1
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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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Stuckert AMM, Summers K. Investigating signal modalities of aposematism in a poison frog. J Evol Biol 2022. [DOI: 10.1111/jeb.14111] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2022] [Revised: 07/11/2022] [Accepted: 07/17/2022] [Indexed: 11/28/2022]
Affiliation(s)
- Adam M. M. Stuckert
- Department of Biology East Carolina University Greenville North Carolina USA
- Department of Biology and Biochemistry University of Houston Houston Texas USA
| | - Kyle Summers
- Department of Biology East Carolina University Greenville North Carolina USA
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3
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da Rocha SM, Magnusson WE, Rojas D, Lima AP. Colour, location and movement: what do models tell us about predation on colour morphs of a poison frog from eastern Amazonia? BEHAVIOUR 2022. [DOI: 10.1163/1568539x-bja10168] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Abstract
Many dendrobatid frogs are known to be aposematic: brightly coloured and unpalatable to predators. To deceive predators, frog models used to test for predatory colour bias must be similar in size, colour, shape, and movement to frogs. We carried out an experiment with moving models of the species Adelphobates galactonotus, in two localities. A. galactonotus is a polytypic frog and each population of the species has a distinct colour. Birds and mammals were the vertebrates responsible for the marks on the models, but there was no difference in frequency of attacks on local-, non-local- and cryptic-colour models. Only invertebrates avoided cryptic models. Different populations of the species seem to be under different predation pressure, but colour differentiation in this species is probably related to other mechanisms, such as sexual selection.
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Affiliation(s)
- Sulamita M.C. da Rocha
- Instituto Nacional de Pesquisas da Amazônia, Programa de Pós-Graduação em Ecologia, Av. André, Araújo 2936, 69011-970 Manaus, AM, Brazil
| | - William E. Magnusson
- Instituto Nacional de Pesquisas da Amazônia, Programa de Pós-Graduação em Ecologia, Av. André, Araújo 2936, 69011-970 Manaus, AM, Brazil
- Instituto Nacional de Pesquisas da Amazônia, Coordenação de Pesquisas em Biodiversidade, Av. André Araújo, 2936, 69011-970, Manaus, AM, Brazil
| | - Diana Rojas
- Ecopescado, P.O. Box 37, 69640-000 Tabatinga, AM, Brazil
| | - Albertina P. Lima
- Instituto Nacional de Pesquisas da Amazônia, Programa de Pós-Graduação em Ecologia, Av. André, Araújo 2936, 69011-970 Manaus, AM, Brazil
- Instituto Nacional de Pesquisas da Amazônia, Coordenação de Pesquisas em Biodiversidade, Av. André Araújo, 2936, 69011-970, Manaus, AM, Brazil
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4
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Contrasting environmental drivers of genetic and phenotypic divergence in an Andean poison frog (Epipedobates anthonyi). Heredity (Edinb) 2022; 128:33-44. [PMID: 34718332 PMCID: PMC8733028 DOI: 10.1038/s41437-021-00481-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2021] [Revised: 10/17/2021] [Accepted: 10/18/2021] [Indexed: 01/03/2023] Open
Abstract
Phenotypic and genetic divergence are shaped by the homogenizing effects of gene flow and the differentiating processes of genetic drift and local adaptation. Herein, we examined the mechanisms that underlie phenotypic (size and color) and genetic divergence in 35 populations (535 individuals) of the poison frog Epipedobates anthonyi along four elevational gradients (0-1800 m asl) in the Ecuadorian Andes. We found phenotypic divergence in size and color despite relatively low genetic divergence at neutral microsatellite loci. Genetic and phenotypic divergence were both explained by landscape resistance between sites (isolation-by-resistance, IBR), likely due to a cold and dry mountain ridge between the northern and southern elevational transects that limits dispersal and separates two color morphs. Moreover, environmental differences among sites also explained genetic and phenotypic divergence, suggesting isolation-by-environment (IBE). When northern and southern transects were analyzed separately, genetic divergence was predicted either by distance (isolation-by-distance, IBD; northern) or environmental resistance between sites (IBR; southern). In contrast, phenotypic divergence was primarily explained by environmental differences among sites, supporting the IBE hypothesis. These results indicate that although distance and geographic barriers are important drivers of population divergence, environmental variation has a two-fold effect on population divergence. On the one hand, landscape resistance between sites reduces gene flow (IBR), while on the other hand, environmental differences among sites exert divergent selective pressures on phenotypic traits (IBE). Our work highlights the importance of studying both genetic and phenotypic divergence to better understand the processes of population divergence and speciation along ecological gradients.
