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Hemingson CR, Cowman PF, Bellwood DR. Analysing biological colour patterns from digital images: An introduction to the current toolbox. Ecol Evol 2024; 14:e11045. [PMID: 38500859 PMCID: PMC10945235 DOI: 10.1002/ece3.11045] [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: 09/07/2023] [Revised: 02/02/2024] [Accepted: 02/03/2024] [Indexed: 03/20/2024] Open
Abstract
Understanding the numerous roles that colouration serves in the natural world has remained a central focus in many evolutionary and ecological studies. However, to accurately characterise and then compare colours or patterns among individuals or species has been historically challenging. In recent years, there have been a myriad of new resources developed that allow researchers to characterise biological colours and patterns, specifically from digital imagery. However, each resource has its own strengths and weaknesses, answers a specific question and requires a detailed understanding of how it functions to be used properly. These nuances can make navigating this emerging field rather difficult. Herein, we evaluate several new techniques for analysing biological colouration, with a specific focus on digital images. First, we introduce fundamental background knowledge about light and perception to be considered when designing and implementing a study of colouration. We then show how numerous modifications can be made to images to ensure consistent formatting prior to analysis. After, we describe many of the new image analysis approaches and their respective functions, highlighting the type of research questions that they can address. We demonstrate how these various techniques can be brought together to examine novel research questions and test specific hypotheses. Finally, we outline potential future directions in colour pattern studies. Our goal is to provide a starting point and pathway for researchers wanting to study biological colour patterns from digital imagery.
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Affiliation(s)
- Christopher R. Hemingson
- The Research Hub for Coral Reef Ecosystem FunctionsJames Cook UniversityTownsvilleQueenslandAustralia
- College of Science and EngineeringJames Cook UniversityTownsvilleQueenslandAustralia
| | - Peter F. Cowman
- Biodiversity and Geosciences Program, Queensland Museum TropicsTownsvilleQueenslandAustralia
| | - David R. Bellwood
- The Research Hub for Coral Reef Ecosystem FunctionsJames Cook UniversityTownsvilleQueenslandAustralia
- College of Science and EngineeringJames Cook UniversityTownsvilleQueenslandAustralia
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2
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Huang G, Song L, Du X, Huang X, Wei F. Evolutionary genomics of camouflage innovation in the orchid mantis. Nat Commun 2023; 14:4821. [PMID: 37563121 PMCID: PMC10415354 DOI: 10.1038/s41467-023-40355-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2023] [Accepted: 07/20/2023] [Indexed: 08/12/2023] Open
Abstract
The orchid mantises achieve camouflage with morphological modifications in body color and pattern, providing an interesting model for understanding phenotypic innovation. However, a reference genome is lacking for the order Mantodea. To unveil the mechanisms of plant-mimicking body coloration and patterns, we performed de novo assembly of two chromosome-level genomes of the orchid mantis and its close relative, the dead leaf mantis. Comparative genomic analysis revealed that the Scarlet gene plays an important role in the synthesis of xanthommatin, an important pigment for mantis camouflage coloration. Combining developmental transcriptomic analysis and genetic engineering experiments, we found that the cuticle was an essential component of the 'petal-like' enlargement, and specific expression in the ventral femur was controlled by Wnt signaling. The prolonged expression of Ultrabithorax (Ubx) accompanied by femoral expansion suggested that Ubx determines leg remodeling in the early developmental stage. We also found evidence of evolution of the Trypsin gene family for insectivory adaptation and ecdysone-dependent sexual dimorphism in body size. Overall, our study presents new genome catalogs and reveals the genetic and evolutionary mechanisms underlying the unique camouflage of the praying mantis, providing evolutionary developmental insights into phenotypic innovation and adaptation.
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Affiliation(s)
- Guangping Huang
- CAS Key Laboratory of Animal Ecology and Conservation Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing, 100101, China
| | - Lingyun Song
- CAS Key Laboratory of Animal Ecology and Conservation Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing, 100101, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Xin Du
- CAS Key Laboratory of Animal Ecology and Conservation Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing, 100101, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Xin Huang
- CAS Key Laboratory of Animal Ecology and Conservation Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing, 100101, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Fuwen Wei
- CAS Key Laboratory of Animal Ecology and Conservation Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing, 100101, China.
- University of Chinese Academy of Sciences, Beijing, 100049, China.
- College of Forestry, Jiangxi Agricultural University, Nanchang, 330045, China.
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3
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Garcia-Elfring A, Sabin CE, Iouchmanov AL, Roffey HL, Samudra SP, Alcala AJ, Osman RS, Lauderdale JD, Hendry AP, Menke DB, Barrett RDH. Piebaldism and chromatophore development in reptiles are linked to the tfec gene. Curr Biol 2023; 33:755-763.e3. [PMID: 36702128 DOI: 10.1016/j.cub.2023.01.004] [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: 08/19/2022] [Revised: 11/12/2022] [Accepted: 01/04/2023] [Indexed: 01/26/2023]
Abstract
Reptiles display great diversity in color and pattern, yet much of what we know about vertebrate coloration comes from classic model species such as the mouse and zebrafish.1,2,3,4 Captive-bred ball pythons (Python regius) exhibit a remarkable degree of color and pattern variation. Despite the wide range of Mendelian color phenotypes available in the pet trade, ball pythons remain an overlooked species in pigmentation research. Here, we investigate the genetic basis of the recessive piebald phenotype, a pattern defect characterized by patches of unpigmented skin (leucoderma). We performed whole-genome sequencing and used a case-control approach to discover a nonsense mutation in the gene encoding the transcription factor tfec, implicating this gene in the leucodermic patches in ball pythons. We functionally validated tfec in a lizard model (Anolis sagrei) using the gene editing CRISPR/Cas9 system and TEM imaging of skin. Our findings show that reading frame mutations in tfec affect coloration and lead to a loss of iridophores in Anolis, indicating that tfec is required for chromatophore development. This study highlights the value of captive-bred ball pythons as a model species for accelerating discoveries on the genetic basis of vertebrate coloration.
