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Tarvin RD, Coleman JL, Donoso DA, Betancourth-Cundar M, López-Hervas K, Gleason KS, Sanders JR, Smith JM, Ron SR, Santos JC, Sedio BE, Cannatella DC, Fitch R. Passive accumulation of alkaloids in non-toxic frogs challenges paradigms of the origins of acquired chemical defenses. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.05.13.593697. [PMID: 38798461 PMCID: PMC11118485 DOI: 10.1101/2024.05.13.593697] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2024]
Abstract
Understanding the origins of novel, complex phenotypes is a major goal in evolutionary biology. Poison frogs of the family Dendrobatidae have evolved the novel ability to acquire alkaloids from their diet for chemical defense at least three times. However, taxon sampling for alkaloids has been biased towards colorful species, without similar attention paid to inconspicuous ones that are often assumed to be undefended. As a result, our understanding of how chemical defense evolved in this group is incomplete. Here we provide new data showing that, in contrast to previous studies, species from each undefended poison frog clade have measurable yet low amounts of alkaloids. We confirm that undefended dendrobatids regularly consume mites and ants, which are known sources of alkaloids. Further, we confirm the presence of alkaloids in two putatively non-toxic frogs from other families. Our data suggest the existence of a phenotypic intermediate between toxin consumption and sequestration-passive accumulation-that differs from active sequestration in that it involves no derived forms of transport and storage mechanisms yet results in low levels of toxin accumulation. We discuss the concept of passive accumulation and its potential role in the origin of chemical defenses in poison frogs and other toxin-sequestering organisms.
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Affiliation(s)
- Rebecca D. Tarvin
- Museum of Vertebrate Zoology and Department of Integrative Biology, University of California, Berkeley, Berkeley, CA 94720 USA
| | - Jeffrey L. Coleman
- Department of Integrative Biology and Biodiversity Collections, University of Texas at Austin, Austin, TX 78712 USA
- Smithsonian Tropical Research Institute, Balboa, Ancón, Republic of Panama
| | - David A. Donoso
- Grupo de Investigación en Ecología Evolutiva en los Trópicos (EETROP), Universidad de las Américas, Quito, Ecuador
- Ecological Networks Lab, Technische Universität Darmstadt, Darmstadt, Germany
| | | | | | - Kimberly S. Gleason
- Department of Chemistry and Physics, Indiana State University, Terre Haute, IN 47809, USA
| | - J. Ryan Sanders
- Department of Chemistry and Physics, Indiana State University, Terre Haute, IN 47809, USA
| | - Jacqueline M. Smith
- Department of Chemistry and Physics, Indiana State University, Terre Haute, IN 47809, USA
| | - Santiago R. Ron
- Museo de Zoología, Escuela de Biología, Facultad de Ciencias Exactas y Naturales, Pontificia Universidad Católica del Ecuador, Quito, Ecuador
| | - Juan C. Santos
- Department of Biological Sciences, St John’s University, NY, USA 11439
| | - Brian E. Sedio
- Department of Integrative Biology and Biodiversity Collections, University of Texas at Austin, Austin, TX 78712 USA
- Smithsonian Tropical Research Institute, Balboa, Ancón, Republic of Panama
| | - David C. Cannatella
- Department of Integrative Biology and Biodiversity Collections, University of Texas at Austin, Austin, TX 78712 USA
| | - Richard Fitch
- Department of Chemistry and Physics, Indiana State University, Terre Haute, IN 47809, USA
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2
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Lawrence JP, Rojas B, Blanchette A, Saporito RA, Mappes J, Fouquet A, Noonan BP. Linking Predator Responses to Alkaloid Variability in Poison Frogs. J Chem Ecol 2023; 49:195-204. [PMID: 36854928 DOI: 10.1007/s10886-023-01412-7] [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: 09/21/2022] [Revised: 02/11/2023] [Accepted: 02/15/2023] [Indexed: 03/02/2023]
Abstract
Many chemically-defended/aposematic species rely on diet for sequestering the toxins with which they defend themselves. This dietary acquisition can lead to variable chemical defenses across space, as the community composition of chemical sources is likely to vary across the range of (an aposematic) species. We characterized the alkaloid content of two populations of the Dyeing Poison Frog (Dendrobates tinctorius) in northeastern French Guiana. Additionally, we conducted unpalatability experiments with naive predators, Blue Tits (Cyanistes caeruleus), using whole-skin secretion cocktails to assess how a model predator would respond to the defense of individuals from each population. While there was some overlap between the two D. tinctorius populations in terms of alkaloid content, our analysis revealed that these two populations are markedly distinct in terms of overall alkaloid profiles. Predator responses to skin secretions differed between the populations. We identified 15 candidate alkaloids (including three previously undescribed) in seven classes that are correlated with predator response in one frog population. We describe alkaloid profile differences between populations for D. tinctorius and provide a novel method for assessing unpalatability of skin secretions and identifying which toxins may contribute to the predator response. In one population, our results suggest 15 alkaloids that are implicated in predator aversive response. This method is the first step in identifying the causal link between alkaloids and behavioral responses of predators, and thus makes sense of how varying alkaloid combinations are capable of eliciting consistent behavioral responses, and eventually driving evolutionary change in aposematic characters (or characteristics).
