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Monteiro JPC, Pröhl H, Lyra ML, Brunetti AE, de Nardin EC, Condez TH, Haddad CFB, Rodríguez A. Expression patterns of melanin-related genes are linked to crypsis and conspicuousness in a pumpkin toadlet. Mol Ecol 2024:e17458. [PMID: 38970414 DOI: 10.1111/mec.17458] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2023] [Revised: 06/14/2024] [Accepted: 06/24/2024] [Indexed: 07/08/2024]
Abstract
Colour signals play pivotal roles in different communication systems, and the evolution of these characters has been associated with behavioural ecology, integumentary production processes and perceptual mechanisms of the species involved. Here, we present the first insight into the molecular and histological basis of skin colour polymorphism within a miniaturized species of pumpkin toadlet, potentially representing the lowest size threshold for colour polytypism in tetrapods. Brachycephalus actaeus exhibits a coloration ranging from cryptic green to conspicuous orange skin, and our findings suggest that colour morphs differ in their capability to be detected by potential predators. We also found that the distribution and abundance of chromatophores are variable in the different colour morphs. The expression pattern of coloration related genes was predominantly associated with melanin synthesis (including dct, edn1, mlana, oca2, pmel, slc24a5, tyrp1 and wnt9a). Up-regulation of melanin genes in grey, green and brown skin was associated with higher melanophore abundance than in orange skin, where xanthophores predominate. Our findings provide a significant foundation for comparing and understanding the diverse pathways that contribute to the evolution of pigment production in the skin of amphibians.
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Affiliation(s)
- Juliane P C Monteiro
- Post-Graduate Program in Biodiversity, Institute of Biosciences, São Paulo State University (UNESP), Rio Claro, São Paulo, Brazil
- Department of Biodiversity and Aquaculture Center (CAUNESP), Institute of Biosciences, São Paulo State University (UNESP), Rio Claro, São Paulo, Brazil
- Center for Research on Biodiversity Dynamics and Climate Change, Institute of Biosciences, São Paulo State University (UNESP), Rio Claro, São Paulo, Brazil
- Institute of Zoology, University of Veterinary Medicine of Hannover, Hannover, Lower Saxony, Germany
| | - Heike Pröhl
- Institute of Zoology, University of Veterinary Medicine of Hannover, Hannover, Lower Saxony, Germany
| | - Mariana L Lyra
- Center for Research on Biodiversity Dynamics and Climate Change, Institute of Biosciences, São Paulo State University (UNESP), Rio Claro, São Paulo, Brazil
- New York University Abu Dhabi, Abu Dhabi, United Arab Emirates
| | - Andrés E Brunetti
- Center for Research on Biodiversity Dynamics and Climate Change, Institute of Biosciences, São Paulo State University (UNESP), Rio Claro, São Paulo, Brazil
- Institute of Subtropical Biology (IBS, UNaM-CONICET), Posadas, Misiones, Argentina
- Department of Insect Symbiosis, Max Planck Institute of Chemical Ecology, Jena, Thuringia, Germany
| | - Eli C de Nardin
- Department of Biodiversity and Aquaculture Center (CAUNESP), Institute of Biosciences, São Paulo State University (UNESP), Rio Claro, São Paulo, Brazil
| | - Thais H Condez
- Center for Research on Biodiversity Dynamics and Climate Change, Institute of Biosciences, São Paulo State University (UNESP), Rio Claro, São Paulo, Brazil
- Department of Earth Sciences, Carleton University, Ottawa, Ontario, Canada
| | - Célio F B Haddad
- Department of Biodiversity and Aquaculture Center (CAUNESP), Institute of Biosciences, São Paulo State University (UNESP), Rio Claro, São Paulo, Brazil
- Center for Research on Biodiversity Dynamics and Climate Change, Institute of Biosciences, São Paulo State University (UNESP), Rio Claro, São Paulo, Brazil
| | - Ariel Rodríguez
- Institute of Zoology, University of Veterinary Medicine of Hannover, Hannover, Lower Saxony, Germany
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2
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Gonzalez M, Carazzone C. Eco-Metabolomics Applied to the Chemical Ecology of Poison Frogs (Dendrobatoidea). J Chem Ecol 2023; 49:570-598. [PMID: 37594619 PMCID: PMC10725362 DOI: 10.1007/s10886-023-01443-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2023] [Revised: 07/03/2023] [Accepted: 07/05/2023] [Indexed: 08/19/2023]
Abstract
Amphibians are one of the most remarkable sources of unique natural products. Biogenic amines, peptides, bufodienolides, alkaloids, and volatile organic compounds have been characterized in different species. The superfamily Dendrobatoidea represents one of the most enigmatic cases of study in chemical ecology because their skin secretome is composed by a complex mixture (i.e. cocktail) of highly lethal and noxious unique alkaloid structures. While chemical defences from dendrobatoids (families Dendrobatidae and Aromobatidae) have been investigated employing ecological, behavioral, phylogenetic and evolutionary perspectives, studies about the analytical techniques needed to perform the chemical characterization have been neglected for many years. Therefore, our aim is to summarize the current methods applied for the characterization of chemical profiles in dendrobatoids and to illustrate innovative Eco-metabolomics strategies that could be translated to this study model. This approach could be extended to natural products other than alkaloids and implemented for the chemical analysis of different species of dendrobatoids employing both low- and high-resolution mass spectrometers. Here, we overview important biological features to be considered, procedures that could be applied to perform the chemical characterization, steps and tools to perform an Eco-metabolomic analysis, and a final discussion about future perspectives.