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Affiliation(s)
- Alan Garcia-Elfring
- Department of Biology, Redpath Museum, McGill University, Montreal, QC H3A 0G4, Canada.
| | - Christina E Sabin
- Department of Genetics, University of Georgia, Athens, GA 30602, USA; Neuroscience Division of the Biomedical and Translational Sciences Institute, University of Georgia, Athens, GA 30602, USA
| | - Anna L Iouchmanov
- Department of Genetics, University of Georgia, Athens, GA 30602, USA
| | - Heather L Roffey
- Biology Department, Vanier College, Montreal, QC H4L 3X9, Canada
| | - Sukhada P Samudra
- Department of Genetics, University of Georgia, Athens, GA 30602, USA
| | - Aaron J Alcala
- Department of Genetics, University of Georgia, Athens, GA 30602, USA
| | - Rida S Osman
- Department of Genetics, University of Georgia, Athens, GA 30602, USA
| | - James D Lauderdale
- Neuroscience Division of the Biomedical and Translational Sciences Institute, University of Georgia, Athens, GA 30602, USA; Department of Cellular Biology, University of Georgia, Athens, GA 30602, USA
| | - Andrew P Hendry
- Department of Biology, Redpath Museum, McGill University, Montreal, QC H3A 0G4, Canada
| | - Douglas B Menke
- Department of Genetics, University of Georgia, Athens, GA 30602, USA
| | - Rowan D H Barrett
- Department of Biology, Redpath Museum, McGill University, Montreal, QC H3A 0G4, Canada.
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4
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Climate and body size have differential roles on melanism evolution across workers in a worldwide ant genus. Oecologia 2022; 199:579-587. [PMID: 35804249 DOI: 10.1007/s00442-022-05211-x] [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: 11/19/2021] [Accepted: 06/14/2022] [Indexed: 10/17/2022]
Abstract
One of the main aspects associated with the diversity in animal colour is the variation in melanization levels. In ectotherms, melanism can be advantageous in aiding thermoregulation through heat absorption. Darker bodies may also serve as a shield from harmful UV-B radiation. Melanism may also confer protection against parasites and predators through improving immunity responses and camouflage in regions with high precipitation, with complex and shaded vegetations and greater diversity of pathogens and parasites. We studied melanism evolution in the globally distributed ant genus Pheidole under the pressures of temperature, UV-B radiation and precipitation, while considering the effects of body size and nest habit, traits that are commonly overlooked. More importantly, we account for worker caste polymorphism, which is marked by distinct roles and behaviours. We revealed for the first time distinct evolutionary trajectories for each worker subcaste. As expected, major workers from species inhabiting locations with lower temperatures and higher precipitation tend to be more melanised. Curiously, we show a slight trend where minor workers of larger species also tend to have darker bodies when inhabiting regions with higher precipitation. Lastly, we did not find evidence for the effects of UV-B radiation and nest habit in the lightness variation of workers. Our paper explores the evolution of ant melanization considering a marked ant worker polymorphism and a wide range of ecological factors. We discuss our findings under the light of the Thermal Melanism Hypothesis, the Photoprotection Hypothesis and the Gloger's Rule.
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Davis AC, Arnocky S. Darwin Versus Wallace: Esthetic Evolution and Preferential Mate Choice. Front Psychol 2022; 13:862385. [PMID: 35693523 PMCID: PMC9174777 DOI: 10.3389/fpsyg.2022.862385] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2022] [Accepted: 04/26/2022] [Indexed: 11/13/2022] Open
Abstract
Dominant theorizing and research surrounding the operation of intersexual selection in evolutionary psychology tends to be guided by an adaptationist framework and aligned with models of sexual selection involving direct benefits (e.g., parental care) and indirect “good gene” and condition-dependent benefits. In this way, evolutionary psychologists more often espouse Alfred Russel Wallaces’ utilitarian viewpoint that traits become attractive because they honestly signal vigor and vitality, which gives priority to natural selection. In doing so, Darwin’s esthetic perspective originally articulated in The Descent of Man and alternative models of sexual selection (e.g., Fisherian runaway), are given less consideration. This is despite some informative reviews on the topic in evolutionary psychology. In the current conceptual analysis, we discuss the potential of Prum’s Lande-Kirkpatrick (LK) null model of sexual selection to help make sense of some of the mixed evidence regarding the links between attractive traits and purported markers of phenotypic and genetic condition. We then consider how the implications of the LK null model can help to shift theoretical assumptions and guide future work in evolutionary psychology on intersexual selection.
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Affiliation(s)
- Adam C Davis
- Human Evolution Laboratory, Department of Psychology, Nipissing University, North Bay, ON, Canada
| | - Steven Arnocky
- Human Evolution Laboratory, Department of Psychology, Nipissing University, North Bay, ON, Canada
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6
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Yuan T, Li Y, Song DP. Interfacial Self-Assembly of Amphiphilic Core-Shell Bottlebrush Block Copolymers Toward Responsive Photonic Balls Bearing Ionic Channels. Macromol Rapid Commun 2022; 43:e2200188. [PMID: 35436806 DOI: 10.1002/marc.202200188] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2022] [Revised: 04/11/2022] [Indexed: 11/11/2022]
Abstract
Photonic balls can be facilely obtained through interfacial self-assembly of amphiphilic bottlebrush block polymers (BBCPs) within a water-in-oil-in-water (w/o/w) multiple emulsion system, and polystyrene (PS) has been employed as the skeleton of the balls showing no responsive properties. Here, we demonstrate the design and synthesis of core-shell BBCPs with a poly(tert-butyl acrylate)-block-polystyrene (PtBA-b-PS) block copolymer as the hydrophobic side chains and poly(ethylene glycol) (PEG) as the hydrophilic block. Interfacial self-assembly of the core-shell BBCPs within shrinking droplets produces porous microspheres with full-spectrum structural colors through an organized spontaneous emulsification (OSE) process. The PtBA core wrapped by PS in the skeleton of the balls can be converted into polyacrylic acid (PAA) forming an ionic channel responsive to pH variations. Consequently, the hydrolyzed photonic balls show different colors under different pH conditions dependent on varied degrees of ionization and hydration of the PAA channel. Reflected colors can be verified using an optical spectrometer, providing an effective strategy for precise pH indication. This article is protected by copyright. All rights reserved.
