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Robinson KE, Moniz HA, Stokes AN, Feldman CR. Where Does All the Poison Go? Investigating Toxicokinetics of Newt (Taricha) Tetrodotoxin (TTX) in Garter Snakes (Thamnophis). J Chem Ecol 2024:10.1007/s10886-024-01517-7. [PMID: 38842636 DOI: 10.1007/s10886-024-01517-7] [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: 02/20/2024] [Revised: 05/14/2024] [Accepted: 05/22/2024] [Indexed: 06/07/2024]
Abstract
Animals that consume toxic diets provide models for understanding the molecular and physiological adaptations to ecological challenges. Garter snakes (Thamnophis) in western North America prey on Pacific newts (Taricha), which employ tetrodotoxin (TTX) as an antipredator defense. These snakes possess mutations in voltage-gated sodium channels (Nav), the molecular targets of TTX, that decrease the binding ability of TTX to sodium channels (target-site resistance). However, genetic variation at these loci that cannot explain all the phenotypic variation in TTX resistance in Thamnophis. We explored a separate means of resistance, toxin metabolism, to determine if TTX-resistant snakes either rapidly remove TTX or sequester TTX. We examined the metabolism and distribution of TTX in the body (toxicokinetics), to determine differences between TTX-resistant and TTX-sensitive snakes in the rates at which TTX is eliminated from organs and the whole body (using TTX half-life as our metric). We assayed TTX half-life in snakes from TTX-resistant and TTX-sensitive populations of three garter snake species with a coevolutionary history with newts (T. atratus, T. couchii, T. sirtalis), as well as two non-resistant "outgroup" species (T. elegans, Pituophis catenifer) that seldom (if ever) engage newts. We found TTX half-life varied across species, populations, and tissues. Interestingly, TTX half-life was shortest in T. elegans and P. catenifer compared to all other snakes. Furthermore, TTX-resistant populations of T. couchii and T. sirtalis eliminated TTX faster (shorter TTX half-life) than their TTX-sensitive counterparts, while populations of TTX-resistant and TTX-sensitive T. atratus showed no difference rates of TTX removal (same TTX half-life). The ability to rapidly eliminate TTX may have permitted increased prey consumption, which may have promoted the evolution of additional resistance mechanisms. Finally, snakes still retain substantial amounts of TTX, and we projected that snakes could be dangerous to their own predators days to weeks following the ingestion of a single newt. Thus, aspects of toxin metabolism may have been key in driving predator-prey relationships, and important in determining other ecological interactions.
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Affiliation(s)
- Kelly E Robinson
- Department of Biology and Program in Ecology, Evolution and Conservation Biology, University of Nevada, Reno, Reno, NV, USA.
- Program in Ecology, Evolution and Conservation Biology, University of Nevada, Reno, NV, USA.
| | - Haley A Moniz
- Department of Biology and Program in Ecology, Evolution and Conservation Biology, University of Nevada, Reno, Reno, NV, USA
- Program in Ecology, Evolution and Conservation Biology, University of Nevada, Reno, NV, USA
- Department of Biological Sciences, California Polytechnic State University, San Luis Obispo, CA, USA
| | - Amber N Stokes
- Department of Biology, California State University Bakersfield, Bakersfield, CA, USA
| | - Chris R Feldman
- Department of Biology and Program in Ecology, Evolution and Conservation Biology, University of Nevada, Reno, Reno, NV, USA
- Program in Ecology, Evolution and Conservation Biology, University of Nevada, Reno, NV, USA
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2
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Hague MTJ, Miller LE, Stokes AN, Feldman CR, Brodie ED, Brodie ED. Conspicuous coloration of toxin-resistant predators implicates additional trophic interactions in a predator-prey arms race. Mol Ecol 2023; 32:4482-4496. [PMID: 36336815 DOI: 10.1111/mec.16772] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2022] [Revised: 10/21/2022] [Accepted: 11/03/2022] [Indexed: 08/08/2023]
Abstract
Antagonistic coevolution between natural enemies can produce highly exaggerated traits, such as prey toxins and predator resistance. This reciprocal process of adaptation and counter-adaptation may also open doors to other evolutionary novelties not directly involved in the phenotypic interface of coevolution. We tested the hypothesis that predator-prey coevolution coincided with the evolution of conspicuous coloration on resistant predators that retain prey toxins. In western North America, common garter snakes (Thamnophis sirtalis) have evolved extreme resistance to tetrodotoxin (TTX) in the coevolutionary arms race with their deadly prey, Pacific newts (Taricha spp.). TTX-resistant snakes can retain large amounts of ingested TTX, which could serve as a deterrent against the snakes' own predators if TTX toxicity and resistance are coupled with a conspicuous warning signal. We evaluated whether arms race escalation covaries with bright red coloration in snake populations across the geographic mosaic of coevolution. Snake colour variation departs from the neutral expectations of population genetic structure and covaries with escalating clines of newt TTX and snake resistance at two coevolutionary hotspots. In the Pacific Northwest, bright red coloration fits an expected pattern of an aposematic warning to avian predators: TTX-resistant snakes that consume highly toxic newts also have relatively large, reddish-orange dorsal blotches. Snake coloration also seems to have evolved with the arms race in California, but overall patterns are less intuitively consistent with aposematism. These results suggest that interactions with additional trophic levels can generate novel traits as a cascading consequence of arms race coevolution across the geographic mosaic.