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5
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Barnett JB, Michalis C, Scott-Samuel NE, Cuthill IC. Colour pattern variation forms local background matching camouflage in a leaf-mimicking toad. J Evol Biol 2021; 34:1531-1540. [PMID: 34465010 DOI: 10.1111/jeb.13923] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2021] [Revised: 08/17/2021] [Accepted: 08/26/2021] [Indexed: 12/26/2022]
Abstract
Optimal camouflage can, in principle, be relatively easily achieved in simple, homogeneous, environments where backgrounds always have the same colour, brightness and patterning. Natural environments are, however, rarely homogenous, and species often find themselves viewed against varied backgrounds where the task of concealment is more challenging. One result of variable backgrounds is the evolution of intraspecific phenotypic variation which may either be generalized, with multiple similarly cryptic patterns, or specialized, with each discrete colour form maximizing concealment against a single component of the background. We investigated the role of phenotypic variation in a highly variable population of the Neotropical toad Rhinella margaritifera using visual modelling and a computer-based detection task. We found that phenotypic variation was not divided into discrete colour morphs, and all toads were well camouflaged against the forest floor. However, although the whole population may appear to consist of random samples from the background, the toads were a particularly close match to the leaf litter, suggesting that they masquerade as dead leaves, which are themselves variable. Furthermore, rather than each colour form being equally effective against a single background, each toad was specialized towards its own particular local surroundings, as suggested by a specialist strategy. Taken together, these data highlight the importance of background matching to a nominally masquerading species, as well as how habitat heterogeneity at multiple spatial scales may affect the evolution of camouflage and phenotypic variation.
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Affiliation(s)
- James B Barnett
- School of Biological Sciences, University of Bristol, Bristol, UK.,Redpath Museum, McGill University, Montreal, QC, Canada.,Department of Psychology, Neuroscience, & Behaviour, McMaster University, Hamilton, ON, Canada
| | | | | | - Innes C Cuthill
- School of Biological Sciences, University of Bristol, Bristol, UK
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6
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Burdfield-Steel E, Kemp DJ. Negative intersexual genetic correlation for colour pattern in a variable aposematic insect. Biol J Linn Soc Lond 2021. [DOI: 10.1093/biolinnean/blab025] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Abstract
Abstract
Despite the fact their coloration functions as an aposematic signal, and is thus expected to be under stabilizing selection, hibiscus harlequin bugs (Tectocoris diophthalmus) show an impressive level of variation in their iridescent coloration both within and between populations. To date the heritability of coloration in this species remains unknown. Here we focus on a single population in New South Wales (the southern part of this species’ Australian range), with the greatest colour variation. We reared full-sib families of known pedigree in the laboratory and analysed the extent of iridescent coloration at adulthood. We then looked for evidence of heritability, condition dependence and antagonistic sexual selection acting on colour in this species. We found significant heritability in the extent of iridescent coloration for both sexes, as well as in development time and body size, but no evidence that condition dependence played a role in the determination of adult coloration. There was, however, a sex by genotype interaction for iridescent cover, in the form of a negative intersexual genetic correlation: in families where sons had high iridescent cover the daughters had low, and vice versa. Our results suggest that different selective pressures may act on coloration in males and females of this species.
