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Nokelainen O, Silvasti SA, Strauss SY, Wahlberg N, Mappes J. Predator selection on phenotypic variability of cryptic and aposematic moths. Nat Commun 2024; 15:1678. [PMID: 38395999 PMCID: PMC10891176 DOI: 10.1038/s41467-024-45329-5] [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: 04/13/2023] [Accepted: 01/17/2024] [Indexed: 02/25/2024] Open
Abstract
Natural selection generally favours phenotypic variability in camouflaged organisms, whereas aposematic organisms are expected to evolve a more uniform warning coloration. However, no comprehensive analysis of the phenotypic consequences of predator selection in aposematic and cryptic species exists. Using state-of-the-art image analysis, we examine 2800 wing images of 82 moth species accessed via three online museum databases. We test whether anti-predator strategy (i.e., camouflage or aposematism) explains intraspecific variation in wing colour and pattern across northern hemisphere moths. In addition, we test two mutually non-exclusive, ecological hypotheses to explain variation in colour pattern: diel-activity or dietary-niche. In this work, taking into account phylogenetic relationships, moth phenotypic variability is best explained by anti-predator strategy with camouflaged moths being more variable in wing patterning than aposematic species.
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Affiliation(s)
- Ossi Nokelainen
- Organismal and Evolutionary Biology Research Programme, Faculty of Biological and Environmental Sciences, University of Helsinki, Viikki Biocenter 3, P.O. Box 65, 40014, Helsinki, Finland.
- Department of Biological and Environmental Science, University of Jyväskylä, P.O. Box 35, FI-40014, Jyväskylä, Finland.
- Open Science Centre, University of Jyväskylä, P.O. Box 35, FI-40014, Jyväskylä, Finland.
| | - Sanni A Silvasti
- Department of Biological and Environmental Science, University of Jyväskylä, P.O. Box 35, FI-40014, Jyväskylä, Finland
- School of Natural Sciences, Macquarie University, Sydney, NSW, 2109, Australia
| | - Sharon Y Strauss
- Department of Evolution and Ecology, University of California at Davis, 2320 Storer Hall, One Shields Avenue, Davis, CA, 95616, USA
- Wissenschaftskolleg zu Berlin, Wallotstrasse 19, Berlin, 14193, Germany
| | - Niklas Wahlberg
- Department of Biology, Lund University, Sölvegatan 37, SE-223 62, Lund, Sweden
| | - Johanna Mappes
- Organismal and Evolutionary Biology Research Programme, Faculty of Biological and Environmental Sciences, University of Helsinki, Viikki Biocenter 3, P.O. Box 65, 40014, Helsinki, Finland.
- Wissenschaftskolleg zu Berlin, Wallotstrasse 19, Berlin, 14193, Germany.
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2
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Almeida DA, Mappes J, Gordon S. Predator-Induced Plasticity on Warning Signal and Larval Life-History Traits of the Aposematic Wood Tiger Moth, Arctia plantaginis. Front Ecol Evol 2021. [DOI: 10.3389/fevo.2021.658177] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Predator-induced plasticity in life-history and antipredator traits during the larval period has been extensively studied in organisms with complex life-histories. However, it is unclear whether different levels of predation could induce warning signals in aposematic organisms. Here, we investigated whether predator-simulated handling affects warning coloration and life-history traits in the aposematic wood tiger moth larva, Arctia plantaginis. As juveniles, a larger orange patch on an otherwise black body signifies a more efficient warning signal against predators but this comes at the costs of conspicuousness and thermoregulation. Given this, one would expect that an increase in predation risk would induce flexible expression of the orange patch. Prior research in this system points to plastic effects being important as a response to environmental changes for life history traits, but we had yet to assess whether this was the case for predation risk, a key driver of this species evolution. Using a full-sib rearing design, in which individuals were reared in the presence and absence of a non-lethal simulated bird attack, we evaluated flexible responses of warning signal size (number of orange segments), growth, molting events, and development time in wood tiger moths. All measured traits except development time showed a significant response to predation. Larvae from the predation treatment developed a more melanized warning signal (smaller orange patch), reached a smaller body size, and molted more often. Our results suggest plasticity is indeed important in aposematic organisms, but in this case may be complicated by the trade-off between costly pigmentation and other life-history traits.
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3
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Echeverri SA, Miller AE, Chen J, McQueen EW, Plakke M, Spicer M, Hoke KL, Stoddard MC, Morehouse NI. How signaling geometry shapes the efficacy and evolution of animal communication systems. Integr Comp Biol 2021; 61:787-813. [PMID: 34021338 DOI: 10.1093/icb/icab090] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
Animal communication is inherently spatial. Both signal transmission and signal reception have spatial biases-involving direction, distance and position-that interact to determine signaling efficacy. Signals, be they visual, acoustic, or chemical, are often highly directional. Likewise, receivers may only be able to detect signals if they arrive from certain directions. Alignment between these directional biases is therefore critical for effective communication, with even slight misalignments disrupting perception of signaled information. In addition, signals often degrade as they travel from signaler to receiver, and environmental conditions that impact transmission can vary over even small spatiotemporal scales. Thus, how animals position themselves during communication is likely to be under strong selection. Despite this, our knowledge regarding the spatial arrangements of signalers and receivers during communication remains surprisingly coarse for most systems. We know even less about how signaler and receiver behaviors contribute to effective signaling alignment over time, or how signals themselves may have evolved to influence and/or respond to these aspects of animal communication. Here, we first describe why researchers should adopt a more explicitly geometric view of animal signaling, including issues of location, direction, and distance. We then describe how environmental and social influences introduce further complexities to the geometry of signaling. We discuss how multimodality offers new challenges and opportunities for signalers and receivers. We conclude with recommendations and future directions made visible by attention to the geometry of signaling.
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Affiliation(s)
| | - Audrey E Miller
- Department of Ecology and Evolutionary Biology, Princeton University, Princeton, NJ
| | - Jason Chen
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, PA.,Department of Biology, Emory University, Atlanta, GA
| | - Eden W McQueen
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, PA
| | - Melissa Plakke
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, PA.,Department of Ecology and Evolutionary Biology, University of Kansas, Lawrence, KS
| | - Michelle Spicer
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, PA.,Biology Department, University of Puget Sound, Tacoma, WA
| | - Kim L Hoke
- Department of Biology, Colorado State University, Fort Collins, CO
| | | | - Nathan I Morehouse
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, PA.,Department of Biological Sciences, University of Cincinnati, Cincinnati, OH
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4
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5
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Fennell JG, Talas L, Baddeley RJ, Cuthill IC, Scott-Samuel NE. The Camouflage Machine: Optimizing protective coloration using deep learning with genetic algorithms. Evolution 2021; 75:614-624. [PMID: 33415740 DOI: 10.1111/evo.14162] [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: 03/13/2020] [Revised: 12/23/2020] [Accepted: 12/23/2020] [Indexed: 12/20/2022]
Abstract
Evolutionary biologists frequently wish to measure the fitness of alternative phenotypes using behavioral experiments. However, many phenotypes are complex. One example is coloration: camouflage aims to make detection harder, while conspicuous signals (e.g., for warning or mate attraction) require the opposite. Identifying the hardest and easiest to find patterns is essential for understanding the evolutionary forces that shape protective coloration, but the parameter space of potential patterns (colored visual textures) is vast, limiting previous empirical studies to a narrow range of phenotypes. Here, we demonstrate how deep learning combined with genetic algorithms can be used to augment behavioral experiments, identifying both the best camouflage and the most conspicuous signal(s) from an arbitrarily vast array of patterns. To show the generality of our approach, we do so for both trichromatic (e.g., human) and dichromatic (e.g., typical mammalian) visual systems, in two different habitats. The patterns identified were validated using human participants; those identified as the best for camouflage were significantly harder to find than a tried-and-tested military design, while those identified as most conspicuous were significantly easier to find than other patterns. More generally, our method, dubbed the "Camouflage Machine," will be a useful tool for identifying the optimal phenotype in high dimensional state spaces.