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Affiliation(s)
- Tengfei Yuan
- Tianjin Key Laboratory of Composite and Functional Materials, School of Materials Science and Engineering, Tianjin University, Tianjin, 300350, China
| | - Yuesheng Li
- Tianjin Key Laboratory of Composite and Functional Materials, School of Materials Science and Engineering, Tianjin University, Tianjin, 300350, China
| | - Dong-Po Song
- Tianjin Key Laboratory of Composite and Functional Materials, School of Materials Science and Engineering, Tianjin University, Tianjin, 300350, China
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7
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Oechler H, Krah FS. Response of Fruit Body Assemblage Color Lightness to Macroclimate and Vegetation Cover. Front Ecol Evol 2022. [DOI: 10.3389/fevo.2022.829981] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Understanding how species relate mechanistically to their environment via traits is a central goal in ecology. Many macroecological rules were found for macroorganisms, however, whether they can explain microorganismal macroecological patterns still requires investigation. Further, whether macroecological rules are also applicable in microclimates is largely unexplored. Here we use fruit body-forming fungi to understand both aspects better. A recent study showed first evidence for the thermal-melanism hypothesis (Bogert’s rule) in fruit body-forming fungi and relied on a continental spatial scale with large grid size. At large spatial extent and grid sizes, other factors like dispersal limitation or local microclimatic variability might influence observed patterns besides the rule of interest. Therefore, we test fungal assemblage fruit body color lightness along a local elevational gradient (mean annual temperature gradient of 7°C) while considering the vegetation cover as a proxy for local variability in microclimate. Using multivariate linear modeling, we found that fungal fruiting assemblages are significantly darker at lower mean annual temperatures supporting the thermal-melanism hypothesis. Further, we found a non-significant trend of assemblage color lightness with vegetation cover. Our results support Bogert’s rule for microorganisms with macroclimate, which was also found for macroorganisms.
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8
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Yu L, Xu X, Li F, Zhou W, Zeng H, Tan EJ, Zhang S, Li D. From crypsis to masquerade: Ontogeny changes the colour defences of a crab spider hiding as bird droppings. Funct Ecol 2022. [DOI: 10.1111/1365-2435.13998] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Long Yu
- State Key Laboratory of Biocatalysis and Enzyme Engineering & Centre for Behavioural Ecology & Evolution School of Life Sciences Hubei University Wuhan China
| | - Xin Xu
- State Key Laboratory of Biocatalysis and Enzyme Engineering & Centre for Behavioural Ecology & Evolution School of Life Sciences Hubei University Wuhan China
- School of Life Sciences Hunan Normal University Changsha China
| | - Fan Li
- State Key Laboratory of Biocatalysis and Enzyme Engineering & Centre for Behavioural Ecology & Evolution School of Life Sciences Hubei University Wuhan China
- Department of Biological Sciences National University of Singapore Singapore
- College of Life Sciences University of Chinese Academy of Sciences Beijing China
| | - Wei Zhou
- Department of Biological Sciences National University of Singapore Singapore
| | - Hua Zeng
- State Key Laboratory of Protein and Plant Gene Research Peking‐Tsinghua Center for Life Sciences Academy for Advanced Interdisciplinary Studies Peking University Beijing China
| | | | - Shichang Zhang
- State Key Laboratory of Biocatalysis and Enzyme Engineering & Centre for Behavioural Ecology & Evolution School of Life Sciences Hubei University Wuhan China
| | - Daiqin Li
- Department of Biological Sciences National University of Singapore Singapore
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9
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Rohner PT. Secondary Sexual Trait Melanization in “Black” Scavenger Flies: Nutritional Plasticity and Its Evolution. Am Nat 2022; 199:168-177. [DOI: 10.1086/717051] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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10
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Yeager J, Barnett JB. The influence of ultraviolet reflectance differs between conspicuous aposematic signals in neotropical butterflies and poison frogs. Ecol Evol 2021; 11:13633-13640. [PMID: 34707805 PMCID: PMC8525173 DOI: 10.1002/ece3.7942] [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: 06/25/2021] [Revised: 07/05/2021] [Accepted: 07/06/2021] [Indexed: 11/07/2022] Open
Abstract
Warning signals are often characterized by highly contrasting, distinctive, and memorable colors. Greater chromatic (hue) and achromatic (brightness) contrast have both been found to contribute to greater signal efficacy, making longwave colored signals (e.g., red and yellow), that are perceived by both chromatic and achromatic visual pathways, particularly common. Conversely, shortwave colors (e.g., blue and ultraviolet) do not contribute to luminance perception yet are also commonly found in warning signals. Our understanding of the role of UV in aposematic signals is currently incomplete as UV perception is not universal, and evidence for its utility is at best mixed. We used visual modeling to quantify how UV affects signal contrast in aposematic heliconiian butterflies and poison frogs both of which reflect UV wavelengths, occupy similar habitats, and share similar classes of predators. Previous work on butterflies has found that UV reflectance does not affect predation risk but is involved in mate choice. As the butterflies, but not the frogs, have UV-sensitive vision, the function of UV reflectance in poison frogs is currently unknown. We found that despite showing up strongly in UV photographs, UV reflectance only appreciably affected visual contrast in the butterflies. As such, these results support the notion that although UV reflectance is associated with intraspecific communication in butterflies, it appears to be nonfunctional in frogs. Consequently, our data highlight that we should be careful when assigning a selection-based benefit to the presence of UV reflectance.
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Affiliation(s)
- Justin Yeager
- Biodiversidad Medio Ambiente y Salud Universidad de Las Américas Quito Ecuador
| | - James B Barnett
- Psychology, Neuroscience & Behaviour McMaster University Hamilton ON Canada
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11
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Affiliation(s)
- Peter M Kappeler
- Behavioral Ecology and Sociobiology Unit, German Primate Center - Leibniz Institute for Primate Biology, Kellnerweg 4, 37077 Göttingen, Germany
- Department of Sociobiology/Anthropology, Georg-August University, Kellnerweg 6, 37077 Göttingen, Germany
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12
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Chen F, Liu Y, Li L, Qi L, Ma Y. Synthesis of Bio-Inspired Guanine Microplatelets: Morphological and Crystallographic Control. Chemistry 2020; 26:16228-16235. [PMID: 32888220 DOI: 10.1002/chem.202003156] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2020] [Revised: 08/18/2020] [Indexed: 12/15/2022]
Abstract
β-Phase anhydrous guanine (β-AG) crystals are one of the most widespread organic crystals to construct optical structures in organisms. Currently, no synthetic method is available that allows for producing guanine crystals with similar control in size, morphology, and crystallography as in biological ones. Herein, a facile one-step synthesis route to fabricate bio-inspired guanine microplatelets with (100) exposing planes in almost pure β-phase is reported. The synthesis is based on a precipitation process of a guanine sodium hydroxide solution in formamide with poly(1-vinylpyrrolidone-co-vinyl acetate) as a morphological additive. Due to their uniform size (ca. 20 μm) and thickness (ca. 110 nm), the crystals represent the first synthetic guanine microplatelets that exhibit strong structural coloration and pearlescent lusters. Moreover, this synthesis route was utilized as a model system to investigate the effects of guanine analogues, including uric acid, hypoxanthine, xanthine, adenine, and guanosine, during the crystallization process. Our results indicate that the introduction of guanine analogues not only can reduce the required synthesis temperature but also provide a versatile control in crystal morphology and polymorph selection between the α-phase AG (α-AG) and β-AG. Turbidity experiments show that the β-AG microplatelets are formed with a fast precipitation rate in comparison to α-AG, suggesting that the formation of β-AG crystals follows a kinetically driven process.