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Affiliation(s)
- Mabel Gonzalez
- Department of Chemistry, Universidad de los Andes, 4976, Bogotá, AA, Colombia.
- Department of Biology, Stanford University, Palo Alto, CA, 94305, USA.
| | - Chiara Carazzone
- Department of Chemistry, Universidad de los Andes, 4976, Bogotá, AA, Colombia.
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3
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Mould MC, Huet M, Senegas L, Milá B, Thébaud C, Bourgeois Y, Chaine AS. Beyond morphs: Inter-individual colour variation despite strong genetic determinism of colour morphs in a wild bird. J Evol Biol 2023; 36:82-94. [PMID: 36484624 PMCID: PMC10107803 DOI: 10.1111/jeb.14124] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2020] [Revised: 05/06/2022] [Accepted: 06/15/2022] [Indexed: 12/13/2022]
Abstract
Categorizing individuals into discrete forms in colour polymorphic species can overlook more subtle patterns in coloration that can be of functional significance. Thus, quantifying inter-individual variation in these species at both within- and between-morph levels is critical to understand the evolution of colour polymorphisms. Here we present analyses of inter-individual colour variation in the Reunion grey white-eye (Zosterops borbonicus), a colour polymorphic wild bird endemic to the island of Reunion in which all highland populations contain two sympatric colour morphs, with birds showing predominantly grey or brown plumage, respectively. We first quantified colour variation across multiple body areas by using a continuous plumage colour score to assess variation in brown-grey coloration as well as smaller scale variation in light patches. To examine the possible causes of among-individual variation, we tested if colour variation in plumage component elements could be explained by genotypes at two markers near a major-effect locus previously related to back coloration in this species, and by other factors such as age, sex and body condition. Overall, grey-brown coloration was largely determined by genetic factors and was best described by three distinct clusters that were associated to genotypic classes (homozygotes and heterozygote), with no effect of age or sex, whereas variation in smaller light patches was primarily related to age and sex. Our results highlight the importance of characterizing subtle plumage variation beyond morph categories that are readily observable since multiple patterns of colour variation may be driven by different mechanisms, have different functions and will likely respond in different ways to selection.
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Affiliation(s)
- Maya C Mould
- Station d'Ecologie Théorique et Expérimentale du CNRS and Université Paul Sabatier (Toulouse III), UPR 2001, Moulis, France
| | - Michèle Huet
- Station d'Ecologie Théorique et Expérimentale du CNRS and Université Paul Sabatier (Toulouse III), UPR 2001, Moulis, France
| | - Lou Senegas
- Station d'Ecologie Théorique et Expérimentale du CNRS and Université Paul Sabatier (Toulouse III), UPR 2001, Moulis, France
| | - Borja Milá
- National Museum of Natural Sciences, Spanish National Research Council (CSIC), Madrid, Spain
| | - Christophe Thébaud
- Laboratoire Évolution et Diversité Biologique (EDB), UMR 5174 Centre National de la Recherche Scientifique (CNRS), Institut de Recherche pour le Développement (IRD), Université Paul Sabatier (Toulouse III), Toulouse Cedex, France
| | - Yann Bourgeois
- School of Biological Sciences, University of Portsmouth, Portsmouth, UK
| | - Alexis S Chaine
- Station d'Ecologie Théorique et Expérimentale du CNRS and Université Paul Sabatier (Toulouse III), UPR 2001, Moulis, France.,Institute for Advanced Studies in Toulouse, Toulouse, France
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4
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Schlippe Justicia L, Fouilloux CA, Rojas B. Poison frog social behaviour under global change: potential impacts and future challenges. Acta Ethol 2022. [DOI: 10.1007/s10211-022-00400-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
AbstractThe current and cascading effects of global change challenges the interactions both between animal individuals (i.e. social and sexual behaviour) and the environment they inhabit. Amphibians are an ecologically diverse class with a wide range of social and sexual behaviours, making them a compelling model to understand the potential adaptations of animals faced with the effects of human-induced rapid environmental changes (HIREC). Poison frogs (Dendrobatoidea) are a particularly interesting system, as they display diverse social behaviours that are shaped by conspecific and environmental interactions, thus offering a tractable system to investigate how closely related species may respond to the impacts of HIREC. Here, we discuss the potential impacts of global change on poison frog behaviour, and the future challenges this group may face in response to such change. We pay special attention to parental care and territoriality, which are emblematic of this clade, and consider how different species may flexibly respond and adapt to increasingly frequent and diverse anthropogenic stress. More specifically, we hypothesise that some parents may increase care (i.e. clutch attendance and distance travelled for tadpole transport) in HIREC scenarios and that species with more generalist oviposition and tadpole deposition behaviours may fare more positively than their less flexible counterparts; we predict that the latter may either face increased competition for resources limited by HIREC or will be forced to adapt and expand their natural preferences. Likewise, we hypothesise that human-driven habitat alteration will disrupt the acoustic and visual communication systems due to increased noise pollution and/or changes in the surrounding light environment. We highlight the need for more empirical research combining behavioural ecology and conservation to better predict species’ vulnerability to global change and efficiently focus conservation efforts.