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Affiliation(s)
- John G Fennell
- School of Psychological Science, University of Bristol, Bristol, UK
| | - Laszlo Talas
- School of Psychological Science, University of Bristol, Bristol, UK
| | | | - Innes C Cuthill
- School of Biological Sciences, University of Bristol, Bristol, UK
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6
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Valkonen JK, Vakkila A, Pesari S, Tuominen L, Mappes J. Protective coloration of European vipers throughout the predation sequence. Anim Behav 2020. [DOI: 10.1016/j.anbehav.2020.04.005] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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7
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Song W, Lee SI, Jablonski PG. Evolution of switchable aposematism: insights from individual-based simulations. PeerJ 2020; 8:e8915. [PMID: 32309047 PMCID: PMC7153555 DOI: 10.7717/peerj.8915] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2019] [Accepted: 03/15/2020] [Indexed: 11/20/2022] Open
Abstract
Some defended prey animals can switch on their normally hidden aposematic signals. This switching may occur in reaction to predators’ approach (pre-attack signals) or attack (post-attack signals). Switchable aposematism has been relatively poorly studied, but we can expect that it might bring a variety of benefits to an aposmetic organism. First, the switching could startle the predators (deimatism). Second, it could facilitate aversive learning. Third, it could minimize exposure or energetic expense, as the signal can be switched off. These potential benefits might offset costs of developing, maintaining and utilizing the switchable traits. Here we focused on the third benefit of switchability, the cost-saving aspect, and developed an individual-based computer simulation of predators and prey. In 88,128 model runs, we observed evolution of permanent, pre-attack, or post-attack aposematic signals of varying strength. We found that, in general, the pre-attack switchable aposematism may require moderate predator learning speed, high basal detectability, and moderate to high signal cost. On the other hand, the post-attack signals may arise under slow predator learning, low basal detectability and high signal cost. When predator population turnover is fast, it may lead to evolution of post-attack aposematic signals that are not conforming to the above tendency. We also suggest that a high switching cost may exert different selection pressure on the pre-attack than the post-attack switchable strategies. To our knowledge, these are the first theoretical attempts to systematically explore the evolution of switchable aposematism relative to permanent aposematism in defended prey. Our simulation model is capable of addressing additional questions beyond the scope of this article, and we open the simulation software, program manual and source code for free public use.
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Affiliation(s)
- Woncheol Song
- Laboratory of Behavioral Ecology and Evolution, School of Biological Sciences, Seoul National University, Seoul, South Korea
| | - Sang-im Lee
- School of Undergraduate Studies, Daegu-Gyeongbuk Institute of Science and Technology, Daegu, South Korea
| | - Piotr G. Jablonski
- Laboratory of Behavioral Ecology and Evolution, School of Biological Sciences, Seoul National University, Seoul, South Korea
- Museum and Institute of Zoology, Polish Academy of Sciences, Warsaw, Poland
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8
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Peng P, Stuart‐Fox D, Chen S, Tan EJ, Kuo G, Blamires SJ, Tso I, Elgar MA. High contrast yellow mosaic patterns are prey attractants for orb‐weaving spiders. Funct Ecol 2020. [DOI: 10.1111/1365-2435.13532] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Affiliation(s)
- Po Peng
- School of BioSciences University of Melbourne Parkville Vic. Australia
| | - Devi Stuart‐Fox
- School of BioSciences University of Melbourne Parkville Vic. Australia
| | - Szu‐Wei Chen
- Agricultural Policy Research Centre Agricultural Technology Research Institute Taipei Taiwan
| | | | - Guan‐Lin Kuo
- Department of Molecular and Cell Biology University of Leicester Leicester UK
| | - Sean J. Blamires
- Evolution & Ecology Research Centre School of Biological Earth & Environmental Sciences The University of New South Wales Sydney NSW Australia
| | - I‐Min Tso
- Department of Life Science Tunghai University Taichung Taiwan
| | - Mark A. Elgar
- School of BioSciences University of Melbourne Parkville Vic. Australia
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9
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Affiliation(s)
- I. C. Cuthill
- School of Biological Sciences University of Bristol Bristol UK
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10
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Fisher KA, Stankowich T. Antipredator strategies of striped skunks in response to cues of aerial and terrestrial predators. Anim Behav 2018. [DOI: 10.1016/j.anbehav.2018.06.023] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
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11
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Briolat ES, Burdfield-Steel ER, Paul SC, Rönkä KH, Seymoure BM, Stankowich T, Stuckert AMM. Diversity in warning coloration: selective paradox or the norm? Biol Rev Camb Philos Soc 2018; 94:388-414. [PMID: 30152037 PMCID: PMC6446817 DOI: 10.1111/brv.12460] [Citation(s) in RCA: 68] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2017] [Revised: 07/25/2018] [Accepted: 07/27/2018] [Indexed: 01/03/2023]
Abstract
Aposematic theory has historically predicted that predators should select for warning signals to converge on a single form, as a result of frequency‐dependent learning. However, widespread variation in warning signals is observed across closely related species, populations and, most problematically for evolutionary biologists, among individuals in the same population. Recent research has yielded an increased awareness of this diversity, challenging the paradigm of signal monomorphy in aposematic animals. Here we provide a comprehensive synthesis of these disparate lines of investigation, identifying within them three broad classes of explanation for variation in aposematic warning signals: genetic mechanisms, differences among predators and predator behaviour, and alternative selection pressures upon the signal. The mechanisms producing warning coloration are also important. Detailed studies of the genetic basis of warning signals in some species, most notably Heliconius butterflies, are beginning to shed light on the genetic architecture facilitating or limiting key processes such as the evolution and maintenance of polymorphisms, hybridisation, and speciation. Work on predator behaviour is changing our perception of the predator community as a single homogenous selective agent, emphasising the dynamic nature of predator–prey interactions. Predator variability in a range of factors (e.g. perceptual abilities, tolerance to chemical defences, and individual motivation), suggests that the role of predators is more complicated than previously appreciated. With complex selection regimes at work, polytypisms and polymorphisms may even occur in Müllerian mimicry systems. Meanwhile, phenotypes are often multifunctional, and thus subject to additional biotic and abiotic selection pressures. Some of these selective pressures, primarily sexual selection and thermoregulation, have received considerable attention, while others, such as disease risk and parental effects, offer promising avenues to explore. As well as reviewing the existing evidence from both empirical studies and theoretical modelling, we highlight hypotheses that could benefit from further investigation in aposematic species. Finally by collating known instances of variation in warning signals, we provide a valuable resource for understanding the taxonomic spread of diversity in aposematic signalling and with which to direct future research. A greater appreciation of the extent of variation in aposematic species, and of the selective pressures and constraints which contribute to this once‐paradoxical phenomenon, yields a new perspective for the field of aposematic signalling.