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Affiliation(s)
- Fenghua Chen
- School of Chemistry and Chemical Engineering, Beijing Institute of Technology, 5 South Zhongguancun Street, Haidian District, Beijing, 100081, P.R. China.,Beijing National Laboratory for Molecular Sciences, College of Chemistry, Peking University, No.5 Yiheyuan Road, Haidian District, Beijing, 100871, P.R. China.,School of Resources and Chemical Engineering, Sanming University, Jingdong Road 25, Sanming, 365004, P.R. China
| | - Yanan Liu
- School of Chemistry and Chemical Engineering, Beijing Institute of Technology, 5 South Zhongguancun Street, Haidian District, Beijing, 100081, P.R. China
| | - Ling Li
- Department of Mechanical Engineering, Virginia Polytechnic Institute and State University, 635 Prices Fork Rd, Blacksburg, VA, 24061, USA
| | - Limin Qi
- Beijing National Laboratory for Molecular Sciences, College of Chemistry, Peking University, No.5 Yiheyuan Road, Haidian District, Beijing, 100871, P.R. China
| | - Yurong Ma
- School of Chemistry and Chemical Engineering, Beijing Institute of Technology, 5 South Zhongguancun Street, Haidian District, Beijing, 100081, P.R. China
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13
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Pembury Smith MQR, Ruxton GD. Camouflage in predators. Biol Rev Camb Philos Soc 2020; 95:1325-1340. [DOI: 10.1111/brv.12612] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2020] [Revised: 04/24/2020] [Accepted: 04/28/2020] [Indexed: 12/29/2022]
Affiliation(s)
| | - Graeme D. Ruxton
- School of Biology University of St Andrews, Dyers Brae House, St Andrews Fife KY16 9TH U.K
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14
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de Souza AR, Mayorquin AZ, Sarmiento CE. Paper wasps are darker at high elevation. J Therm Biol 2020; 89:102535. [PMID: 32364980 DOI: 10.1016/j.jtherbio.2020.102535] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2019] [Revised: 01/21/2020] [Accepted: 02/09/2020] [Indexed: 11/15/2022]
Abstract
High mountains are harsh environments in which colder temperatures and higher levels of UV-B radiation are common. These abiotic conditions strongly affect animals' biology, often constraining their survival and reproduction. As a result, adaptations to live in such habitats are expected to evolve. Body color is thought to be adaptive to the environment that animals experience. Tegument melanization improves heat gain and provides photoprotection. Therefore, at high elevation, ectotherms are expected to be darker (well-melanized). We test this prediction in the paper wasp Agelaia pallipes (Hymenoptera: Vespidae), a species distributed across an elevational gradient in the Colombian Andes. We used Malaise traps and sampled a total of 146 wasps along nine elevations, ranging from 2,600-3,380 m above sea level. Standard digital photography was used to measure the body luminance and colour patterning in different body parts of dry-preserved specimens. There was striking variation in body luminance (darker and lighter), color patterning (patched, smoothed, homogeneous) and surface texture (shiny and matte), but the kind and degree of variation depended on the body part examined. Wasps from higher elevations had darker thoraces, confirming our prediction. Besides, at high elevation, the frequency of wasps with a matte rather than a shiny face strongly increased. Overall, our findings support the thermal melanism hypothesis and suggest that intraspecific color variation might be an adaptation to the environment of paper wasps.
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Affiliation(s)
- André R de Souza
- Departamento de Biologia, Faculdade de Filosofia Ciências e Letras de Ribeirão Preto, Universidade de São Paulo, Av. Bandeirantes 3900, 14040-901, São Paulo, Brazil.
| | - Angie Z Mayorquin
- Universidad Nacional de Colombia, Instituto de Ciencias Naturales, Cr 30 No. 45 03 edif 425, of. 303, Bogotá, Colombia.
| | - Carlos E Sarmiento
- Universidad Nacional de Colombia, Instituto de Ciencias Naturales, Cr 30 No. 45 03 edif 425, of. 303, Bogotá, Colombia.
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15
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Wu S, Chang CM, Mai GS, Rubenstein DR, Yang CM, Huang YT, Lin HH, Shih LC, Chen SW, Shen SF. Artificial intelligence reveals environmental constraints on colour diversity in insects. Nat Commun 2019; 10:4554. [PMID: 31591404 PMCID: PMC6779759 DOI: 10.1038/s41467-019-12500-2] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2019] [Accepted: 09/10/2019] [Indexed: 11/09/2022] Open
Abstract
Explaining colour variation among animals at broad geographic scales remains challenging. Here we demonstrate how deep learning-a form of artificial intelligence-can reveal subtle but robust patterns of colour feature variation along an ecological gradient, as well as help identify the underlying mechanisms generating this biogeographic pattern. Using over 20,000 images with precise GPS locality information belonging to nearly 2,000 moth species from Taiwan, our deep learning model generates a 2048-dimension feature vector that accurately predicts each species' mean elevation based on colour and shape features. Using this multidimensional feature vector, we find that within-assemblage image feature variation is smaller in high elevation assemblages. Structural equation modeling suggests that this reduced image feature diversity is likely the result of colder environments selecting for darker colouration, which limits the colour diversity of assemblages at high elevations. Ultimately, with the help of deep learning, we will be able to explore the endless forms of natural morphological variation at unpreceded depths.