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Affiliation(s)
- Emily Burdfield-Steel
- Institute of Biodiversity and Ecosystem Dynamics, University of Amsterdam, Amsterdam, The Netherlands
- Department of Biological Sciences, Faculty of Science and Engineering, Macquarie University, North Ryde, NSW, Australia
| | - Darrell J Kemp
- Department of Biological Sciences, Faculty of Science and Engineering, Macquarie University, North Ryde, NSW, Australia
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7
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Rich C, Reilly SB, Sinervo B. Relaxed predation selection on rare morphs of Ensatina salamanders (Caudata: Plethodontidae) promotes a polymorphic population in a novel dune sand habitat. Biol J Linn Soc Lond 2021. [DOI: 10.1093/biolinnean/blaa211] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Abstract
The ring species Ensatina represents a classic example of locally adapted lineages. The Monterey ensatina (Ensatina eschscholtzii eschscholtzii) is a cryptic subspecies with brown coloration, although a recently discovered polymorphic population within a wind-blown sand region also contains leucistic (pink) and xanthistic (orange) morphs. In the present study, the frequency of leucism/xanthism was mapped across the subspecies’ range, revealing that these morphs are generally rare or absent except within regions containing light-coloured substrate. Attack rates were estimated using clay models of the three morphs, deployed only at the crepuscular period and during the night, on both light and dark substrates at a site within the dune sand region. Model selection found that the interaction between morph and substrate colour best predicted attack rates. Typical morphs had equal attack rates on both substrates while xanthistic and leucistic morphs incurred significantly fewer attacks on light vs. dark substrate, and there was no significant difference in attack rates among morphs on light substrates. These results support the idea that xanthistic and leucistic morphs are poorly adapted for dark substrates compared to typical morphs, but they are more or less equally adapted for light substrates. We suggest that this microgeographic island of relaxed selection on light-coloured morphs helps to explain the existence of this polymorphic population.
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Affiliation(s)
- Caitlyn Rich
- Department of Ecology and Evolutionary Biology, University of California, Santa Cruz, CA, USA
| | - Sean B Reilly
- Department of Ecology and Evolutionary Biology, University of California, Santa Cruz, CA, USA
| | - Barry Sinervo
- Department of Ecology and Evolutionary Biology, University of California, Santa Cruz, CA, USA
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8
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Goedert D, Clement D, Calsbeek R. Evolutionary trade‐offs may interact with physiological constraints to maintain color variation. ECOL MONOGR 2020. [DOI: 10.1002/ecm.1430] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Debora Goedert
- Department of Biological Sciences Dartmouth College Hanover03755 New Hampshire USA
- Ministry of Education of Brazil CAPES Foundation Brasília DF95616Brazil
| | - Dale Clement
- Department of Biological Sciences Dartmouth College Hanover03755 New Hampshire USA
| | - Ryan Calsbeek
- Department of Biological Sciences Dartmouth College Hanover03755 New Hampshire USA
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9
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Rößler DC, Lötters S, Veith M, Fugmann M, Peters C, Künzel S, Krehenwinkel H. An amplicon sequencing protocol for attacker identification from DNA traces left on artificial prey. Methods Ecol Evol 2020. [DOI: 10.1111/2041-210x.13459] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Daniela C. Rößler
- FAS Center for Systems Biology Harvard University Cambridge MA USA
- Department of Biogeography Trier University Trier Germany
| | - Stefan Lötters
- Department of Biogeography Trier University Trier Germany
| | - Michael Veith
- Department of Biogeography Trier University Trier Germany
| | | | | | - Sven Künzel
- Max Planck Institute for Evolutionary Biology Plön Germany
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10
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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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11
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Toxicity and Alkaloid Profiling of the Skin of the Golfo Dulcean Poison Frog Phyllobates vittatus (Dendrobatidae). J Chem Ecol 2019; 45:914-925. [PMID: 31802386 DOI: 10.1007/s10886-019-01116-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2019] [Revised: 09/30/2019] [Accepted: 10/10/2019] [Indexed: 01/01/2023]
Abstract
Frogs in the genus Phyllobates are known for the presence of batrachotoxin, a highly toxic alkaloid, in their skin. Nevertheless, Phyllobates frogs from Costa Rica and Panama (P. lugubris and P. vittatus) are considered non-toxic, as they have been reported to harbor low concentrations of this alkaloid. However, the potential toxicity of Central American Phyllobates has not been assessed experimentally. Our goal was to determine the toxicity of the whole skin of P. vittatus, an endemic species from the Southeastern Pacific region of Costa Rica. We performed median lethal dose (LD50) tests in mice to determine general toxicity, and an irritant assay based on the behavioral responses of mice to subcutaneous injection, to determine differences in irritability, as a measure of toxicity, among three study localities. Using UPLC-ESI-QTOF, we obtained chemical profiles of the methanolic extract of frog skins. Due to the absence of mortality at the studied doses, we were unable to estimate LD50. However, we recorded a list of toxicity symptoms in mice that are consistent with cardiotoxic effects, and found that mice presented more symptoms at higher concentrations of skin extracts during the first hour of the LD50 assays, recovering completely at all doses by the end of the assay. On the other hand, we did not detect differences in irritability among studied localities. Additionally, we putatively identified three toxic alkaloids (Batrachotoxinin A, DHQ 251A and Lehm 275A). This study provides the first experimental data on the toxicity and associated symptoms in mice, as well as the chemical profile of the skin of P. vittatus. We suggest that the skin alkaloids of P. vitattus may confer a chemical defense towards predators.