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Affiliation(s)
- Emmanuelle S Briolat
- Centre for Ecology & Conservation, College of Life & Environmental Sciences, University of Exeter, Penryn Campus, Penryn, Cornwall, TR10 9FE, U.K
| | - Emily R Burdfield-Steel
- Centre of Excellence in Biological Interactions, Department of Biological and Environmental Science, University of Jyväskylä, Jyväskylä, 40014, Finland
| | - Sarah C Paul
- Centre for Ecology & Conservation, College of Life & Environmental Sciences, University of Exeter, Penryn Campus, Penryn, Cornwall, TR10 9FE, U.K.,Department of Chemical Ecology, Bielefeld University, Universitätsstraße 25, 33615, Bielefeld, Germany
| | - Katja H Rönkä
- Centre of Excellence in Biological Interactions, Department of Biological and Environmental Science, University of Jyväskylä, Jyväskylä, 40014, Finland.,Organismal and Evolutionary Biology Research Programme, Faculty of Biological and Environmental Sciences, University of Helsinki, Helsinki, 00014, Finland
| | - Brett M Seymoure
- Department of Biology, Colorado State University, Fort Collins, CO 80525, U.S.A.,Department of Fish, Wildlife, and Conservation Biology, Colorado State University, Fort Collins, CO 80525, U.S.A
| | - Theodore Stankowich
- Department of Biological Sciences, California State University, Long Beach, CA 90840, U.S.A
| | - Adam M M Stuckert
- Department of Biology, East Carolina University, 1000 E Fifth St, Greenville, NC 27858, U.S.A
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12
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Merilaita S, Kelley JL. Scary clowns: adaptive function of anemonefish coloration. J Evol Biol 2018; 31:1558-1571. [PMID: 29978521 DOI: 10.1111/jeb.13350] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2018] [Revised: 06/20/2018] [Accepted: 07/03/2018] [Indexed: 01/02/2023]
Abstract
Clownfishes, with their showy coloration, are well known for their symbiosis with sea anemones and for their hierarchical reproductive system, but the function of their coloration is unclear. We used a phylogeny of 27 clownfish species to test whether fish coloration (i) serves a protective function that involves their anemone hosts, or (ii) signals species identity in species with overlapping host ranges that can potentially share the same host. We tested for an association between fish colour pattern traits, host morphology and host toxicity and examined coloration in relation to host sharing and geographic proximity. Fish with fewer stripes occupied fewer anemone species, and hosts with shorter tentacles, than fish with multiple stripes. There was a negative relationship between anemone toxicity and tentacle length and these protective traits together were correlated with the evolution of stripes. Host sharing or range overlap was not associated with coloration divergence. We propose that ancestral anemonefishes had multiple stripes that served for hiding/camouflage among the hosts' long tentacles, whereas increased specialization towards fewer and more toxic hosts (with shorter tentacles) led to the use of coloration as an aposematic signal. The intriguing notion that an aposematic signal could advertise the defence of another species may reflect the unique symbiotic relationship between anemonefishes and their hosts.
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Affiliation(s)
- Sami Merilaita
- Department of Biology, University of Turku, Turku, Finland
| | - Jennifer L Kelley
- School of Biological Sciences, The University of Western Australia, Perth, WA, Australia
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13
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Distance-dependent defensive coloration in the poison frog Dendrobates tinctorius, Dendrobatidae. Proc Natl Acad Sci U S A 2018; 115:6416-6421. [PMID: 29866847 DOI: 10.1073/pnas.1800826115] [Citation(s) in RCA: 47] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Poison dart frogs provide classic examples of warning signals: potent toxins signaled by distinctive, conspicuous coloration. We show that, counterintuitively, the bright yellow and blue-black color of Dendrobates tinctorius (Dendrobatidae) also provides camouflage. Through computational modeling of predator vision, and a screen-based detection experiment presenting frogs at different spatial resolutions, we demonstrate that at close range the frog is highly detectable, but from a distance the colors blend together, forming effective camouflage. This result was corroborated with an in situ experiment, which found survival to be background-dependent, a feature more associated with camouflage than aposematism. Our results suggest that in D. tinctorius the distribution of pattern elements, and the particular colors expressed, act as a highly salient close range aposematic signal, while simultaneously minimizing detectability to distant observers.
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Valkonen JK, Mappes J. Resemblance of a model species and its mimic: Response to Bury and Cichoń. CONSERVATION BIOLOGY : THE JOURNAL OF THE SOCIETY FOR CONSERVATION BIOLOGY 2018; 32:487-489. [PMID: 29337378 DOI: 10.1111/cobi.13070] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/16/2017] [Revised: 11/06/2017] [Accepted: 12/01/2017] [Indexed: 06/07/2023]
Affiliation(s)
- Janne K Valkonen
- University of Jyväskylä, Department of Biological and Environmental Science, Centre of Excellence in Biological Interactions, P.O. Box 35, FI 40014, Finland
| | - Johanna Mappes
- University of Jyväskylä, Department of Biological and Environmental Science, Centre of Excellence in Biological Interactions, P.O. Box 35, FI 40014, Finland
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15
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Seymoure BM. Enlightening Butterfly Conservation Efforts: The Importance of Natural Lighting for Butterfly Behavioral Ecology and Conservation. INSECTS 2018; 9:E22. [PMID: 29439549 PMCID: PMC5872287 DOI: 10.3390/insects9010022] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/11/2018] [Revised: 01/29/2018] [Accepted: 02/06/2018] [Indexed: 11/16/2022]
Abstract
Light is arguably the most important abiotic factor for living organisms. Organisms evolved under specific lighting conditions and their behavior, physiology, and ecology are inexorably linked to light. Understanding light effects on biology could not be more important as present anthropogenic effects are greatly changing the light environments in which animals exist. The two biggest anthropogenic contributors changing light environments are: (1) anthropogenic lighting at night (i.e., light pollution); and (2) deforestation and the built environment. I highlight light importance for butterfly behavior, physiology, and ecology and stress the importance of including light as a conservation factor for conserving butterfly biodiversity. This review focuses on four parts: (1) Introducing the nature and extent of light. (2) Visual and non-visual light reception in butterflies. (3) Implications of unnatural lighting for butterflies across several different behavioral and ecological contexts. (4). Future directions for quantifying the threat of unnatural lighting on butterflies and simple approaches to mitigate unnatural light impacts on butterflies. I urge future research to include light as a factor and end with the hopeful thought that controlling many unnatural light conditions is simply done by flipping a switch.
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Affiliation(s)
- Brett M Seymoure
- Department of Biology and Department of Fish, Wildlife, and Conservation Biology, Colorado State University, Fort Collins, CO 80523, USA.