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Affiliation(s)
- Shipher Wu
- Biodiversity Research Center, Academia Sinica, Taipei, 11529, Taiwan
| | - Chun-Min Chang
- Institute of Information Science, Academia Sinica, Taipei, 11529, Taiwan
| | - Guan-Shuo Mai
- Biodiversity Research Center, Academia Sinica, Taipei, 11529, Taiwan
| | - Dustin R Rubenstein
- Department of Ecology, Evolution and Environmental Biology, Columbia University, New York, NY, 10027, USA
- Center for Integrative Animal Behavior, Columbia University, New York, NY, 10027, USA
| | - Chen-Ming Yang
- Institute of Information Science, Academia Sinica, Taipei, 11529, Taiwan
| | - Yu-Ting Huang
- Institute of Information Science, Academia Sinica, Taipei, 11529, Taiwan
| | - Hsu-Hong Lin
- Taiwan Endemic Species Research Institute, Nantou, 552, Taiwan
| | - Li-Cheng Shih
- Taiwan Endemic Species Research Institute, Nantou, 552, Taiwan
| | - Sheng-Wei Chen
- Institute of Information Science, Academia Sinica, Taipei, 11529, Taiwan.
| | - Sheng-Feng Shen
- Biodiversity Research Center, Academia Sinica, Taipei, 11529, Taiwan.
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16
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Cooption of the pteridine biosynthesis pathway underlies the diversification of embryonic colors in water striders. Proc Natl Acad Sci U S A 2019; 116:19046-19054. [PMID: 31484764 PMCID: PMC6754612 DOI: 10.1073/pnas.1908316116] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Understanding how existing genomic content can be reused to generate new phenotypes is important for understanding how species diversify. Here, we address this question by studying the origin of a phenotype consisting of bright coloration in the embryos of water striders. We found that the pteridine biosynthesis pathway, originally active in the eyes, has been coopted in the embryo to produce various colors in the antennae and legs. The coopted pathway remained stable for over 200 million years, yet resulted in a striking diversification of colors and color patterns during the evolution of water striders. This work demonstrates how the activation of a complete pathway in new developmental contexts can drive the evolution of novelty and fuel species diversification. Naturalists have been fascinated for centuries by animal colors and color patterns. While widely studied at the adult stage, we know little about color patterns in the embryo. Here, we study a trait consisting of coloration that is specific to the embryo and absent from postembryonic stages in water striders (Gerromorpha). By combining developmental genetics with chemical and phylogenetic analyses across a broad sample of species, we uncovered the mechanisms underlying the emergence and diversification of embryonic colors in this group of insects. We show that the pteridine biosynthesis pathway, which ancestrally produces red pigment in the eyes, has been recruited during embryogenesis in various extraocular tissues including antennae and legs. In addition, we discovered that this cooption is common to all water striders and initially resulted in the production of yellow extraocular color. Subsequently, 6 lineages evolved bright red color and 2 lineages lost the color independently. Despite the high diversity in colors and color patterns, we show that the underlying biosynthesis pathway remained stable throughout the 200 million years of Gerromorpha evolutionary time. Finally, we identified erythropterin and xanthopterin as the pigments responsible for these colors in the embryo of various species. These findings demonstrate how traits can emerge through the activation of a biosynthesis pathway in new developmental contexts.
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Is eliciting disgust responses from its predators beneficial for toxic prey? Anim Behav 2019. [DOI: 10.1016/j.anbehav.2019.07.007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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18
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Krah FS, Büntgen U, Schaefer H, Müller J, Andrew C, Boddy L, Diez J, Egli S, Freckleton R, Gange AC, Halvorsen R, Heegaard E, Heideroth A, Heibl C, Heilmann-Clausen J, Høiland K, Kar R, Kauserud H, Kirk PM, Kuyper TW, Krisai-Greilhuber I, Norden J, Papastefanou P, Senn-Irlet B, Bässler C. European mushroom assemblages are darker in cold climates. Nat Commun 2019; 10:2890. [PMID: 31253790 PMCID: PMC6599080 DOI: 10.1038/s41467-019-10767-z] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2018] [Accepted: 05/30/2019] [Indexed: 12/22/2022] Open
Abstract
Thermal melanism theory states that dark-colored ectotherm organisms are at an advantage at low temperature due to increased warming. This theory is generally supported for ectotherm animals, however, the function of colors in the fungal kingdom is largely unknown. Here, we test whether the color lightness of mushroom assemblages is related to climate using a dataset of 3.2 million observations of 3,054 species across Europe. Consistent with the thermal melanism theory, mushroom assemblages are significantly darker in areas with cold climates. We further show differences in color phenotype between fungal lifestyles and a lifestyle differentiated response to seasonality. These results indicate a more complex ecological role of mushroom colors and suggest functions beyond thermal adaption. Because fungi play a crucial role in terrestrial carbon and nutrient cycles, understanding the links between the thermal environment, functional coloration and species' geographical distributions will be critical in predicting ecosystem responses to global warming.
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Affiliation(s)
- Franz-Sebastian Krah
- Plant Biodiversity Research Group, Department of Ecology & Ecosystem Management, Technische Universität München, 85354, Freising, Germany.
- Bavarian Forest National Park, 94481, Grafenau, Germany.