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12
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Preferences for and use of light microhabitats differ among and within populations of a polytypic poison frog. Biol J Linn Soc Lond 2019. [DOI: 10.1093/biolinnean/blz186] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Abstract
Anti-predator strategies can influence trade-offs governing other activities important to fitness. Crypsis, for example, might make conspicuous sexual display especially costly, whereas aposematism might reduce or remove such costs. We tested for correlates of anti-predator strategy in Oophaga pumilio, a polytypic poison frog with morphs spanning the crypsis–aposematism continuum. In the wild, males of visually conspicuous morphs display from conspicuous perches and behave as if they perceive predation risk to be low. We thus predicted that, given a choice of ambient light microhabitats, these males would use high ambient light conditions the most and be most likely to perch in high-light conditions. We found no evidence that differently colored male O. pumilio preferentially used bright microhabitats or that ambient light influenced perching in a morph-specific manner. Independent of light conditions, males from the most conspicuous population perched the least, but the most conspicuous individuals from a polymorphic population perched the most. These patterns suggest that preferences do not necessarily underlie among-morph differences observed in the wild. This could be explained, and remain consistent with theory, if risk aversion is shaped, in part, by experience.
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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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Cyriac VP, Kodandaramaiah U. Conspicuous colours reduce predation rates in fossorial uropeltid snakes. PeerJ 2019; 7:e7508. [PMID: 31428543 PMCID: PMC6698130 DOI: 10.7717/peerj.7508] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2019] [Accepted: 07/17/2019] [Indexed: 01/04/2023] Open
Abstract
Uropeltid snakes (Family Uropeltidae) are non-venomous, fossorial snakes that are found above ground occasionally, during which time they are exposed to predation. Many species are brightly coloured, mostly on the ventral surface, but these colours are expected to have no function below the ground. Observations have shown that the cephalic resemblance (resemblance to heads) of uropeltid tails may direct attacks of predators towards the hardened tails, thereby potentially increasing handling times for predators. Experiments have also shown that predators learn to avoid prey that are non-toxic and palatable but are difficult to capture, hard to process or require long handling time when such prey advertise their unprofitability through conspicuous colours. We here postulate that uropeltid snakes use their bright colours to signal long handling times associated with attack deflection to the tails, thereby securing reduced predation from predators that can learn to associate colour with handling time. Captive chicken experiments with dough models mimicking uropeltids indicate that attacks were more common on the tail than on the head. Field experiments with uropeltid clay models show that the conspicuous colours of these snakes decrease predation rates compared to cryptic models, but a novel conspicuous colour did not confer such a benefit. Overall, our experiments provide support for our hypothesis that the conspicuous colours of these snakes reduce predation, possibly because these colours advertise unprofitability due to long handling times.