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Barnett JB, Cuthill IC, Scott-Samuel NE. Distance-dependent pattern blending can camouflage salient aposematic signals. Proc Biol Sci 2018; 284:rspb.2017.0128. [PMID: 28679722 DOI: 10.1098/rspb.2017.0128] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2017] [Accepted: 06/01/2017] [Indexed: 11/12/2022] Open
Abstract
The effect of viewing distance on the perception of visual texture is well known: spatial frequencies higher than the resolution limit of an observer's visual system will be summed and perceived as a single combined colour. In animal defensive colour patterns, distance-dependent pattern blending may allow aposematic patterns, salient at close range, to match the background to distant observers. Indeed, recent research has indicated that reducing the distance from which a salient signal can be detected can increase survival over camouflage or conspicuous aposematism alone. We investigated whether the spatial frequency of conspicuous and cryptically coloured stripes affects the rate of avian predation. Our results are consistent with pattern blending acting to camouflage salient aposematic signals effectively at a distance. Experiments into the relative rate of avian predation on edible model caterpillars found that increasing spatial frequency (thinner stripes) increased survival. Similarly, visual modelling of avian predators showed that pattern blending increased the similarity between caterpillar and background. These results show how a colour pattern can be tuned to reveal or conceal different information at different distances, and produce tangible survival benefits.
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Affiliation(s)
- James B Barnett
- School of Biological Sciences, University of Bristol, Bristol Life Sciences Building, 24 Tyndall Avenue, Bristol BS8 1TQ, UK
| | - Innes C Cuthill
- School of Biological Sciences, University of Bristol, Bristol Life Sciences Building, 24 Tyndall Avenue, Bristol BS8 1TQ, UK
| | - Nicholas E Scott-Samuel
- School of Experimental Psychology, University of Bristol, 12a Priory Road, Bristol BS8 1TU, UK
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17
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Barnett JB, Cuthill IC, Scott-Samuel NE. Distance-dependent aposematism and camouflage in the cinnabar moth caterpillar ( Tyria jacobaeae, Erebidae). ROYAL SOCIETY OPEN SCIENCE 2018; 5:171396. [PMID: 29515858 PMCID: PMC5830747 DOI: 10.1098/rsos.171396] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/14/2017] [Accepted: 01/18/2018] [Indexed: 07/27/2023]
Abstract
Defended prey often use distinctive, conspicuous, colours to advertise their unprofitability to potential predators (aposematism). These warning signals are frequently made up of salient, high contrast, stripes which have been hypothesized to increase the speed and accuracy of predator avoidance learning. Limitations in predator visual acuity, however, mean that these patterns cannot be resolved when viewed from a distance, and adjacent patches of colour will blend together (pattern blending). We investigated how saliency changes at different viewing distances in the toxic and brightly coloured cinnabar moth caterpillar (Tyria jacobaeae). We found that although the caterpillars' orange-and-black stripes are highly salient at close range, when viewed from a distance the colours blend together to match closely those of the background. Cinnabar caterpillars therefore produce a distance-dependent signal combining salient aposematism with targeted background matching camouflage, without necessarily compromising the size or saturation of their aposematic signal.
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Affiliation(s)
- James B. Barnett
- School of Biological Sciences, University of Bristol, Bristol Life Sciences Building, 24 Tyndall Avenue, Bristol BS8 1TQ, UK
| | - Innes C. Cuthill
- School of Biological Sciences, University of Bristol, Bristol Life Sciences Building, 24 Tyndall Avenue, Bristol BS8 1TQ, UK
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18
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Aluthwattha ST, Harrison RD, Ranawana KB, Xu C, Lai R, Chen J. Does spatial variation in predation pressure modulate selection for aposematism? Ecol Evol 2017; 7:7560-7572. [PMID: 28944039 PMCID: PMC5606884 DOI: 10.1002/ece3.3221] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2017] [Revised: 05/25/2017] [Accepted: 05/30/2017] [Indexed: 11/16/2022] Open
Abstract
It is widely believed that aposematic signals should be conspicuous, but in nature, they vary from highly conspicuous to near cryptic. Current theory, including the honest signal or trade‐off hypotheses of the toxicity–conspicuousness relationship, cannot explain why adequately toxic species vary substantially in their conspicuousness. Through a study of similarly toxic Danainae (Nymphalidae) butterflies and their mimics that vary remarkably in their conspicuousness, we show that the benefits of conspicuousness vary along a gradient of predation pressure. Highly conspicuous butterflies experienced lower avian attack rates when background predation pressure was low, but attack rates increased rapidly as background predation pressure increased. Conversely, the least conspicuous butterflies experienced higher attack rates at low predation pressures, but at high predation pressures, they appeared to benefit from crypsis. Attack rates of intermediately conspicuous butterflies remained moderate and constant along the predation pressure gradient. Mimics had a similar pattern but higher attack rates than their models and mimics tended to imitate the signal of less attacked model species along the predation pressure gradient. Predation pressure modulated signal fitness provides a possible mechanism for the maintenance of variation in conspicuousness of aposematic signals, as well as the initial survival of conspicuous signals in cryptic populations in the process of aposematic signal evolution, and an alternative explanation for the evolutionary gain and loss of mimicry.
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Affiliation(s)
- S Tharanga Aluthwattha
- Key Laboratory of Tropical Forest Ecology Xishuangbanna Tropical Botanical Garden Chinese Academy of Sciences Mengla Yunnan China.,University of Chinese Academy of Sciences Beijing China
| | - Rhett D Harrison
- World Agroforestry Centre, East & Southern Africa Region Woodlands, Lusaka Zambia
| | | | - Cheng Xu
- Kunming Institute of Zoology Chinese Academy of Sciences Kunming Yunnan China
| | - Ren Lai
- Kunming Institute of Zoology Chinese Academy of Sciences Kunming Yunnan China
| | - Jin Chen
- Key Laboratory of Tropical Forest Ecology Xishuangbanna Tropical Botanical Garden Chinese Academy of Sciences Mengla Yunnan China
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Klomp DA, Stuart-Fox D, Cassidy EJ, Ahmad N, Ord TJ. Color pattern facilitates species recognition but not signal detection: a field test using robots. Behav Ecol 2017. [DOI: 10.1093/beheco/arw186] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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20
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Barnett JB, Redfern AS, Bhattacharyya-Dickson R, Clifton O, Courty T, Ho T, Hopes A, McPhee T, Merrison K, Owen R, Scott-Samuel NE, Cuthill IC. Stripes for warning and stripes for hiding: spatial frequency and detection distance. Behav Ecol 2016. [DOI: 10.1093/beheco/arw168] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
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21
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Barnett JB, Scott-Samuel NE, Cuthill IC. Aposematism: balancing salience and camouflage. Biol Lett 2016; 12:20160335. [PMID: 27484645 PMCID: PMC5014027 DOI: 10.1098/rsbl.2016.0335] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2016] [Accepted: 07/08/2016] [Indexed: 11/12/2022] Open
Abstract
Aposematic signals are often characterized by high conspicuousness. Larger and brighter signals reinforce avoidance learning, distinguish defended from palatable prey and are more easily memorized by predators. Conspicuous signalling, however, has costs: encounter rates with naive, specialized or nutritionally stressed predators are likely to increase. It has been suggested that intermediate levels of aposematic conspicuousness can evolve to balance deterrence and detectability, especially for moderately defended species. The effectiveness of such signals, however, has not yet been experimentally tested under field conditions. We used dough caterpillar-like baits to test whether reduced levels of aposematic conspicuousness can have survival benefits when predated by wild birds in natural conditions. Our results suggest that, when controlling for the number and intensity of internal contrast boundaries (stripes), a reduced-conspicuousness aposematic pattern can have a survival advantage over more conspicuous signals, as well as cryptic colours. Furthermore, we find a survival benefit from the addition of internal contrast for both high and low levels of conspicuousness. This adds ecological validity to evolutionary models of aposematic saliency and the evolution of honest signalling.
