and females often differ in their environments, the sexes may use changes in body color differently, reflecting sexual dimorphism in ecological, behavioral, or morphological traits. Green anole lizards, Anolis carolinensis, frequently switch their dorsal body color between bright green and dark brown, a change that requires only seconds, but little is known regarding sexual dimorphism in their color change. We tested three hypotheses for the function of body color (thermoregulation, camouflage via background-matching, and social communication) to determine the ecological role(s) of physiological color change in anoles. First, we examined instantaneous body color to determine relationships between body color and body temperature, substrate color and type, and whether these varied between the sexes. Next, we examined the association between color change and behavioral displays. Altogether, we found that males were more likely to be green than females, and larger lizards were more often green than smaller ones, but there was no evidence that anole body color was associated with body temperature or background color during the summer breeding season. Instead, our results show that although the sexes change their color at approximately the same rates, males changed color more frequently during social displays, while females remained green when displaying. In sum, social communication appears to be the primary function of anole color change, although the functions of body color may differ in the nonbreeding season.
Significance statement
Many animals can change their body color in response to their environments, and in many species, males and females experience different environments. In this study, we examined whether the sexes of green anole lizards use the ability to rapidly change their body color between green and brown for different functions. We found that, when a lizard was first sighted, its body color did not appear to match its background color in either sex (suggesting that color change does not contribute to avoidance of detection by potential predators), and body color was not associated with temperature for either sex (i.e., color was unlikely to influence body temperature). Yet, males changed color more often when performing social displays to other lizards, while females remained green during social displays. Thus, rapid color change plays an important role in social communication in both sexes, highlighting how males and females may use the same behavior to convey different messages.
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10
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Shidemantle G, Blackwood J, Horn K, Velasquez I, Ronan E, Reinke B, Hua J. The morphological effects of artificial light at night on amphibian predators and prey are masked at the community level. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2022; 308:119604. [PMID: 35691446 DOI: 10.1016/j.envpol.2022.119604] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/19/2022] [Revised: 06/06/2022] [Accepted: 06/08/2022] [Indexed: 06/15/2023]
Abstract
Artificial light at night (ALAN) is a pervasive pollutant that influences wildlife at both the individual and community level. In this study, we tested the individual-level effects of ALAN on three species of tadpole prey and their newt predators by measuring prey pigmentation and predator and prey mass. Then we evaluated whether the individual-level effects of ALAN on pigmentation and mass had cascading community-level effects by assessing the outcome of predator-prey interactions. We found that spring peepers exposed to ALAN were significantly darker than those reared under control conditions. Additionally, wood frogs reared in ALAN conditions were significantly smaller than those reared in control conditions. In contrast, Eastern newts collected earlier in the spring that were exposed to ALAN were significantly larger than controls while those collected later in the spring were not affected by ALAN, suggesting phenological differences in the effect of ALAN. To understand how changes in pigmentation and size due to ALAN influence predation rates, we ran predation assays in both ALAN-polluted and ALAN-free outdoor environments. After the predation assay, the size disparity in wood frogs reared in ALAN was eliminated such that there was no longer a treatment difference in wood frog size, likely due to size-selective predation. This demonstrates the beneficial nature of predators' selective pressure on prey populations. Lastly, despite individual-level effects of ALAN on pigmentation and mass, we did not detect cascading community-level effects on predation rates. Overall, this study highlights important species-level distinctions in the effects of ALAN. It also emphasizes the need to incorporate ecological complexity to understand the net impact of ALAN.
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Affiliation(s)
| | - Jurnee Blackwood
- Binghamton University, 4400 Vestal Pkway East, Binghamton, NY, 13902, USA
| | - Kelsey Horn
- Binghamton University, 4400 Vestal Pkway East, Binghamton, NY, 13902, USA
| | - Isabela Velasquez
- Binghamton University, 4400 Vestal Pkway East, Binghamton, NY, 13902, USA
| | - Emily Ronan
- Binghamton University, 4400 Vestal Pkway East, Binghamton, NY, 13902, USA
| | - Beth Reinke
- Northeastern Illinois University, 5500 N St Louis Ave, Chicago, IL, 60625, USA
| | - Jessica Hua
- Binghamton University, 4400 Vestal Pkway East, Binghamton, NY, 13902, USA
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