1
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van den Berg CP, Santon M, Endler JA, Cheney KL. Highly defended nudibranchs "escape" to visually distinct background habitats. Behav Ecol 2024; 35:arae053. [PMID: 39086666 PMCID: PMC11289952 DOI: 10.1093/beheco/arae053] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2023] [Revised: 06/06/2024] [Accepted: 07/03/2024] [Indexed: 08/02/2024] Open
Abstract
The "escape and radiate" hypothesis predicts that once species have evolved aposematism, defended species can utilize more visually diverse visual backgrounds as they "escape" the need to be well camouflaged. This enables species to explore new ecological niches, resulting in increased diversification rates. To test this hypothesis "escape" component, we examined whether the background habitats of 12 nudibranch mollusk species differed among species depending on the presence and strength of chemical defenses. We obtained a rich array of color pattern statistics using quantitative color pattern analysis to analyze backgrounds viewed through the eyes of a potential predator (triggerfish, Rhinecanthus aculeatus). Color pattern analysis was done at viewing distances simulating an escalating predation sequence. We identified 4 latent factors comprising 17 noncorrelated color pattern parameters, which captured the among-species variability associated with differences in chemical defenses. We found that chemically defended species, indeed, were found on visually distinct backgrounds with increased color and luminance contrast, independent of viewing distance. However, we found no evidence for increased among-species background diversity coinciding with the presence and strength of chemical defenses. Our results agree with the "escape and radiate" hypothesis, suggesting that potent chemical defenses in Dorid nudibranchs coincide with spatiochromatic differences of visual background habitats perceived by potential predators.
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Affiliation(s)
- Cedric P van den Berg
- School of the Environment, The University of Queensland, University Drive, St. Lucia, QLD 4072, Australia
- School of Biological Sciences, University of Bristol, 24 Tyndall Ave, Bristol, BS8 1TQ, United Kingdom
| | - Matteo Santon
- School of Biological Sciences, University of Bristol, 24 Tyndall Ave, Bristol, BS8 1TQ, United Kingdom
| | - John A Endler
- School of Life and Environmental Sciences, Deakin University, Waurn Ponds, VIC 3216, Australia
| | - Karen L Cheney
- School of the Environment, The University of Queensland, University Drive, St. Lucia, QLD 4072, Australia
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2
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van den Berg CP, Santon M, Endler JA, Drummond L, Dawson BR, Santiago C, Weber N, Cheney KL. Chemical defences indicate bold colour patterns with reduced variability in aposematic nudibranchs. Proc Biol Sci 2024; 291:20240953. [PMID: 39013421 PMCID: PMC11251778 DOI: 10.1098/rspb.2024.0953] [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: 12/12/2023] [Revised: 05/31/2024] [Accepted: 05/31/2024] [Indexed: 07/18/2024] Open
Abstract
The selective factors that shape phenotypic diversity in prey communities with aposematic animals are diverse and coincide with similar diversity in the strength of underlying secondary defences. However, quantitative assessments of colour pattern variation and the strength of chemical defences in assemblages of aposematic species are lacking. We quantified colour pattern diversity using quantitative colour pattern analysis (QCPA) in 13 dorid nudibranch species (Infraorder: Doridoidei) that varied in the strength of their chemical defences. We accounted for the physiological properties of a potential predator's visual system (a triggerfish, Rhinecanthus aculeatus) and modelled the appearance of nudibranchs from multiple viewing distances (2 and 10 cm). We identified distinct colour pattern properties associated with the presence and strength of chemical defences. Specifically, increases in chemical defences indicated increases in colour pattern boldness (i.e. visual contrast elicited via either or potentially coinciding chromatic, achromatic and/or spatial contrast). Colour patterns were also less variable among species with chemical defences when compared to undefended species. Our results indicate correlations between secondary defences and diverse, bold colouration while showing that chemical defences coincide with decreased colour pattern variability among species. Our study suggests that complex spatiochromatic properties of colour patterns perceived by potential predators can be used to make inferences on the presence and strength of chemical defences.
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Affiliation(s)
- Cedric P. van den Berg
- Marine Sensory Ecology Group, School of the Environment, The University of Queensland, Brisbane4072, Australia
- Ecology of Vision Laboratory, School of Biological Sciences, University of Bristol, BristolBS8 1TQ, UK
| | - Matteo Santon
- Ecology of Vision Laboratory, School of Biological Sciences, University of Bristol, BristolBS8 1TQ, UK
| | - John A. Endler
- Zoology and Ecology, Tropical Environments Sciences, College of Science & Engineering, James Cook University, Cairns, QLD4878, Australia
| | - Leon Drummond
- Marine Sensory Ecology Group, School of the Environment, The University of Queensland, Brisbane4072, Australia
| | - Bethany R. Dawson
- Marine Sensory Ecology Group, School of the Environment, The University of Queensland, Brisbane4072, Australia
| | - Carl Santiago
- Marine Sensory Ecology Group, School of the Environment, The University of Queensland, Brisbane4072, Australia
| | - Nathalie Weber
- Faculty of Biology and Medicine, School of Biological Sciences, The University of Lausanne, Lausanne1015, Switzerland
| | - Karen L. Cheney
- Marine Sensory Ecology Group, School of the Environment, The University of Queensland, Brisbane4072, Australia
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3
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Ahmad N, Singh S, AlAjmi MF, Hussain A, Raza K. CropGCNN: color space-based crop disease classification using group convolutional neural network. PeerJ Comput Sci 2024; 10:e2136. [PMID: 39145206 PMCID: PMC11322995 DOI: 10.7717/peerj-cs.2136] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2024] [Accepted: 05/28/2024] [Indexed: 08/16/2024]
Abstract
Classifying images is one of the most important tasks in computer vision. Recently, the best performance for image classification tasks has been shown by networks that are both deep and well-connected. These days, most datasets are made up of a fixed number of color images. The input images are taken in red green blue (RGB) format and classified without any changes being made to the original. It is observed that color spaces (basically changing original RGB images) have a major impact on classification accuracy, and we delve into the significance of color spaces. Moreover, datasets with a highly variable number of classes, such as the PlantVillage dataset utilizing a model that incorporates numerous color spaces inside the same model, achieve great levels of accuracy, and different classes of images are better represented in different color spaces. Furthermore, we demonstrate that this type of model, in which the input is preprocessed into many color spaces simultaneously, requires significantly fewer parameters to achieve high accuracy for classification. The proposed model basically takes an RGB image as input, turns it into seven separate color spaces at once, and then feeds each of those color spaces into its own Convolutional Neural Network (CNN) model. To lessen the load on the computer and the number of hyperparameters needed, we employ group convolutional layers in the proposed CNN model. We achieve substantial gains over the present state-of-the-art methods for the classification of crop disease.
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Affiliation(s)
- Naeem Ahmad
- Department of Computer Applications, National Institute of Technology Raipur (NITR), Raipur, India
| | - Shubham Singh
- Department of Computer Applications, National Institute of Technology Raipur (NITR), Raipur, India
| | - Mohamed Fahad AlAjmi
- Department of Pharmacognosy, College of Pharmacy, King Saud University, Riyadh, Saudi Arabia
| | - Afzal Hussain
- Department of Pharmacognosy, College of Pharmacy, King Saud University, Riyadh, Saudi Arabia
| | - Khalid Raza
- Department of Computer Science, Jamia Millia Islamia, New Delhi, India
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4
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Crowell HL, Curlis JD, Weller HI, Davis Rabosky AR. Ecological drivers of ultraviolet colour evolution in snakes. Nat Commun 2024; 15:5213. [PMID: 38890335 PMCID: PMC11189474 DOI: 10.1038/s41467-024-49506-4] [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: 06/15/2023] [Accepted: 06/05/2024] [Indexed: 06/20/2024] Open
Abstract
Ultraviolet (UV) colour patterns invisible to humans are widespread in nature. However, research bias favouring species with conspicuous colours under sexual selection can limit our assessment of other ecological drivers of UV colour, like interactions between predators and prey. Here we demonstrate widespread UV colouration across Western Hemisphere snakes and find stronger support for a predator defence function than for reproduction. We find that UV colouration has evolved repeatedly in species with ecologies most sensitive to bird predation, with no sexual dichromatism at any life stage. By modelling visual systems of potential predators, we find that snake conspicuousness correlates with UV colouration and predator cone number, providing a plausible mechanism for selection. Our results suggest that UV reflectance should not be assumed absent in "cryptically coloured" animals, as signalling beyond human visual capacities may be a key outcome of species interactions in many taxa for which UV colour is likely underreported.
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Affiliation(s)
- Hayley L Crowell
- Department of Ecology and Evolutionary Biology and Museum of Zoology (UMMZ), University of Michigan, Ann Arbor, MI, 48109, USA
| | - John David Curlis
- Department of Ecology and Evolutionary Biology and Museum of Zoology (UMMZ), University of Michigan, Ann Arbor, MI, 48109, USA
| | - Hannah I Weller
- Department of Ecology, Evolution and Organismal Biology, Brown University, Providence, RI, 02912, USA
- Helsinki Institute of Life Sciences, University of Helsinki, Helsinki, Uusimaa, 00790, Finland
| | - Alison R Davis Rabosky
- Department of Ecology and Evolutionary Biology and Museum of Zoology (UMMZ), University of Michigan, Ann Arbor, MI, 48109, USA.
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5
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Briolat ES, Hancock GRA, Troscianko J. Adapting genetic algorithms for artificial evolution of visual patterns under selection from wild predators. PLoS One 2024; 19:e0295106. [PMID: 38753609 PMCID: PMC11098352 DOI: 10.1371/journal.pone.0295106] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2023] [Accepted: 04/26/2024] [Indexed: 05/18/2024] Open
Abstract
Camouflage is a widespread and well-studied anti-predator strategy, yet identifying which patterns provide optimal protection in any given scenario remains challenging. Besides the virtually limitless combinations of colours and patterns available to prey, selection for camouflage strategies will depend on complex interactions between prey appearance, background properties and predator traits, across repeated encounters between co-evolving predators and prey. Experiments in artificial evolution, pairing psychophysics detection tasks with genetic algorithms, offer a promising way to tackle this complexity, but sophisticated genetic algorithms have so far been restricted to screen-based experiments. Here, we present methods to test the evolution of colour patterns on physical prey items, under selection from wild predators in the field. Our techniques expand on a recently-developed open-access pattern generation and genetic algorithm framework, modified to operate alongside artificial predation experiments. In this system, predators freely interact with prey, and the order of attack determines the survival and reproduction of prey patterns into future generations. We demonstrate the feasibility of these methods with a case study, in which free-flying birds feed on artificial prey deployed in semi-natural conditions, against backgrounds differing in three-dimensional complexity. Wild predators reliably participated in this experiment, foraging for 11 to 16 generations of artificial prey and encountering a total of 1,296 evolved prey items. Changes in prey pattern across generations indicated improvements in several metrics of similarity to the background, and greater edge disruption, although effect sizes were relatively small. Computer-based replicates of these trials, with human volunteers, highlighted the importance of starting population parameters for subsequent evolution, a key consideration when applying these methods. Ultimately, these methods provide pathways for integrating complex genetic algorithms into more naturalistic predation trials. Customisable open-access tools should facilitate application of these tools to investigate a wide range of visual pattern types in more ecologically-relevant contexts.