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Affiliation(s)
- Michael T J Hague
- Division of Biological Sciences, University of Montana, Missoula, Montana, USA
| | - Lauren E Miller
- Department of Biology, University of Virginia, Charlottesville, Virginia, USA
| | - Amber N Stokes
- Department of Biology, California State University, Bakersfield, California, USA
| | - Chris R Feldman
- Department of Biology, University of Nevada, Reno, Nevada, USA
| | - Edmund D Brodie
- Department of Biology, Utah State University, Logan, Utah, USA
| | - Edmund D Brodie
- Department of Biology, University of Virginia, Charlottesville, Virginia, USA
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3
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Inoue T, Mori A, Yoshinaga N, Mori N. Intrinsic Factors Associated with Dietary Toxin Quantity and Concentration in the Nuchal Glands of a Natricine Snake Rhabdophis Tigrinus. J Chem Ecol 2023; 49:133-141. [PMID: 36881327 DOI: 10.1007/s10886-023-01415-4] [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: 12/20/2022] [Revised: 02/23/2023] [Accepted: 02/24/2023] [Indexed: 03/08/2023]
Abstract
The snake Rhabdophis tigrinus sequesters cardiotonic steroids, bufadienolides (BDs), from ingested toads and stores them in the nuchal glands as defensive toxins. It has previously been shown that there are individual differences in the total quantity of BDs stored in the nuchal glands of adult R. tigrinus and that BD quantities and profiles of R. tigrinus exhibit geographic variation. However, no previous study has examined the total quantity of BDs as a percentage of body mass (relative BD quantity) and the concentration of BDs in the nuchal gland fluid (BD gland concentration). In addition, intrinsic factors that are associated with relative BD quantity and BD concentration have not been examined within a single population. We collected 158 adult snakes from an area of central Japan from May to October and analyzed their BD quantities by UV analysis. We assessed individual differences in BD quantity, relative BD quantity and BD gland concentration. We found that 1) in approximately 60% of the 158 individuals, the BD gland concentration was greater than 50%; 2) body length and body condition are positively correlated with relative BD quantity and BD gland concentration; 3) even in a single population, individual differences of BD quantity are large, and are greater in females than in males; and 4) relative BD quantity and BD gland concentration of females during the gestation season are lower than those during the non-gestation season.
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Affiliation(s)
- Takato Inoue
- Division of Applied Life Science, Graduate School of Agriculture, Kyoto University, Sakyo, Kyoto, 606-8502, Japan.
| | - Akira Mori
- Department of Zoology, Graduate School of Science, Kyoto University, Sakyo, Kyoto, 606-8502, Japan
| | - Naoko Yoshinaga
- Division of Applied Life Science, Graduate School of Agriculture, Kyoto University, Sakyo, Kyoto, 606-8502, Japan
| | - Naoki Mori
- Division of Applied Life Science, Graduate School of Agriculture, Kyoto University, Sakyo, Kyoto, 606-8502, Japan
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4
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Melnikova DI, Magarlamov TY. An Overview of the Anatomical Distribution of Tetrodotoxin in Animals. Toxins (Basel) 2022; 14:toxins14080576. [PMID: 36006238 PMCID: PMC9412668 DOI: 10.3390/toxins14080576] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2022] [Revised: 08/15/2022] [Accepted: 08/19/2022] [Indexed: 11/23/2022] Open
Abstract
Tetrodotoxin (TTX), a potent paralytic sodium channel blocker, is an intriguing marine toxin. Widely distributed in nature, TTX has attracted attention in various scientific fields, from biomedical studies to environmental safety concerns. Despite a long history of studies, many issues concerning the biosynthesis, origin, and spread of TTX in animals and ecosystems remain. This review aims to summarize the current knowledge on TTX circulation inside TTX-bearing animal bodies. We focus on the advances in TTX detection at the cellular and subcellular levels, providing an expanded picture of intra-organismal TTX migration mechanisms. We believe that this review will help address the gaps in the understanding of the biological function of TTX and facilitate the development of further studies involving TTX-bearing animals.