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Affiliation(s)
- Vivek Philip Cyriac
- IISER-TVM Centre for Research and Education in Ecology and Evolution and School of Biology, Indian Institute of Science Education and Research Thiruvananthapuram, Thiruvananthapuram, Kerala, India
| | - Ullasa Kodandaramaiah
- IISER-TVM Centre for Research and Education in Ecology and Evolution and School of Biology, Indian Institute of Science Education and Research Thiruvananthapuram, Thiruvananthapuram, Kerala, India
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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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Klonoski K, Bi K, Rosenblum EB. Phenotypic and genetic diversity in aposematic Malagasy poison frogs (genus Mantella). Ecol Evol 2019; 9:2725-2742. [PMID: 30891212 PMCID: PMC6406014 DOI: 10.1002/ece3.4943] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2018] [Revised: 12/07/2018] [Accepted: 01/02/2019] [Indexed: 12/17/2022] Open
Abstract
Intraspecific color variation has long fascinated evolutionary biologists. In species with bright warning coloration, phenotypic diversity is particularly compelling because many factors, including natural and sexual selection, contribute to intraspecific variation. To better understand the causes of dramatic phenotypic variation in Malagasy poison frogs, we quantified genetic structure and color and pattern variation across three closely related species, Mantella aurantiaca, Mantella crocea, and Mantella milotympanum. Although our restriction site-associated DNA (RAD) sequencing approach identified clear genetic clusters, they do not align with current species designations, which has important conservation implications for these imperiled frogs. Moreover, our results suggest that levels of intraspecific color variation within this group have been overestimated, while species diversity has been underestimated. Within major genetic clusters, we observed distinct patterns of variation including: populations that are phenotypically similar yet genetically distinct, populations where phenotypic and genetic breaks coincide, and populations that are genetically similar but have high levels of within-population phenotypic variation. We also detected admixture between two of the major genetic clusters. Our study suggests that several mechanisms-including hybridization, selection, and drift-are contributing to phenotypic diversity. Ultimately, our work underscores the need for a reevaluation of how polymorphic and polytypic populations and species are classified, especially in aposematic organisms.
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Affiliation(s)
- Karina Klonoski
- Department of Environmental Science, Policy, and ManagementUniversity of California, BerkeleyBerkeleyCalifornia
- Museum of Vertebrate ZoologyUniversity of California, BerkeleyBerkeleyCalifornia
| | - Ke Bi
- Museum of Vertebrate ZoologyUniversity of California, BerkeleyBerkeleyCalifornia
- Computational Genomics Resource Laboratory (CGRL), California Institute for Quantitative Biosciences (QB3)University of California, BerkeleyBerkeleyCalifornia
| | - Erica Bree Rosenblum
- Department of Environmental Science, Policy, and ManagementUniversity of California, BerkeleyBerkeleyCalifornia
- Museum of Vertebrate ZoologyUniversity of California, BerkeleyBerkeleyCalifornia
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17
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Akcali CK, Adán Pérez-Mendoza H, Salazar-Valenzuela D, Kikuchi DW, Guayasamin JM, Pfennig DW. Evaluating the utility of camera traps in field studies of predation. PeerJ 2019; 7:e6487. [PMID: 30828493 PMCID: PMC6394347 DOI: 10.7717/peerj.6487] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2018] [Accepted: 01/19/2019] [Indexed: 11/29/2022] Open
Abstract
Artificial prey techniques—wherein synthetic replicas of real organisms are placed in natural habitats—are widely used to study predation in the field. We investigated the extent to which videography could provide additional information to such studies. As a part of studies on aposematism and mimicry of coral snakes (Micrurus) and their mimics, observational data from 109 artificial snake prey were collected from video-recording camera traps in three locations in the Americas (terra firme forest, Tiputini Biodiversity Station, Ecuador; premontane wet forest, Nahá Reserve, Mexico; longleaf pine forest, Southeastern Coastal Plain, North Carolina, USA). During 1,536 camera days, a total of 268 observations of 20 putative snake predator species were recorded in the vicinity of artificial prey. Predators were observed to detect artificial prey 52 times, but only 21 attacks were recorded. Mammals were the most commonly recorded group of predators near replicas (243) and were responsible for most detections (48) and attacks (20). There was no difference between avian or mammalian predators in their probability of detecting replicas nor in their probability of attacking replicas after detecting them. Bite and beak marks left on clay replicas registered a higher ratio of avian:mammalian attacks than videos registered. Approximately 61.5% of artificial prey monitored with cameras remained undetected by predators throughout the duration of the experiments. Observational data collected from videos could provide more robust inferences on the relative fitness of different prey phenotypes, predator behavior, and the relative contribution of different predator species to selection on prey. However, we estimate that the level of predator activity necessary for the benefit of additional information that videos provide to be worth their financial costs is achieved in fewer than 20% of published artificial prey studies. Although we suggest future predation studies employing artificial prey to consider using videography as a tool to inspire new, more focused inquiry, the investment in camera traps is unlikely to be worth the expense for most artificial prey studies until the cost:benefit ratio decreases.