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Affiliation(s)
- Emmanuelle S. Briolat
- Faculty of Environment, Centre for Ecology and Conservation, Science and Economy, University of Exeter, Penryn, Cornwall, United Kingdom
| | - George R. A. Hancock
- Faculty of Environment, Centre for Ecology and Conservation, Science and Economy, University of Exeter, Penryn, Cornwall, United Kingdom
- Faculty of Biological and Environmental Sciences, University of Helsinki, Helsinki, Finland
| | - Jolyon Troscianko
- Faculty of Environment, Centre for Ecology and Conservation, Science and Economy, University of Exeter, Penryn, Cornwall, United Kingdom
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6
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Peng F, Sun X, van Vloten C, Correll J, Langdon M, Ngochanthra W, Johnson K, Amador Kane S. Hybrid Mimulus flowers attract a new pollinator. THE NEW PHYTOLOGIST 2024; 242:1324-1332. [PMID: 38482697 DOI: 10.1111/nph.19668] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/03/2023] [Accepted: 02/23/2024] [Indexed: 04/12/2024]
Abstract
Hybridization is common in flowering plants and is believed to be an important force driving adaptation and speciation. The flowers of hybrids often exhibit new trait combinations, which, theoretically, could attract new species of pollinators. In this study, we found that the hybrids between a hummingbird-pollinated species Mimulus cardinalis and a self-pollinated species Mimulus parishii attract bumblebees (Bombus impatiens), a pollinator not attracted to either of the progenitor species. This novel attraction is explained by new combinations of floral traits in hybrids, including, most importantly, petal color, in addition to nectar concentration and corolla size. To understand how petal color variation is perceived by bumblebees, we performed reflectance spectroscopy and multispectral imaging to model the flower appearance in bee vision. This analysis showed that color variation would impact the ease of detection. We also found that YUP, the genetic locus responsible for a large portion of floral color variation and previously shown to be important in bee interactions with other Mimulus species, also played an important role in this novel attraction. These results together suggest that the attraction of new pollinators to hybrid plants could be an underexplored avenue for pollinator shift and speciation.
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Affiliation(s)
- Foen Peng
- Department of Biology, Haverford College, Haverford, PA, 19041, USA
| | - Xiaohe Sun
- Department of Biology, Haverford College, Haverford, PA, 19041, USA
| | | | - Jude Correll
- Department of Biology, Haverford College, Haverford, PA, 19041, USA
| | - Marlena Langdon
- Department of Biology, Haverford College, Haverford, PA, 19041, USA
| | | | - Karl Johnson
- Department of Biology, Haverford College, Haverford, PA, 19041, USA
| | - Suzanne Amador Kane
- Department of Physics and Astronomy, Haverford College, Haverford, PA, 19041, USA
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7
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van den Berg CP, Condon ND, Conradsen C, White TE, Cheney KL. Automated workflows using Quantitative Colour Pattern Analysis (QCPA): a guide to batch processing and downstream data analysis. Evol Ecol 2024; 38:387-397. [PMID: 38946730 PMCID: PMC11208187 DOI: 10.1007/s10682-024-10291-7] [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: 11/16/2023] [Accepted: 02/05/2024] [Indexed: 07/02/2024]
Abstract
Animal and plant colouration presents a striking dimension of phenotypic variation, the study of which has driven general advances in ecology, evolution, and animal behaviour. Quantitative Colour Pattern Analysis (QCPA) is a dynamic framework for analysing colour patterns through the eyes of non-human observers. However, its extensive array of user-defined image processing and analysis tools means image analysis is often time-consuming. This hinders the full use of analytical power provided by QCPA and its application to large datasets. Here, we offer a robust and comprehensive batch script, allowing users to automate many QCPA workflows. We also provide a complimentary set of useful R scripts for downstream data extraction and analysis. The presented batch processing extension will empower users to further utilise the analytical power of QCPA and facilitate the development of customised semi-automated workflows. Such quantitatively scaled workflows are crucial for exploring colour pattern spaces and developing ever-richer frameworks for analysing organismal colouration accounting for visual perception in animals other than humans. These advances will, in turn, facilitate testing hypotheses on the function and evolution of vision and signals at quantitative and qualitative scales, which are otherwise computationally unfeasible. Supplementary Information The online version contains supplementary material available at 10.1007/s10682-024-10291-7.
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Affiliation(s)
- Cedric P. van den Berg
- School of the Environment, The University of Queensland, Brisbane, QLD 4072 Australia
- School of Life and Environmental Sciences, The University of Sydney, Sydney, NSW 2050 Australia
- School of Biological Sciences, University of Bristol, Bristol, BS8 1TQ UK
| | - Nicholas D. Condon
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, QLD 4072 Australia
| | - Cara Conradsen
- School of the Environment, The University of Queensland, Brisbane, QLD 4072 Australia
| | - Thomas E. White
- School of Life and Environmental Sciences, The University of Sydney, Sydney, NSW 2050 Australia
| | - Karen L. Cheney
- School of the Environment, The University of Queensland, Brisbane, QLD 4072 Australia
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8
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John L, Santon M, Michiels NK. Scorpionfish adjust skin pattern contrast on different backgrounds. Ecol Evol 2024; 14:e11124. [PMID: 38476704 PMCID: PMC10928359 DOI: 10.1002/ece3.11124] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2023] [Revised: 02/06/2024] [Accepted: 02/23/2024] [Indexed: 03/14/2024] Open
Abstract
The two scorpionfish species Scorpaena maderensis and S. porcus are well camouflaged ambush predators that rapidly change body colouration to adjust to background colour in less than 1 min. We tested whether individuals of both species also adjust body pattern to that of the background. We placed fish on backgrounds of different pattern granularity and quantified the change in fish body pattern over 1 min. We used calibrated image analysis to analyse the patterns from the visual perspective of a prey fish species using a granularity (pattern energy) analysis and an image clustering approach. In our experiment, fish did not change their most contrasting pattern components as defined by the dominant marking size, but changed their average marking size. Moreover, fish responded with a change in pattern in contrast to the different experimental backgrounds, especially when compared to the acclimation phase. These results indicate that scorpionfish have one main pattern that can be adjusted by modulating its internal contrast. A reduction in pattern contrast could thereby improve background matching, while an increase could promote camouflage via disruptive colouration.
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Affiliation(s)
- Leonie John
- Animal Evolutionary EcologyInstitute of Evolution and Ecology, University of TübingenTübingenGermany
| | - Matteo Santon
- Ecology of Vision Group, School of Biological SciencesUniversity of BristolBristolUK
| | - Nico K. Michiels
- Animal Evolutionary EcologyInstitute of Evolution and Ecology, University of TübingenTübingenGermany
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9
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Li Z, Wang L, Liu X, Li J, Yun HS, Wang Z, Zhang X, Wong TS, Shen S. Brochosome-inspired binary metastructures for pixel-by-pixel thermal signature control. SCIENCE ADVANCES 2024; 10:eadl4027. [PMID: 38427742 PMCID: PMC11094652 DOI: 10.1126/sciadv.adl4027] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/16/2023] [Accepted: 01/26/2024] [Indexed: 03/03/2024]
Abstract
Microscale thermal signature control using incoherent heat sources remains challenging, despite recent advancements in plasmonic materials and phase-change materials. Inspired by leafhopper-generated brochosomes, we design binary metastructures functioning as pixel twins to achieve pixelated thermal signature control at the microscale. In the infrared range, the pixel twins exhibit distinct emissivities, creating thermal counterparts of "0-1" binary states for storing and displaying information. In the visible range, the engineered surface morphology of the pixel twins ensures similar scattering behaviors. This renders them visually indistinguishable, thereby concealing the stored information. The brochosome-like pixel twins are self-emitting when thermally excited. Their structure-enabled functions do not rely on the permittivities of specific materials, which distinguishes them from the conventional laser-illuminated plasmonic holographic metasurfaces. The unique combination of visible camouflage and infrared display offers a systemic solution to microscale spatial control of thermal signatures and has substantial implications for optical security, anticounterfeiting, and data encryption.
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Affiliation(s)
- Zhuo Li
- Department of Mechanical Engineering, Carnegie Mellon University, Pittsburgh, PA 15213, USA
| | - Lin Wang
- Department of Mechanical Engineering, The Pennsylvania State University, University Park, PA 16802, USA
- Materials Research Institute, The Pennsylvania State University, University Park, PA 16802, USA
| | - Xiu Liu
- Department of Mechanical Engineering, Carnegie Mellon University, Pittsburgh, PA 15213, USA
| | - Jiayu Li
- Department of Mechanical Engineering, Carnegie Mellon University, Pittsburgh, PA 15213, USA
| | - Hyeong Seok Yun
- Department of Mechanical Engineering, Carnegie Mellon University, Pittsburgh, PA 15213, USA
| | - Zexiao Wang
- Department of Mechanical Engineering, Carnegie Mellon University, Pittsburgh, PA 15213, USA
| | - Xu Zhang
- Department of Electrical and Computer Engineering, Carnegie Mellon University, Pittsburgh, PA 15213, USA
| | - Tak-Sing Wong
- Department of Mechanical Engineering, The Pennsylvania State University, University Park, PA 16802, USA
- Materials Research Institute, The Pennsylvania State University, University Park, PA 16802, USA
- Department of Biomedical Engineering, The Pennsylvania State University, University Park, PA 16802, USA
| | - Sheng Shen
- Department of Mechanical Engineering, Carnegie Mellon University, Pittsburgh, PA 15213, USA
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10
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Caves EM, Davis AL, Nowicki S, Johnsen S. Backgrounds and the evolution of visual signals. Trends Ecol Evol 2024; 39:188-198. [PMID: 37802667 DOI: 10.1016/j.tree.2023.09.006] [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: 05/10/2023] [Revised: 09/04/2023] [Accepted: 09/08/2023] [Indexed: 10/08/2023]
Abstract
Color signals which mediate behavioral interactions across taxa and contexts are often thought of as color 'patches' - parts of an animal that appear colorful compared to other parts of that animal. Color patches, however, cannot be considered in isolation because how a color is perceived depends on its visual background. This is of special relevance to the function and evolution of signals because backgrounds give rise to a fundamental tradeoff between color signal detectability and discriminability: as its contrast with the background increases, a color patch becomes more detectable, but discriminating variation in that color becomes more difficult. Thus, the signal function of color patches can only be fully understood by considering patch and background together as an integrated whole.
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Affiliation(s)
- Eleanor M Caves
- Department of Ecology, Evolution, and Marine Biology, University of California Santa Barbara, Santa Barbara, CA 93106, USA.
| | | | - Stephen Nowicki
- Department of Biology, Duke University, Durham, NC, 27708, USA
| | - Sönke Johnsen
- Department of Biology, Duke University, Durham, NC, 27708, USA
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11
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Carlson ML, Stoddard MC. Evolution of Plumage Patterns in a Pattern Morphospace: A Phylogenetic Analysis of Melanerpine Woodpeckers. Am Nat 2024; 203:55-72. [PMID: 38207134 DOI: 10.1086/727508] [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] [Indexed: 01/13/2024]
Abstract
AbstractPlumage patterns of melanerpine (Melanerpes-Sphyrapicus) woodpeckers are strikingly diverse. Understanding the evolution and function of this diversity is challenging because of the difficulty of quantifying plumage patterns. We use a three-dimensional space to characterize the evolution of melanerpine achromatic plumage patterns. The axes of the space are three pattern features (spatial frequency, orientation, and contrast) quantified using two-dimensional fast Fourier transformation of museum specimen images. Mapping plumage in pattern space reveals differences in how species and subclades occupy the space. To quantify these differences, we derive two new measures of pattern: pattern diversity (diversity across plumage patches within a species) and pattern uniqueness (divergence of patterns from those of other species). We estimate that the melanerpine ancestor had mottled plumage and find that pattern traits across patches and subclades evolve at different rates. We also find that smaller species are more likely to display horizontal face patterning. We promote pattern spaces as powerful tools for investigating animal pattern evolution.