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5
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van Thiel J, Khan MA, Wouters RM, Harris RJ, Casewell NR, Fry BG, Kini RM, Mackessy SP, Vonk FJ, Wüster W, Richardson MK. Convergent evolution of toxin resistance in animals. Biol Rev Camb Philos Soc 2022; 97:1823-1843. [PMID: 35580905 PMCID: PMC9543476 DOI: 10.1111/brv.12865] [Citation(s) in RCA: 20] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2021] [Revised: 04/22/2022] [Accepted: 04/26/2022] [Indexed: 12/17/2022]
Abstract
Convergence is the phenomenon whereby similar phenotypes evolve independently in different lineages. One example is resistance to toxins in animals. Toxins have evolved many times throughout the tree of life. They disrupt molecular and physiological pathways in target species, thereby incapacitating prey or deterring a predator. In response, molecular resistance has evolved in many species exposed to toxins to counteract their harmful effects. Here, we review current knowledge on the convergence of toxin resistance using examples from a wide range of toxin families. We explore the evolutionary processes and molecular adaptations driving toxin resistance. However, resistance adaptations may carry a fitness cost if they disrupt the normal physiology of the resistant animal. Therefore, there is a trade‐off between maintaining a functional molecular target and reducing toxin susceptibility. There are relatively few solutions that satisfy this trade‐off. As a result, we see a small set of molecular adaptations appearing repeatedly in diverse animal lineages, a phenomenon that is consistent with models of deterministic evolution. Convergence may also explain what has been called ‘autoresistance’. This is often thought to have evolved for self‐protection, but we argue instead that it may be a consequence of poisonous animals feeding on toxic prey. Toxin resistance provides a unique and compelling model system for studying the interplay between trophic interactions, selection pressures and the molecular mechanisms underlying evolutionary novelties.
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Affiliation(s)
- Jory van Thiel
- Institute of Biology Leiden, Leiden University, Sylviusweg 72, 2333 BE Leiden, The Netherlands
| | - Muzaffar A Khan
- Institute of Biology Leiden, Leiden University, Sylviusweg 72, 2333 BE Leiden, The Netherlands
| | - Roel M Wouters
- Institute of Biology Leiden, Leiden University, Sylviusweg 72, 2333 BE Leiden, The Netherlands
| | - Richard J Harris
- Venom Evolution Lab, School of Biological Sciences, University of Queensland, St Lucia, 4072, Australia
| | - Nicholas R Casewell
- Centre for Snakebite Research & Interventions, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool L3 5QA, U.K
| | - Bryan G Fry
- Venom Evolution Lab, School of Biological Sciences, University of Queensland, St Lucia, 4072, Australia
| | - R Manjunatha Kini
- Department of Biological Sciences, National University of Singapore, Singapore, 117558, Singapore.,Department of Pharmacology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, 117600, Singapore.,Department of Biochemistry, Medical College of Virginia, Virginia Commonwealth University, Richmond, VA, 23298, U.S.A
| | - Stephen P Mackessy
- School of Biological Sciences, University of Northern Colorado, Greeley, CO, 80639-0017, U.S.A
| | - Freek J Vonk
- Naturalis Biodiversity Center, Darwinweg 2, 2333 CR Leiden, The Netherlands.,Amsterdam Institute of Molecular and Life Sciences, Division of BioAnalytical Chemistry, Department of Chemistry and Pharmaceutical Sciences, Vrije Universiteit Amsterdam, De Boelelaan 1085, 1081HV Amsterdam, The Netherlands
| | - Wolfgang Wüster
- Molecular Ecology and Fisheries Genetics Laboratory, School of Natural Sciences, Bangor University, Bangor, LL57 2UW, U.K
| | - Michael K Richardson
- Institute of Biology Leiden, Leiden University, Sylviusweg 72, 2333 BE Leiden, The Netherlands
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How Phylogenetics Can Elucidate the Chemical Ecology of Poison Frogs and Their Arthropod Prey. J Chem Ecol 2022; 48:384-400. [PMID: 35352271 DOI: 10.1007/s10886-022-01352-8] [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: 12/12/2021] [Revised: 02/01/2022] [Accepted: 02/06/2022] [Indexed: 10/18/2022]
Abstract
The sequestration by neotropical poison frogs (Dendrobatidae) of an amazing array of defensive alkaloids from oribatid soil mites has motivated an exciting research theme in chemical ecology, but the details of mite-to-frog transfer remain hidden. To address this, McGugan et al. (2016, Journal of Chemical Ecology 42:537-551) used the little devil poison frog (Oophaga sylvatica) and attempted to simultaneously characterize the prey mite alkaloids, the predator skin alkaloids, and identify the mites using DNA sequences. Heethoff et al. (2016, Journal of Chemical Ecology 42:841-844) argued that none of the mite families to which McGugan et al. allocated the prey was thought to possess alkaloids. Heethoff et al. concluded from analyses including additional sequences that the mite species were unlikely to be close relatives of the defended mites. We re-examine this by applying more appropriate phylogenetic methods to broader and denser taxonomic samples of mite sequences using the same gene (CO1). We found, over trees based on CO1 datasets, only weak support (except in one case) for branches critical to connecting the evolution of alkaloid sequestration with the phylogeny of mites. In contrast, a well-supported analysis of the 18S ribosomal gene suggests at least two independent evolutionary origins of oribatid alkaloids. We point out impediments in the promising research agenda, namely a paucity of genetic, chemical, and taxonomic information, and suggest how phylogenetics can elucidate at a broader level the evolution of chemical defense in prey arthropods, sequestration by predators, and the impact of alkaloids on higher-order trophic interactions.