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Affiliation(s)
- Christopher K Akcali
- Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA.,North Carolina Museum of Natural Sciences, Raleigh, NC, USA
| | | | | | - David W Kikuchi
- Department of Ecology and Evolutionary Biology, University of Arizona, Tucson, AZ, USA
| | - Juan M Guayasamin
- Colegio de Ciencias Biológicas y Ambientales, Universidad San Francisco de Quito, Quito, Ecuador
| | - David W Pfennig
- Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
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18
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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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19
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20
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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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21
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Distance-dependent defensive coloration in the poison frog Dendrobates tinctorius, Dendrobatidae. Proc Natl Acad Sci U S A 2018; 115:6416-6421. [PMID: 29866847 DOI: 10.1073/pnas.1800826115] [Citation(s) in RCA: 47] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Poison dart frogs provide classic examples of warning signals: potent toxins signaled by distinctive, conspicuous coloration. We show that, counterintuitively, the bright yellow and blue-black color of Dendrobates tinctorius (Dendrobatidae) also provides camouflage. Through computational modeling of predator vision, and a screen-based detection experiment presenting frogs at different spatial resolutions, we demonstrate that at close range the frog is highly detectable, but from a distance the colors blend together, forming effective camouflage. This result was corroborated with an in situ experiment, which found survival to be background-dependent, a feature more associated with camouflage than aposematism. Our results suggest that in D. tinctorius the distribution of pattern elements, and the particular colors expressed, act as a highly salient close range aposematic signal, while simultaneously minimizing detectability to distant observers.
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22
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Affiliation(s)
- Tim Caro
- Department of Wildlife, Fish and Conservation Biology, University of California, Davis, CA, USA
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23
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Casas-Cardona S, Márquez R, Vargas-Salinas F. Different colour morphs of the poison frogAndinobates bombetes(Dendrobatidae) are similarly effective visual predator deterrents. Ethology 2018. [DOI: 10.1111/eth.12729] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Affiliation(s)
- Santiago Casas-Cardona
- Grupo de Evolución, Ecología y Conservación (EECO); Programa de Biología; Facultad de Ciencias Básicas y Tecnologías; Universidad del Quindío; Armenia Colombia
| | - Roberto Márquez
- Department of Ecology and Evolution; University of Chicago; Chicago IL USA
| | - Fernando Vargas-Salinas
- Grupo de Evolución, Ecología y Conservación (EECO); Programa de Biología; Facultad de Ciencias Básicas y Tecnologías; Universidad del Quindío; Armenia Colombia
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24
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Wang LY, Huang WS, Tang HC, Huang LC, Lin CP. Too hard to swallow: a secret secondary defence of an aposematic insect. ACTA ACUST UNITED AC 2018; 221:jeb.172486. [PMID: 29180599 DOI: 10.1242/jeb.172486] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2017] [Accepted: 11/20/2017] [Indexed: 01/03/2023]
Abstract
Anti-predator strategies are significant components of adaptation in prey species. Aposematic prey are expected to possess effective defences that have evolved simultaneously with their warning colours. This study tested the hypothesis of the defensive function and ecological significance of the hard body in aposematic Pachyrhynchus weevils pioneered by Alfred Russel Wallace nearly 150 years ago. We used predation trials with Japalura tree lizards to assess the survivorship of 'hard' (mature) versus 'soft' (teneral) and 'clawed' (intact) versus 'clawless' (surgically removed) weevils. The ecological significance of the weevil's hard body was evaluated by assessing the hardness of the weevils, the local prey insects, and the bite forces of the lizard populations. The existence of toxins or deterrents in the weevil was examined by gas chromatography-mass spectrometry (GC-MS). All 'hard' weevils were instantly spat out after being bitten once and survived attacks by the lizards. In contrast, the 'soft' weevils were chewed and subsequently swallowed. The results were the same regardless of the presence or absence of the weevil's tarsal claws. The hardness of 'hard' Pachyrhynchus weevils was significantly higher than the average hardness of other prey insects in the same habitat and the mean bite forces of the local lizards. The four candidate compounds of the weevil identified by GC-MS had no known toxic or repellent functions against vertebrates. These results reveal that the hardness of aposematic prey functions as an effective secondary defence, and they provide a framework for understanding the spatio-temporal interactions between vertebrate predators and aposematic insect prey.