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12
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Vasas V, Lowell MC, Villa J, Jamison QD, Siegle AG, Katta PKR, Bhagavathula P, Kevan PG, Fulton D, Losin N, Kepplinger D, Yetzbacher MK, Salehian S, Forkner RE, Hanley D. Recording animal-view videos of the natural world using a novel camera system and software package. PLoS Biol 2024; 22:e3002444. [PMID: 38261631 PMCID: PMC10805291 DOI: 10.1371/journal.pbio.3002444] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2022] [Accepted: 11/21/2023] [Indexed: 01/25/2024] Open
Abstract
Plants, animals, and fungi display a rich tapestry of colors. Animals, in particular, use colors in dynamic displays performed in spatially complex environments. Although current approaches for studying colors are objective and repeatable, they miss the temporal variation of color signals entirely. Here, we introduce hardware and software that provide ecologists and filmmakers the ability to accurately record animal-perceived colors in motion. Specifically, our Python codes transform photos or videos into perceivable units (quantum catches) for animals of known photoreceptor sensitivity. The plans and codes necessary for end-users to capture animal-view videos are all open source and publicly available to encourage continual community development. The camera system and the associated software package will allow ecologists to investigate how animals use colors in dynamic behavioral displays, the ways natural illumination alters perceived colors, and other questions that remained unaddressed until now due to a lack of suitable tools. Finally, it provides scientists and filmmakers with a new, empirically grounded approach for depicting the perceptual worlds of nonhuman animals.
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Affiliation(s)
- Vera Vasas
- School of Biological and Behavioural Sciences, Queen Mary University of London, London, United Kingdom
| | - Mark C. Lowell
- Theorem Engine, Alexandria, Virginia, United States of America
- Department of Biology, George Mason University, Fairfax, Virginia, United States of America
| | - Juliana Villa
- Department of Biology, George Mason University, Fairfax, Virginia, United States of America
| | - Quentin D. Jamison
- Department of Biology, George Mason University, Fairfax, Virginia, United States of America
| | - Anna G. Siegle
- Department of Biology, George Mason University, Fairfax, Virginia, United States of America
| | - Pavan Kumar Reddy Katta
- Department of Computer Science, George Mason University, Fairfax, Virginia, United States of America
| | - Pushyami Bhagavathula
- Department of Computer Science, George Mason University, Fairfax, Virginia, United States of America
| | - Peter G. Kevan
- School of Environmental Sciences, University of Guelph, Guelph, Canada
| | - Drew Fulton
- Drew Fulton Photography, Gainesville, Florida, United States of America
| | - Neil Losin
- Day’s Edge Productions, San Diego, California, United States of America
| | - David Kepplinger
- Department of Statistics, George Mason University, Fairfax, Virginia, United States of America
| | | | - Shakiba Salehian
- Department of Biology, George Mason University, Fairfax, Virginia, United States of America
| | - Rebecca E. Forkner
- Department of Biology, George Mason University, Fairfax, Virginia, United States of America
| | - Daniel Hanley
- Department of Biology, George Mason University, Fairfax, Virginia, United States of America
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13
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Anderson CM, Fink T, McKinnon JS. Ultrastructural analysis of throat dermal tissue and chromatophore components in the threespine stickleback ( Gasterosteus aculeatus). PeerJ 2023; 11:e16248. [PMID: 38077425 PMCID: PMC10704984 DOI: 10.7717/peerj.16248] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2022] [Accepted: 09/15/2023] [Indexed: 12/18/2023] Open
Abstract
The threespine stickleback (Gasterosteus aculeatus) is an important model for studying the evolution of nuptial coloration, but histological analyses of color are largely lacking. Previous analyses of one nuptial coloration trait, orange-red coloration along the body, have indicated carotenoids are the main pigment producing this color. In addition, recent gene expression studies found variation in the correlates of throat coloration between the sexes and between populations, raising the possibility of variation in the mechanisms underlying superficially similar coloration. We used transmission electron microscopy (TEM) to investigate the histological correlates of color in the throat dermal tissue of threespine stickleback from Western North America, within and between sexes, populations, and ecotypes. Ultrastructural analysis revealed carotenoid-containing erythrophores to be the main chromatophore component associated with orange-red coloration in both males and females across populations. In individuals where some darkening of the throat tissue was present, with no obvious orange-red coloration, erythrophores were not detected. Melanophore presence was more population-specific in expression, including being the only chromatophore component detected in a population of darker fish. We found no dermal chromatophore units within colorless throat tissue. This work confirms the importance of carotenoids and the erythrophore in producing orange-red coloration across sexes, as well as melanin within the melanophore in producing darkened coloration, but does not reveal broad histological differences among populations with similar coloration.
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Affiliation(s)
| | - Thomas Fink
- Department of Biology, East Carolina University, Greenville, NC, United States of America
| | - Jeffrey S. McKinnon
- Department of Biology, East Carolina University, Greenville, NC, United States of America
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14
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Muñoz-Amezcua CE, Tapia-McClung H, Rao D. When a glimpse is enough: Partial mimicry of jumping spiders by insects. Behav Processes 2023; 213:104956. [PMID: 37805082 DOI: 10.1016/j.beproc.2023.104956] [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: 05/30/2023] [Revised: 09/28/2023] [Accepted: 10/04/2023] [Indexed: 10/09/2023]
Abstract
Many flies and moths mimic the frontal appearance of jumping spiders. This type of mimicry, which we term as partial mimicry, can be distinguished from Batesian mimicry since the mimic has spider resembling patterns only in certain parts of the body, and not the entire body. The presence of spider-like patterns is obvious only at certain angles suggesting that the mimic is frequently targeted by its predators from particular angles. We tested this hypothesis using Deep Convolutional Neural Networks (DCNNs). First, we trained the network on images of forward facing jumping spiders, where features such as the large principal eyes, small lateral eyes and outstretched legs were evident. Then we tested the classifier on images of jumping spider mimicking flies and moths. A probability value according to the likelihood of the image being a jumping spider or not was assigned by the classifier. We show that the classifier was more likely to misidentify mimicking flies and moths as jumping spiders, but that this probability varied according to the species tested. We further tested it on images of flies from different angles and by taking into consideration the visual acuity of potential predators. Our results suggest that neural networks can be efficient tools for testing evolutionary hypotheses, and that partial mimicry may be a result of the effect of the signaling angle and orientation of the mimics in combination with the likelihood that predators may depend on cognitive shortcuts to identify insects as prey. Further experiments incorporating the properties of the visual system of predators (such as vision in ultraviolet) would result in a better understanding of the evolution of partial mimicry.
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Affiliation(s)
- Carlos E Muñoz-Amezcua
- Wolfram Alpha LLC, Champaign, IL, USA; Faculty of Biology and Psychology, University of Göttingen, Göttingen 37077, Germany
| | - Horacio Tapia-McClung
- Instituto de Investigaciones en Inteligencia Artificial, Universidad Veracruzana, Mexico
| | - Dinesh Rao
- Instituto de Biotecnologia y Ecologia Aplicada, Universidad Veracruzana, Mexico.
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15
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Arbon JJ, Hahn LG, McIvor GE, Thornton A. Competition and generalization impede cultural formation in wild jackdaws. Proc Biol Sci 2023; 290:20230705. [PMID: 37554031 PMCID: PMC10410225 DOI: 10.1098/rspb.2023.0705] [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: 03/24/2023] [Accepted: 07/14/2023] [Indexed: 08/10/2023] Open
Abstract
Animal cultures have now been demonstrated experimentally in diverse taxa from flies to great apes. However, experiments commonly use tasks with unrestricted access to equal pay-offs and innovations seeded by demonstrators who are trained to exhibit strong preferences. Such conditions may not reflect those typically found in nature. For example, the learned preferences of natural innovators may be weaker, while competition for depleting resources can favour switching between strategies and generalizing from past experience. Here we show that in experiments where wild jackdaws (Corvus monedula) can freely discover depleting supplies of novel foods, generalization has a powerful effect on learning, allowing individuals to exploit multiple new opportunities through both social and individual learning. Further, in contrast to studies with trained demonstrators, individuals that were first to innovate showed weak preferences. As a consequence, many individuals ate all available novel foods, displaying no strong preference and no group-level culture emerged. Individuals followed a 'learn from adults' strategy, but other demographic factors played a minimal role in shaping social transmission. These results demonstrate the importance of generalization in allowing animals to exploit new opportunities and highlight how natural competitive dynamics may impede the formation of culture.
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Affiliation(s)
- Josh J. Arbon
- Centre for Ecology and Conservation, University of Exeter, Treliever Road, Penryn, Cornwall, UK
- School of Biological Sciences, University of Bristol, Tyndall Avenue, Bristol, UK
| | - Luca G. Hahn
- Centre for Ecology and Conservation, University of Exeter, Treliever Road, Penryn, Cornwall, UK
| | - Guillam E. McIvor
- Centre for Ecology and Conservation, University of Exeter, Treliever Road, Penryn, Cornwall, UK
| | - Alex Thornton
- Centre for Ecology and Conservation, University of Exeter, Treliever Road, Penryn, Cornwall, UK
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16
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Barrone J, Vidal MC, Stevenson R. Sphingid caterpillars conspicuous patches do not function as distractive marks or warning against predators. Ecol Evol 2023; 13:e10334. [PMID: 37492454 PMCID: PMC10363802 DOI: 10.1002/ece3.10334] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2023] [Revised: 07/01/2023] [Accepted: 07/05/2023] [Indexed: 07/27/2023] Open
Abstract
To avoid predation by visual predators, caterpillars can be cryptic to decrease detectability or aposematic to warn predators of potential unpalatability. However, for some species, it is not clear if conspicuous patches are selected to avoid predation. For example, Pandora sphinx (Eumorpha pandorus, Lepidoptera: Sphingidae) caterpillars are assumed to be palatable and have both cryptic (green, brown) and conspicuous (orange, red) color morphs. Five lateral, off-white to yellow patches on either side may serve as a warning for predators or to draw attention away from the caterpillar's form to function as distractive marks. We conducted a field study in three temperate fragmented forests in Massachusetts to investigate the potential utility of E. pandorus coloration and conspicuous patches. Using four plasticine caterpillar prey model treatments, green and red with and without lateral conspicuous patches, we tested the effects of color, patch patterning, and seasonality on attack rates by a variety of taxa. We found that 43% of the prey models (n = 964) had bite marks by an array of predators including arthropods (67.5%), birds (18.2%), rodents (11.5%), and large mammals (2.8%). Arthropods as dominant predators align with conclusions from previous studies of prey models placed near ground level. Attack rates peaked for arthropods in late August and early September but were more constant across trials for vertebrates. Arthropods, a heterogeneous group, as indicated by the variety of bite marks, showed significantly higher attack rates on green colored prey models and a tendency of higher attack on solid (non-patch patterned) prey models. Vertebrates, more visually oriented predators, had significantly higher attack rates on red colored prey models and patch patterned prey models. Thus, our results did not suggest that conspicuous patch patterning reduced predation and therefore, we did not find support for the distractive mark hypothesis or warning hypothesis. Further, our study shows clear contrasting interpretations by different predators regarding visual defensive strategies.