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7
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Hanifin CT, Kudo Y, Yotsu-Yamashita M. Chemical Ecology of the North American Newt Genera Taricha and Notophthalmus. PROGRESS IN THE CHEMISTRY OF ORGANIC NATURAL PRODUCTS 2022; 118:101-130. [PMID: 35416518 DOI: 10.1007/978-3-030-92030-2_3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
The North American newt genera Taricha and Notophthalmus (order Caudata) are well known for the combination of potent toxicity, aposematic coloration, and striking defense postures that protects these animals from predation. This suite of traits is centered around the neurotoxin tetrodotoxin, which causes paralysis and death in metazoans by disrupting the initiation and propagation of electrical signals in the nerves and muscles. Tetrodotoxin defends newts from predation across multiple life history stages and its role in generating arms-race coevolution between Taricha newts and garter snake (genus Thamnophis) predators is well studied. However, understanding the broader picture of chemical defenses in Taricha and Notophthalmus requires an expanded comprehension of the defensive chemical ecology of tetrodotoxin that includes possible coevolutionary interactions with insect egg predators, protection against parasites, as well as mimicry complexes associated with tetrodotoxin and aposematic coloration in both genera. Herein the authors review what is known about the structure, function, and pharmacology of tetrodotoxin to explore its evolution and chemical ecology in the North American newt. Focus is made specifically on the origin and possible biosynthesis of tetrodotoxin in these taxa as well as providing an expanded picture of the web of interactions that contribute to landscape level patterns of toxicity and defense in Taricha and Notophthalmus.
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Affiliation(s)
- Charles T Hanifin
- Department of Biology, Utah State University, 320 N. Aggie Blvd, Vernal, UT, 84078, USA.
| | - Yuta Kudo
- Graduate School of Agricultural Science, Tohoku University, 468-1 Aramaki-Aza-Aoba, Aoba-ku, Sendai, Miyagi, 980-8572, Japan
| | - Mari Yotsu-Yamashita
- Graduate School of Agricultural Science & Frontier Research Institute for Interdisciplinary Sciences, Tohoku University, 468-1 Aramaki-Aza-Aoba, Aoba-ku, Sendai, Miyagi, 980-8572, Japan
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8
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Durso AM, Neuman-Lee LA, Hopkins GR, Brodie ED. Stable isotope analysis suggests that tetrodotoxin-resistant Common Gartersnakes (Thamnophis sirtalis) rarely feed on newts in the wild. CAN J ZOOL 2021. [DOI: 10.1139/cjz-2020-0215] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Toxin-resistant predators may suffer costs from eating chemically defended prey and do not feed exclusively on toxic prey. Common Gartersnakes (Thamnophis sirtalis (Linnaeus, 1758)) have been considered the drivers of an evolutionary arms race with highly toxic newts (genus Taricha Gray, 1850), which they consume with few or no deleterious effects. However, how frequently newts are consumed in nature is less clear. To address this question, we investigated the diets of Th. sirtalis at a site in central Oregon where snakes have high levels of resistance and newts have high levels of tetrodotoxin in the skin. Because snake diets are difficult to quantify using traditional means, we used stable isotopes to estimate the proportion of Th. sirtalis diets made up of newts. Our estimate for the proportion of Th. sirtalis diet made up of Rough-skinned Newts (Taricha granulosa (Skilton, 1849)) at this site is 3.2%. Mole Salamanders (genus Ambystoma Tschudi, 1838) were predicted to be the most important prey, followed by slugs, chorus frogs, and mice, with a very minor role for earthworms. Our results demonstrate that even though Th. sirtalis are physiologically capable of consuming toxic prey, they do not often do so. Generalist predators can be exposed to very strong selection from, and exert reciprocal selection on even rarely eaten, chemically defended prey.