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Affiliation(s)
- Lu-Yi Wang
- Department of Life Science, National Taiwan Normal University, Taipei 11677, Taiwan
| | - Wen-San Huang
- Department of Biology, National Museum of Natural Science, Taichung 40453, Taiwan
| | - Hsin-Chieh Tang
- Department of Conservation and Research Center, Taipei Zoo, Taipei 11656, Taiwan
| | - Lung-Chun Huang
- Department of Conservation and Research Center, Taipei Zoo, Taipei 11656, Taiwan
| | - Chung-Ping Lin
- Department of Life Science, National Taiwan Normal University, Taipei 11677, Taiwan .,Laboratory of Forest Ecology, Graduate School of Agriculture, Kyoto University, Kyoto 606-8502, Japan
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25
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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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26
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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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27
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Willmott KR, Robinson Willmott JC, Elias M, Jiggins CD. Maintaining mimicry diversity: optimal warning colour patterns differ among microhabitats in Amazonian clearwing butterflies. Proc Biol Sci 2017; 284:20170744. [PMID: 28539522 PMCID: PMC5454276 DOI: 10.1098/rspb.2017.0744] [Citation(s) in RCA: 39] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2017] [Accepted: 05/02/2017] [Indexed: 11/12/2022] Open
Abstract
Mimicry is one of the best-studied examples of adaptation, and recent studies have provided new insights into the role of mimicry in speciation and diversification. Classical Müllerian mimicry theory predicts convergence in warning signal among protected species, yet tropical butterflies are exuberantly diverse in warning colour patterns, even within communities. We tested the hypothesis that microhabitat partitioning in aposematic butterflies and insectivorous birds can lead to selection for different colour patterns in different microhabitats and thus help maintain mimicry diversity. We measured distribution across flight height and topography for 64 species of clearwing butterflies (Ithomiini) and their co-mimics, and 127 species of insectivorous birds, in an Amazon rainforest community. For the majority of bird species, estimated encounter rates were non-random for the two most abundant mimicry rings. Furthermore, most butterfly species in these two mimicry rings displayed the warning colour pattern predicted to be optimal for anti-predator defence in their preferred microhabitats. These conclusions were supported by a field trial using butterfly specimens, which showed significantly different predation rates on colour patterns in two microhabitats. We therefore provide the first direct evidence to support the hypothesis that different mimicry patterns can represent stable, community-level adaptations to differing biotic environments.
