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Van Tran D, Nishikawa K. Variation in Ventral Coloration Pattern and Aposematism in Tropical Warty Newts. Zoolog Sci 2024; 41:275-280. [PMID: 38809866 DOI: 10.2108/zs230109] [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: 11/13/2023] [Accepted: 01/23/2024] [Indexed: 05/31/2024]
Abstract
Aposematic coloration plays a crucial role in animal defense, and it is shaped by a complex interplay of factors such as physiological limitations and sexual and natural selection. Warty newts within the genus Paramesotriton exhibit significant variation in ventral coloration. In this study, we quantified the percentage of red ventral area to investigate aposematic ventral coloration in Paramesotriton deloustali and P. guangxiensis across eight populations in northern Vietnam. To assess the interaction between predators and the aposematic signals, we conducted experiments employing three types of clay replicas of newts: dorsal, red ventral, and black ventral models. Our findings revealed a significant variation in the red ventral area among different populations. Additionally, a significant correlation was detected between the red ventral area of the newt and the annual temperature range. In clay model experiments, a significant difference in predator attack rates was observed between dorsal and ventral clay models. Interestingly, there was no significant difference in attack rates between red and black ventral types. Our study suggested that the variation in the red ventral area of warty newts is probably influenced by multiple factors, including genetic constraints, sex, ambient environment, and diet. Furthermore, our results supported the effectiveness of displaying aposematic coloration as an antipredator defense mechanism in warty newts. However, variations in body size and the pressure of mammal predation might not play a significant role in determining aposematic coloration.
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Affiliation(s)
- Dung Van Tran
- Graduate School of Human and Environmental Studies, Kyoto University, Yoshida Nihonmatsu-cho, Sakyo-ku, Kyoto 606-8501, Japan,
- Vietnam National University of Forestry, Xuan Mai, Chuong My, Ha Noi, Vietnam
| | - Kanto Nishikawa
- Graduate School of Human and Environmental Studies, Kyoto University, Yoshida Nihonmatsu-cho, Sakyo-ku, Kyoto 606-8501, Japan
- Graduate School of Global Environmental Studies, Kyoto University, Yoshida Hon-machi, Sakyo-ku, Kyoto 606-8501, Japan
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2
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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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3
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Mochida K, Mori A. Antipredator behavior of newts (Cynops pyrrhogaster) against snakes. PLoS One 2021; 16:e0258218. [PMID: 34843491 PMCID: PMC8629279 DOI: 10.1371/journal.pone.0258218] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2021] [Accepted: 09/21/2021] [Indexed: 11/29/2022] Open
Abstract
Newts and salamanders show remarkable diversity in antipredator behavior, developed to enhance their chemical defenses and/or aposematism. The present study reports on the antipredator behavior of newts (Cynops pyrrhogaster) in response to snakes. Newts displayed a significant amount of tail-wagging and tail-undulation in response to a contact stimulus from the snake’s tongue, which is a snake-specific predator stimulus, as compared to a control stimulus (behavioral scores: tongue, 1.05 ± 0.41; control, 0.15 ± 0.15). Newts that were kept in warm temperature conditions, 20°C (at which snakes are active in nature), performed tail displays more frequently than newts kept in low-temperature conditions, 4°C (at which snakes are inactive in nature). Our results suggest that the tail displays of C. pyrrhogaster could function as an antipredator defense; they direct a snake’s attention to its tail to prevent the snake from attacking more vulnerable body parts. We also discussed the reason for inter-populational variation in the tendency of newts to perform tail displays.