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Affiliation(s)
- Andrew M. Durso
- Department of Biological Sciences, Florida Gulf Coast University, Ft. Myers, FL 33965, USA
- Department of Biology and the Ecology Center, Utah State University, Logan, UT 84322, USA
| | - Lorin A. Neuman-Lee
- Department of Biological Sciences, Arkansas State University, Jonesboro, AR 72404, USA
- Department of Biology and the Ecology Center, Utah State University, Logan, UT 84322, USA
| | - Gareth R. Hopkins
- Department of Biology, Western Oregon University, Monmouth, OR 97361, USA
- Department of Biology and the Ecology Center, Utah State University, Logan, UT 84322, USA
| | - Edmund D. Brodie
- Department of Biology and the Ecology Center, Utah State University, Logan, UT 84322, USA
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9
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Characterization of Color Pattern Dimorphism in Turks and Caicos Boas, Chilabothrus chrysogaster chrysogaster, on Big Ambergris Cay, Turks and Caicos Islands. J HERPETOL 2020. [DOI: 10.1670/18-051] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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10
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Inoue T, Nakata R, Savitzky AH, Yoshinaga N, Mori A, Mori N. Variation in Bufadienolide Composition of Parotoid Gland Secretion From Three Taxa of Japanese Toads. J Chem Ecol 2020; 46:997-1009. [PMID: 32996040 DOI: 10.1007/s10886-020-01217-y] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2020] [Revised: 08/14/2020] [Accepted: 09/06/2020] [Indexed: 11/25/2022]
Abstract
Toads of the genus Bufo synthesize and accumulate bufadienolides (BDs) in their parotoid glands. BDs are cardiotonic steroids that play an important role in defense against the toads' predators. Three bufonid taxa occur in mainland Japan, Bufo japonicus formosus, B. j. japonicus, and B. torrenticola. The chemical structures of BDs isolated from B. j. formosus were studied several decades ago, but there is no further information on the toxic components of Japanese toads and their metabolism. In this study, we analyzed BDs of toads from throughout Japan and compared the BD profiles by liquid chromatography/mass spectrometry (LC/MS) and hierarchical cluster analysis (HCA). We observed BDs in three taxa of Japanese toads, and identified five of the most common BDs by nuclear magnetic resonance (NMR) analyses. Of the five BDs, only bufalin was detected in all individuals. HCA of individual BD profiles divided the three taxa into five primary clusters and several subclusters. This result indicates that BD profiles differ both among and within the taxa. The clustering pattern of BDs is generally concordant with a phylogenetic tree reconstructed from the mitochondrial cytochrome b gene of Japanese toads. Our results suggest that the BDs of Japanese toads have diversified not in response to specific selective pressures, but simply due to population structuring over evolutionary time.
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Affiliation(s)
- Takato Inoue
- Division of Applied Life Science, Graduate School of Agriculture, Kyoto University, Kitashirakawa, Sakyo, Kyoto, Kyoto, 606-8502, Japan
| | - Ryu Nakata
- Division of Applied Life Science, Graduate School of Agriculture, Kyoto University, Kitashirakawa, Sakyo, Kyoto, Kyoto, 606-8502, Japan
- Department of Bioscience and Biotechnology, Kyoto University of Advanced Science, 1-1 Nanjo Otani, Sogabe, Kameoka, Kyoto, 621-8555, Japan
| | - Alan H Savitzky
- Department of Biology, Utah State University, Logan, UT, 84322-5305, USA
| | - Naoko Yoshinaga
- Division of Applied Life Science, Graduate School of Agriculture, Kyoto University, Kitashirakawa, Sakyo, Kyoto, Kyoto, 606-8502, Japan
| | - Akira Mori
- Department of Zoology, Graduate School of Science, Kyoto University, Kitashirakwa, Sakyo, Kyoto, Kyoto, 606-8502, Japan
| | - Naoki Mori
- Division of Applied Life Science, Graduate School of Agriculture, Kyoto University, Kitashirakawa, Sakyo, Kyoto, Kyoto, 606-8502, Japan.
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11
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Venable CP, Langkilde T. Eastern Fence Lizards (Sceloporus undulatus) display an ontogenetic shift in relative consumption of native and invasive prey. CAN J ZOOL 2019. [DOI: 10.1139/cjz-2018-0228] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Interactions between invasive prey and native predators can provide an opportunity to better understand predator–prey dynamics and how these may change through ontogeny. Eastern Fence Lizards (Sceloporus undulatus (Bosc and Daudin in Sonnini and Latreille, 1801)) are ant specialist, particularly as juveniles. Invasive red imported fire ants (Solenopsis invicta Buren, 1972) pose a lethal risk to S. undulatus that eat them, especially smaller-bodied juveniles. We examine ontogenetic shifts in S. undulatus consumption of toxic invasive fire ants versus palatable native pyramid ants (Dorymyrmex bureni (Trager, 1988)). We predicted that hatchlings should avoid eating fire ants in favor of native ants, whereas less-vulnerable adults should take advantage of both prey sources. However, when given the choice between fire ants and native ants, hatchlings consumed similar numbers of these species, whereas adults consumed nearly three times as many native ants as invasive fire ants. Increased consumption of fire ants in adulthood could be the result of lifetime experience, strategies to safely consume fire ants, ontogenetic shifts in the ability to distinguish between ants, or reduced costs to adults of eating venomous ants. Future research should aim to distinguish these alternative mechanisms and examine the long-term consequences of native species incorporating toxic invasive prey into their diets.