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Affiliation(s)
- James B Barnett
- School of Biological Sciences, University of Bristol, Bristol Life Sciences Building, 24 Tyndall Avenue, Bristol BS8 1TQ, UK
| | - Nicholas E Scott-Samuel
- School of Experimental Psychology, University of Bristol, 12a Priory Road, Bristol BS8 1TU, UK
| | - Innes C Cuthill
- School of Biological Sciences, University of Bristol, Bristol Life Sciences Building, 24 Tyndall Avenue, Bristol BS8 1TQ, UK
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22
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Honma A, Mappes J, Valkonen JK. Warning coloration can be disruptive: aposematic marginal wing patterning in the wood tiger moth. Ecol Evol 2015; 5:4863-74. [PMID: 26640666 PMCID: PMC4662304 DOI: 10.1002/ece3.1736] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2015] [Revised: 08/28/2015] [Accepted: 08/31/2015] [Indexed: 11/10/2022] Open
Abstract
Warning (aposematic) and cryptic colorations appear to be mutually incompatible because the primary function of the former is to increase detectability, whereas the function of the latter is to decrease it. Disruptive coloration is a type of crypsis in which the color pattern breaks up the outline of the prey, thus hindering its detection. This delusion can work even when the prey's pattern elements are highly contrasting; thus, it is possible for an animal's coloration to combine both warning and disruptive functions. The coloration of the wood tiger moth (Parasemia plantaginis) is such that the moth is conspicuous when it rests on vegetation, but when it feigns death and drops to the grass- and litter-covered ground, it is hard to detect. This death-feigning behavior therefore immediately switches the function of its coloration from signaling to camouflage. We experimentally tested whether the forewing patterning of wood tiger moths could function as disruptive coloration against certain backgrounds. Using actual forewing patterns of wood tiger moths, we crafted artificial paper moths and placed them on a background image resembling a natural litter and grass background. We manipulated the disruptiveness of the wing pattern so that all (marginal pattern) or none (nonmarginal pattern) of the markings extended to the edge of the wing. Paper moths, each with a hidden palatable food item, were offered to great tits (Parus major) in a large aviary where the birds could search for and attack the "moths" according to their detectability. The results showed that prey items with the disruptive marginal pattern were attacked less often than prey without it. However, the disruptive function was apparent only when the prey was brighter than the background. These results suggest that warning coloration and disruptive coloration can work in concert and that the moth, by feigning death, can switch the function of its coloration from warning to disruptive.
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Affiliation(s)
- Atsushi Honma
- University of Jyväskylä Department of Biological and Environmental Science Centre of Excellence in Biological Interactions P.O. Box 35 Jyväskylä 40014 Finland ; Department of Ecosystem Studies School of Environmental Science The University of Shiga Prefecture 2500 Hassaka-cho Hikone City Shiga 522-8533 Japan
| | - Johanna Mappes
- University of Jyväskylä Department of Biological and Environmental Science Centre of Excellence in Biological Interactions P.O. Box 35 Jyväskylä 40014 Finland
| | - Janne K Valkonen
- University of Jyväskylä Department of Biological and Environmental Science Centre of Excellence in Biological Interactions P.O. Box 35 Jyväskylä 40014 Finland
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23
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Mochida K, Zhang WY, Toda M. The function of body coloration of the hai coral snake Sinomicrurus japonicus boettgeri. Zool Stud 2015; 54:e33. [PMID: 31966120 DOI: 10.1186/s40555-015-0110-2] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2014] [Accepted: 02/02/2015] [Indexed: 11/10/2022]
Abstract
BACKGROUND Prey animals often protect themselves from visual hunting predators via their body coloration, which encompasses various visual effects. When a prey animal displays a certain color pattern on its body surface, its protective function and effect are largely dependent on how a predator would encounter and perceive the prey animal.Asian coral snakes of the genus Sinomicrurus,which are venomous, display black bands and stripes on their orange body coloration. The banded pattern has been characterized as an aposematic signal in the New World coral snakes, but the stripes generally occur in cryptic snakes. We investigated the function of this complex color pattern, which might be interpreted as aposematic and cryptic, in Sinomicrurus japonicusboettgeri. RESULTS First, plasticine replica experiments were conducted to assess whether natural avian predators avoid the colorpattern of S.japonicus boettgeri;the results showed that they attacked the coral snake replicas and the control replicas with coloration similar to another prey snake, suggesting that the body coloration of S. japonicus boettgeri did not function aposematically in the wild. Second, we evaluated the chromatic contrast of the snake coloration with backgrounds from their natural habitats based on the avian predator visual systems. The body coloration of S. japonicus boettgeri showed the same, or lower, contrast levels with natural backgrounds than those of sympatric cryptic snakes, suggesting that the coloration was ineffective as an aposematic signal. CONCLUSIONS These results imply that the body coloration of S. japonicus boettgeri would work as crypsis through background matching or disruptive camouflage rather than aposematism.
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Affiliation(s)
- Koji Mochida
- Tropical Biosphere Research Center, University of Ryukyus, Nishihara, Okinawa 903-0213, Japan
| | - Wan-Yu Zhang
- Graduate School of Engineering and Science, University of Ryukyus, Nishihara, Okinawa 903-0213, Japan
| | - Mamoru Toda
- Tropical Biosphere Research Center, University of Ryukyus, Nishihara, Okinawa 903-0213, Japan
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24
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Andersson M. Aposematism and crypsis in a rodent: antipredator defence of the Norwegian lemming. Behav Ecol Sociobiol 2015. [DOI: 10.1007/s00265-014-1868-7] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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25
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Samia DSM, Blumstein DT, Stankowich T, Cooper WE. Fifty years of chasing lizards: new insights advance optimal escape theory. Biol Rev Camb Philos Soc 2015; 91:349-66. [PMID: 25620002 DOI: 10.1111/brv.12173] [Citation(s) in RCA: 77] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2014] [Revised: 11/28/2014] [Accepted: 12/11/2014] [Indexed: 11/30/2022]
Abstract
Systematic reviews and meta-analyses often examine data from diverse taxa to identify general patterns of effect sizes. Meta-analyses that focus on identifying generalisations in a single taxon are also valuable because species in a taxon are more likely to share similar unique constraints. We conducted a comprehensive phylogenetic meta-analysis of flight initiation distance in lizards. Flight initiation distance (FID) is a common metric used to quantify risk-taking and has previously been shown to reflect adaptive decision-making. The past decade has seen an explosion of studies focused on quantifying FID in lizards, and, because lizards occur in a wide range of habitats, are ecologically diverse, and are typically smaller and differ physiologically from the better studied mammals and birds, they are worthy of detailed examination. We found that variables that reflect the costs or benefits of flight (being engaged in social interactions, having food available) as well as certain predator effects (predator size and approach speed) had large effects on FID in the directions predicted by optimal escape theory. Variables that were associated with morphology (with the exception of crypsis) and physiology had relatively small effects, whereas habitat selection factors typically had moderate to large effect sizes. Lizards, like other taxa, are very sensitive to the costs of flight.