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Affiliation(s)
- Julia Barrone
- Department of BiologyUniversity of Massachusetts BostonBostonMassachusettsUSA
| | - Mayra C. Vidal
- Department of BiologyUniversity of Massachusetts BostonBostonMassachusettsUSA
| | - Robert Stevenson
- Department of BiologyUniversity of Massachusetts BostonBostonMassachusettsUSA
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Troscianko J, Osorio D. A model of colour appearance based on efficient coding of natural images. PLoS Comput Biol 2023; 19:e1011117. [PMID: 37319266 DOI: 10.1371/journal.pcbi.1011117] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2022] [Accepted: 04/20/2023] [Indexed: 06/17/2023] Open
Abstract
An object's colour, brightness and pattern are all influenced by its surroundings, and a number of visual phenomena and "illusions" have been discovered that highlight these often dramatic effects. Explanations for these phenomena range from low-level neural mechanisms to high-level processes that incorporate contextual information or prior knowledge. Importantly, few of these phenomena can currently be accounted for in quantitative models of colour appearance. Here we ask to what extent colour appearance is predicted by a model based on the principle of coding efficiency. The model assumes that the image is encoded by noisy spatio-chromatic filters at one octave separations, which are either circularly symmetrical or oriented. Each spatial band's lower threshold is set by the contrast sensitivity function, and the dynamic range of the band is a fixed multiple of this threshold, above which the response saturates. Filter outputs are then reweighted to give equal power in each channel for natural images. We demonstrate that the model fits human behavioural performance in psychophysics experiments, and also primate retinal ganglion responses. Next, we systematically test the model's ability to qualitatively predict over 50 brightness and colour phenomena, with almost complete success. This implies that much of colour appearance is potentially attributable to simple mechanisms evolved for efficient coding of natural images, and is a well-founded basis for modelling the vision of humans and other animals.
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Affiliation(s)
- Jolyon Troscianko
- Centre for Ecology & Conservation, University of Exeter, Penryn, United Kingdom
| | - Daniel Osorio
- School of Life Sciences, University of Sussex, Brighton, United Kingdom
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18
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Yang C, Chen S, Wang J. Ontogenetic color change in the tail of blue-tailed skinks ( Plestodion elegans). Ecol Evol 2023; 13:e10152. [PMID: 37287854 PMCID: PMC10242887 DOI: 10.1002/ece3.10152] [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: 11/08/2022] [Revised: 05/14/2023] [Accepted: 05/22/2023] [Indexed: 06/09/2023] Open
Abstract
Ontogenetic color change in animals is an interesting evolution-related phenomenon that has been studied by evolutionary biologists for decades. However, obtaining quantitative and continuous color measurements throughout the life cycle of animals is a challenge. To understand the rhythm of change in tail color and sexual dichromatism, we used a spectrometer to measure the tail color of blue-tailed skink (Plestiodon elegans) from birth to sexual maturity. Lab color space was selected due to its simplicity, fastness, and accuracy and depends on the visual sense of the observer for measuring the tail color of skinks. A strong relationship was observed between color indexes (values of L*, a*, b*) and growth time of skink. The luminance of tail color decreased from juveniles to adults in both sexes. Moreover, we observed differences in color rhythms between the sexes, which may be influenced by different behavioral strategies used by them. This study provides continuous measurements of change in tail color in skinks from juveniles to adults and offers insights into their sex-based differences. While this study does not provide direct evidence to explain the potential factors that drive dichromatism between the sexes of lizards, our finding could serve as a reference for future studies exploring possible mechanisms of ontogenetic color change in reptiles.
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Affiliation(s)
- Chen Yang
- Sichuan Zoige Alpine Wetland Ecosystem National Observation and Research StationSouthwest Minzu UniversityChenghuChina
- Chengdu Institute of BiologyChinese Academy of SciencesChengduChina
| | - Siheng Chen
- School of Artificial IntelligenceBeijing University of Posts and TelecommunicationsBeijingChina
| | - Jie Wang
- Chengdu Institute of BiologyChinese Academy of SciencesChengduChina
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19
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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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20
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Wang C, Zhang R, Wei X, Wang L, Wu P, Yao Q. Deep learning and sub-band fluorescence imaging-based method for caries and calculus diagnosis embeddable on different smartphones. BIOMEDICAL OPTICS EXPRESS 2023; 14:866-882. [PMID: 36874478 PMCID: PMC9979668 DOI: 10.1364/boe.479818] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/04/2022] [Revised: 12/28/2022] [Accepted: 01/13/2023] [Indexed: 06/18/2023]
Abstract
Popularizing community and home early caries screening is essential for caries prevention and treatment. However, a high-precision, low-cost, and portable automated screening tool is currently lacking. This study constructed an automated diagnosis model for dental caries and calculus using fluorescence sub-band imaging combined with deep learning. The proposed method is divided into two stages: the first stage collects imaging information of dental caries in different fluorescence spectral bands and obtains six-channel fluorescence images. The second stage employs a 2-D-3-D hybrid convolutional neural network combined with the attention mechanism for classification and diagnosis. The experiments demonstrate that the method has competitive performance compared to existing methods. In addition, the feasibility of transferring this approach to different smartphones is discussed. This highly accurate, low-cost, portable method has potential applications in community and at-home caries detection.
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Affiliation(s)
- Cheng Wang
- Department of Optical Science and Engineering, Academy for Engineering and Technology, Fudan University, Shanghai 200433, China
- State Key Laboratory of Applied Optics, Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences, Changchun 130033, China
| | - Rongjun Zhang
- Department of Optical Science and Engineering, Academy for Engineering and Technology, Fudan University, Shanghai 200433, China
| | - Xiaoling Wei
- Department of Endodontics, Shanghai Stomatological Hospital, Shanghai Key Laboratory of Craniomaxillofacial Development and Diseases, Fudan University, Shanghai 200001, China
| | - Le Wang
- Department of Optical Science and Engineering, Academy for Engineering and Technology, Fudan University, Shanghai 200433, China
| | - Peiyu Wu
- Department of Optical Science and Engineering, Academy for Engineering and Technology, Fudan University, Shanghai 200433, China
- State Key Laboratory of Applied Optics, Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences, Changchun 130033, China
| | - Qi Yao
- Department of Optical Science and Engineering, Academy for Engineering and Technology, Fudan University, Shanghai 200433, China
- State Key Laboratory of Applied Optics, Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences, Changchun 130033, China
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21
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Mitchell LJ, Cortesi F, Marshall NJ, Cheney KL. Higher ultraviolet skin reflectance signals submissiveness in the anemonefish, Amphiprion akindynos. Behav Ecol 2023; 34:19-32. [PMID: 36789393 PMCID: PMC9918861 DOI: 10.1093/beheco/arac089] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2022] [Revised: 08/25/2022] [Accepted: 08/29/2022] [Indexed: 11/14/2022] Open
Abstract
Ultraviolet (UV) vision is widespread among teleost fishes, of which many exhibit UV skin colors for communication. However, aside from its role in mate selection, few studies have examined the information UV signaling conveys in other socio-behavioral contexts. Anemonefishes (subfamily, Amphiprioninae) live in a fascinating dominance hierarchy, in which a large female and male dominate over non-breeding subordinates, and body size is the primary cue for dominance. The iconic orange and white bars of anemonefishes are highly UV-reflective, and their color vision is well tuned to perceive the chromatic contrast of skin, which we show here decreases in the amount of UV reflectance with increasing social rank. To test the function of their UV-skin signals, we compared the outcomes of staged contests over dominance between size-matched Barrier Reef anemonefish (Amphiprion akindynos) in aquarium chambers viewed under different UV-absorbing filters. Fish under UV-blocking filters were more likely to win contests, where fish under no-filter or neutral-density filter were more likely to submit. For contests between fish in no-filter and neutral density filter treatments, light treatment had no effect on contest outcome (win/lose). We also show that sub-adults were more aggressive toward smaller juveniles placed under a UV filter than a neutral density filter. Taken together, our results show that UV reflectance or UV contrast in anemonefish can modulate aggression and encode dominant and submissive cues, when changes in overall intensity are controlled for.
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Affiliation(s)
- Laurie J Mitchell
- School of Biological Sciences, Faculty of Science, The University of Queensland, Brisbane, QLD 4072, Australia
- Queensland Brain Institute, The University of Queensland, Brisbane, QLD 4072, Australia
| | - Fabio Cortesi
- Queensland Brain Institute, The University of Queensland, Brisbane, QLD 4072, Australia
| | - N Justin Marshall
- Queensland Brain Institute, The University of Queensland, Brisbane, QLD 4072, Australia
| | - Karen L Cheney
- School of Biological Sciences, Faculty of Science, The University of Queensland, Brisbane, QLD 4072, Australia
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22
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Effects of anthropogenic noise on cognition, bill color, and growth in the zebra finch (Taeniopygia guttata). Acta Ethol 2022. [DOI: 10.1007/s10211-022-00406-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
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23
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Rao D, Long SM, Tapia-McClung H, Salgado-Espinosa K, Narendra A, Aguilar-Arguello S, Robledo-Ospina L, Rodriguez-Morales D, Jakob EM. Visual signals in the wing display of a tephritid fly deter jumping spider attacks. J Exp Biol 2022; 225:286139. [PMID: 36478243 DOI: 10.1242/jeb.244223] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2022] [Accepted: 11/28/2022] [Indexed: 12/14/2022]
Abstract
Visual animal communication, whether to the same or to other species, is largely conducted through dynamic and colourful signals. For a signal to be effective, the signaller must capture and retain the attention of the receiver. Signal efficacy is also dependent on the sensory limitations of the receiver. However, most signalling studies consider movement and colour separately, resulting in a partial understanding of the signal in question. We explored the structure and function of predator-prey signalling in the jumping spider-tephritid fly system, where the prey performs a wing waving display that deters an attack from the predator. Using a custom-built spider retinal tracker combined with visual modelling, as well as behavioural assays, we studied the effect of fly wing movement and colour on the jumping spider's visual system. We show that jumping spiders track their prey less effectively during wing display and this can be attributed to a series of fluctuations in chromatic and achromatic contrasts arising from the wing movements. These results suggest that displaying flies deter spider attacks by manipulating the movement biases of the spider's visual system. Our results emphasise the importance of receiver attention on the evolution of interspecific communication.