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Affiliation(s)
- Cameron P. Venable
- Department of Biology, The Pennsylvania State University, University Park, PA 16802, USA
| | - Tracy Langkilde
- Department of Biology, The Pennsylvania State University, University Park, PA 16802, USA
- Intercollege Graduate Degree Program in Ecology, The Center for Brain, Behavior and Cognition, The Huck Institutes of the Life Sciences, The Pennsylvania State University, University Park, PA 16802, USA
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12
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Amézquita A, Ramos Ó, González MC, Rodríguez C, Medina I, Simões PI, Lima AP. Conspicuousness, color resemblance, and toxicity in geographically diverging mimicry: The pan-Amazonian frogAllobates femoralis. Evolution 2017; 71:1039-1050. [DOI: 10.1111/evo.13170] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2016] [Revised: 11/11/2016] [Accepted: 11/21/2016] [Indexed: 01/26/2023]
Affiliation(s)
- Adolfo Amézquita
- Department of Biological Sciences; Universidad de los Andes; Cra 1 #18A-10 Bogotá 111711 Colombia
| | - Óscar Ramos
- Department of Biological Sciences; Universidad de los Andes; Cra 1 #18A-10 Bogotá 111711 Colombia
| | - Mabel Cristina González
- Department of Biological Sciences; Universidad de los Andes; Cra 1 #18A-10 Bogotá 111711 Colombia
| | - Camilo Rodríguez
- Department of Biological Sciences; Universidad de los Andes; Cra 1 #18A-10 Bogotá 111711 Colombia
| | - Iliana Medina
- Department of Biological Sciences; Universidad de los Andes; Cra 1 #18A-10 Bogotá 111711 Colombia
| | - Pedro Ivo Simões
- Laboratório de Sistemática de Vertebrados; Pontifícia Universidade Católica do Rio Grande do Sul; Av. Ipiranga 6681, Prédio 40, sala 110 Porto Alegre CEP 90619-900 Brasil
- Coordenação de Pesquisas en Biodiversidade; Instituto Nacional de Pesquisas da Amazônia (INPA); Av. André Araujo 2936 Manaus CEP 69011-970 Brasil
| | - Albertina Pimentel Lima
- Coordenação de Pesquisas en Biodiversidade; Instituto Nacional de Pesquisas da Amazônia (INPA); Av. André Araujo 2936 Manaus CEP 69011-970 Brasil
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13
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Nesbit CM, Menéndez R, Roberts MR, Wilby A. Associational resistance or susceptibility: the indirect interaction between chemically-defended and non-defended herbivore prey via a shared predator. OIKOS 2016. [DOI: 10.1111/oik.03157] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Affiliation(s)
| | - Rosa Menéndez
- Lancaster Environment Centre; Lancaster University; Lancaster Lancashire LA1 4YQ UK
| | - Mike R. Roberts
- Lancaster Environment Centre; Lancaster University; Lancaster Lancashire LA1 4YQ UK
| | - Andrew Wilby
- Lancaster Environment Centre; Lancaster University; Lancaster Lancashire LA1 4YQ UK
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14
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Bell BD. A review of potential alpine newt (Ichthyosaura alpestris) impacts on native frogs in New Zealand. J R Soc N Z 2016. [DOI: 10.1080/03036758.2016.1216455] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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A PUFFERFISH (TETRADON NIGROVIRIDIS) AVAILABLE IN THE COMMON PET TRADE HARBORS LETHAL CONCENTRATIONS OF TETRODOTOXIN: A CASE STUDY OF POISONING IN A CUVIER'S DWARF CAIMAN (PALEOSUCHUS PALPEBROSUS). J Zoo Wildl Med 2016; 47:676-80. [PMID: 27468050 DOI: 10.1638/2015-0077.1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Many pufferfish possess tetrodotoxin (TTX). Unaware of this fact, the owner of a 3-mo-old pet Cuvier's dwarf caiman ( Paleosuchus palpebrosus ) fed the caiman a green spotted pufferfish ( Tetraodon nigroviridis ), acquired from a local discount department store. The caiman was nonresponsive within an hour of consumption of the fish. The caiman was presented for veterinary evaluation but died despite intensive medical care. High-performance liquid chromatography and a competitive inhibition enzyme immunoassay were used to determine whether the pufferfish was tetrodotoxic and whether the deceased caiman had TTX in its system. Skin and liver of the pufferfish harbored high concentrations of TTX, and the caiman had TTX in the blood, liver, and kidney. The clinical signs and presence of TTX in the caiman suggest that the caiman succumbed to tetrodotoxicosis. The implication is that lethally poisonous species are available commercially and pose a danger to other pets and possibly small children.