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Affiliation(s)
- Diogo S M Samia
- Laboratory of Theoretical Ecology and Synthesis, Federal University of Goiás, CP. 131, 74001-970 Goiânia, Brazil
| | - Daniel T Blumstein
- Department of Ecology and Evolutionary Biology, University of California, 621 Young Drive South, Los Angeles, CA 90095-1606, U.S.A
| | - Theodore Stankowich
- Department of Biological Sciences, California State University, 1250 Bellflower Blvd., Long Beach, CA 90840, U.S.A
| | - William E Cooper
- Department of Biology, Indiana University Purdue University Fort Wayne, Fort Wayne, IN 46835, U.S.A
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27
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McLean CA, Moussalli A, Stuart-Fox D. Local adaptation and divergence in colour signal conspicuousness between monomorphic and polymorphic lineages in a lizard. J Evol Biol 2014; 27:2654-64. [DOI: 10.1111/jeb.12521] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2014] [Revised: 08/22/2014] [Accepted: 09/26/2014] [Indexed: 11/28/2022]
Affiliation(s)
- C. A. McLean
- Department of Zoology; The University of Melbourne; Parkville Vic. Australia
- Sciences Department; Museum Victoria; Carlton Gardens Vic. Australia
| | - A. Moussalli
- Sciences Department; Museum Victoria; Carlton Gardens Vic. Australia
| | - D. Stuart-Fox
- Department of Zoology; The University of Melbourne; Parkville Vic. Australia
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28
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Hegna RH, Mappes J. Influences of geographic differentiation in the forewing warning signal of the wood tiger moth in Alaska. Evol Ecol 2014. [DOI: 10.1007/s10682-014-9734-7] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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29
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Avian predators change their foraging strategy on defended prey when undefended prey are hard to find. Anim Behav 2014. [DOI: 10.1016/j.anbehav.2014.04.030] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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30
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Karpestam E, Merilaita S, Forsman A. Body size influences differently the detectabilities of colour morphs of cryptic prey. Biol J Linn Soc Lond 2014. [DOI: 10.1111/bij.12291] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Einat Karpestam
- Ecology and Evolution in Microbial Model Systems; EEMIS; Department of Biology and Environmental Science; Linnaeus University; SE-391 82 Kalmar Sweden
| | - Sami Merilaita
- Behavioural and Evolutionary Ecology Group; Environmental Biology; Department of Biosciences; Åbo Akademi University; FI-20520 Turku Finland
| | - Anders Forsman
- Ecology and Evolution in Microbial Model Systems; EEMIS; Department of Biology and Environmental Science; Linnaeus University; SE-391 82 Kalmar Sweden
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31
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Nokelainen O, Valkonen J, Lindstedt C, Mappes J. Changes in predator community structure shifts the efficacy of two warning signals in Arctiid moths. J Anim Ecol 2014; 83:598-605. [PMID: 24164666 DOI: 10.1111/1365-2656.12169] [Citation(s) in RCA: 92] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2013] [Accepted: 10/21/2013] [Indexed: 11/27/2022]
Abstract
Polymorphism in warning coloration is puzzling because positive frequency-dependent selection by predators is expected to promote monomorphic warning signals in defended prey. We studied predation on the warning-coloured wood tiger moth (Parasemia plantaginis) by using artificial prey resembling white and yellow male colour morphs in five separate populations with different naturally occurring morph frequencies. We tested whether predation favours one of the colour morphs over the other and whether that is influenced either by local, natural colour morph frequencies or predator community composition. We found that yellow specimens were attacked less than white ones regardless of the local frequency of the morphs indicating frequency-independent selection, but predation did depend on predator community composition: yellows suffered less attacks when Paridae were abundant, whereas whites suffered less attacks when Prunellidae were abundant. Our results suggest that spatial heterogeneity in predator community composition can generate a geographical mosaic of selection facilitating the evolution of polymorphic warning signals. This is the first time this mechanism gains experimental support. Altogether, this study sheds light on the evolution of adaptive coloration in heterogeneous environments.
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Affiliation(s)
- Ossi Nokelainen
- Department of Biological and Environmental Science, Centre of Excellence in Biological Interactions, University of Jyväskylä, Jyväskylä, P.O. Box 35, 40014, Finland
| | - Janne Valkonen
- Department of Biological and Environmental Science, Centre of Excellence in Biological Interactions, University of Jyväskylä, Jyväskylä, P.O. Box 35, 40014, Finland
| | - Carita Lindstedt
- Department of Biological and Environmental Science, Centre of Excellence in Biological Interactions, University of Jyväskylä, Jyväskylä, P.O. Box 35, 40014, Finland
| | - Johanna Mappes
- Department of Biological and Environmental Science, Centre of Excellence in Biological Interactions, University of Jyväskylä, Jyväskylä, P.O. Box 35, 40014, Finland
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Flores EE, Stevens M, Moore AJ, Blount JD. Diet, development and the optimization of warning signals in post‐metamorphic green and black poison frogs. Funct Ecol 2013. [DOI: 10.1111/1365-2435.12084] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Eric E. Flores
- Centre for Ecology and Conservation College of Life & Environmental Sciences University of Exeter Cornwall Campus Penryn TR10 9EZ UK
| | - Martin Stevens
- Department of Zoology University of Cambridge Downing Street Cambridge CB2 3EJ UK
| | - Allen J. Moore
- Centre for Ecology and Conservation College of Life & Environmental Sciences University of Exeter Cornwall Campus Penryn TR10 9EZ UK
- Department of Genetics University of Georgia Athens GA 30602 USA
| | - Jonathan D. Blount
- Centre for Ecology and Conservation College of Life & Environmental Sciences University of Exeter Cornwall Campus Penryn TR10 9EZ UK
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34
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Ruiz-Rodríguez M, Avilés JM, Cuervo JJ, Parejo D, Ruano F, Zamora-Muñoz C, Sergio F, López-Jiménez L, Tanferna A, Martín-Vivaldi M. Does avian conspicuous colouration increase or reduce predation risk? Oecologia 2013; 173:83-93. [PMID: 23386048 DOI: 10.1007/s00442-013-2599-6] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2012] [Accepted: 01/18/2013] [Indexed: 10/27/2022]
Abstract
Animals often announce their unprofitability to predators through conspicuous coloured signals. Here we tested whether the apparently conspicuous colour designs of the four European Coraciiformes and Upupiformes species may have evolved as aposematic signals, or whether instead they imply a cost in terms of predation risk. Because previous studies suggested that these species are unpalatable, we hypothesized that predators could avoid targeting them based on their colours. An experiment was performed where two artificial models of each bird species were exposed simultaneously to raptor predators, one painted so as to resemble the real colour design of these birds, and the other one painted using cryptic colours. Additionally, we used field data on the black kite's diet to compare the selection of these four species to that of other avian prey. Conspicuous models were attacked in equal or higher proportions than their cryptic counterparts, and the attack rate on the four species increased with their respective degree of contrast against natural backgrounds. The analysis of the predator's diet revealed that the two least attacked species were negatively selected in nature despite their abundance. Both conspicuous and cryptic models of one of the studied species (the hoopoe) received fewer attacks than cryptic models of the other three species, suggesting that predators may avoid this species for characteristics other than colour. Globally, our results suggest that the colour of coraciiforms and upupiforms does not function as an aposematic signal that advises predators of their unprofitability, but also that conspicuous colours may increase predation risk in some species, supporting thus the handicap hypothesis.