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Affiliation(s)
- Koji Mochida
- Department of Zoology, Graduate School of Science, Kyoto University, Kyoto, Japan
- Wildlife Research Center, Kyoto University, Kyoto, Japan
- Primate Research Institute, Kyoto University, Kyoto, Japan
- Nagasaki Institute of Applied Science, Kyoto, Japan
- * E-mail:
| | - Akira Mori
- Department of Zoology, Graduate School of Science, Kyoto University, Kyoto, Japan
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4
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Gordon SP, Burdfield-Steel E, Kirvesoja J, Mappes J. Safety in Numbers: How Color Morph Frequency Affects Predation Risk in an Aposematic Moth. Am Nat 2021; 198:128-141. [PMID: 34143722 DOI: 10.1086/714528] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
AbstractPolymorphic warning signals in aposematic systems are enigmatic because predator learning should favor the most common form, creating positive frequency-dependent survival. However, many populations exhibit variation in warning signals. There are various selective mechanisms that can counter positive frequency-dependent selection and lead to temporal or spatial warning signal diversification. Examining these mechanisms and their effects requires first confirming whether the most common morphs are favored at both local and regional scales. Empirical examples of this are uncommon and often include potentially confounding factors, such as a lack of knowledge of predator identity and behavior. We tested how bird behavior influences the survival of three coexisting morphs of the aposematic wood tiger moth Arctia plantaginis offered to a sympatric predator (great tit Parus major) at different frequencies. We found that although positive frequency-dependent selection is present, its strength is affected by predator characteristics and varying prey profitability. These results highlight the need to understand predator foraging in natural communities with variable prey defenses in order to better examine how behavioral interactions shape evolutionary outcomes.
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5
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Galarza JA. Comparative transcriptomics of albino and warningly-coloured caterpillars. Ecol Evol 2021; 11:7507-7517. [PMID: 34188830 PMCID: PMC8216890 DOI: 10.1002/ece3.7581] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2020] [Revised: 03/29/2021] [Accepted: 04/01/2021] [Indexed: 12/23/2022] Open
Abstract
Coloration is perhaps one of the most prominent adaptations for survival and reproduction of many taxa. Coloration is of particular importance for aposematic species, which rely on their coloring and patterning acting as a warning signal to deter predators. Most research has focused on the evolution of warning coloration by natural selection. However, little information is available for color mutants of aposematic species, particularly at the genomic level. Here, I compare the transcriptomes of albino mutant caterpillars of the aposematic wood tiger moth (Arctia plantaginis) to those of their full sibs having their distinctive orange-black warning coloration. The results showed >290 differentially expressed genes genome-wide. Genes involved in the immune system, structural constituents of cuticular, and immunity were mostly downregulated in the albino caterpillars. Surprisingly, higher expression was observed in core melanin genes from albino caterpillars, suggesting that melanin synthesis may be disrupted in terminal ends of the pathway during its final conversion. Taken together, these results suggest that caterpillar albinism may not be due to a depletion of melanin precursor genes. In contrast, the albino condition may result from the combination of faulty melanin conversion late in its synthesis and structural deficiencies in the cuticular preventing its deposition. The results are discussed in the context of how albinism may impact individuals of aposematic species in the wild.
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Affiliation(s)
- Juan A. Galarza
- Dpartment of Biological and Environmental ScienceUniversity of JyväskyläJyväskyläFinland
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6
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Rönkä K, Valkonen JK, Nokelainen O, Rojas B, Gordon S, Burdfield‐Steel E, Mappes J. Geographic mosaic of selection by avian predators on hindwing warning colour in a polymorphic aposematic moth. Ecol Lett 2020; 23:1654-1663. [DOI: 10.1111/ele.13597] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2020] [Revised: 05/16/2020] [Accepted: 07/28/2020] [Indexed: 01/05/2023]