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Affiliation(s)
- Dinesh Rao
- Instituto de Biotecnologia y Ecologia Aplicada, Universidad Veracruzana, 91090 Xalapa, Veracruz, Mexico
| | - Skye M Long
- Department of Biology, University of Massachusetts, Amherst, MA 01003, USA
| | - Horacio Tapia-McClung
- Instituto de Investigacion en Inteligencia Artificial, Universidad Veracruzana, 91097 Xalapa, Veracruz, Mexico
| | - Kevin Salgado-Espinosa
- Instituto de Biotecnologia y Ecologia Aplicada, Universidad Veracruzana, 91090 Xalapa, Veracruz, Mexico
| | - Ajay Narendra
- School of Natural Sciences, Macquarie University, Sydney, NSW 2109, Australia
| | | | - Luis Robledo-Ospina
- Instituto de Biotecnologia y Ecologia Aplicada, Universidad Veracruzana, 91090 Xalapa, Veracruz, Mexico
| | - Dulce Rodriguez-Morales
- Instituto de Biotecnologia y Ecologia Aplicada, Universidad Veracruzana, 91090 Xalapa, Veracruz, Mexico.,Instituo de Neuroetologia, Universidad Veracruzana, 91190 Xalapa, Veracruz, Mexico
| | - Elizabeth M Jakob
- Department of Biology, University of Massachusetts, Amherst, MA 01003, USA
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24
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van den Berg CP, Endler JA, Papinczak DEJ, Cheney KL. Using colour pattern edge contrast statistics to predict detection speed and success in triggerfish (Rhinecanthus aculeatus). J Exp Biol 2022; 225:285905. [PMID: 36354306 PMCID: PMC9789405 DOI: 10.1242/jeb.244677] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2022] [Accepted: 10/26/2022] [Indexed: 11/12/2022]
Abstract
Edge detection is important for object detection and recognition. However, we do not know whether edge statistics accurately predict the detection of prey by potential predators. This is crucial given the growing availability of image analysis software and their application across non-human visual systems. Here, we investigated whether Boundary Strength Analysis (BSA), Local Edge Intensity Analysis (LEIA) and the Gabor edge disruption ratio (GabRat) could predict the speed and success with which triggerfish (Rhinecanthus aculeatus) detected patterned circular stimuli against a noisy visual background, in both chromatic and achromatic presentations. We found various statistically significant correlations between edge statistics and detection speed depending on treatment and viewing distance; however, individual pattern statistics only explained up to 2% of the variation in detection time, and up to 6% when considering edge statistics simultaneously. We also found changes in fish response over time. While highlighting the importance of spatial acuity and relevant viewing distances in the study of visual signals, our results demonstrate the importance of considering explained variation when interpreting colour pattern statistics in behavioural experiments. We emphasize the need for statistical approaches suitable for investigating task-specific predictive relationships and ecological effects when considering animal behaviour. This is particularly important given the ever-increasing dimensionality and size of datasets in the field of visual ecology.
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Affiliation(s)
- Cedric P. van den Berg
- Visual Ecology Lab, School of Biological Sciences, The University of Queensland, St Lucia, QLD 4072, Australia,Author for correspondence ()
| | - John A. Endler
- Centre for Integrative Ecology, School of Life and Environmental Sciences, Deakin University, Geelong, VIC 3216, Australia
| | - Daniel E. J. Papinczak
- Visual Ecology Lab, School of Biological Sciences, The University of Queensland, St Lucia, QLD 4072, Australia
| | - Karen L. Cheney
- Visual Ecology Lab, School of Biological Sciences, The University of Queensland, St Lucia, QLD 4072, Australia
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25
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Mark CJ, O'Hanlon JC, Holwell GI. Camouflage in lichen moths: Field predation experiments and avian vision modelling demonstrate the importance of wing pattern elements and background for survival. J Anim Ecol 2022; 91:2358-2369. [PMID: 36169598 PMCID: PMC10092008 DOI: 10.1111/1365-2656.13817] [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: 02/02/2022] [Accepted: 09/15/2022] [Indexed: 12/15/2022]
Abstract
Background matching is perhaps the most ubiquitous form of defensive camouflage in the animal kingdom, an adaptive strategy that relies on the visual resemblance between a prey organism and its background to promote concealment from predators. The importance of background matching has been acknowledged for over a century, yet despite its renown and apparent pervasiveness, few studies exist that have objectively quantified its occurrence and tested the functional significance of background matching in a specific animal study system. The North Island lichen moth Declana atronivea presents a fascinating system to investigate such anti-predator coloration. This species possesses high contrast black and white forewings that appear to resemble lichen. Here we assessed the contribution of background matching to the antipredator defence of D. atronivea using field predation experiments with realistic models. We found that D. atronivea coloration confers a significant survival advantage against native avian predators when on lichen backgrounds compared to bark backgrounds, with an intermediate level of predation occurring when models were near, but not on lichen. This suggests that D. atronivea wing patterns are an adaptation for background matching. We subsequently used calibrated digital photography, avian vision modelling and image analysis techniques to objectively quantify the degree of background matching exhibited by D. atronivea and assessed the contribution of different visual elements (colour, luminance and pattern) to camouflage in this species. Only the pattern elements of D. atronivea presented a close match to that of the lichen backgrounds, with both chromatic and achromatic cues found to be poor predictors of background matching in this species. This study is one of the first to integrate vision modelling, quantitative image analysis and field predation experiments using realistic models to objectively quantify the level and functional significance of background matching in a real species, and presents an ideal system for further investigating the interrelation between multiple mechanisms of camouflage.
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Affiliation(s)
- Cassandra J Mark
- School of Biological Sciences, The University of Auckland, Auckland, New Zealand
| | - James C O'Hanlon
- School of Science and Technology, University of New England, Armidale, New South Wales, Australia
| | - Gregory I Holwell
- School of Biological Sciences, The University of Auckland, Auckland, New Zealand
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26
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Honza M, Koleček J, Piálek L, Piálková R, Požgayová M, Procházka P, Štětková G, Jelínek V, Hughes AE, Šulc M. Multiple parasitism in an evictor brood parasite: patterns revealed by long-term monitoring, continuous video recording, and genetic analyses. Behav Ecol Sociobiol 2022. [DOI: 10.1007/s00265-022-03270-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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27
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Chan WP, Rabideau Childers R, Ashe S, Tsai CC, Elson C, Keleher KJ, Sipe RLH, Maier CA, Sourakov A, Gall LF, Bernard GD, Soucy ER, Yu N, Pierce NE. A high-throughput multispectral imaging system for museum specimens. Commun Biol 2022; 5:1318. [PMID: 36456867 PMCID: PMC9715708 DOI: 10.1038/s42003-022-04282-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2022] [Accepted: 11/18/2022] [Indexed: 12/05/2022] Open
Abstract
We present an economical imaging system with integrated hardware and software to capture multispectral images of Lepidoptera with high efficiency. This method facilitates the comparison of colors and shapes among species at fine and broad taxonomic scales and may be adapted for other insect orders with greater three-dimensionality. Our system can image both the dorsal and ventral sides of pinned specimens. Together with our processing pipeline, the descriptive data can be used to systematically investigate multispectral colors and shapes based on full-wing reconstruction and a universally applicable ground plan that objectively quantifies wing patterns for species with different wing shapes (including tails) and venation systems. Basic morphological measurements, such as body length, thorax width, and antenna size are automatically generated. This system can increase exponentially the amount and quality of trait data extracted from museum specimens.
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Affiliation(s)
- Wei-Ping Chan
- Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, MA, USA.
- Museum of Comparative Zoology, Harvard University, Cambridge, MA, USA.
| | - Richard Rabideau Childers
- Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, MA, USA
- Museum of Comparative Zoology, Harvard University, Cambridge, MA, USA
| | - Sorcha Ashe
- Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, MA, USA
| | - Cheng-Chia Tsai
- Department of Applied Physics and Applied Mathematics, Columbia University, New York, NY, USA
| | - Caroline Elson
- Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, MA, USA
| | - Kirsten J Keleher
- Department of Forestry and Environmental Resources, North Carolina State University, Raleigh, NC, USA
- Department of Neurobiology and Behavior, Cornell University, Ithaca, NY, USA
| | | | - Crystal A Maier
- Museum of Comparative Zoology, Harvard University, Cambridge, MA, USA
| | - Andrei Sourakov
- McGuire Center for Lepidoptera and Biodiversity, Florida Museum of Natural History, University of Florida, Gainesville, FL, USA
| | - Lawrence F Gall
- Computer Systems Office & Division of Entomology, Peabody Museum of Natural History, Yale University, New Haven, CT, USA
| | - Gary D Bernard
- Department of Electrical and Computer Engineering, University of Washington, Seattle, WA, USA
| | - Edward R Soucy
- Center for Brain Science, Harvard University, Cambridge, MA, USA
| | - Nanfang Yu
- Department of Applied Physics and Applied Mathematics, Columbia University, New York, NY, USA
| | - Naomi E Pierce
- Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, MA, USA.
- Museum of Comparative Zoology, Harvard University, Cambridge, MA, USA.
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28
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Yorzinski JL, Troscianko J, Briolat E, Schapiro SJ, Whitham W. A songbird can detect the eyes of conspecifics under daylight and artificial nighttime lighting. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2022; 313:120000. [PMID: 35995296 DOI: 10.1016/j.envpol.2022.120000] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/21/2022] [Revised: 07/25/2022] [Accepted: 08/16/2022] [Indexed: 06/15/2023]
Abstract
Eyes convey important information about the external and internal worlds of animals. Individuals can follow the gaze of others to learn about the location of salient objects as well as assess eye qualities to evaluate the health, age or other internal states of conspecifics. Because of the increasing prevalence of artificial lighting at night (ALAN), urbanized individuals can potentially garner information from conspecific eyes under both daylight and ALAN. We tested this possibility using a visual modeling approach in which we estimated the maximum distance at which individuals could detect conspecific eyes under daylight and high levels of ALAN. We also estimated the minimum light level at which individuals could detect conspecific eyes. Great-tailed grackles (Quiscalus mexicanus) were used as our study species because they are highly social and are unusual among birds in that they regularly gather at nocturnal roosts in areas with high levels of ALAN. This visual modelling approach revealed that grackles can detect conspecific eyes under both daylight and ALAN, regardless of iris coloration. The grackles could detect conspecific eyes at farther distances in daylight compared to ALAN. Our results highlight the potential importance of lighting conditions in shaping social interactions.
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Affiliation(s)
- Jessica L Yorzinski
- Department of Ecology and Conservation Biology, Texas A&M University, College Station, TX, USA.
| | - Jolyon Troscianko
- Centre for Ecology & Conservation, University of Exeter, Penryn, United Kingdom
| | - Emmanuelle Briolat
- Centre for Ecology & Conservation, University of Exeter, Penryn, United Kingdom
| | - Steven J Schapiro
- Department of Comparative Medicine, The University of Texas MD Anderson Cancer Center, Bastrop, TX, USA
| | - Will Whitham
- Department of Ecology and Conservation Biology, Texas A&M University, College Station, TX, USA; Department of Comparative Medicine, The University of Texas MD Anderson Cancer Center, Bastrop, TX, USA
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29
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Miller AE, Hogan BG, Stoddard MC. Color in motion: Generating 3-dimensional multispectral models to study dynamic visual signals in animals. Front Ecol Evol 2022. [DOI: 10.3389/fevo.2022.983369] [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
Analyzing color and pattern in the context of motion is a central and ongoing challenge in the quantification of animal coloration. Many animal signals are spatially and temporally variable, but traditional methods fail to capture this dynamism because they use stationary animals in fixed positions. To investigate dynamic visual displays and to understand the evolutionary forces that shape dynamic colorful signals, we require cross-disciplinary methods that combine measurements of color, pattern, 3-dimensional (3D) shape, and motion. Here, we outline a workflow for producing digital 3D models with objective color information from museum specimens with diffuse colors. The workflow combines multispectral imaging with photogrammetry to produce digital 3D models that contain calibrated ultraviolet (UV) and human-visible (VIS) color information and incorporate pattern and 3D shape. These “3D multispectral models” can subsequently be animated to incorporate both signaler and receiver movement and analyzed in silico using a variety of receiver-specific visual models. This approach—which can be flexibly integrated with other tools and methods—represents a key first step toward analyzing visual signals in motion. We describe several timely applications of this workflow and next steps for multispectral 3D photogrammetry and animation techniques.