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16
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Responses of Natricine Snakes to Predatory Threat: A Mini-Review and Research Prospectus. J HERPETOL 2016. [DOI: 10.1670/15-103] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Panão I, Carrascosa C, Jaber JR, Raposo A. Puffer fish and its consumption: To eat or not to eat? FOOD REVIEWS INTERNATIONAL 2015. [DOI: 10.1080/87559129.2015.1075213] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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Stokes AN, Ray AM, Buktenica MW, Gall BG, Paulson E, Paulson D, French SS, Brodie ED, Brodie ED. Otter Predation onTaricha granulosaand Variation in Tetrodotoxin Levels with Elevation. ACTA ACUST UNITED AC 2015. [DOI: 10.1898/nwn13-19.1] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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19
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Wilson N, Stokes A, Hopkins G, Brodie, Jr. E, Williams C. Functional and physiological resistance of crayfish to amphibian toxins: tetrodotoxin resistance in the white river crayfish (Procambarus acutus). CAN J ZOOL 2014. [DOI: 10.1139/cjz-2014-0128] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Freshwater crayfish are reported to consume early life-history stages of a number of toxic amphibians. Although previous research indicates toxic amphibians are palatable to crayfish, the potential toxicity associated with consumption of toxic prey has been poorly described. We sought to characterise the supposed tetrodotoxin (TTX) resistance of freshwater crayfish, which have been observed to eat the eggs and larvae of toxic Taricha Gray, 1850 newts. White river crayfish (Procambarus acutus (Girard, 1852)) consumed 7.7 ± 4.0 Rough-skinned Newt (Taricha granulosa (Skilton, 1849)) eggs (mean ± SD) when offered 10 eggs in controlled feeding trials. Eggs were determined to contain a concentration of 1239 ± 571 ng (mean ± SD) of TTX. A dose-response assay was then performed to compare ingested doses with physiological TTX resistance. Crayfish were highly susceptible to TTX when administered as an intramuscular injection; TTX doses of 0.1 mass-adjusted mouse units were lethal to 100% of P. acutus crayfish. We established that while crayfish were capable consumers of highly toxic newt eggs, these decapods did not demonstrate physiological resistance to TTX. These findings suggest that crayfish have some functional resistance that renders them capable of consuming TTX-bearing prey despite a lack of physiological resistance to TTX.
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Affiliation(s)
- N.J. Wilson
- Sansom Institute for Health Research, University of South Australia, City East Campus, Frome Road, Adelaide, SA 5000, Australia
| | - A.N. Stokes
- Department of Biology, Utah State University, 5305 Old Main Hill, Logan, UT 84322, USA
| | - G.R. Hopkins
- Department of Biology, Utah State University, 5305 Old Main Hill, Logan, UT 84322, USA
| | - E.D. Brodie, Jr.
- Department of Biology, Utah State University, 5305 Old Main Hill, Logan, UT 84322, USA
| | - C.R. Williams
- Sansom Institute for Health Research, University of South Australia, City East Campus, Frome Road, Adelaide, SA 5000, Australia
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Khor S, Wood SA, Salvitti L, Taylor DI, Adamson J, McNabb P, Cary SC. Investigating diet as the source of tetrodotoxin in Pleurobranchaea maculata. Mar Drugs 2013; 12:1-16. [PMID: 24368566 PMCID: PMC3917257 DOI: 10.3390/md12010001] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2013] [Revised: 11/18/2013] [Accepted: 12/02/2013] [Indexed: 11/18/2022] Open
Abstract
The origin of tetrodotoxin (TTX) is highly debated; researchers have postulated either an endogenous or exogenous source with the host accumulating TTX symbiotically or via food chain transmission. The aim of this study was to determine whether the grey side-gilled sea slug (Pleurobranchaea maculata) could obtain TTX from a dietary source, and to attempt to identify this source through environmental surveys. Eighteen non-toxic P. maculata were maintained in aquariums and twelve were fed a TTX-containing diet. Three P. maculata were harvested after 1 h, 24 h, 17 days and 39 days and TTX concentrations in their stomach, gonad, mantle and remaining tissue/fluids determined using liquid chromatography-mass spectrometry. Tetrodotoxin was detected in all organs/tissue after 1 h with an average uptake of 32%. This decreased throughout the experiment (21%, 15% and 9%, respectively). Benthic surveys at sites with dense populations of toxic P. maculata detected very low or no TTX in other organisms. This study demonstrates that P. maculata can accumulate TTX through their diet. However, based on the absence of an identifiable TTX source in the environment, in concert with the extremely high TTX concentrations and short life spans of P. maculata, it is unlikely to be the sole TTX source for this species.
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Affiliation(s)
- Serena Khor
- Department of Biological Sciences, University of Waikato, Private Bag 3105, Hamilton 3240, New Zealand; E-Mails: (S.K.); (L.S.); (S.C.C.)
| | - Susanna A. Wood
- Department of Biological Sciences, University of Waikato, Private Bag 3105, Hamilton 3240, New Zealand; E-Mails: (S.K.); (L.S.); (S.C.C.)
- Cawthron Institute, Nelson 7042, New Zealand; E-Mails: (D.I.T.); (J.A.); (P.M.)