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5
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Yuan ML, Jung C, Bell RC, Nelson JL. Aposematic patterns shift continuously throughout the life of poison frogs. J Zool (1987) 2022. [DOI: 10.1111/jzo.12977] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Affiliation(s)
- M. L. Yuan
- Center for Population Biology University of California Davis CA USA
- Department of Evolution and Ecology University of California Davis CA USA
| | - C. Jung
- Department of Environmental Science, Policy, and Management University of California Berkeley CA USA
| | - R. C. Bell
- Department of Herpetology California Academy of Sciences San Francisco CA USA
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6
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Yeager J, Barnett JB. The influence of ultraviolet reflectance differs between conspicuous aposematic signals in neotropical butterflies and poison frogs. Ecol Evol 2021; 11:13633-13640. [PMID: 34707805 PMCID: PMC8525173 DOI: 10.1002/ece3.7942] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2021] [Revised: 07/05/2021] [Accepted: 07/06/2021] [Indexed: 11/07/2022] Open
Abstract
Warning signals are often characterized by highly contrasting, distinctive, and memorable colors. Greater chromatic (hue) and achromatic (brightness) contrast have both been found to contribute to greater signal efficacy, making longwave colored signals (e.g., red and yellow), that are perceived by both chromatic and achromatic visual pathways, particularly common. Conversely, shortwave colors (e.g., blue and ultraviolet) do not contribute to luminance perception yet are also commonly found in warning signals. Our understanding of the role of UV in aposematic signals is currently incomplete as UV perception is not universal, and evidence for its utility is at best mixed. We used visual modeling to quantify how UV affects signal contrast in aposematic heliconiian butterflies and poison frogs both of which reflect UV wavelengths, occupy similar habitats, and share similar classes of predators. Previous work on butterflies has found that UV reflectance does not affect predation risk but is involved in mate choice. As the butterflies, but not the frogs, have UV-sensitive vision, the function of UV reflectance in poison frogs is currently unknown. We found that despite showing up strongly in UV photographs, UV reflectance only appreciably affected visual contrast in the butterflies. As such, these results support the notion that although UV reflectance is associated with intraspecific communication in butterflies, it appears to be nonfunctional in frogs. Consequently, our data highlight that we should be careful when assigning a selection-based benefit to the presence of UV reflectance.
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Affiliation(s)
- Justin Yeager
- Biodiversidad Medio Ambiente y Salud Universidad de Las Américas Quito Ecuador
| | - James B Barnett
- Psychology, Neuroscience & Behaviour McMaster University Hamilton ON Canada
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7
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Bertolesi GE, Debnath N, Atkinson-Leadbeater K, Niedzwiecka A, McFarlane S. Distinct type II opsins in the eye decode light properties for background adaptation and behavioural background preference. Mol Ecol 2021; 30:6659-6676. [PMID: 34592025 DOI: 10.1111/mec.16203] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2021] [Revised: 09/02/2021] [Accepted: 09/10/2021] [Indexed: 12/17/2022]
Abstract
Crypsis increases survival by reducing predator detection. Xenopus laevis tadpoles decode light properties from the substrate to induce two responses: a cryptic coloration response where dorsal skin pigmentation is adjusted to the colour of the substrate (background adaptation) and a behavioural crypsis where organisms move to align with a specific colour surface (background preference). Both processes require organisms to detect reflected light from the substrate. We explored the relationship between background adaptation and preference and the light properties able to trigger both responses. We also analysed which retinal photosensor (type II opsin) is involved. Our results showed that these two processes are segregated mechanistically, as there is no correlation between the preference for a specific background with the level of skin pigmentation, and different dorsal retina-localized type II opsins appear to underlie the two crypsis modes. Indeed, inhibition of melanopsin affects background adaptation but not background preference. Instead, we propose pinopsin is the photosensor involved in background preference. pinopsin mRNA is co-expressed with mRNA for the sws1 cone photopigment in dorsally located photoreceptors. Importantly, the developmental onset of pinopsin expression aligns with the emergence of the preference for a white background, but after the background adaptation phenotype appears. Furthermore, white background preference of tadpoles is associated with increased pinopsin expression, a feature that is lost in premetamorphic froglets along with a preference for a white background. Thus, our data show a mechanistic dissociation between background adaptation and background preference, and we suggest melanopsin and pinopsin, respectively, initiate the two responses.