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Affiliation(s)
- J P Lawrence
- Department of Biology, University of Mississippi, University, MS, 38677, USA. .,Lyman Briggs College, Michigan State University, East Lansing, MI, 48825, USA.
| | - Bibiana Rojas
- Department of Biology and Environmental Science, University of Jyväskylä, P.O. Box 35, 40014, Jyväskylä, Finland.,Konrad Lorenz Institute of Ethology, Department of Interdisciplinary Life Sciences, University of Veterinary Medicine Vienna, Savoyenstraße 1, 1160, Vienna, Austria
| | - Annelise Blanchette
- Department of Biology, John Carroll University, University Heights, OH, 44118, USA.,Department of Ecology and Evolutionary Biology, Tulane University, New Orleans, LA, 70118, USA
| | - Ralph A Saporito
- Department of Biology, John Carroll University, University Heights, OH, 44118, USA
| | - Johanna Mappes
- Department of Biology and Environmental Science, University of Jyväskylä, P.O. Box 35, 40014, Jyväskylä, Finland.,Organismal and Evolutionary Biology Research Programme, Faculty of Biological and Environmental Sciences, Helsinki University, Helsinki, Finland
| | - Antoine Fouquet
- Laboratoire Evolution et Diversité Biologique, UMR5174, Université Paul Sabatier, 31062, Toulouse Cedex 9, France
| | - Brice P Noonan
- Department of Biology, University of Mississippi, University, MS, 38677, USA
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3
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Gonzalez M, Palacios-Rodriguez P, Hernandez-Restrepo J, González-Santoro M, Amézquita A, Brunetti AE, Carazzone C. First characterization of toxic alkaloids and volatile organic compounds (VOCs) in the cryptic dendrobatid Silverstoneia punctiventris. Front Zool 2021; 18:39. [PMID: 34446035 PMCID: PMC8390233 DOI: 10.1186/s12983-021-00420-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2021] [Accepted: 06/14/2021] [Indexed: 11/24/2022] Open
Abstract
Background Poison frogs are known for the outstanding diversity of alkaloid-based chemical defences with promising therapeutic applications. However, current knowledge about chemical defences in Dendrobatoidea superfamily has two sources of bias. First, cryptic, brown-colored species have been neglected in comparison to those conspicuously colored, and second, there has been little interest in characterizing metabolites other than alkaloids mediating defensive functions. In an effort to contribute to fill the gap of knowledge about cryptic species and broadening the spectrum of compounds analyzed we have applied head-space solid phase microextraction coupled to gas chromatography and mass spectrometry (HS-SPME/GC-MS) for extracting amphibian alkaloids and volatile organic compounds (VOCs) from Silverstoneia punctiventris. Results Using the skin from 8 specimens in 4 biological replicates we have found 33 different compounds. Twenty of them were classified as VOCs into 15 chemical classes including alkanes, alcohols, carbonyl compounds, methylpyridines, benzothiazoles, N-alkylpyrrolidines, pyrazines, and sesquiterpenoids, some of which were previously reported as repellents, defence compounds or defence pheromones in other organisms, and as sex pheromones in a treefrog. Interestingly, six of the remaining compounds were identified as alkaloids previously reported in other toxic/unpalatable dendrobatid frogs. Conclusions This is the first report of alkaloids and VOCs found in the Silverstoneia genus, which has been assumed for decades as non-chemically defended. This study establishes HS-SPME/GC-MS as a new application for a simultaneous approach to amphibian alkaloids and VOCs in poison frogs while opens up new research questions to assess the co-occurrence of both type of compounds and to investigate the evolutionary significance of a defence gradient that includes olfactory avoidance, unpalatability, and toxicity in dendrobatids. In addition, our results show that amphibian alkaloids could have a dual function (olfactory at distance, taste by contact) never explored before neither in Silverstonaeia nor in any other dendrobatid species. Supplementary Information The online version contains supplementary material available at 10.1186/s12983-021-00420-1.