Affiliation(s)
- Katja Rönkä
- Department of Biological and Environmental Science University of Jyväskylä Jyväskylä Finland
- Helsinki Institute of Life SciencesUniversity of Helsinki Helsinki Finland
- Organismal and Evolutionary Biology Research Programme Faculty of Biological and Environmental Sciences University of Helsinki Helsinki Finland
| | - Janne K. Valkonen
- Department of Biological and Environmental Science University of Jyväskylä Jyväskylä Finland
| | - Ossi Nokelainen
- Department of Biological and Environmental Science University of Jyväskylä Jyväskylä Finland
| | - Bibiana Rojas
- Department of Biological and Environmental Science University of Jyväskylä Jyväskylä Finland
| | - Swanne Gordon
- Department of Biological and Environmental Science University of Jyväskylä Jyväskylä Finland
- Department of Biology Washington University in St. Louis St. Louis MO USA
| | - Emily Burdfield‐Steel
- Department of Biological and Environmental Science University of Jyväskylä Jyväskylä Finland
- Institute for Biodiversity and Ecosystem Dynamics University of Amsterdam Amsterdam The Netherlands
| | - Johanna Mappes
- Department of Biological and Environmental Science University of Jyväskylä Jyväskylä Finland
- Organismal and Evolutionary Biology Research Programme Faculty of Biological and Environmental Sciences University of Helsinki Helsinki Finland
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7
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Dallagnol Vargas N, Guimarães M, Caorsi V, Wolff Bordignon D, Borges‐Martins M. An experimental assessment of the antipredatory function of green dorsal coloration in poisonous Neotropical red‐bellied toads. J Zool (1987) 2019. [DOI: 10.1111/jzo.12740] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Affiliation(s)
- Natália Dallagnol Vargas
- Programa de Pós‐graduação em Biologia Animal Departamento de Zoologia Instituto de Biociências Universidade Federal do Rio Grande do Sul Porto Alegre Rio Grande do Sul Brazil
| | - Murilo Guimarães
- Programa de Pós‐graduação em Biologia Animal Departamento de Zoologia Instituto de Biociências Universidade Federal do Rio Grande do Sul Porto Alegre Rio Grande do Sul Brazil
| | - Valentina Caorsi
- Programa de Pós‐graduação em Biologia Animal Departamento de Zoologia Instituto de Biociências Universidade Federal do Rio Grande do Sul Porto Alegre Rio Grande do Sul Brazil
- The Istituto Agrario di San Michele all’Adige Research and Innovation Centre Fondazione Edmund Mach San Michele all’Adige TN Italy
| | - Debora Wolff Bordignon
- Programa de Pós‐graduação em Biologia Animal Departamento de Zoologia Instituto de Biociências Universidade Federal do Rio Grande do Sul Porto Alegre Rio Grande do Sul Brazil
| | - Márcio Borges‐Martins
- Programa de Pós‐graduação em Biologia Animal Departamento de Zoologia Instituto de Biociências Universidade Federal do Rio Grande do Sul Porto Alegre Rio Grande do Sul Brazil
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8
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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 2019; 94:388-414. [PMID: 30152037 PMCID: PMC6446817 DOI: 10.1111/brv.12460] [Citation(s) in RCA: 68] [Impact Index Per Article: 13.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [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 SciencesUniversity of ExeterPenryn Campus, Penryn, Cornwall, TR10 9FEU.K.
| | - Emily R. Burdfield‐Steel
- Centre of Excellence in Biological Interactions, Department of Biological and Environmental ScienceUniversity of JyväskyläJyväskylä, 40014Finland
| | - Sarah C. Paul
- Centre for Ecology & Conservation, College of Life & Environmental SciencesUniversity of ExeterPenryn Campus, Penryn, Cornwall, TR10 9FEU.K.
- Department of Chemical EcologyBielefeld UniversityUniversitätsstraße 25, 33615, BielefeldGermany
| | - Katja H. Rönkä
- Centre of Excellence in Biological Interactions, Department of Biological and Environmental ScienceUniversity of JyväskyläJyväskylä, 40014Finland
- Organismal and Evolutionary Biology Research Programme, Faculty of Biological and Environmental SciencesUniversity of HelsinkiHelsinki, 00014Finland
| | - Brett M. Seymoure
- Department of BiologyColorado State UniversityFort CollinsCO 80525U.S.A.
- Department of Fish, Wildlife, and Conservation BiologyColorado State UniversityFort CollinsCO 80525U.S.A.
| | - Theodore Stankowich
- Department of Biological SciencesCalifornia State UniversityLong BeachCA 90840U.S.A.
| | - Adam M. M. Stuckert
- Department of BiologyEast Carolina University1000 E Fifth St, GreenvilleNC 27858U.S.A.
