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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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Paris JR, Whiting JR, Daniel MJ, Ferrer Obiol J, Parsons PJ, van der Zee MJ, Wheat CW, Hughes KA, Fraser BA. A large and diverse autosomal haplotype is associated with sex-linked colour polymorphism in the guppy. Nat Commun 2022; 13:1233. [PMID: 35264556 PMCID: PMC8907176 DOI: 10.1038/s41467-022-28895-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2021] [Accepted: 02/16/2022] [Indexed: 11/22/2022] Open
Abstract
Male colour patterns of the Trinidadian guppy (Poecilia reticulata) are typified by extreme variation governed by both natural and sexual selection. Since guppy colour patterns are often inherited faithfully from fathers to sons, it has been hypothesised that many of the colour trait genes must be physically linked to sex determining loci as a ‘supergene’ on the sex chromosome. Here, we phenotype and genotype four guppy ‘Iso-Y lines’, where colour was inherited along the patriline for 40 generations. Using an unbiased phenotyping method, we confirm the breeding design was successful in creating four distinct colour patterns. We find that genetic differentiation among the Iso-Y lines is repeatedly associated with a diverse haplotype on an autosome (LG1), not the sex chromosome (LG12). Moreover, the LG1 haplotype exhibits elevated linkage disequilibrium and evidence of sex-specific diversity in the natural source population. We hypothesise that colour pattern polymorphism is driven by Y-autosome epistasis. Extreme colour pattern variation in male Trinidadian guppies are influenced by natural selection and sexual selection. Here, the authors phenotype and genotype four guppy lineages finding that colour pattern is associated with a diverse haplotype on an autosome.
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Affiliation(s)
- Josephine R Paris
- Department of Biosciences, University of Exeter, Stocker Road, Exeter, EX4 4QD, UK.
| | - James R Whiting
- Department of Biosciences, University of Exeter, Stocker Road, Exeter, EX4 4QD, UK
| | - Mitchel J Daniel
- Department of Biological Science, Florida State University, 319 Stadium Drive, Tallahassee, FL, 32304, USA
| | - Joan Ferrer Obiol
- Departament de Microbiologia, Genètica i Estadística and Institut de Recerca de la Biodiversitat, Universitat de Barcelona, Barcelona, Catalonia, Spain
| | - Paul J Parsons
- Department of Biosciences, University of Exeter, Stocker Road, Exeter, EX4 4QD, UK.,NERC Environmental Omics Facility, School of Biosciences, University of Sheffield, Sheffield, S10 2TN, UK
| | - Mijke J van der Zee
- Department of Biosciences, University of Exeter, Stocker Road, Exeter, EX4 4QD, UK
| | | | - Kimberly A Hughes
- Department of Biological Science, Florida State University, 319 Stadium Drive, Tallahassee, FL, 32304, USA
| | - Bonnie A Fraser
- Department of Biosciences, University of Exeter, Stocker Road, Exeter, EX4 4QD, UK
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Fuller RC. Revisiting old truths: The evolution of male coloration in guppies as a function of predation. Mol Ecol 2022; 31:1333-1336. [PMID: 35100465 DOI: 10.1111/mec.16376] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2021] [Revised: 01/11/2022] [Accepted: 01/24/2022] [Indexed: 11/27/2022]
Abstract
The Trinidadian guppy, Poecilia reticulata, is a long-studied model for the evolution of trade-offs in male nuptial coloration as a function of female mating preferences versus predation risk. Previous work suggests that female mating preferences favor the evolution of increased conspicuous male coloration in low predation populations. In contrast, high predation risk shifts the balance towards reduced conspicuous coloration. In a From the Cover article in this issue of Molecular Ecology, Yong, Croft, Troscianko, Ramnarine, and Wilson (2021) use visual detection models to estimate the 'conspicuousness' of male color patterns as seen by guppies and their predators. The study fails to find robust patterns of increased conspicuousness in low predation populations. Only one of eight measures of conspicuousness showed parallel changes between high and low predation regimes, forcing us to re-consider the validity and repeatability of this classic example of parallel evolution.
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Affiliation(s)
- Rebecca C Fuller
- Department of Evolution, Ecology, and Behavior, University of Illinois, Champaign, IL, 61820, USA
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