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30
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Endler JA, Raggay DM, Maerowitz-McMahan S, Reznick DN, Fuller RC. Visual Background Choice and Light Environment Affect Male Guppy Visual Contrast. Vision (Basel) 2022; 6:vision6030056. [PMID: 36136749 PMCID: PMC9500966 DOI: 10.3390/vision6030056] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2022] [Revised: 09/01/2022] [Accepted: 09/02/2022] [Indexed: 11/16/2022] Open
Abstract
Male guppies (Poecilia reticulata) have multiple colored spots and perform courtship displays near the edges of streams in Trinidad in shallow water flowing through rainforest. Depending upon the orientation of the pair, the female sees the male displays against gravel or other stream bed substrates or against the spacelight—the roughly uniform light coming from the water column away from the bank. We observed courting pairs in two adjacent natural streams and noted the directions of each male display. We found that the female sees the male more often against spacelight than against gravel when females either faced the spacelight from the opposite bank or from downstream, or both. Visual modelling using natural substrate reflectances and field light measurements showed higher chromatic contrast of males against spacelight than against substrates independent of the two ambient light environments used during displays, but achromatic contrast depended upon the ambient light habitat. This suggests that courtship involves both chromatic and achromatic contrast. We conclude that the orientation of courting pairs and the ambient light spectrum should be accounted for in studies of mate choice, because the visual background and light affect visibility, and these differ with orientation.
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Affiliation(s)
- John A. Endler
- Centre for Integrative Ecology, School of Life and Environmental Sciences, Deakin University, Waurn Ponds, VIC 3216, Australia
- Correspondence:
| | - Dara-Marie Raggay
- Department of Life Sciences, University of the West Indies, St Augustine 999183, Trinidad and Tobago
| | | | - David N. Reznick
- Department of Biology, University of California, Riverside, CA 92521, USA
| | - Rebecca C. Fuller
- School of Integrative Biology, University of Illinois at Urbana-Champaign, Champaign, IL 61820, USA
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31
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Kemp DJ. Multiple views on animal coloration: a comment on Postema et al. Behav Ecol 2022. [DOI: 10.1093/beheco/arac083] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Darrell J Kemp
- School of Natural Sciences, Macquarie University , North Ryde, New South Wales, 2109 , Australia
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32
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Šulc M, Hughes AE, Mari L, Troscianko J, Tomášek O, Albrecht T, Jelínek V. Nest sanitation as an effective defence against brood parasitism. Anim Cogn 2022; 25:991-1002. [PMID: 35778546 DOI: 10.1007/s10071-022-01646-0] [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: 01/31/2022] [Revised: 06/06/2022] [Accepted: 06/09/2022] [Indexed: 11/28/2022]
Abstract
Egg rejection is a crucial defence strategy against brood parasitism that requires the host to correctly recognise the foreign egg. Rejection behaviour has, thus, evolved in many hosts, facilitated by the visual differences between the parasitic and host eggs, and driving hosts to rely on colour and pattern cues. On the other hand, the need to recognise non-egg-shaped objects to carry out nest sanitation led birds to evolve the ability to discriminate and eject objects using mainly shape cues. However, little is known regarding the evolutionary significance of rejection behaviour in general and the cognitive processes underlying it. Here, we investigated the response of the barn swallow (Hirundo rustica) during pre-laying and laying stages to four objects types that differed in shape (eggs vs stars) and colour/pattern (mimetic vs non-mimetic) to investigate (1) what cognitive mechanisms are involved in object discrimination and (2) whether egg rejection is a direct defence against brood parasitism, or simply a product of nest sanitation. We found that swallows ejected stars more often than eggs in both stages, indicating that swallows possess a template for the shape of their eggs. Since the effect of colour/pattern on ejection decisions was minor, we suggest that barn swallows have not evolved a direct defence against brood parasitism but instead, egg ejection might be a product of their well-developed nest sanitation behaviour. Nonetheless, the fact that mimetic eggs were ejected especially in the pre-laying stage shows that nest sanitation could be an effective defence against poorly timed brood parasitism.
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Affiliation(s)
- Michal Šulc
- Institute of Vertebrate Biology, Czech Academy of Sciences, Brno, Czech Republic.
| | - Anna E Hughes
- Department of Psychology, University of Essex, Colchester, UK
| | - Lisandrina Mari
- Institute of Vertebrate Biology, Czech Academy of Sciences, Brno, Czech Republic
| | - Jolyon Troscianko
- Centre for Life and Environmental Sciences, University of Exeter, Penryn, UK
| | - Oldřich Tomášek
- Institute of Vertebrate Biology, Czech Academy of Sciences, Brno, Czech Republic.,Department of Zoology, Masaryk University, Brno, Czech Republic
| | - Tomáš Albrecht
- Institute of Vertebrate Biology, Czech Academy of Sciences, Brno, Czech Republic.,Department of Zoology, Charles University, Prague, Czech Republic
| | - Václav Jelínek
- Institute of Vertebrate Biology, Czech Academy of Sciences, Brno, Czech Republic
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33
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Whitham W, Schapiro SJ, Troscianko J, Yorzinski JL. Chimpanzee (Pan troglodytes) gaze is conspicuous at ecologically-relevant distances. Sci Rep 2022; 12:9249. [PMID: 35661127 PMCID: PMC9166731 DOI: 10.1038/s41598-022-13273-3] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2022] [Accepted: 05/23/2022] [Indexed: 11/25/2022] Open
Abstract
Chimpanzee (Pan troglodytes) sclera appear much darker than the white sclera of human eyes, to such a degree that the direction of chimpanzee gaze may be concealed from conspecifics. Recent debate surrounding this topic has produced mixed results, with some evidence suggesting that (1) primate gaze is indeed concealed from their conspecifics, and (2) gaze colouration is among the suite of traits that distinguish uniquely social and cooperative humans from other primates (the cooperative eye hypothesis). Using a visual modelling approach that properly accounts for specific-specific vision, we reexamined this topic to estimate the extent to which chimpanzee eye coloration is discriminable. We photographed the faces of captive chimpanzees and quantified the discriminability of their pupil, iris, sclera, and surrounding skin. We considered biases of cameras, lighting conditions, and commercial photography software along with primate visual acuity, colour sensitivity, and discrimination ability. Our visual modeling of chimpanzee eye coloration suggests that chimpanzee gaze is visible to conspecifics at a range of distances (within approximately 10 m) appropriate for many species-typical behaviours. We also found that chimpanzee gaze is discriminable to the visual system of primates that chimpanzees prey upon, Colobus monkeys. Chimpanzee sclera colour does not effectively conceal gaze, and we discuss this result with regard to the cooperative eye hypothesis, the evolution of primate eye colouration, and methodological best practices for future primate visual ecology research.
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Affiliation(s)
- Will Whitham
- Department of Ecology and Conservation Biology, Texas A&M University, College Station, TX, USA. .,Department of Comparative Medicine, UT MD Anderson Cancer Center, Bastrop, TX, USA.
| | - Steven J Schapiro
- Department of Comparative Medicine, UT MD Anderson Cancer Center, Bastrop, TX, USA
| | - Jolyon Troscianko
- Centre for Ecology and Conservation, University of Exeter, Exeter, UK
| | - Jessica L Yorzinski
- Department of Ecology and Conservation Biology, Texas A&M University, College Station, TX, USA
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34
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Hancock GRA, Troscianko J. CamoEvo: An open access toolbox for artificial camouflage evolution experiments. Evolution 2022; 76:870-882. [PMID: 35313008 PMCID: PMC9314924 DOI: 10.1111/evo.14476] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2021] [Accepted: 02/03/2022] [Indexed: 01/21/2023]
Abstract
Camouflage research has long shaped our understanding of evolution by natural selection, and elucidating the mechanisms by which camouflage operates remains a key question in visual ecology. However, the vast diversity of color patterns found in animals and their backgrounds, combined with the scope for complex interactions with receiver vision, presents a fundamental challenge for investigating optimal camouflage strategies. Genetic algorithms (GAs) have provided a potential method for accounting for these interactions, but with limited accessibility. Here, we present CamoEvo, an open-access toolbox for investigating camouflage pattern optimization by using tailored GAs, animal and egg maculation theory, and artificial predation experiments. This system allows for camouflage evolution within the span of just 10-30 generations (∼1-2 min per generation), producing patterns that are both significantly harder to detect and that are optimized to their background. CamoEvo was built in ImageJ to allow for integration with an array of existing open access camouflage analysis tools. We provide guides for editing and adjusting the predation experiment and GA as well as an example experiment. The speed and flexibility of this toolbox makes it adaptable for a wide range of computer-based phenotype optimization experiments.
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Affiliation(s)
- George R. A. Hancock
- Centre for Ecology and ConservationUniversity of ExeterPenrynTR10 9FEUnited Kingdom
| | - Jolyon Troscianko
- Centre for Ecology and ConservationUniversity of ExeterPenrynTR10 9FEUnited Kingdom
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35
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Nokelainen O, Galarza JA, Kirvesoja J, Suisto K, Mappes J. Genetic colour variation visible for predators and conspecifics is concealed from humans in a polymorphic moth. J Evol Biol 2022; 35:467-478. [PMID: 35239231 PMCID: PMC9314616 DOI: 10.1111/jeb.13994] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2021] [Revised: 01/31/2022] [Accepted: 02/06/2022] [Indexed: 11/29/2022]
Abstract
The definition of colour polymorphism is intuitive: genetic variants express discretely coloured phenotypes. This classification is, however, elusive as humans form subjective categories or ignore differences that cannot be seen by human eyes. We demonstrate an example of a ‘cryptic morph’ in a polymorphic wood tiger moth (Arctia plantaginis), a phenomenon that may be common among well‐studied species. We used pedigree data from nearly 20,000 individuals to infer the inheritance of hindwing colouration. The evidence supports a single Mendelian locus with two alleles in males: WW and Wy produce the white and yy the yellow hindwing colour. The inheritance could not be resolved in females as their hindwing colour varies continuously with no clear link with male genotypes. Next, we investigated if the male genotype can be predicted from their phenotype by machine learning algorithms and by human observers. Linear discriminant analysis grouped male genotypes with 97% accuracy, whereas humans could only group the yy genotype. Using vision modelling, we also tested whether the genotypes have differential discriminability to humans, moth conspecifics and their bird predators. The human perception was poor separating the genotypes, but avian and moth vision models with ultraviolet sensitivity could separate white WW and Wy males. We emphasize the importance of objective methodology when studying colour polymorphism. Our findings indicate that by‐eye categorization methods may be problematic, because humans fail to see differences that can be visible for relevant receivers. Ultimately, receivers equipped with different perception than ours may impose selection to morphs hidden from human sight.