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9
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Fabricant SA, Burdfield-Steel ER, Umbers K, Lowe EC, Herberstein ME. Warning signal plasticity in hibiscus harlequin bugs. Evol Ecol 2018. [DOI: 10.1007/s10682-018-9946-3] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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10
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Rojas B, Burdfield-Steel E, De Pasqual C, Gordon S, Hernández L, Mappes J, Nokelainen O, Rönkä K, Lindstedt C. Multimodal Aposematic Signals and Their Emerging Role in Mate Attraction. Front Ecol Evol 2018. [DOI: 10.3389/fevo.2018.00093] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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11
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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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12
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Clemente-Carvalho RB, Vaira M, King LE, Koscinski D, Bonansea MI, Lougheed SC. Phytogeographic patterns and cryptic diversity in an aposematic toad from NW Argentina. Mol Phylogenet Evol 2017; 116:248-256. [PMID: 28750851 DOI: 10.1016/j.ympev.2017.07.013] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2016] [Revised: 07/19/2017] [Accepted: 07/20/2017] [Indexed: 11/15/2022]
Abstract
The Yungas Redbelly Toad, Melanophryniscus rubriventris, is patchily distributed in Argentina, confined to the upland portion (1000-2000m above sea level) of the montane forests of northern and central regions of Salta, and in central-eastern and south-eastern Jujuy. This species is known for its striking aposematic color variation across its geographic distribution, and was once treated as a complex of three subspecies based on distinctive color patterns. Here we assess the geographical genetic variation within M. rubriventris and quantify divergence in color and pattern among individuals sampled from Northwestern Argentina. We compare multi-gene phylogeography of M. rubriventris to patterns of dorsal and ventral coloration to test whether evolutionary affinities predict variation in warning color. Our results reveal two well-supported species lineages: one confined to the extreme northern portion of our sampling area, and the other extending over most of the Argentine portion of the species' range, within which there are two populations. However, these well-supported evolutionary relationships do not mirror the marked variation in warning coloration. This discordance between DNA genealogy and warning color variation may reflect selection brought about by differences in local predation pressures, potentially coupled with effects of sexual selection and thermoregulation.
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Affiliation(s)
| | - Marcos Vaira
- Centro de Investigaciones y Transferencia de Jujuy, Conicet - Universidad Nacional de Jujuy, Gorriti 237, 4600 S.S. de Jujuy, Argentina.
| | - Laura E King
- Wildlife Preservation Canada, 5420 Highway 6 North Guelph, Ontario, N1H 6J2, Canada.
| | - Daria Koscinski
- Department of Biology, University of Western Ontario, London, Ontario, N6A 5B7, Canada.
| | - Maria I Bonansea
- Facultad de Ciencias Agrarias, Universidad Nacional de Jujuy, Alberdi 47, 4600 S. S. de Jujuy, Argentina.
| | - Stephen C Lougheed
- Department of Biology, Queen's University, Kingston, Ontario K7L 3N6, Canada.
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13
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Arenas LM, Stevens M. Diversity in warning coloration is easily recognized by avian predators. J Evol Biol 2017; 30:1288-1302. [PMID: 28338250 PMCID: PMC5518184 DOI: 10.1111/jeb.13074] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2016] [Revised: 01/14/2017] [Accepted: 03/10/2017] [Indexed: 11/29/2022]
Abstract
Warning coloration is a widespread strategy to alert predators about prey unprofitability. The success of this strategy partly depends on predators being able to learn and recognize certain signals as indicators of toxicity, and theory predicts that this is easier if signals converge on similar colours. However, the diversity in warning signal form is astonishing, contradicting predictions. Here, we quantified ladybird signal diversity with respect to avian vision, measuring how unique and discernible each signal is from one another. In addition, we measured signal conspicuousness against a series of backgrounds, namely an average green, average brown, and where we collected each species, to determine whether signals are more contrasting against the ladybirds' local substrates than compared to average ones. This allowed us to establish whether there are local adaptations in conspicuousness that promote signal diversity. We found that while ladybird signals are unique and recognizable, specialist species are more contrasting against the background they are most commonly found on. However, overall our study suggests that warning signals have evolved to be effective against a wide range of natural backgrounds, partly explaining the success of this strategy in nature.