| | - Ulf Büntgen
- Department of Geography, University of Cambridge, Cambridge, CB2 3EN, UK
- Research Unit Biodiversity & Conservation Biology, Swiss Federal Research Institute WSL, 8903, Birmensdorf, Switzerland
- Global Change Research Centre and Masaryk University, 61300, Brno, Czech Republic
| | - Hanno Schaefer
- Plant Biodiversity Research Group, Department of Ecology & Ecosystem Management, Technische Universität München, 85354, Freising, Germany
| | - Jörg Müller
- Bavarian Forest National Park, 94481, Grafenau, Germany
- Field Station Fabrikschleichach, Department of Animal Ecology and Tropical Biology, Biocenter University of Würzburg, 96181, Rauhenebrach, Germany
| | - Carrie Andrew
- Norwegian Institute for Nature Research, Gaustadalléen 21, NO-0349, Oslo, Norway
| | - Lynne Boddy
- School of Biosciences, Cardiff University, Cardiff, CF10 3AX, UK
| | - Jeffrey Diez
- Department of Botany and Plant Sciences, University of California, Riverside, CA, 92521, USA
| | - Simon Egli
- Research Unit Biodiversity & Conservation Biology, Swiss Federal Research Institute WSL, 8903, Birmensdorf, Switzerland
| | - Robert Freckleton
- Department of Animal & Plant Sciences, University of Sheffield, Sheffield, S10 2TN, UK
| | - Alan C Gange
- School of Biological Sciences, Royal Holloway, University of London, Egham, Surrey, TW20 0EX, UK
| | - Rune Halvorsen
- Natural History Museum, University of Oslo, Blindern, 0318, Oslo, Norway
| | - Einar Heegaard
- Norwegian Institute of Bioeconomy Research, 5244, Fana, Norway
| | - Antje Heideroth
- Bavarian Forest National Park, 94481, Grafenau, Germany
- Ecology Research Group, Department of Biology, Philipps Uuniversity Marburg, 35043, Marburg, Germany
| | | | - Jacob Heilmann-Clausen
- Center for Macroecology, Evolution and Climate, Natural History Museum of Denmark, University of Copenhagen, 2100, Copenhagen, Denmark
| | - Klaus Høiland
- Norwegian Institute for Nature Research, Gaustadalléen 21, NO-0349, Oslo, Norway
| | - Ritwika Kar
- Centre for Plant Molecular Biology, Developmental Genetics, University of Tübingen, 72076, Tuebingen, Germany
| | - Håvard Kauserud
- Norwegian Institute for Nature Research, Gaustadalléen 21, NO-0349, Oslo, Norway
| | - Paul M Kirk
- Mycology Section, Jodrell Laboratory, Royal Botanic Gardens Kew, Surrey, TW9 3DS, UK
| | - Thomas W Kuyper
- Department of Soil Quality, Wageningen University, 6700 AA, Wageningen, The Netherlands
| | - Irmgard Krisai-Greilhuber
- Division of Systematic and Evolutionary Botany, Department of Botany and Biodiversity Research, University of Vienna, 1030, Vienna, Austria
| | - Jenni Norden
- Norwegian Institute for Nature Research, Gaustadalléen 21, NO-0349, Oslo, Norway
| | - Phillip Papastefanou
- TUM School of Life Sciences Weihenstephan, Land Surface-Atmosphere Interactions, Technical University of Munich, 85354, Freising, Germany
| | - Beatrice Senn-Irlet
- Research Unit Biodiversity & Conservation Biology, Swiss Federal Research Institute WSL, 8903, Birmensdorf, Switzerland
| | - Claus Bässler
- Bavarian Forest National Park, 94481, Grafenau, Germany.
- Technical University of Munich, Chair for Terrestrial Ecology, 85354, Freising, Germany.
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Figon F, Casas J. Ommochromes in invertebrates: biochemistry and cell biology. Biol Rev Camb Philos Soc 2019; 94:156-183. [PMID: 29989284 DOI: 10.1111/brv.12441] [Citation(s) in RCA: 48] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2018] [Revised: 06/09/2018] [Accepted: 06/12/2018] [Indexed: 01/24/2023]
Abstract
Ommochromes are widely occurring coloured molecules of invertebrates, arising from tryptophan catabolism through the so-called Tryptophan → Ommochrome pathway. They are mainly known to mediate compound eye vision, as well as reversible and irreversible colour patterning. Ommochromes might also be involved in cell homeostasis by detoxifying free tryptophan and buffering oxidative stress. These biological functions are directly linked to their unique chromophore, the phenoxazine/phenothiazine system. The most recent reviews on ommochrome biochemistry were published more than 30 years ago, since when new results on the enzymes of the ommochrome pathway, on ommochrome photochemistry as well as on their antiradical capacities have been obtained. Ommochromasomes are the organelles where ommochromes are synthesised and stored. Hence, they play an important role in mediating ommochrome functions. Ommochromasomes are part of the lysosome-related organelles (LROs) family, which includes other pigmented organelles such as vertebrate melanosomes. Ommochromasomes are unique because they are the only LRO for which a recycling process during reversible colour change has been described. Herein, we provide an update on ommochrome biochemistry, photoreactivity and antiradical capacities to explain their diversity and behaviour both in vivo and in vitro. We also highlight new biochemical techniques, such as quantum chemistry, metabolomics and crystallography, which could lead to major advances in their chemical and functional characterisation. We then focus on ommochromasome structure and formation by drawing parallels with the well-characterised melanosomes of vertebrates. The biochemical, genetic, cellular and microscopic tools that have been applied to melanosomes should provide important information on the ommochromasome life cycle. We propose LRO-based models for ommochromasome biogenesis and recycling that could be tested in the future. Using the context of insect compound eyes, we finally emphasise the importance of an integrated approach in understanding the biological functions of ommochromes.
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Affiliation(s)
- Florent Figon
- Institut de Recherche sur la Biologie de l'Insecte, UMR CNRS 7261, Université de Tours, 37200 Tours, France
| | - Jérôme Casas
- Institut de Recherche sur la Biologie de l'Insecte, UMR CNRS 7261, Université de Tours, 37200 Tours, France
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Teleost Fish-Specific Preferential Retention of Pigmentation Gene-Containing Families After Whole Genome Duplications in Vertebrates. G3-GENES GENOMES GENETICS 2018; 8:1795-1806. [PMID: 29599177 PMCID: PMC5940169 DOI: 10.1534/g3.118.200201] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Vertebrate pigmentation is a highly diverse trait mainly determined by neural crest cell derivatives. It has been suggested that two rounds (1R/2R) of whole-genome duplications (WGDs) at the basis of vertebrates allowed changes in gene regulation associated with neural crest evolution. Subsequently, the teleost fish lineage experienced other WGDs, including the teleost-specific Ts3R before teleost radiation and the more recent Ss4R at the basis of salmonids. As the teleost lineage harbors the highest number of pigment cell types and pigmentation diversity in vertebrates, WGDs might have contributed to the evolution and diversification of the pigmentation gene repertoire in teleosts. We have compared the impact of the basal vertebrate 1R/2R duplications with that of the teleost-specific Ts3R and salmonid-specific Ss4R WGDs on 181 gene families containing genes involved in pigmentation. We show that pigmentation genes (PGs) have been globally more frequently retained as duplicates than other genes after Ts3R and Ss4R but not after the early 1R/2R. This is also true for non-pigmentary paralogs of PGs, suggesting that the function in pigmentation is not the sole key driver of gene retention after WGDs. On the long-term, specific categories of PGs have been repeatedly preferentially retained after ancient 1R/2R and Ts3R WGDs, possibly linked to the molecular nature of their proteins (e.g., DNA binding transcriptional regulators) and their central position in protein-protein interaction networks. Taken together, our results support a major role of WGDs in the diversification of the pigmentation gene repertoire in the teleost lineage, with a possible link with the diversity of pigment cell lineages observed in these animals compared to other vertebrates.