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Affiliation(s)
- Gabriel E Bertolesi
- Hotchkiss Brain Institute, Alberta Children's Hospital Research Institute, Calgary, Alberta, Canada.,Department of Cell Biology and Anatomy, Alberta Children's Hospital Research Institute, Calgary, Alberta, Canada
| | - Nilakshi Debnath
- Hotchkiss Brain Institute, Alberta Children's Hospital Research Institute, Calgary, Alberta, Canada.,Department of Cell Biology and Anatomy, Alberta Children's Hospital Research Institute, Calgary, Alberta, Canada
| | | | - Anna Niedzwiecka
- Department of Chemistry, University of Calgary, Calgary, Alberta, Canada
| | - Sarah McFarlane
- Hotchkiss Brain Institute, Alberta Children's Hospital Research Institute, Calgary, Alberta, Canada.,Department of Cell Biology and Anatomy, Alberta Children's Hospital Research Institute, Calgary, Alberta, Canada
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8
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Blurring of ancient wall paintings caused by binder decay in the pigment layer. Sci Rep 2020; 10:21075. [PMID: 33273650 PMCID: PMC7713070 DOI: 10.1038/s41598-020-78117-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2019] [Accepted: 10/26/2020] [Indexed: 11/24/2022] Open
Abstract
In this paper, the effect of binder decay rather than a change in the pigments on the blurring of ancient wall paintings was researched. The simulated wall paintings were prepared by brushing an aqueous solution containing gelatine and ochre grains on the surface of cylindrical compressed soil samples. Then, the dried samples were calcined at 650 °C for 2 h to obtain the simulated wall paintings with the degraded binder gelatine. Next, the calcined samples were brushed with a certain amount of acetone solution containing an ionic liquid ([BMIm]PF6) to obtain the corresponding repaired samples. Based on the results from various characterization methods (UV–vis, FTIR, XRD, XPS, SEM, TG), the following conclusions were drawn. The degradation of the binder caused by calcination increases the surface roughness of the painting layer, resulting in enhanced scattering. In this case, because scattering decrease the light absorption by the pigments, even if unchanged pigment exists in the painting layer, its colour can become blurred. The filling of the ionic liquid into the pores caused by gelatine decay in the painting layer can decrease the scattering, and the blurred colour can be restored to some extent. As typical examples, this principle was successfully applied to restore the blurred colour of an ancient Chinese wall painting (Tang Dynasty) and a pottery (Eastern Han Dynasty).
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9
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Yeager J, Barnett JB. Ultraviolet components offer minimal contrast enhancement to an aposematic signal. Ecol Evol 2020; 10:13576-13582. [PMID: 33391663 PMCID: PMC7771128 DOI: 10.1002/ece3.6969] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2020] [Revised: 09/23/2020] [Accepted: 09/28/2020] [Indexed: 12/03/2022] Open
Abstract
Aposematic and sexual signals are often characterized by bright, highly contrasting colors. Many species can see colors beyond the human visible spectrum, and ultraviolet (UV) reflection has been found to play an important role in communication and sexual selection. However, the role of UV in aposematic signals is poorly explored. Poison frogs frequently produce high-contrast signals that have been linked to both aposematism and intraspecific communication. Yet despite considerable efforts studying interspecific and intraspecific diversity in color, poison frogs are not known to perceive UV, and UV reflection of the integument has not been described. We report UV-reflective spots in a population of Oophaga sylvatica and quantify the effect of UV on visual contrast with models of avian vision. We found that the frogs are highly contrasting, but UV had a minimal effect on signal saliency. These data highlight the importance of considering UV reflectance within aposematic signals, but that UV should not necessarily be regarded as an independent signal.