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Affiliation(s)
- L M Arenas
- Department of Zoology, University of Cambridge, Cambridge, UK.,Centre for Ecology & Conservation, College of Life & Environmental Sciences, University of Exeter, Penryn, Cornwall, UK
| | - M Stevens
- Centre for Ecology & Conservation, College of Life & Environmental Sciences, University of Exeter, Penryn, Cornwall, UK
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14
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Rowland HM, Fulford AJ, Ruxton GD. Predator learning differences affect the survival of chemically defended prey. Anim Behav 2017. [DOI: 10.1016/j.anbehav.2016.11.029] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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15
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Pegram KV, Han HA, Rutowski RL. Warning Signal Efficacy: Assessing the Effects of Color, Iridescence, and Time of Day in the Field. Ethology 2015. [DOI: 10.1111/eth.12403] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
| | - Hanh A. Han
- School of Life Sciences; Arizona State University; Tempe AZ USA
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16
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Paluh DJ, Kenison EK, Saporito RA. Frog or Fruit? The Importance of Color and Shape to Bird Predators in Clay Model Experiments. COPEIA 2015. [DOI: 10.1643/ce-13-126] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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17
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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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18
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Rojas DP, Stow A, Amézquita A, Simões PI, Lima AP. No predatory bias with respect to colour familiarity for the aposematic Adelphobates galactonotus (Anura: Dendrobatidae). BEHAVIOUR 2015. [DOI: 10.1163/1568539x-00003297] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Aposematic colouration deters visually oriented predators because conspicuous signals are easier to detect and associate with unpalatability. Consequently, brightly coloured prey that are novel are predicted to be preyed on more than those with bright but typical colours. Here we evaluated whether predatory bias is associated with the colour differences observed at two different localities for a large, conspicuously coloured and poisonous Amazonian frog, Adelphobates galactonotus. At each locality predation experiments were carried out using frog models of two naturally occurring colours of the study species (blue and orange) and a control (brown). We found no evidence that novel colours were more vulnerable to predation than local colours. These results do not therefore support our hypothesis that predatory bias explains the geographic variation of colour in A. galactonotus.
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Affiliation(s)
- Diana Patricia Rojas
- aCoordenação de Biodiversidade, Instituto Nacional de Pesquisas da Amazônia, P.O. Box 2223, 69011-970 Manaus, AM, Brazil
| | - Adam Stow
- bDepartment of Biological Sciences, Macquarie University, Sydney, NSW, Australia
| | - Adolfo Amézquita
- cDepartment of Biological Sciences, Universidad de los Andes, Bogotá, Colombia
| | - Pedro Ivo Simões
- aCoordenação de Biodiversidade, Instituto Nacional de Pesquisas da Amazônia, P.O. Box 2223, 69011-970 Manaus, AM, Brazil
- dLaboratório de Sistemática de Vertebrados, Pontificia Universidade Católica do Rio Grande do Sul, Porto Alegre, RS, Brazil
| | - Albertina Pimentel Lima
- aCoordenação de Biodiversidade, Instituto Nacional de Pesquisas da Amazônia, P.O. Box 2223, 69011-970 Manaus, AM, Brazil
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19
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20
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Galarza JA, Nokelainen O, Ashrafi R, Hegna RH, Mappes J. Temporal relationship between genetic and warning signal variation in the aposematic wood tiger moth (Parasemia plantaginis). Mol Ecol 2014; 23:4939-57. [PMID: 25211063 DOI: 10.1111/mec.12913] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2013] [Revised: 09/05/2014] [Accepted: 09/08/2014] [Indexed: 11/29/2022]
Abstract
Many plants and animals advertise unpalatability through warning signals in the form of colour and shape. Variation in warning signals within local populations is not expected because they are subject to directional selection. However, mounting evidence of warning signal variation within local populations suggests that other selective forces may be acting. Moreover, different selective pressures may act on the individual components of a warning signal. At present, we have a limited understanding about how multiple selection processes operate simultaneously on warning signal components, and even less about their temporal and spatial dynamics. Here, we examined temporal variation of several wing warning signal components (colour, UV-reflectance, signal size and pattern) of two co-occurring colour morphs of the aposematic wood tiger moth (Parasemia plantaginis). Sampling was carried out in four geographical regions over three consecutive years. We also evaluated each morph's temporal genetic structure by analysing mitochondrial sequence data and nuclear microsatellite markers. Our results revealed temporal differences between the morphs for most signal components measured. Moreover, variation occurred differently in the fore- and hindwings. We found no differences in the genetic structure between the morphs within years and regions, suggesting single local populations. However, local genetic structure fluctuated temporally. Negative correlations were found between variation produced by neutrally evolving genetic markers and those of the different signal components, indicating a non-neutral evolution for most warning signal components. Taken together, our results suggest that differential selection on warning signal components and fluctuating population structure can be one explanation for the maintenance of warning signal variation in this aposematic species.