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Caro T, Allen WL. Interspecific visual signalling in animals and plants: a functional classification. Philos Trans R Soc Lond B Biol Sci 2018; 372:rstb.2016.0344. [PMID: 28533461 DOI: 10.1098/rstb.2016.0344] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/29/2017] [Indexed: 11/12/2022] Open
Abstract
Organisms frequently gain advantages when they engage in signalling with individuals of other species. Here, we provide a functionally structured framework of the great variety of interspecific visual signals seen in nature, and then describe the different signalling mechanisms that have evolved in response to each of these functional requirements. We propose that interspecific visual signalling can be divided into six major functional categories: anti-predator, food acquisition, anti-parasite, host acquisition, reproductive and agonistic signalling, with each function enabled by several distinct mechanisms. We support our classification by reviewing the ecological and behavioural drivers of interspecific signalling in animals and plants, principally focusing on comparative studies that address large-scale patterns of diversity. Collating diverse examples of interspecific signalling into an organized set of functional and mechanistic categories places anachronistic behavioural and morphological labels in fresh context, clarifies terminology and redirects research effort towards understanding environmental influences driving interspecific signalling in nature.This article is part of the themed issue 'Animal coloration: production, perception, function and application'.
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Affiliation(s)
- Tim Caro
- Department of Wildlife, Fish and Conservation Biology and Center for Population Biology, University of California, Davis, CA 95616, USA
| | - William L Allen
- Department of Biosciences, Swansea University, Singleton Park, Swansea SA2 8PP, Wales, UK
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Hongjamrassilp W, Summers AP, Hastings PA. Heterochrony in fringeheads (Neoclinus) and amplification of an extraordinary aggressive display in the Sarcastic Fringehead (Teleostei: Blenniiformes). J Morphol 2018; 279:626-635. [PMID: 29399857 DOI: 10.1002/jmor.20798] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2017] [Revised: 12/04/2017] [Accepted: 01/21/2018] [Indexed: 12/30/2022]
Abstract
The Sarcastic Fringehead (Neoclinus blanchardi, Teleostei) exhibits an extreme version of a common aggressive display, the "gaping display," in which an open mouth is presented toward an opponent. Males of this species have extremely long jaws that extend posteriorly well past the posterior margin of the head and are flared laterally during the gaping display. In this study, we explored morphological traits related to this extraordinary display in this and related species of blennies. Morphological modifications include enlargement of the buccopalatal membrane, elongation of the maxilla via an uncalcified posterior extension, and evolution of a novel hinge between the anterior maxilla and lacrimal bones permitting lateral movement of the upper jaw. Geometric morphometry using the truss network system, thin-plate spline, and PCA of three closely related species of Neoclinus indicate that the elongate maxilla of N. blanchardi most likely evolved via acceleration (faster growth compared to outgroups) and hypermorphosis (continued growth to a larger body size), both forms of peramorphic heterochrony. Coloration and fluorescence of the buccopalatal membrane may also serve to amplify the extraordinary gaping display of the Sarcastic Fringehead.
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Affiliation(s)
- Watcharapong Hongjamrassilp
- Marine Biology Research Division, Scripps Institution of Oceanography, University of California, San Diego, La Jolla, California, 92093
| | - Adam P Summers
- Friday Harbor Laboratories, University of Washington, Friday Harbor, Washington, 98250
| | - Philip A Hastings
- Marine Biology Research Division, Scripps Institution of Oceanography, University of California, San Diego, La Jolla, California, 92093
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Penacchio O, Lovell PG, Harris JM. Is countershading camouflage robust to lighting change due to weather? ROYAL SOCIETY OPEN SCIENCE 2018; 5:170801. [PMID: 29515822 PMCID: PMC5830711 DOI: 10.1098/rsos.170801] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/29/2017] [Accepted: 12/11/2017] [Indexed: 05/16/2023]
Abstract
Countershading is a pattern of coloration thought to have evolved in order to implement camouflage. By adopting a pattern of coloration that makes the surface facing towards the sun darker and the surface facing away from the sun lighter, the overall amount of light reflected off an animal can be made more uniformly bright. Countershading could hence contribute to visual camouflage by increasing background matching or reducing cues to shape. However, the usefulness of countershading is constrained by a particular pattern delivering 'optimal' camouflage only for very specific lighting conditions. In this study, we test the robustness of countershading camouflage to lighting change due to weather, using human participants as a 'generic' predator. In a simulated three-dimensional environment, we constructed an array of simple leaf-shaped items and a single ellipsoidal target 'prey'. We set these items in two light environments: strongly directional 'sunny' and more diffuse 'cloudy'. The target object was given the optimal pattern of countershading for one of these two environment types or displayed a uniform pattern. By measuring detection time and accuracy, we explored whether and how target detection depended on the match between the pattern of coloration on the target object and scene lighting. Detection times were longest when the countershading was appropriate to the illumination; incorrectly camouflaged targets were detected with a similar pattern of speed and accuracy to uniformly coloured targets. We conclude that structural changes in light environment, such as caused by differences in weather, do change the effectiveness of countershading camouflage.
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Affiliation(s)
- Olivier Penacchio
- School of Psychology and Neuroscience, University of St Andrews, St Andrews, Fife KY16 9JP, UK
| | - P. George Lovell
- Division of Psychology, Social and Health Sciences, Abertay University, Dundee DD1 1HG, UK
| | - Julie M. Harris
- School of Psychology and Neuroscience, University of St Andrews, St Andrews, Fife KY16 9JP, UK
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Wang LY, Huang WS, Tang HC, Huang LC, Lin CP. Too hard to swallow: a secret secondary defence of an aposematic insect. ACTA ACUST UNITED AC 2018; 221:jeb.172486. [PMID: 29180599 DOI: 10.1242/jeb.172486] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2017] [Accepted: 11/20/2017] [Indexed: 01/03/2023]
Abstract
Anti-predator strategies are significant components of adaptation in prey species. Aposematic prey are expected to possess effective defences that have evolved simultaneously with their warning colours. This study tested the hypothesis of the defensive function and ecological significance of the hard body in aposematic Pachyrhynchus weevils pioneered by Alfred Russel Wallace nearly 150 years ago. We used predation trials with Japalura tree lizards to assess the survivorship of 'hard' (mature) versus 'soft' (teneral) and 'clawed' (intact) versus 'clawless' (surgically removed) weevils. The ecological significance of the weevil's hard body was evaluated by assessing the hardness of the weevils, the local prey insects, and the bite forces of the lizard populations. The existence of toxins or deterrents in the weevil was examined by gas chromatography-mass spectrometry (GC-MS). All 'hard' weevils were instantly spat out after being bitten once and survived attacks by the lizards. In contrast, the 'soft' weevils were chewed and subsequently swallowed. The results were the same regardless of the presence or absence of the weevil's tarsal claws. The hardness of 'hard' Pachyrhynchus weevils was significantly higher than the average hardness of other prey insects in the same habitat and the mean bite forces of the local lizards. The four candidate compounds of the weevil identified by GC-MS had no known toxic or repellent functions against vertebrates. These results reveal that the hardness of aposematic prey functions as an effective secondary defence, and they provide a framework for understanding the spatio-temporal interactions between vertebrate predators and aposematic insect prey.