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Affiliation(s)
- Justin Yeager
- Biodiversidad Medio Ambiente y SaludUniversidad de Las AméricasQuitoEcuador
| | - James B. Barnett
- Department of Psychology, Neuroscience & BehaviourMcMaster UniversityHamiltonONCanada
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10
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Conspecific and Predator Perception of the Red Oophaga pumilio Morph from the Central Caribbean of Costa Rica. J HERPETOL 2020. [DOI: 10.1670/19-110] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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11
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Nielsen ME, Mappes J. Out in the open: behavior's effect on predation risk and thermoregulation by aposematic caterpillars. Behav Ecol 2020; 31:1031-1039. [PMID: 32760178 PMCID: PMC7390994 DOI: 10.1093/beheco/araa048] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2019] [Revised: 03/31/2020] [Accepted: 05/06/2020] [Indexed: 11/14/2022] Open
Abstract
Warning coloration should be under strong stabilizing selection but often displays considerable intraspecific variation. Opposing selection on color by predators and temperature is one potential explanation for this seeming paradox. Despite the importance of behavior for both predator avoidance and thermoregulation, its role in mediating selection by predators and temperature on warning coloration has received little attention. Wood tiger moth caterpillars, Arctia plantaginis, have aposematic coloration, an orange patch on the black body. The size of the orange patch varies considerably: individuals with larger patches are safer from predators, but having a small patch is beneficial in cool environments. We investigated microhabitat preference by these caterpillars and how it interacted with their coloration. We expected caterpillar behavior to reflect a balance between spending time exposed to maximize basking and spending time concealed to avoid detection by predators. Instead, we found that caterpillars preferred exposed locations regardless of their coloration. Whether caterpillars were exposed or concealed had a strong effect on both temperature and predation risk, but caterpillars in exposed locations were both much warmer and less likely to be attacked by a bird predator (great tits, Parus major). This shared optimum may explain why we observed so little variation in caterpillar behavior and demonstrates the important effects of behavior on multiple functions of coloration.
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Affiliation(s)
- Matthew E Nielsen
- Department of Biological and Environmental Sciences, University of Jyväskylä, Survontie 9 C, Jyväskylä, Finland
- Department of Zoology, Stockholm University, Svante Arrhenius väg 18b, Stockholm, Sweden
| | - Johanna Mappes
- Department of Biological and Environmental Sciences, University of Jyväskylä, Survontie 9 C, Jyväskylä, Finland
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12
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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: 3] [Impact Index Per Article: 0.8] [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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13
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Rojas B, Pašukonis A. From habitat use to social behavior: natural history of a voiceless poison frog, Dendrobates tinctorius. PeerJ 2019; 7:e7648. [PMID: 31576237 PMCID: PMC6753930 DOI: 10.7717/peerj.7648] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2019] [Accepted: 08/09/2019] [Indexed: 01/01/2023] Open
Abstract
Descriptive studies of natural history have always been a source of knowledge on which experimental work and scientific progress rely. Poison frogs are a well-studied group of small Neotropical frogs with diverse parental behaviors, distinct calls, and bright colors that warn predators about their toxicity; and a showcase of advances in fundamental biology through natural history observations. The dyeing poison frog, Dendrobates tinctorius, is emblematic of the Guianas region, widespread in the pet trade, and increasingly popular in research. This species shows several unusual behaviors, such as the lack of advertisement calls and the aggregation around tree-fall gaps, which remain poorly described and understood. Here, we summarize our observations from a natural population of D. tinctorius in French Guiana collected over various field trips between 2009 and 2017; our aim is to provide groundwork for future fundamental and applied research spanning parental care, animal dispersal, disease spread, habitat use in relation to color patterns, and intra-specific communication, to name a few. We report sex differences in habitat use and the striking invasion of tree-fall gaps; describe their courtship and aggressive behaviors; document egg development and tadpole transport; and discuss how the knowledge generated by this study could set the grounds for further research on the behavior, ecology, and conservation of this species.
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Affiliation(s)
- Bibiana Rojas
- Department of Biological and Environmental Science, University of Jyväskylä, Jyväskylä, Finland
| | - Andrius Pašukonis
- Department of Biology, Stanford University, Stanford, CA, USA
- Department of Cognitive Biology, University of Vienna, Vienna, Austria
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14
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Abstract
With our comprehensive set of field (model survival), laboratory (controlled learning, palatability, toxin analysis), and molecular data, we provide evidence that polymorphism can persist in an aposematic population, despite expectations of positive frequency-dependent selection. We show that this can happen if prey species carrying a strong signal can exploit predator learning to elicit broad avoidance of many signals, even if predators only have experience with a single signal. This could allow novel signals to be protected within a population of aposematic prey. Thus, under the expectations of broad generalization coupled with limited gene flow, weak aposematic signals can persist, contributing to the overall diversity of signals found within aposematic species. Aposematic organisms couple conspicuous warning signals with a secondary defense to deter predators from attacking. Novel signals of aposematic prey are expected to be selected against due to positive frequency-dependent selection. How, then, can novel phenotypes persist after they arise, and why do so many aposematic species exhibit intrapopulation signal variability? Using a polytypic poison frog (Dendrobates tinctorius), we explored the forces of selection on variable aposematic signals using 2 phenotypically distinct (white, yellow) populations. Contrary to expectations, local phenotype was not always better protected compared to novel phenotypes in either population; in the white population, the novel phenotype evoked greater avoidance in natural predators. Despite having a lower quantity of alkaloids, the skin extracts from yellow frogs provoked higher aversive reactions by birds than white frogs in the laboratory, although both populations differed from controls. Similarly, predators learned to avoid the yellow signal faster than the white signal, and generalized their learned avoidance of yellow but not white. We propose that signals that are easily learned and broadly generalized can protect rare, novel signals, and weak warning signals (i.e., signals with poor efficacy and/or poor defense) can persist when gene flow among populations, as in this case, is limited. This provides a mechanism for the persistence of intrapopulation aposematic variation, a likely precursor to polytypism and driver of speciation.