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Affiliation(s)
- Ossi Nokelainen
- Department of Biological and Environmental Science, University of Jyväskylä, Jyväskylä, Finland.,Organismal and Evolutionary Biology Research Program, Faculty of Biological and Environmental Sciences, University of Helsinki, Helsinki University, Helsinki, Finland
| | - Juan A Galarza
- Department of Biological and Environmental Science, University of Jyväskylä, Jyväskylä, Finland.,Organismal and Evolutionary Biology Research Program, Faculty of Biological and Environmental Sciences, University of Helsinki, Helsinki University, Helsinki, Finland
| | - Jimi Kirvesoja
- Department of Biological and Environmental Science, University of Jyväskylä, Jyväskylä, Finland
| | - Kaisa Suisto
- Department of Biological and Environmental Science, University of Jyväskylä, Jyväskylä, Finland
| | - Johanna Mappes
- Department of Biological and Environmental Science, University of Jyväskylä, Jyväskylä, Finland.,Organismal and Evolutionary Biology Research Program, Faculty of Biological and Environmental Sciences, University of Helsinki, Helsinki University, Helsinki, Finland
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36
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Assessing male gelada chest patches: color measurement and physiological mechanisms. Mamm Biol 2022. [DOI: 10.1007/s42991-021-00211-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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37
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Do male panther chameleons use different aspects of color change to settle disputes? Naturwissenschaften 2022; 109:13. [DOI: 10.1007/s00114-022-01784-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2021] [Revised: 12/23/2021] [Accepted: 01/06/2022] [Indexed: 10/19/2022]
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38
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Robledo-Ospina LE, Rao D. Dangerous visions: a review of visual antipredator strategies in spiders. Evol Ecol 2022. [DOI: 10.1007/s10682-022-10156-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
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39
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Wuthrich KL, Nagel A, Swierk L. Rapid Body Color Change Provides Lizards with Facultative Crypsis in the Eyes of Their Avian Predators. Am Nat 2021; 199:277-290. [DOI: 10.1086/717678] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Affiliation(s)
- Kelly Lin Wuthrich
- Department of Biological Sciences, Binghamton University, State University of New York, Binghamton, New York 13902
| | - Amber Nagel
- Department of Chemical Engineering, University of Oklahoma, Norman, Oklahoma 73019
| | - Lindsey Swierk
- Department of Biological Sciences, Binghamton University, State University of New York, Binghamton, New York 13902
- School of the Environment, Yale University, New Haven, Connecticut 06511; and Amazon Conservatory for Tropical Studies, Iquitos, Loreto 16001, Perú
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40
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McLellan CF, Scott-Samuel NE, Cuthill IC. Birds learn to avoid aposematic prey by using the appearance of host plants. Curr Biol 2021; 31:5364-5369.e4. [PMID: 34624210 DOI: 10.1016/j.cub.2021.09.048] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2021] [Revised: 08/23/2021] [Accepted: 09/17/2021] [Indexed: 11/30/2022]
Abstract
The conspicuous warning signal of aposematic animals is learned by their predators, and the resulting avoidance benefits both parties.1-4 Given evidence that birds can distinguish the profitability of prey from the environmental context in which they appear,5 aposematic insects' host plants might also provide an important cue to foraging predators.6 The aposematic cinnabar moth (Tyria jacobaeae) larva is a specialist on its ragwort (Senecio spp.) host plant,7 presenting a consistent environment with which it could be reliably associated. Additionally, ragwort's defensive toxins prevent non-specialist, profitable insects from feeding on it.8 Thus, avian predators may recognize cues from ragwort, most likely its conspicuous yellow flowers,9,10 and use this information to avoid cinnabars. To test this hypothesis, we exposed artificial cinnabar and non-signaling "caterpillar" targets to wild avian predation by presenting them on ragwort and non-toxic host plants. We also manipulated the presence or absence of ragwort flowers on hosts. In doing so, we show that both targets are better protected on the cinnabar's natural ragwort host and that birds use ragwort's distinctive yellow flowers as the cue to avoidance. Additionally, we found that naive predators do not make prey host foraging distinctions, indicating that this avoidance behavior is learned through experience. Our findings are among the first to suggest that a host plant's features act as an extended phenotype that signals the toxicity of the prey that live on it. This prey-host relationship may facilitate the initial evolution of toxicity in non-signaling prey, but also inhibit the evolution of aposematic signals themselves. VIDEO ABSTRACT.
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Affiliation(s)
| | | | - Innes C Cuthill
- School of Biological Sciences, University of Bristol, Bristol, UK
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41
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Winters AE, Chan W, White AM, van den Berg CP, Garson MJ, Cheney KL. Weapons or deterrents? Nudibranch molluscs use distinct ecological modes of chemical defence against predators. J Anim Ecol 2021; 91:831-844. [PMID: 34839542 DOI: 10.1111/1365-2656.13643] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2021] [Accepted: 11/15/2021] [Indexed: 11/28/2022]
Abstract
Defensive chemicals are used by plants and animals to reduce the risk of predation through different mechanisms, including toxins that cause injury and harm (weapons) and unpalatable or odiferous compounds that prevent attacks (deterrents). However, whether effective defences are both toxins and deterrents, or work in just one modality is often unclear. In this study, our primary aim was to determine whether defensive compounds stored by nudibranch molluscs acted as weapons (in terms of being toxic), deterrents (in terms of being distasteful) or both. Our secondary aim was to investigate the response of different taxa to these defensive compounds. To do this, we identified secondary metabolites in 30 species of nudibranch molluscs and investigated their deterrent properties using antifeedant assays with three taxa: rock pool shrimp, Palaemon serenus, and two fish species: triggerfish Rhinecanthus aculeatus and toadfish Tetractenos hamiltoni. We compared these results to toxicity assays using brine shrimp Artemia sp. and previously published toxicity data with a damselfish Chromis viridis. Overall, we found no clear relationship between palatability and toxicity, but instead classified defensive compounds into the following categories: Class I & II-highly unpalatable and highly toxic; Class I-weakly unpalatable and highly toxic; Class II-highly unpalatable but weakly toxic; WR (weak response)-weakly unpalatable and weakly toxic. We also found eight extracts from six species that did not display activity in any assays indicating they may have very limited chemical defensive mechanisms (NR, no response). We found that the different classes of secondary metabolites were similarly unpalatable to fish and shrimp, except extracts from Phyllidiidae nudibranchs (isonitriles) that were highly unpalatable to shrimp but weakly unpalatable to fish. Our results pave the way towards better understanding how animal chemical defences work against a variety of predators. We highlight the need to disentangle weapons and deterrents in future work on anti-predator defences to better understand the foraging decisions faced by predators, the resultant selection pressures imposed on prey and the evolution of different anti-predator strategies.
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Affiliation(s)
- Anne E Winters
- School of Biological Sciences, The University of Queensland, Brisbane, Qld, Australia
| | - Weili Chan
- School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, Qld, Australia
| | - Andrew M White
- School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, Qld, Australia
| | - Cedric P van den Berg
- School of Biological Sciences, The University of Queensland, Brisbane, Qld, Australia
| | - Mary J Garson
- School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, Qld, Australia
| | - Karen L Cheney
- School of Biological Sciences, The University of Queensland, Brisbane, Qld, Australia
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42
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Hosseini F, Lotfalizadeh H, Rakhshani E, Norouzi M, Butterworth NJ, Dadpour M. Significance of wing interference patterns as taxonomic characters in Aphidiinae (Hymenoptera: Braconidae). J ZOOL SYST EVOL RES 2021. [DOI: 10.1111/jzs.12542] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Affiliation(s)
- Farnaz Hosseini
- Plant Protection Research Department East Azarbaijan Agricultural and Natural Resources Research & Education Center AREEO Tabriz Iran
| | - Hossein Lotfalizadeh
- Plant Protection Research Department East Azarbaijan Agricultural and Natural Resources Research & Education Center AREEO Tabriz Iran
| | - Ehsan Rakhshani
- Department of Plant Protection College of Agriculture University of Zabol Zabol Iran
| | - Majid Norouzi
- Department of Plant Breeding and Biotechnology Faculty of Agriculture University of Tabriz Tabriz Iran
| | | | - Mohammadreza Dadpour
- Department of Horticultural Sciences Faculty of Agriculture University of Tabriz Tabriz Iran
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Lunau K, Scaccabarozzi D, Willing L, Dixon K. A bee's eye view of remarkable floral colour patterns in the south-west Australian biodiversity hotspot revealed by false colour photography. ANNALS OF BOTANY 2021; 128:821-824. [PMID: 34216211 PMCID: PMC8577209 DOI: 10.1093/aob/mcab088] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/22/2021] [Accepted: 06/30/2021] [Indexed: 06/13/2023]
Abstract
BACKGROUND AND AIMS Colour pattern is a key cue of bee attraction selectively driving the appeal of pollinators. It comprises the main colour of the flower with extra fine patterns, indicating a reward focal point such as nectar, nectaries, pollen, stamens and floral guides. Such advertising of floral traits guides visitation by the insects, ensuring precision in pollen gathering and deposition. The study, focused in the Southwest Australian Floristic Region, aimed to spot bee colour patterns that are usual and unusual, missing, accomplished by mimicry of pollen and anthers, and overlapping between mimic-model species in floral mimicry cases. METHODS Floral colour patterns were examined by false colour photography in 55 flower species of multiple highly diverse natural plant communities in south-west Australia. False colour photography is a method to transform a UV photograph and a colour photograph into a false colour photograph based on the trichromatic vision of bees. This method is particularly effective for rapid screening of large numbers of flowers for the presence of fine-scale bee-sensitive structures and surface roughness that are not detectable using standard spectrophotometry. KEY RESULTS Bee- and bird-pollinated flowers showed the expected but also some remarkable and unusual previously undetected floral colour pattern syndromes. Typical colour patterns include cases of pollen and flower mimicry and UV-absorbing targets. Among the atypical floral colour patterns are unusual white and UV-reflecting flowers of bee-pollinated plants, bicoloured floral guides, consistently occurring in Fabaceae spp., and flowers displaying a selective attractiveness to birds only. In the orchid genera (Diuris and Thelymitra) that employ floral mimicry of model species, we revealed a surprising mimicry phenomenon of anthers mimicked in turn by model species. CONCLUSION The study demonstrates the applicability of 'bee view' colour imaging for deciphering pollinator cues in a biodiverse flora with potential to be applied to other eco regions. The technique provides an exciting opportunity for indexing floral traits on a biome scale to establish pollination drivers of ecological and evolutionary relevance.
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Affiliation(s)
- Klaus Lunau
- Institute of Sensory Ecology, Heinrich-Heine University Düsseldorf, Germany
| | - Daniela Scaccabarozzi
- School of Molecular and Life Sciences, Curtin University, Perth, Western Australia, Australia
| | - Larissa Willing
- Institute of Sensory Ecology, Heinrich-Heine University Düsseldorf, Germany
| | - Kingsley Dixon
- School of Molecular and Life Sciences, Curtin University, Perth, Western Australia, Australia
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Abstract
The giant panda (Ailuropoda melanoleuca) is an iconic mammal, but the function of its black-and-white coloration is mysterious. Using photographs of giant pandas taken in the wild and state-of-the-art image analysis, we confirm the counterintuitive hypothesis that their coloration provides camouflage in their natural environment. The black fur blends into dark shades and tree trunks, whereas white fur matches foliage and snow when present, and intermediate pelage tones match rocks and ground. At longer viewing distances giant pandas show high edge disruption that breaks up their outline, and up close they rely more on background matching. The results are consistent across acuity-corrected canine, feline, and human vision models. We also show quantitatively that the species animal-to-background colour matching falls within the range of other species that are widely recognised as cryptic. Thus, their coloration is an adaptation to provide background matching in the visual environment in which they live and simultaneously to afford distance-dependent disruptive coloration, the latter of which constitutes the first computational evidence of this form of protective coloration in mammals.