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Affiliation(s)
- Lu-Yi Wang
- Department of Life Science, National Taiwan Normal University, Taipei 11677, Taiwan
| | - Wen-San Huang
- Department of Biology, National Museum of Natural Science, Taichung 40453, Taiwan
| | - Hsin-Chieh Tang
- Department of Conservation and Research Center, Taipei Zoo, Taipei 11656, Taiwan
| | - Lung-Chun Huang
- Department of Conservation and Research Center, Taipei Zoo, Taipei 11656, Taiwan
| | - Chung-Ping Lin
- Department of Life Science, National Taiwan Normal University, Taipei 11677, Taiwan .,Laboratory of Forest Ecology, Graduate School of Agriculture, Kyoto University, Kyoto 606-8502, Japan
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Roland AB, Santos JC, Carriker BC, Caty SN, Tapia EE, Coloma LA, O'Connell LA. Radiation of the polymorphic Little Devil poison frog ( Oophaga sylvatica) in Ecuador. Ecol Evol 2017; 7:9750-9762. [PMID: 29188006 PMCID: PMC5696431 DOI: 10.1002/ece3.3503] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2017] [Revised: 09/03/2017] [Accepted: 09/13/2017] [Indexed: 01/16/2023] Open
Abstract
Some South American poison frogs (Dendrobatidae) are chemically defended and use bright aposematic colors to warn potential predators of their unpalatability. Aposematic signals are often frequency-dependent where individuals deviating from a local model are at a higher risk of predation. However, extreme diversity in the aposematic signal has been documented in poison frogs, especially in Oophaga. Here, we explore the phylogeographic pattern among color-divergent populations of the Little Devil poison frog Oophaga sylvatica by analyzing population structure and genetic differentiation to evaluate which processes could account for color diversity within and among populations. With a combination of PCR amplicons (three mitochondrial and three nuclear markers) and genome-wide markers from a double-digested RAD (ddRAD) approach, we characterized the phylogenetic and genetic structure of 199 individuals from 13 populations (12 monomorphic and 1 polymorphic) across the O. sylvatica distribution. Individuals segregated into two main lineages by their northern or southern latitudinal distribution. A high level of genetic and phenotypic polymorphism within the northern lineage suggests ongoing gene flow. In contrast, low levels of genetic differentiation were detected among the southern lineage populations and support recent range expansions from populations in the northern lineage. We propose that a combination of climatic gradients and structured landscapes might be promoting gene flow and phylogenetic diversification. Alternatively, we cannot rule out that the observed phenotypic and genomic variations are the result of genetic drift on near or neutral alleles in a small number of genes.
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Affiliation(s)
| | - Juan C. Santos
- Department of Biological SciencesSt. John's UniversityQueensNYUSA
| | | | | | - Elicio E. Tapia
- Centro Jambatu de Investigación y Conservación de AnfibiosFundación OtongaQuitoEcuador
| | - Luis A. Coloma
- Centro Jambatu de Investigación y Conservación de AnfibiosFundación OtongaQuitoEcuador
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Penacchio O, Harris JM, Lovell PG. Establishing the behavioural limits for countershaded camouflage. Sci Rep 2017; 7:13672. [PMID: 29057907 PMCID: PMC5651847 DOI: 10.1038/s41598-017-13914-y] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2017] [Accepted: 09/20/2017] [Indexed: 11/09/2022] Open
Abstract
Countershading is a ubiquitous patterning of animals whereby the side that typically faces the highest illumination is darker. When tuned to specific lighting conditions and body orientation with respect to the light field, countershading minimizes the gradient of light the body reflects by counterbalancing shadowing due to illumination, and has therefore classically been thought of as an adaptation for visual camouflage. However, whether and how crypsis degrades when body orientation with respect to the light field is non-optimal has never been studied. We tested the behavioural limits on body orientation for countershading to deliver effective visual camouflage. We asked human participants to detect a countershaded target in a simulated three-dimensional environment. The target was optimally coloured for crypsis in a reference orientation and was displayed at different orientations. Search performance dramatically improved for deviations beyond 15 degrees. Detection time was significantly shorter and accuracy significantly higher than when the target orientation matched the countershading pattern. This work demonstrates the importance of maintaining body orientation appropriate for the displayed camouflage pattern, suggesting a possible selective pressure for animals to orient themselves appropriately to enhance crypsis.
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Affiliation(s)
- Olivier Penacchio
- School of Psychology and Neuroscience, University of St. Andrews, St. Andrews, Fife KY16 9JP, UK.
| | - Julie M Harris
- School of Psychology and Neuroscience, University of St. Andrews, St. Andrews, Fife KY16 9JP, UK
| | - P George Lovell
- Division of Psychology, Social and Health Sciences, Abertay University, Dundee, DD1 1HG, UK
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Cuthill IC, Allen WL, Arbuckle K, Caspers B, Chaplin G, Hauber ME, Hill GE, Jablonski NG, Jiggins CD, Kelber A, Mappes J, Marshall J, Merrill R, Osorio D, Prum R, Roberts NW, Roulin A, Rowland HM, Sherratt TN, Skelhorn J, Speed MP, Stevens M, Stoddard MC, Stuart-Fox D, Talas L, Tibbetts E, Caro T. The biology of color. Science 2017; 357:357/6350/eaan0221. [DOI: 10.1126/science.aan0221] [Citation(s) in RCA: 353] [Impact Index Per Article: 50.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
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