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15
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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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16
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Rößler DC, Lötters S, Mappes J, Valkonen JK, Menin M, Lima AP, Pröhl H. Sole coloration as an unusual aposematic signal in a Neotropical toad. Sci Rep 2019; 9:1128. [PMID: 30718568 PMCID: PMC6362010 DOI: 10.1038/s41598-018-37705-1] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2018] [Accepted: 12/10/2018] [Indexed: 12/11/2022] Open
Abstract
Many animals have evolved remarkable strategies to avoid predation. In diurnal, toxic harlequin toads (Atelopus) from the Amazon basin, we find a unique colour signal. Some Atelopus populations have striking red soles of the hands and feet, visible only when walking. When stationary, the toads are hard to detect despite their yellow-black dorsal coloration. Consequently, they switch between high and low conspicuousness. Interestingly, some populations lack the extra colour display of the soles. We found comprehensive support that the red coloration can act as an aposematic signal directed towards potential predators: red soles are significantly more conspicuous than soles lacking red coloration to avian predators and the presence of the red signal significantly increases detection. Further, toads with red soles show bolder behaviour by using higher sites in the vegetation than those lacking this signal. Field experiments hint at a lower attack risk for clay models with red soles than for those lacking the signal, in a population where the red soles naturally occur. We suggest that the absence of the signal may be explained by a higher overall attack risk or potential differences of predator community structure between populations.
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Affiliation(s)
- Daniela C Rößler
- Department of Biogeography, Trier University, Universitätsring 15, 54296, Trier, Germany.
| | - Stefan Lötters
- Department of Biogeography, Trier University, Universitätsring 15, 54296, Trier, Germany
| | - Johanna Mappes
- Centre of Excellence in Biological Interactions, Department of Biological and Environmental Science, University of Jyväskylä, P.O. Box 35, 40014, Jyväskylä, Finland
| | - Janne K Valkonen
- Centre of Excellence in Biological Interactions, Department of Biological and Environmental Science, University of Jyväskylä, P.O. Box 35, 40014, Jyväskylä, Finland
| | - Marcelo Menin
- Department of Biology, Institute of Biological Sciences, Amazonas Federal University, Av. General Rodrigo Otávio Jordão Ramos 3000, 69077-000, Manaus, Brazil
| | - Albertina P Lima
- Coordenação de Pesquisas em Biodiversidade, Instituto Nacional de Pesquisas da Amazônia, Av. André Araujo 2936, 69011-970, Manaus, Brazil
| | - Heike Pröhl
- Institute of Zoology, University of Veterinary Medicine Hannover, Bünteweg 17, 30559, Hannover, Germany
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Resolving tradeoffs among crypsis, escape behavior, and microhabitat use in sexually dichromatic species. Oecologia 2018; 189:91-104. [PMID: 30430233 DOI: 10.1007/s00442-018-4301-5] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2018] [Accepted: 11/08/2018] [Indexed: 10/27/2022]
Abstract
Variation in color pattern between populations of cryptic animals is common and typically attributed to selection pressures from visual predators combined with variation in substrate composition. However, little is known about how cryptic color pattern relates to varied rates of predation, and few studies simultaneously analyze patterns of escape behavior and microhabitat use along with variation in color pattern, even though these traits evolve in tandem. Here, we use a combination of calibrated photographs and spectrometry to examine the influence of spatial heterogeneity in rates of predation on dorsal brightness in the Florida scrub lizard (Sceloporus woodi), a cryptic and sexually dimorphic species. Simultaneously, we analyze patterns of escape behavior and microhabitat use measured in the field. The results of this study indicate that populations inhabiting environments of increased predation have less color variation and more closely match the color of local substrate than populations sampled in environments of relaxed predation. Populations exposed to increased predation also show more pronounced escape behavior and are more selective in their use of microhabitat. Interestingly, geographic variation of dorsal brightness, escape behavior, and microhabitat use were greater for females than for males. Our results not only provide empirical evidence for theories of adaptive coloration, but suggest that sexual dichromatism can be maintained by selection pressures related to predation.