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Affiliation(s)
- M Ruiz-Rodríguez
- Department of Functional and Evolutionary Biology, Estación Experimental de Zonas Áridas, Almería, Spain.
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35
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Hegna RH, Nokelainen O, Hegna JR, Mappes J. To quiver or to shiver: increased melanization benefits thermoregulation, but reduces warning signal efficacy in the wood tiger moth. Proc Biol Sci 2013; 280:20122812. [PMID: 23363631 DOI: 10.1098/rspb.2012.2812] [Citation(s) in RCA: 75] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Melanin production is often considered costly, yet beneficial for thermoregulation. Studies of variation in melanization and the opposing selective forces that underlie its variability contribute greatly to understanding natural selection. We investigated whether melanization benefits are traded off with predation risk to promote observed local and geographical variation in the warning signal of adult male wood tiger moths (Parasemia plantaginis). Warning signal variation is predicted to reduce survival in aposematic species. However, in P. plantaginis, male hindwings are either yellow or white in Europe, and show continuous variation in melanized markings that cover 20 to 90 per cent of the hindwing. We found that the amount of melanization increased from 40 to 59 per cent between Estonia (58° N) and north Finland (67° N), suggesting melanization carries thermoregulatory benefits. Our thermal measurements showed that more melanic individuals warmed up more quickly on average than less melanic individuals, which probably benefits flight in cold temperatures. With extensive field experiments in central Finland and the Alpine region, we found that more melanic individuals suffered increased predation. Together, our data suggest that warning signal efficiency is constrained by thermoregulatory benefits. Differences in relative costs and benefits of melanin probably help to maintain the geographical warning signal differences.
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Affiliation(s)
- Robert H Hegna
- Department of Biology and Environmental Science, Centre of Excellence in Biological Interactions, University of Jyväskylä, Survontie 9, Jyväskylä, Finland.
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36
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Aronsson M, Gamberale-Stille G. Evidence of signaling benefits to contrasting internal color boundaries in warning coloration. Behav Ecol 2012. [DOI: 10.1093/beheco/ars170] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
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37
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Karpestam E, Merilaita S, Forsman A. Reduced predation risk for melanistic pygmy grasshoppers in post-fire environments. Ecol Evol 2012; 2:2204-12. [PMID: 23139879 PMCID: PMC3488671 DOI: 10.1002/ece3.338] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2012] [Revised: 06/21/2012] [Accepted: 06/22/2012] [Indexed: 12/02/2022] Open
Abstract
The existence of melanistic (black) color forms in many species represents interesting model systems that have played important roles for our understanding of selective processes, evolution of adaptations, and the maintenance of variation. A recent study reported on rapid evolutionary shifts in frequencies of the melanistic forms in replicated populations of Tetrix subulata pygmy grasshoppers; the incidence of the melanistic form was higher in recently burned areas with backgrounds blackened by fire than in nonburned areas, and it declined over time in postfire environments. Here, we tested the hypothesis that the frequency shifts of the black color variant were driven, at least in part, by changes in the selective regime imposed by visual predators. To study detectability of the melanistic form, we presented human "predators" with images of black grasshoppers and samples of the natural habitat on computer screens. We demonstrate that the protective value of black coloration differs between burnt and nonburnt environments and gradually increases in habitats that have been more blackened by fire. These findings support the notion that a black color pattern provides improved protection from visually oriented predators against blackened backgrounds and implicate camouflage and predation as important drivers of fire melanism in pygmy grasshoppers.
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Affiliation(s)
- Einat Karpestam
- Ecology and Evolution in Microbial Model Systems, EEMiS, School of Natural Sciences, Linnaeus UniversityKalmar, Sweden
| | - Sami Merilaita
- Environmental and Marine Biology, Åbo Akademi UniversityTurku, Finland
| | - Anders Forsman
- Ecology and Evolution in Microbial Model Systems, EEMiS, School of Natural Sciences, Linnaeus UniversityKalmar, Sweden
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38
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IHALAINEN EIRA, LINDSTEDT CARITA. Do avian predators select for seasonal polyphenism in the European map butterfly Araschnia levana (Lepidoptera: Nymphalidae)? Biol J Linn Soc Lond 2012. [DOI: 10.1111/j.1095-8312.2012.01922.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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39
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Worms under cover: relationships between performance in learning tasks and personality in great tits (Parus major). Anim Cogn 2012; 15:763-70. [PMID: 22532072 DOI: 10.1007/s10071-012-0500-3] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2011] [Revised: 04/05/2012] [Accepted: 04/11/2012] [Indexed: 10/28/2022]
Abstract
In animals, individual differences in learning ability are common and are in part explained by genetic differences, developmental conditions and by general experience. Yet, not all variations in learning are well understood. Individual differences in learning may be associated with elementary individual characteristics that are consistent across situations and over time, commonly referred to as personality or temperament. Here, we tested whether or not male great tits (Parus major) from two selection lines for fast or slow exploratory behaviour, an operational measure for avian personality, vary in their learning performance in two related consecutive tasks. In the first task, birds had to associate a colour with a reward whereas in the second task, they had to associate a new colour with a reward ignoring the previously rewarded colour. Slow explorers had shorter latencies to approach the experimental device compared with fast explorers in both tasks, but birds from the two selection lines did not differ in accomplishing the first task, that is, to associate a colour with a reward. However, in the second task, fast explorers had longer latencies to solve the trials than slow explorers. Moreover, relative to the number of trials needed to reach the learning criteria in the first task, birds from the slow selection line took more trials to associate a new colour with a reward while ignoring the previously learned association compared with birds from the fast selection line. Overall, the experiments suggest that personality in great tits is not strongly related to learning per se in such an association task, but that birds from different selection lines might express different learning strategies as birds from the different selection lines were differently affected by their previous learning performance.