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Affiliation(s)
- Mabel Gonzalez
- Department of Chemistry, Universidad de los Andes, Bogotá, AA, 4976, Colombia
| | | | | | | | - Adolfo Amézquita
- Department of Biological Sciences, Universidad de los Andes, Bogotá, AA, 4976, Colombia
| | - Andrés E Brunetti
- Laboratorio de Genética Evolutiva, Instituto de Biología Subtropical (CONICET - UNaM), Facultad de Ciencias Exactas, Universidad Nacional de Misiones, N3300, Posadas, Argentina.,Departamento de Ciências Biomoleculares, Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, 14040-903, Ribeirão Preto, SP, Brazil
| | - Chiara Carazzone
- Department of Chemistry, Universidad de los Andes, Bogotá, AA, 4976, Colombia.
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Barros ADL, Lima AP, Fachin-Espinar MT, Nunez CV. Evaluation of benzocaine-based anesthetic gel in anuran skins extracts: A case study using the frog Lithodytes lineatus (Anura: Leptodactylidae). PLoS One 2020; 15:e0243654. [PMID: 33290419 PMCID: PMC7723253 DOI: 10.1371/journal.pone.0243654] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2020] [Accepted: 11/20/2020] [Indexed: 11/24/2022] Open
Abstract
Extracts made from the skin of dead Lithodytes lineatus frog individuals with the application of the benzocaine-based anesthetic gel, introduced into the oral cavity, were analyzed by 1H Nuclear Magnetic Resonance to investigate whether the application of this product (oral) can make studies that use extracts from the skins of these animals unfeasible. For comparison, we used skins of another species of anuran following the same death protocol. No trace of the benzocaine substance was found in the 1H-NMR spectra of the skin extracts from any of the tested anuran species. Still, using the hierarchical clustering model, it was possible to observe the formation of well-defined groups between the skin extracts of anurans and the anesthetic used to kill these animals. Our results suggest that the lethal dose of benzocaine in gel used inside the mouth of frogs may have no influence on potential results regarding the chemical composition or even bioassays using extracts made from the skin of these animals killed under this protocol since there was no detection of this substance for the analyzed samples.
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Affiliation(s)
- André de Lima Barros
- Departamento de Ecologia, Instituto Nacional de Pesquisas da Amazônia–INPA, Manaus, Amazonas, Brasil
- Laboratório de Bioprospecção e Biotecnologia—LABB, Instituto Nacional de Pesquisas da Amazônia–INPA, Manaus, Amazonas, Brasil
- * E-mail:
| | - Albertina Pimentel Lima
- Departamento de Ecologia, Instituto Nacional de Pesquisas da Amazônia–INPA, Manaus, Amazonas, Brasil
| | - Maria Teresa Fachin-Espinar
- Laboratório de Bioprospecção e Biotecnologia—LABB, Instituto Nacional de Pesquisas da Amazônia–INPA, Manaus, Amazonas, Brasil
| | - Cecilia Veronica Nunez
- Laboratório de Bioprospecção e Biotecnologia—LABB, Instituto Nacional de Pesquisas da Amazônia–INPA, Manaus, Amazonas, Brasil
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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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Geographically separated orange and blue populations of the Amazonian poison frog Adelphobates galactonotus (Anura, Dendrobatidae) do not differ in alkaloid composition or palatability. CHEMOECOLOGY 2019. [DOI: 10.1007/s00049-019-00291-3] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Sanchez E, Rodríguez A, Grau JH, Lötters S, Künzel S, Saporito RA, Ringler E, Schulz S, Wollenberg Valero KC, Vences M. Transcriptomic Signatures of Experimental Alkaloid Consumption in a Poison Frog. Genes (Basel) 2019; 10:genes10100733. [PMID: 31546679 PMCID: PMC6827147 DOI: 10.3390/genes10100733] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2019] [Revised: 09/14/2019] [Accepted: 09/17/2019] [Indexed: 01/19/2023] Open
Abstract
In the anuran family Dendrobatidae, aposematic species obtain their toxic or unpalatable alkaloids from dietary sources, a process known as sequestering. To understand how toxicity evolved in this family, it is paramount to elucidate the pathways of alkaloid processing (absorption, metabolism, and sequestering). Here, we used an exploratory skin gene expression experiment in which captive-bred dendrobatids were fed alkaloids. Most of these experiments were performed with Dendrobates tinctorius, but some trials were performed with D. auratus, D. leucomelas and Allobates femoralis to explore whether other dendrobatids would show similar patterns of gene expression. We found a consistent pattern of up-regulation of genes related to muscle and mitochondrial processes, probably due to the lack of mutations related to alkaloid resistance in these species. Considering conserved pathways of drug metabolism in vertebrates, we hypothesize alkaloid degradation is a physiological mechanism of resistance, which was evidenced by a strong upregulation of the immune system in D. tinctorius, and of complement C2 across the four species sampled. Probably related to this strong immune response, we found several skin keratins downregulated, which might be linked to a reduction of the cornified layer of the epidermis. Although not conclusive, our results offer candidate genes and testable hypotheses to elucidate alkaloid processing in poison frogs.