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Henning T, Mittelbach M, Ismail SA, Acuña-Castillo RH, Weigend M. A case of behavioural diversification in male floral function - the evolution of thigmonastic pollen presentation. Sci Rep 2018; 8:14018. [PMID: 30232353 PMCID: PMC6145904 DOI: 10.1038/s41598-018-32384-4] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2018] [Accepted: 09/05/2018] [Indexed: 11/09/2022] Open
Abstract
Obvious movements of plant organs have fascinated scientists for a long time. They have been studied extensively, but few behavioural studies to date have dealt with them, and hardly anything is known about their evolution. Here, we present a large experimental dataset on the stamen movement patterns found in the Loasaceae subfam. Loasoideae (Cornales). An evolutionary transition from autonomous-only to a combination of autonomous and thigmonastic stamen movement with increased complexity was experimentally demonstrated. We compare the stamen movement patterns with extensive pollinator observations and discuss it in the context of male mating behavior. Thigmonastic pollen presentation via stamen movements appears to be a crucial component of floral adaptation to pollinator behaviour, evolving in concert with complex adjustments of flower signal, reward and morphology. We hypothesize that rapid adjustments of pollen presentation timing may play a significant role in the diversification of this plant group, representing a striking example for the evolutionary significance of plant behaviour.
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Affiliation(s)
- Tilo Henning
- Botanic Garden and Botanical Museum Berlin-Dahlem, Freie Universität Berlin, Königin-Luise-Str. 6-8, 14195, Berlin, Germany.
| | - Moritz Mittelbach
- Institute of Biologie, Freie Universität Berlin, Altensteinstr. 6, 14195, Berlin, Germany
| | - Sascha A Ismail
- School of Biological Sciences, University of Aberdeen, 23 St. Machar Drive, Aberdeen, AB24 3UU, Scotland
| | - Rafael H Acuña-Castillo
- Nees Institut für Biodiversität der Pflanzen, Rheinische Friedrich-Wilhelms-Universität Bonn, Meckenheimer Allee 170, 53115, Bonn, Germany.,Universidad de Costa Rica, Escuela de Biología, Apdo, Postal: 11501-2060, San Pedro de Montes de Oca, Costa Rica
| | - Maximilian Weigend
- Nees Institut für Biodiversität der Pflanzen, Rheinische Friedrich-Wilhelms-Universität Bonn, Meckenheimer Allee 170, 53115, Bonn, Germany
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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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20
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An Empirical Test Indicates Only Qualitatively Honest Aposematic Signaling Within a Population of Vertebrates. J HERPETOL 2018. [DOI: 10.1670/17-047] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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21
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Dreher CE, Rodríguez A, Cummings ME, Pröhl H. Mating status correlates with dorsal brightness in some but not all poison frog populations. Ecol Evol 2017; 7:10503-10512. [PMID: 29299233 PMCID: PMC5743646 DOI: 10.1002/ece3.3531] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2017] [Revised: 08/31/2017] [Accepted: 09/14/2017] [Indexed: 02/04/2023] Open
Abstract
Sexual signals are important for intraspecific communication and mate selection, but their evolution may be driven by both natural and sexual selection, and stochastic processes. Strawberry poison frogs (Oophaga pumilio) show strong color divergence among populations, but coloration also varies among individuals of the same population. The importance of coloration for female mate choice has been studied intensely, and sexual selection seems to affect color divergence in strawberry poison frogs. However, the effect of coloration on mating success under field conditions has received very little attention. Furthermore, few studies examined how phenotypic variation among individuals of the same color morph affects mate selection under natural conditions. We measured the spectral reflectance of courting and noncourting individuals and their background substrates in three geographically separated populations. In one population (Sarapiquí, Costa Rica), we found that naturally occurring courting pairs of males and females had significantly brighter dorsal coloration than individual males and females not engaged in courtship interactions. Our field observations suggest that, in the wild, females prefer brighter males while the reason for the higher courtship activity of brighter females remains unclear. Overall our results imply that brightness differences among individuals of the same color morph may actually affect reproductive success in some populations of strawberry poison frogs.