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40
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Bjarnholt N, Nakonieczny M, Kędziorski A, Debinski DM, Matter SF, Olsen CE, Zagrobelny M. Occurrence of Sarmentosin and Other Hydroxynitrile Glucosides in Parnassius (Papilionidae) Butterflies and Their Food Plants. J Chem Ecol 2012; 38:525-37. [DOI: 10.1007/s10886-012-0114-x] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2011] [Revised: 03/28/2012] [Accepted: 03/30/2012] [Indexed: 11/25/2022]
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41
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BOHLIN TITTI, GAMBERALE-STILLE GABRIELLA, MERILAITA SAMI, EXNEROVÁ ALICE, ŠTYS PAVEL, TULLBERG BIRGITTAS. The detectability of the colour pattern in the aposematic firebug, Pyrrhocoris apterus: an image-based experiment with human ‘predators’. Biol J Linn Soc Lond 2012. [DOI: 10.1111/j.1095-8312.2011.01834.x] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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42
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Bonansea MI, Vaira M. Geographic and intrapopulational variation in colour and patterns of an aposematic toad, Melanophryniscus rubriventris (Amphibia, Anura, Bufonidae). AMPHIBIA-REPTILIA 2012. [DOI: 10.1163/156853811x619754] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The aposematic toad genus Melanophryniscus is a polymorphic group with noticeable variation in colour and pattern. Here, we objectively evaluate variation in spectral reflectance and quantify variation in patterning within and among populations of the species M. rubriventris in NW Argentina. We conducted spectrophotometric analysis on 69 individuals and recorded dorsal and ventral pattern morphs of 727 individuals from six populations. We found high divergence in the reflectance spectra, the extent of brightly coloured areas, and the skin alkaloid profiles with no correlation among coloration varieties, alkaloid profiles, and the geographic distance between populations. Our analyses imply subdivision of sampled populations groupings based mostly on different dorsal colorations. Our results also reveal that populations with very similar patterns may differ markedly in colour and vice versa. It is striking that these aposematic toads show a pronounced variation in colour and patterning among and within populations showing individuals with a conspicuous bright dorsal colouration but also morphs with a rather cryptic black or drab colouration. However, the known presence of several alkaloids classes in all populations suggests that all morphs might be equally unpalatable.
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Affiliation(s)
- Maria Ines Bonansea
- 1CONICET – Centro de Investigaciones Básicas y Aplicadas, Universidad Nacional de Jujuy, Gorriti 237, Jujuy, Argentina e Instituto de Bio y Geociencias, Universidad Nacional de Salta, Mendoza 2, 4400, Salta, Argentina
- 2Facultad de Ciencias Agrarias, Universidad Nacional de Jujuy, Alberdi 47, 4600, Jujuy, Argentina
| | - Marcos Vaira
- 1CONICET – Centro de Investigaciones Básicas y Aplicadas, Universidad Nacional de Jujuy, Gorriti 237, Jujuy, Argentina e Instituto de Bio y Geociencias, Universidad Nacional de Salta, Mendoza 2, 4400, Salta, Argentina
- 2Facultad de Ciencias Agrarias, Universidad Nacional de Jujuy, Alberdi 47, 4600, Jujuy, Argentina
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Caro T, Melville C. Investigating colouration in large and rare mammals: the case of the giant anteater. ETHOL ECOL EVOL 2012. [DOI: 10.1080/03949370.2011.587835] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/14/2022]
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45
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Stankowich T, Caro T, Cox M. BOLD COLORATION AND THE EVOLUTION OF APOSEMATISM IN TERRESTRIAL CARNIVORES. Evolution 2011; 65:3090-9. [DOI: 10.1111/j.1558-5646.2011.01334.x] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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46
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47
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Matter SF, Roland J. Effects of experimental population extinction for the spatial population dynamics of the butterfly Parnassius smintheus. OIKOS 2010. [DOI: 10.1111/j.1600-0706.2010.18666.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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48
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Abstract
Defensive coloration that reduces the risk of predation is considered to be widespread in animals. Many closely related species adopt differing coloration strategies during the life cycle, including crypsis, conspicuousness, and ontogenic change between the two coloration types. Here, we use a dynamic state-dependent approach to use ecological and intrinsic factors to predict the proportion of the developmental period of immature animals that should be spent as cryptic or conspicuous, and when conspicuous coloration should be reliably associated with investment in defenses. The model predicts that animals should change color more than once during development only in specific circumstances. In contrast, change from crypsis to conspicuous can occur over a range of conditions related to the frequency of detection by predators, but may also depend on the opportunity costs of crypsis and the effect of size on the deterrent effect of conspicuous coloration. We also report the results of a survey of coloration strategies in lepidopteron larvae, and note a qualitative agreement with the predictions of our model in the relationship between body size and coloration strategy. Our results provide explanations for several widespread antipredator coloration phenomena in prey animals, and provide a comprehensive predictive framework for the types of coloration strategies that are employed in nature.
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Affiliation(s)
- Andrew D Higginson
- Division of Ecology & Evolutionary Biology, Faculty of Biomedical & Life Sciences, University of Glasgow, Glasgow G12 8QQ, United Kingdom.
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49
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Stuart-Fox D, Moussalli A. Camouflage, communication and thermoregulation: lessons from colour changing organisms. Philos Trans R Soc Lond B Biol Sci 2009; 364:463-70. [PMID: 19000973 DOI: 10.1098/rstb.2008.0254] [Citation(s) in RCA: 175] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Organisms capable of rapid physiological colour change have become model taxa in the study of camouflage because they are able to respond dynamically to the changes in their visual environment. Here, we briefly review the ways in which studies of colour changing organisms have contributed to our understanding of camouflage and highlight some unique opportunities they present. First, from a proximate perspective, comparison of visual cues triggering camouflage responses and the visual perception mechanisms involved can provide insight into general visual processing rules. Second, colour changing animals can potentially tailor their camouflage response not only to different backgrounds but also to multiple predators with different visual capabilities. We present new data showing that such facultative crypsis may be widespread in at least one group, the dwarf chameleons. From an ultimate perspective, we argue that colour changing organisms are ideally suited to experimental and comparative studies of evolutionary interactions between the three primary functions of animal colour patterns: camouflage; communication; and thermoregulation.
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Affiliation(s)
- Devi Stuart-Fox
- Department of Zoology, The University of Melbourne, Melbourne, Victoria 3010, Australia.
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50
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Stevens M, Merilaita S. Defining disruptive coloration and distinguishing its functions. Philos Trans R Soc Lond B Biol Sci 2009; 364:481-8. [PMID: 18990673 DOI: 10.1098/rstb.2008.0216] [Citation(s) in RCA: 195] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Disruptive coloration breaks up the shape and destroys the outline of an object, hindering detection. The principle was first suggested approximately a century ago, but, although research has significantly increased, the field remains conceptually unstructured and no unambiguous definition exists. This has resulted in variable use of the term, making it difficult to formulate testable hypotheses that are comparable between studies, slowing down advancement in this field. Related to this, a range of studies do not effectively distinguish between disruption and other forms of camouflage. Here, we give a formal definition of disruptive coloration, reorganize a range of sub-principles involved in camouflage and argue that five in particular are specifically related to disruption: differential blending; maximum disruptive contrast; disruption of surface through false edges; disruptive marginal patterns; and coincident disruptive coloration. We discuss how disruptive coloration can be optimized, how it can relate to other forms of camouflage markings and where future work is particularly needed.
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Affiliation(s)
- Martin Stevens
- Department of Zoology, University of Cambridge, Downing Street, Cambridge CB2 3EJ, UK.
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