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Affiliation(s)
- Juan A Galarza
- Centre of Excellence in Biological Interactions, Department of Biological and Environmental Science, University of Jyväskylä, Survontie 9, Jyväskylä, 40500, Finland
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21
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Speed MP, Franks DW. Antagonistic evolution in an aposematic predator-prey signaling system. Evolution 2014; 68:2996-3007. [PMID: 25132560 DOI: 10.1111/evo.12498] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2013] [Accepted: 07/02/2014] [Indexed: 11/29/2022]
Abstract
Warning signals within species, such as the bright colors of chemically defended animals, are usually considered mutualistic, monomorphic traits. Such a view is however increasingly at odds with the growing empirical literature, showing nontrivial levels of signal variation within prey populations. Key to understanding this variation, we argue, could be a recognition that toxicity levels frequently vary within populations because of environmental heterogeneity. Inequalities in defense may undermine mutualistic monomorphic signaling, causing evolutionary antagonism between loci that determine appearance of less well-defended and better defended prey forms within species. In this article, we apply a stochastic model of evolved phenotypic plasticity to the evolution of prey signals. We show that when toxicity levels vary, then antagonistic interactions can lead to evolutionary conflict between alleles at different signaling loci, causing signal evolution, "red queen-like" evolutionary chase, and one or more forms of signaling equilibria. A key prediction is that variation in the way that predators use information about toxicity levels in their attack behaviors profoundly affects the evolutionary characteristics of the prey signaling systems. Environmental variation is known to cause variation in many qualities that organisms signal; our approach may therefore have application to other signaling systems.
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Affiliation(s)
- Michael P Speed
- Department of Evolution, Ecology and Behaviour, Institute of Integrative Biology, Faculty of Health and Life Sciences, University of Liverpool, Liverpool L69 7ZB, United Kingdom.
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22
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Fabricant SA, Herberstein ME. Hidden in plain orange: aposematic coloration is cryptic to a colorblind insect predator. Behav Ecol 2014. [DOI: 10.1093/beheco/aru157] [Citation(s) in RCA: 26] [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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23
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Willink B, García-Rodríguez A, Bolaños F, Pröhl H. The interplay between multiple predators and prey colour divergence. Biol J Linn Soc Lond 2014. [DOI: 10.1111/bij.12355] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Affiliation(s)
- Beatriz Willink
- Escuela de Biología; Universidad de Costa Rica; Ciudad Universitaria Rodrigo Facio 2060 San José Costa Rica
- Department of Biology; Lund University; SE-223 62 Lund Sweden
| | - Adrián García-Rodríguez
- Museo de Zoología; Universidad de Costa Rica; Ciudad Universitaria Rodrigo Facio 2060 San José Costa Rica
- Departamento de Botanica, Ecologia e Zoologia; Universidade Federal do Rio Grande do Norte; Natal Rio Grande do Norte Brazil
| | - Federico Bolaños
- Escuela de Biología; Universidad de Costa Rica; Ciudad Universitaria Rodrigo Facio 2060 San José Costa Rica
| | - Heike Pröhl
- Institute of Zoology; University of Veterinary Medicine of Hannover; Bünteweg 17 30559 Hannover Germany
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24
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A Test of Aposematism in the Dendrobatid Poison FrogOophaga pumilio: The Importance of Movement in Clay Model Experiments. J HERPETOL 2014. [DOI: 10.1670/13-027] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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25
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Sanabria EA, Vaira M, Quiroga LB, Akmentins MS, Pereyra LC. Variation of thermal parameters in two different color morphs of a diurnal poison toad, Melanophryniscus rubriventris (Anura: Bufonidae). J Therm Biol 2014; 41:1-5. [PMID: 24679965 DOI: 10.1016/j.jtherbio.2014.01.005] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2013] [Revised: 01/28/2014] [Accepted: 01/29/2014] [Indexed: 11/15/2022]
Abstract
We study the variation in thermal parameters in two contrasting populations Yungas Redbelly Toads (Melanophryniscus rubriventris) with different discrete color phenotypes comparing field body temperatures, critical thermal maximum and heating rates. We found significant differences in field body temperatures of the different morphs. Temperatures were higher in toads with a high extent of dorsal melanization. No variation was registered in operative temperatures between the study locations at the moment of capture and processing. Critical thermal maximum of toads was positively related with the extent of dorsal melanization. Furthermore, we founded significant differences in heating rates between morphs, where individuals with a high extent of dorsal melanization showed greater heating rates than toads with lower dorsal melanization. The color pattern-thermal parameter relationship observed may influence the activity patterns and body size of individuals. Body temperature is a modulator of physiological and behavioral functions in amphibians, influencing daily and seasonal activity, locomotor performance, digestion rate and growth rate. It is possible that some growth constraints may arise due to the relationship of color pattern-metabolism allowing different morphs to attain similar sizes at different locations instead of body-size clines.