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White TE, Locke A, Latty T. Heightened condition dependent expression of structural coloration in the faces, but not wings, of male and female flies. Curr Zool 2021; 68:600-607. [PMID: 36324536 PMCID: PMC9616059 DOI: 10.1093/cz/zoab087] [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: 07/18/2021] [Accepted: 10/13/2021] [Indexed: 11/16/2022] Open
Abstract
Structurally colored sexual signals are a conspicuous and widespread class of ornament used in mate choice, though the extent to which they encode information on the quality of their bearers is not fully resolved. Theory predicts that signaling traits under strong sexual selection as honest indicators should evolve to be more developmentally integrated and exaggerated than nonsexual traits, thereby leading to heightened condition dependence. Here, we test this prediction through examination of the sexually dimorphic faces and wings of the cursorial fly Lispe cana. Males and females possess structural UV-white and golden faces, respectively, and males present their faces and wings to females during close-range, ground-based courtship displays, thereby creating the opportunity for mutual inspection. Across a field-collected sample of individuals, we found that the appearance of the faces of both sexes scaled positively with individual condition, though along separate axes. Males in better condition expressed brighter faces as modeled according to conspecific flies, whereas condition scaled with facial saturation in females. We found no such relationships for their wing interference pattern nor abdomens, with the latter included as a nonsexual control. Our results suggest that the structurally colored faces, but not the iridescent wings, of male and female L. cana are reliable guides to individual quality and support the broader potential for structural colors as honest signals. They also highlight the potential for mutual mate choice in this system, while arguing for 1 of several alternate signaling roles for wing interferences patterns among the myriad taxa which bear them.
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Affiliation(s)
- Thomas E White
- School of Life and Environmental Sciences, The University of Sydney, Sydney 2106, Australia
| | - Amy Locke
- School of Life and Environmental Sciences, The University of Sydney, Sydney 2106, Australia
| | - Tanya Latty
- School of Life and Environmental Sciences, The University of Sydney, Sydney 2106, Australia
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Comparison of digital photography and spectrometry for evaluating colour perception in humans and other trichromatic species. Behav Ecol Sociobiol 2021. [DOI: 10.1007/s00265-021-03071-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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Narbona E, del Valle JC, Arista M, Buide ML, Ortiz PL. Major Flower Pigments Originate Different Colour Signals to Pollinators. Front Ecol Evol 2021. [DOI: 10.3389/fevo.2021.743850] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Flower colour is mainly due to the presence and type of pigments. Pollinator preferences impose selection on flower colour that ultimately acts on flower pigments. Knowing how pollinators perceive flowers with different pigments becomes crucial for a comprehensive understanding of plant-pollinator communication and flower colour evolution. Based on colour space models, we studied whether main groups of pollinators, specifically hymenopterans, dipterans, lepidopterans and birds, differentially perceive flower colours generated by major pigment groups. We obtain reflectance data and conspicuousness to pollinators of flowers containing one of the pigment groups more frequent in flowers: chlorophylls, carotenoids and flavonoids. Flavonoids were subsequently classified in UV-absorbing flavonoids, aurones-chalcones and the anthocyanins cyanidin, pelargonidin, delphinidin, and malvidin derivatives. We found that flower colour loci of chlorophylls, carotenoids, UV-absorbing flavonoids, aurones-chalcones, and anthocyanins occupied different regions of the colour space models of these pollinators. The four groups of anthocyanins produced a unique cluster of colour loci. Interestingly, differences in colour conspicuousness among the pigment groups were almost similar in the bee, fly, butterfly, and bird visual space models. Aurones-chalcones showed the highest chromatic contrast values, carotenoids displayed intermediate values, and chlorophylls, UV-absorbing flavonoids and anthocyanins presented the lowest values. In the visual model of bees, flowers with UV-absorbing flavonoids (i.e., white flowers) generated the highest achromatic contrasts. Ours findings suggest that in spite of the almost omnipresence of floral anthocyanins in angiosperms, carotenoids and aurones-chalcones generates higher colour conspicuousness for main functional groups of pollinators.
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Glimm T, Kiskowski M, Moreno N, Chiari Y. Capturing and analyzing pattern diversity: an example using the melanistic spotted patterns of leopard geckos. PeerJ 2021; 9:e11829. [PMID: 34595062 PMCID: PMC8436963 DOI: 10.7717/peerj.11829] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2021] [Accepted: 06/30/2021] [Indexed: 11/20/2022] Open
Abstract
Animal color patterns are widely studied in ecology, evolution, and through mathematical modeling. Patterns may vary among distinct body parts such as the head, trunk or tail. As large amounts of photographic data is becoming more easily available, there is a growing need for general quantitative methods for capturing and analyzing the full complexity and details of pattern variation. Detailed information on variation in color pattern elements is necessary to understand how patterns are produced and established during development, and which evolutionary forces may constrain such a variation. Here, we develop an approach to capture and analyze variation in melanistic color pattern elements in leopard geckos. We use this data to study the variation among different body parts of leopard geckos and to draw inferences about their development. We compare patterns using 14 different indices such as the ratio of melanistic versus total area, the ellipticity of spots, and the size of spots and use these to define a composite distance between two patterns. Pattern presence/absence among the different body parts indicates a clear pathway of pattern establishment from the head to the back legs. Together with weak within-individual correlation between leg patterns and main body patterns, this suggests that pattern establishment in the head and tail may be independent from the rest of the body. We found that patterns vary greatest in size and density of the spots among body parts and individuals, but little in their average shapes. We also found a correlation between the melanistic patterns of the two front legs, as well as the two back legs, and also between the head, tail and trunk, especially for the density and size of the spots, but not their shape or inter-spot distance. Our data collection and analysis approach can be applied to other organisms to study variation in color patterns between body parts and to address questions on pattern formation and establishment in animals.
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Affiliation(s)
- Tilmann Glimm
- Department of Mathematics, Western Washington University, Bellingham, WA, United States of America
| | - Maria Kiskowski
- Department of Mathematics and Statistics, University of South Alabama, Mobile, AL, United States of America
| | - Nickolas Moreno
- Department of Biology, George Mason University, Fairfax, VA, United States of America
| | - Ylenia Chiari
- Department of Biology, George Mason University, Fairfax, VA, United States of America
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O’Connor TK, Sandoval MC, Wang J, Hans JC, Takenaka R, Child M, Whiteman NK. Ecological basis and genetic architecture of crypsis polymorphism in the desert clicker grasshopper (Ligurotettix coquilletti). Evolution 2021; 75:2441-2459. [PMID: 34370317 PMCID: PMC8932956 DOI: 10.1111/evo.14321] [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: 04/30/2021] [Revised: 07/09/2021] [Accepted: 07/20/2021] [Indexed: 11/28/2022]
Abstract
Color polymorphic species can offer exceptional insight into the ecology and genetics of adaptation. Although the genetic architecture of animal coloration is diverse, many color polymorphisms are associated with large structural variants and maintained by biotic interactions. Grasshoppers are notably polymorphic in both color and karyotype, which makes them excellent models for understanding the ecological drivers and genetic underpinnings of color variation. Banded and uniform morphs of the desert clicker grasshopper (Ligurotettix coquilletti) are found across the western deserts of North America. To address the hypothesis that predation maintains local color polymorphism and shapes regional crypsis variation, we surveyed morph frequencies and tested for covariation with two predation environments. Morphs coexisted at intermediate frequencies at most sites, consistent with local balancing selection. Morph frequencies covaried with the appearance of desert substrate-an environment used only by females-suggesting that ground-foraging predators are major agents of selection on crypsis. We next addressed the hypothesized link between morph variation and genome structure. To do so, we designed an approach for detecting inversions and indels using only RADseq data. The banded morph was perfectly correlated with a large putative indel. Remarkably, indel dominance differed among populations, a rare example of dominance evolution in nature.
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Affiliation(s)
- Timothy K. O’Connor
- Department of Integrative Biology, University of California, Berkeley, CA 94720
- Current address: Department of Ecology and Evolution, University of Chicago, Chicago, IL 60637
| | - Marissa C. Sandoval
- Department of Integrative Biology, University of California, Berkeley, CA 94720
| | - Jiarui Wang
- Department of Integrative Biology, University of California, Berkeley, CA 94720
| | - Jacob C. Hans
- Department of Entomology, University of California, Riverside, CA 92521
| | - Risa Takenaka
- Molecular and Cellular Biology Graduate Program, University of Washington, Seattle, WA 98195
- Division of Basic Sciences, Fred Hutchinson Cancer Research Center, Seattle, WA 98109
| | - Myron Child
- School of Biological Sciences, University of Utah, Salt Lake City, UT 84112
| | - Noah K. Whiteman
- Department of Integrative Biology, University of California, Berkeley, CA 94720
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Valvo JJ, Aponte JD, Daniel MJ, Dwinell K, Rodd H, Houle D, Hughes KA. Using Delaunay triangulation to sample whole-specimen color from digital images. Ecol Evol 2021; 11:12468-12484. [PMID: 34594513 PMCID: PMC8462138 DOI: 10.1002/ece3.7992] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2021] [Accepted: 07/21/2021] [Indexed: 11/26/2022] Open
Abstract
Color variation is one of the most obvious examples of variation in nature, but biologically meaningful quantification and interpretation of variation in color and complex patterns are challenging. Many current methods for assessing variation in color patterns classify color patterns using categorical measures and provide aggregate measures that ignore spatial pattern, or both, losing potentially important aspects of color pattern.Here, we present Colormesh, a novel method for analyzing complex color patterns that offers unique capabilities. Our approach is based on unsupervised color quantification combined with geometric morphometrics to identify regions of putative spatial homology across samples, from histology sections to whole organisms. Colormesh quantifies color at individual sampling points across the whole sample.We demonstrate the utility of Colormesh using digital images of Trinidadian guppies (Poecilia reticulata), for which the evolution of color has been frequently studied. Guppies have repeatedly evolved in response to ecological differences between up- and downstream locations in Trinidadian rivers, resulting in extensive parallel evolution of many phenotypes. Previous studies have, for example, compared the area and quantity of discrete color (e.g., area of orange, number of black spots) between these up- and downstream locations neglecting spatial placement of these areas. Using the Colormesh pipeline, we show that patterns of whole-animal color variation do not match expectations suggested by previous work.Colormesh can be deployed to address a much wider range of questions about color pattern variation than previous approaches. Colormesh is thus especially suited for analyses that seek to identify the biologically important aspects of color pattern when there are multiple competing hypotheses or even no a priori hypotheses at all.
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Affiliation(s)
- Jennifer J. Valvo
- Department of Biological ScienceFlorida State UniversityTallahasseeFloridaUSA
| | - Jose David Aponte
- Department of Cell Biology and AnatomyUniversity of CalgaryCalgaryABCanada
| | - Mitch J. Daniel
- Department of Biological ScienceFlorida State UniversityTallahasseeFloridaUSA
| | - Kenna Dwinell
- Department of Biological ScienceFlorida State UniversityTallahasseeFloridaUSA
| | - Helen Rodd
- Department of Ecology and Evolutionary BiologyUniversity of TorontoTorontoONCanada
| | - David Houle
- Department of Biological ScienceFlorida State UniversityTallahasseeFloridaUSA
| | - Kimberly A. Hughes
- Department of Biological ScienceFlorida State UniversityTallahasseeFloridaUSA
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