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Affiliation(s)
- Eugenia Sanchez
- Zoological Institute, Technische Universität Braunschweig, 38106 Braunschweig, Germany.
- Department of Biology, Stanford University, Stanford, CA 94305, USA.
| | - Ariel Rodríguez
- Institut fur Zoologie, Tierärztliche Hochschule Hannover, 30559 Hannover, Germany.
| | - Jose H Grau
- Museum für Naturkunde Berlin, Leibniz-Institut für Evolutions- und Biodiversitätsforschung, 10115 Berlin, Germany.
| | - Stefan Lötters
- Biogeography Department, Trier University, 54296 Trier, Germany.
| | - Sven Künzel
- Department of Evolutionary Genetics, Max Planck Institute for Evolutionary Biology, 24306 Plön, Germany.
| | - Ralph A Saporito
- Department of Biology, John Carroll University, University Heights, OH 44118, USA.
| | - Eva Ringler
- Messerli Research Institute, University of Veterinary Medicine Vienna, Medical University of Vienna, and University of Vienna, A-1210 Vienna, Austria.
- Department of Integrative Zoology, University of Vienna, A-1090 Vienna, Austria.
| | - Stefan Schulz
- Institute of Organic Chemistry, Technische Universität Braunschweig, 38106 Braunschweig, Germany.
| | | | - Miguel Vences
- Zoological Institute, Technische Universität Braunschweig, 38106 Braunschweig, Germany.
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8
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Lawrence JP, Rojas B, Fouquet A, Mappes J, Blanchette A, Saporito RA, Bosque RJ, Courtois EA, Noonan BP. Weak warning signals can persist in the absence of gene flow. Proc Natl Acad Sci U S A 2019; 116:19037-19045. [PMID: 31481623 PMCID: PMC6754554 DOI: 10.1073/pnas.1901872116] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
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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Affiliation(s)
- J P Lawrence
- Department of Biology, University of Mississippi, University, MS 38677;
| | - Bibiana Rojas
- Department of Biological and Environmental Science, University of Jyväskylä, 40014 Jyväskylä, Finland;
| | - Antoine Fouquet
- Laboratoire Evolution et Diversité Biologique, Centre National de la Recherche Scientifique, UMR5174, 31062 Toulouse cedex 9, France
| | - Johanna Mappes
- Department of Biological and Environmental Science, University of Jyväskylä, 40014 Jyväskylä, Finland
| | - Annelise Blanchette
- Department of Biology, John Carroll University, University Heights, OH 44118
| | - Ralph A Saporito
- Department of Biology, John Carroll University, University Heights, OH 44118
| | | | - Elodie A Courtois
- Laboratoire Ecologie, Evolution, Interactions des Systèmes Amazoniens, Centre de Recherche de Montabo, Universite de Guyane, BP 70620, 97334 Cayenne cedex, France
| | - Brice P Noonan
- Department of Biology, University of Mississippi, University, MS 38677
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9
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Márquez R, Ramírez‐Castañeda V, Amézquita A. Does batrachotoxin autoresistance coevolve with toxicity in
Phyllobates
poison‐dart frogs? Evolution 2019; 73:390-400. [DOI: 10.1111/evo.13672] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2018] [Accepted: 11/29/2018] [Indexed: 12/01/2022]
Affiliation(s)
- Roberto Márquez
- Department of Ecology and Evolution University of Chicago 1101 East 57th St. Chicago Illinois 60637
- Department of Biological Sciences Universidad de los Andes A.A. 4976 Bogotá Colombia
| | | | - Adolfo Amézquita
- Department of Biological Sciences Universidad de los Andes A.A. 4976 Bogotá Colombia
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10
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Mebs D, Yotsu-Yamashita M, Pogoda W, Vargas Alvarez J, Ernst R, Köhler G, Toennes SW. Lack of alkaloids and tetrodotoxin in the neotropical frogs Allobates spp. (Aromobatidae) and Silverstoneia flotator (Dendrobatidae). Toxicon 2018; 152:103-105. [DOI: 10.1016/j.toxicon.2018.07.027] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2018] [Revised: 07/24/2018] [Accepted: 07/31/2018] [Indexed: 01/08/2023]
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