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Affiliation(s)
- Eduardo A Sanabria
- CONICET, Instituto de Ciencias Básicas, Facultad de Filosofía Humanidades y Artes, Universidad Nacional de San Juan, Avenida José Ignacio de la Roza 230 (O), 5400 San Juan, Argentina.
| | - Marcos Vaira
- Centro de Investigaciones y Transferencia de Jujuy (CIT-JUJUY) CONICET, Universidad Nacional de Jujuy, Av. Bolivia 1711 (4600), Jujuy, Argentina; San Salvador de Jujuy, Argentinae Instituto de Bio y Geociencias del NOA, Universidad Nacional de Salta, Salta, Argentina.
| | - Lorena B Quiroga
- Departamento de Biología, Facultad de Ciencias Exactas, Físicas y Naturales, Universidad Nacional de San Juan, San Juan, Argentina.
| | - Mauricio S Akmentins
- Centro de Investigaciones y Transferencia de Jujuy (CIT-JUJUY) CONICET, Universidad Nacional de Jujuy, Av. Bolivia 1711 (4600), Jujuy, Argentina; San Salvador de Jujuy, Argentinae Instituto de Bio y Geociencias del NOA, Universidad Nacional de Salta, Salta, Argentina.
| | - Laura C Pereyra
- Centro de Investigaciones y Transferencia de Jujuy (CIT-JUJUY) CONICET, Universidad Nacional de Jujuy, Av. Bolivia 1711 (4600), Jujuy, Argentina; San Salvador de Jujuy, Argentinae Instituto de Bio y Geociencias del NOA, Universidad Nacional de Salta, Salta, Argentina.
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26
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Chatelain M, Halpin C, Rowe C. Ambient temperature influences birds' decisions to eat toxic prey. Anim Behav 2013; 86:733-740. [PMID: 24109148 PMCID: PMC3791422 DOI: 10.1016/j.anbehav.2013.07.007] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2013] [Revised: 05/16/2013] [Accepted: 07/03/2013] [Indexed: 02/04/2023]
Abstract
Aposematic prey warn predators of their toxicity using conspicuous signals. However, predators regularly include aposematic prey in their diets, particularly when they are in a poor energetic state and in need of nutrients. We investigated whether or not an environmental factor, ambient temperature, could change the energetic state of predators and lead to an increased intake of prey that they know to contain toxins. We found that European starlings, Sturnus vulgaris, increased their consumption of mealworm, Tenebrio molitor, prey containing quinine (a mild toxin) when the ambient temperature was reduced below their thermoneutral zone from 20 °C to 6 °C. The birds differed in their sensitivity to changes in ambient temperature, with heavier birds increasing the number of toxic prey they ate more rapidly with decreasing temperature compared to birds with lower body mass. This could have been the result of their requiring more nutrients at lower temperatures or being better able to detoxify quinine. Taken together, our results suggest that conspicuous coloration may be more costly at lower temperatures, and that aposematic prey may need to invest more in chemical defences as temperatures decline. Our study also provides novel insights into what factors affect birds' decisions to eat toxic prey, and demonstrates that selection pressures acting on prey defences can vary with changing temperature across days, seasons, climes, and potentially in response to climate change. We investigated the effect of temperature on birds' decisions to eat toxic prey. As it got cooler, birds were more likely to eat prey containing toxins. Heavier birds were more sensitive to changes in temperature. Selection pressures on prey defences will change over days, seasons and climes.
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Affiliation(s)
- M. Chatelain
- Museum National d'Histoire Naturelle, Paris, France
| | - C.G. Halpin
- Centre for Behaviour and Evolution, Institute of Neuroscience, Newcastle University, Newcastle, U.K
| | - C. Rowe
- Centre for Behaviour and Evolution, Institute of Neuroscience, Newcastle University, Newcastle, U.K
- Correspondence: C. Rowe, Centre for Behaviour and Evolution, Institute of Neuroscience, Newcastle University, Henry Wellcome Building, Framlington Place, Newcastle NE2 4HH, U.K.