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Affiliation(s)
- Corinna E Dreher
- Institute of Zoology University of Veterinary Medicine Hannover, Foundation Hannover Germany
| | - Ariel Rodríguez
- Institute of Zoology University of Veterinary Medicine Hannover, Foundation Hannover Germany
| | - Molly E Cummings
- Section of Integrative Biology University of Texas Austin TX USA
| | - Heike Pröhl
- Institute of Zoology University of Veterinary Medicine Hannover, Foundation Hannover Germany
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22
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Santos JC, Baquero M, Barrio-Amorós C, Coloma LA, Erdtmann LK, Lima AP, Cannatella DC. Aposematism increases acoustic diversification and speciation in poison frogs. Proc Biol Sci 2015; 281:20141761. [PMID: 25320164 DOI: 10.1098/rspb.2014.1761] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Multimodal signals facilitate communication with conspecifics during courtship, but they can also alert eavesdropper predators. Hence, signallers face two pressures: enticing partners to mate and avoiding detection by enemies. Undefended organisms with limited escape abilities are expected to minimize predator recognition over mate attraction by limiting or modifying their signalling. Alternatively, organisms with anti-predator mechanisms such as aposematism (i.e. unprofitability signalled by warning cues) might elaborate mating signals as a consequence of reduced predation. We hypothesize that calls diversified in association with aposematism. To test this, we assembled a large acoustic signal database for a diurnal lineage of aposematic and cryptic/non-defended taxa, the poison frogs. First, we showed that aposematic and non-aposematic species share similar extinction rates, and aposematic lineages diversify more and rarely revert to the non-aposematic phenotype. We then characterized mating calls based on morphological (spectral), behavioural/physiological (temporal) and environmental traits. Of these, only spectral and temporal features were associated with aposematism. We propose that with the evolution of anti-predator defences, reduced predation facilitated the diversification of vocal signals, which then became elaborated or showy via sexual selection.
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Affiliation(s)
- Juan C Santos
- Biodiversity Research Centre, University of British Columbia, Vancouver, British Columbia, Canada V6T 1Z4 National Evolutionary Synthesis Center, Suite A200, 2024 West Main St., Durham, NC 27705, USA
| | - Margarita Baquero
- Department of Biological Sciences, Mississippi State University, Starkville, MS 39762, USA
| | | | - Luis A Coloma
- Centro Jambatu de Investigación y Conservación de Anfibios, Fundación Otonga, Geovanni Farina 566 y Baltra, San Rafael, Quito, Ecuador
| | - Luciana K Erdtmann
- Instituto Nacional de Pesquisas da Amazônia - INPA, Manaus, Amazonas, Brazil
| | - Albertina P Lima
- Instituto Nacional de Pesquisas da Amazônia - INPA, Manaus, Amazonas, Brazil
| | - David C Cannatella
- Department of Integrative Biology and Texas Natural History Collections, University of Texas, 1 University Station C0990, Austin, TX 78712, USA
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23
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Dreher CE, Cummings ME, Pröhl H. An Analysis of Predator Selection to Affect Aposematic Coloration in a Poison Frog Species. PLoS One 2015; 10:e0130571. [PMID: 26110826 PMCID: PMC4481408 DOI: 10.1371/journal.pone.0130571] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2015] [Accepted: 05/22/2015] [Indexed: 11/19/2022] Open
Abstract
Natural selection is widely noted to drive divergence of phenotypic traits. Predation pressure can facilitate morphological divergence, for example the evolution of both cryptic and conspicuous coloration in animals. In this context Dendrobatid frogs have been used to study evolutionary forces inducing diversity in protective coloration. The polytypic strawberry poison frog (Oophaga pumilio) shows strong divergence in aposematic coloration among populations. To investigate whether predation pressure is important for color divergence among populations of O. pumilio we selected four mainland populations and two island populations from Costa Rica and Panama. Spectrometric measurements of body coloration were used to calculate color and brightness contrasts of frogs as an indicator of conspicuousness for the visual systems of several potential predators (avian, crab and snake) and a conspecific observer. Additionally, we conducted experiments using clay model frogs of different coloration to investigate whether the local coloration of frogs is better protected than non-local color morphs, and if predator communities vary among populations. Overall predation risk differed strongly among populations and interestingly was higher on the two island populations. Imprints on clay models indicated that birds are the main predators while attacks of other predators were rare. Furthermore, clay models of local coloration were equally likely to be attacked as those of non-local coloration. Overall conspicuousness (and brightness contrast) of local frogs was positively correlated with attack rates by birds across populations. Together with results from earlier studies we conclude that conspicuousness honestly indicates toxicity to avian predators. The different coloration patterns among populations of strawberry poison frogs in combination with behavior and toxicity might integrate into equally efficient anti-predator strategies depending on local predation and other ecological factors.
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Affiliation(s)
- Corinna E Dreher
- Institute of Zoology, University of Veterinary Medicine Hannover, Foundation, Hannover, Germany.
| | - Molly E Cummings
- Department of Integrative Biology, University of Texas, Austin, TX, United States of America
| | - Heike Pröhl
- Institute of Zoology, University of Veterinary Medicine Hannover, Foundation, Hannover, Germany
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