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Affiliation(s)
- Keith R Willmott
- McGuire Center for Lepidoptera and Biodiversity, Florida Museum of Natural History, University of Florida, Gainesville, FL 32611, USA
| | | | - Marianne Elias
- Institut de Systématique, Evolution, Biodiversité, ISYEB-UMR 7205-CNRS, MNHN, UPMC, EPHE, Muséum National d'Histoire Naturelle, Sorbonne Universités, 57 rue Cuvier, CP50, Paris 75005, France
| | - Chris D Jiggins
- Department of Zoology, University of Cambridge, Downing Street, Cambridge CB2 3EJ, UK
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28
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The effects of background coloration and dark spots on the risk of predation in poison frog models. Evol Ecol 2017. [DOI: 10.1007/s10682-017-9903-6] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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29
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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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30
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Bateman PW, Fleming PA, Wolfe AK. A different kind of ecological modelling: the use of clay model organisms to explore predator–prey interactions in vertebrates. J Zool (1987) 2016. [DOI: 10.1111/jzo.12415] [Citation(s) in RCA: 49] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- P. W. Bateman
- Department of Environment and Agriculture Curtin University Perth, Bentley WA Australia
| | - P. A. Fleming
- School of Veterinary and Life Sciences Murdoch University Perth, Murdoch WA Australia
| | - A. K. Wolfe
- Department of Environment and Agriculture Curtin University Perth, Bentley WA Australia
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31
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Schulte LM, Saporito RA, Davison I, Summers K. The palatability of Neotropical poison frogs in predator-prey systems: do alkaloids make the difference? Biotropica 2016. [DOI: 10.1111/btp.12404] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Lisa M. Schulte
- Department of Biology; East Carolina University; 1001 E Tenth Street Greenville NC 27858 USA
| | - Ralph A. Saporito
- Department of Biology; John Carroll University; University Heights OH 44118 USA
| | - Ian Davison
- Department of Biology; East Carolina University; 1001 E Tenth Street Greenville NC 27858 USA
| | - Kyle Summers
- Department of Biology; East Carolina University; 1001 E Tenth Street Greenville NC 27858 USA
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32
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Kraemer AC, Serb JM, Adams DC. Both novelty and conspicuousness influence selection by mammalian predators on the colour pattern ofPlethodon cinereus(Urodela: Plethodontidae). Biol J Linn Soc Lond 2016. [DOI: 10.1111/bij.12780] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Andrew C. Kraemer
- Department of Ecology, Evolution, and Organismal Biology; Iowa State University; Ames IA 50011 USA
| | - Jeanne M. Serb
- Department of Ecology, Evolution, and Organismal Biology; Iowa State University; Ames IA 50011 USA
| | - Dean C. Adams
- Department of Ecology, Evolution, and Organismal Biology; Iowa State University; Ames IA 50011 USA
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33
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Twomey E, Vestergaard JS, Venegas PJ, Summers K. Mimetic Divergence and the Speciation Continuum in the Mimic Poison Frog Ranitomeya imitator. Am Nat 2015; 187:205-24. [PMID: 26807748 DOI: 10.1086/684439] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
While divergent ecological adaptation can drive speciation, understanding the factors that facilitate or constrain this process remains a major goal in speciation research. Here, we study two mimetic transition zones in the poison frog Ranitomeya imitator, a species that has undergone a Müllerian mimetic radiation to establish four morphs in Peru. We find that mimetic morphs are strongly phenotypically differentiated, producing geographic clines with varying widths. However, distinct morphs show little neutral genetic divergence, and landscape genetic analyses implicate isolation by distance as the primary determinant of among-population genetic differentiation. Mate choice experiments suggest random mating at the transition zones, although certain allopatric populations show a preference for their own morph. We present evidence that this preference may be mediated by color pattern specifically. These results contrast with an earlier study of a third transition zone, in which a mimetic shift was associated with reproductive isolation. Overall, our results suggest that the three known mimetic transition zones in R. imitator reflect a speciation continuum, which we have characterized at the geographic, phenotypic, behavioral, and genetic levels. We discuss possible explanations for variable progress toward speciation, suggesting that multifarious selection on both mimetic color pattern and body size may be responsible for generating reproductive isolation.
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34
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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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35
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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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Dugas MB, Richards-Zawacki CL. A captive breeding experiment reveals no evidence of reproductive isolation among lineages of a polytypic poison frog. Biol J Linn Soc Lond 2015. [DOI: 10.1111/bij.12571] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Matthew B. Dugas
- Department of Ecology and Evolutionary Biology; Tulane University; 400 Lindy Boggs Building New Orleans LA 70118 USA
| | - Corinne L. Richards-Zawacki
- Department of Ecology and Evolutionary Biology; Tulane University; 400 Lindy Boggs Building New Orleans LA 70118 USA
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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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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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