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27
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Mochida K, Kitada M, Ikeda K, Toda M, Takatani T, Arakawa O. Spatial and Temporal Instability of Local Biotic Community Mediate a Form of Aposematic Defense in Newts, Consisting of Carotenoid-Based Coloration and Tetrodotoxin. J Chem Ecol 2013; 39:1186-92. [DOI: 10.1007/s10886-013-0342-8] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2013] [Revised: 07/31/2013] [Accepted: 08/29/2013] [Indexed: 11/27/2022]
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28
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Parasite infection has little effect on sexual signals and reproductive behaviour in strawberry poison frogs. Evol Ecol 2013. [DOI: 10.1007/s10682-013-9634-2] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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29
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Adaptive colouration in amphibians. Semin Cell Dev Biol 2013; 24:553-61. [DOI: 10.1016/j.semcdb.2013.05.004] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2012] [Revised: 04/12/2013] [Accepted: 05/01/2013] [Indexed: 11/20/2022]
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30
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Willink B, Brenes-Mora E, Bolaños F, Pröhl H. Not everything is black and white: color and behavioral variation reveal a continuum between cryptic and aposematic strategies in a polymorphic poison frog. Evolution 2013; 67:2783-94. [PMID: 24094333 DOI: 10.1111/evo.12153] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2012] [Accepted: 04/15/2013] [Indexed: 11/28/2022]
Abstract
Aposematism and crypsis are often viewed as two extremes of a continuum of visual conspicuousness to predators. Theory predicts that behavioral and coloration conspicuousness should vary in tandem along the conspicuousness spectrum for antipredator strategies to be effective. Here we used visual modeling of contrast and behavioral observations to examine the conspicuousness of four populations of the granular poison frog, Oophaga granulifera, which exhibits almost continuous variation in dorsal color. The patterns of geographic variation in color, visual contrast, and behavior support a gradient of overall conspicuousness along the distribution of O. granulifera. Red and green populations, at the extremes of the color distribution, differ in all elements of color, contrast, and behavior, strongly reflecting aposematic and cryptic strategies. However, there is no smooth cline in any elements of behavior or coloration between the two extremes. Instead populations of intermediate colors attain intermediate conspicuousness by displaying different combinations of aposematic and cryptic traits. We argue that coloration divergence among populations may be linked to the evolution of a gradient of strategies to balance the costs of detection by predators and the benefits of learned aversion.
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Affiliation(s)
- Beatriz Willink
- Sistema de Estudios de Posgrado, Universidad de Costa Rica, Ciudad Universitaria, San José, 2060, Costa Rica.
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31
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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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32
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Valkonen JK, Nokelainen O, Niskanen M, Kilpimaa J, Björklund M, Mappes J. Variation in predator species abundance can cause variable selection pressure on warning signaling prey. Ecol Evol 2012; 2:1971-6. [PMID: 22957197 PMCID: PMC3433999 DOI: 10.1002/ece3.315] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2012] [Revised: 06/08/2012] [Accepted: 06/12/2012] [Indexed: 11/22/2022] Open
Abstract
Predation pressure is expected to drive visual warning signals to evolve toward conspicuousness. However, coloration of defended species varies tremendously and can at certain instances be considered as more camouflaged rather than conspicuous. Recent theoretical studies suggest that the variation in signal conspicuousness can be caused by variation (within or between species) in predators' willingness to attack defended prey or by the broadness of the predators' signal generalization. If some of the predator species are capable of coping with the secondary defenses of their prey, selection can favor reduced prey signal conspicuousness via reduced detectability or recognition. In this study, we combine data collected during three large-scale field experiments to assess whether variation in avian predator species (red kite, black kite, common buzzard, short-toed eagle, and booted eagle) affects the predation pressure on warningly and non-warningly colored artificial snakes. Predation pressure varied among locations and interestingly, if common buzzards were abundant, there were disadvantages to snakes possessing warning signaling. Our results indicate that predator community can have important consequences on the evolution of warning signals. Predators that ignore the warning signal and defense can be the key for the maintenance of variation in warning signal architecture and maintenance of inconspicuous signaling.
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