- Author to whom correspondence should be addressed; E-Mail: ; Tel.: +64-3-548-2319; Fax: +64-3-546-9464
| | - Lauren Salvitti
- Department of Biological Sciences, University of Waikato, Private Bag 3105, Hamilton 3240, New Zealand; E-Mails: (S.K.); (L.S.); (S.C.C.)
| | - David I. Taylor
- Cawthron Institute, Nelson 7042, New Zealand; E-Mails: (D.I.T.); (J.A.); (P.M.)
| | - Janet Adamson
- Cawthron Institute, Nelson 7042, New Zealand; E-Mails: (D.I.T.); (J.A.); (P.M.)
| | - Paul McNabb
- Cawthron Institute, Nelson 7042, New Zealand; E-Mails: (D.I.T.); (J.A.); (P.M.)
- Department of Chemistry, Otago University, Dunedin 9054, New Zealand
| | - Stephen Craig Cary
- Department of Biological Sciences, University of Waikato, Private Bag 3105, Hamilton 3240, New Zealand; E-Mails: (S.K.); (L.S.); (S.C.C.)
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Nelsen DR, Nisani Z, Cooper AM, Fox GA, Gren ECK, Corbit AG, Hayes WK. Poisons, toxungens, and venoms: redefining and classifying toxic biological secretions and the organisms that employ them. Biol Rev Camb Philos Soc 2013; 89:450-65. [PMID: 24102715 DOI: 10.1111/brv.12062] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2012] [Revised: 08/15/2013] [Accepted: 08/16/2013] [Indexed: 01/02/2023]
Abstract
Despite extensive study of poisonous and venomous organisms and the toxins they produce, a review of the literature reveals inconsistency and ambiguity in the definitions of 'poison' and 'venom'. These two terms are frequently conflated with one another, and with the more general term, 'toxin.' We therefore clarify distinctions among three major classes of toxins (biological, environmental, and anthropogenic or man-made), evaluate prior definitions of venom which differentiate it from poison, and propose more rigorous definitions for poison and venom based on differences in mechanism of delivery. We also introduce a new term, 'toxungen', thereby partitioning toxic biological secretions into three categories: poisons lacking a delivery mechanism, i.e. ingested, inhaled, or absorbed across the body surface; toxungens delivered to the body surface without an accompanying wound; and venoms, delivered to internal tissues via creation of a wound. We further propose a system to classify toxic organisms with respect to delivery mechanism (absent versus present), source (autogenous versus heterogenous), and storage of toxins (aglandular versus glandular). As examples, a frog that acquires toxins from its diet, stores the secretion within cutaneous glands, and transfers the secretion upon contact or ingestion would be heteroglandular-poisonous; an ant that produces its own toxins, stores the secretion in a gland, and sprays it for defence would be autoglandular-toxungenous; and an anemone that produces its own toxins within specialized cells that deliver the secretion via a penetrating wound would be autoaglandular-venomous. Adoption of our scheme should benefit our understanding of both proximate and ultimate causes in the evolution of these toxins.
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Affiliation(s)
- David R Nelsen
- Department of Earth and Biological Sciences, Loma Linda University, 11065 Campus Street, Loma Linda, CA, 92350, U.S.A
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Development of a non-lethal biopsy technique for estimating total tetrodotoxin concentrations in the grey side-gilled sea slug Pleurobranchaea maculata. Toxicon 2013; 74:27-33. [PMID: 23916603 DOI: 10.1016/j.toxicon.2013.07.024] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2013] [Revised: 07/19/2013] [Accepted: 07/25/2013] [Indexed: 11/20/2022]
Abstract
High concentrations of tetrodotoxin (TTX) have been detected in some New Zealand populations of Pleurobranchaea maculata (grey side-gilled sea slug). Within toxic populations there is significant variability in TTX concentrations among individuals, with up to 60-fold differences measured. This variability has led to challenges when conducting controlled laboratory experiments. The current method for assessing TTX concentrations within P. maculata is lethal, thus multiple individuals must be harvested at each sampling point to produce statistically meaningful data. In this study a method was developed for taking approximately 200 mg tissue biopsies using a TemnoEvolution(®) 18G × 11 cm Biopsy Needle inserted transversely into the foot. Correlation between the TTX concentrations in the biopsy sample and total TTX levels and in individual tissues were assessed. Six P. maculata were biopsied twice (nine days apart) and each individual was frozen immediately following the second sampling. Tetrodotoxin concentrations in biopsy samples and in the gonad, stomach, mantle and the remaining combined tissues and fluids were measured using liquid chromatography-mass spectrometry. Based on the proportional weight of the organs/tissues a total TTX concentration for each individual was calculated. There were strong correlations between biopsy TTX concentrations and the total (r(2) = 0.88), stomach (r(2) = 0.92) and gonad (r(2) = 0.83) TTX concentrations. This technique will enable more robust laboratory studies to be undertaken, thereby assisting in understanding TTX kinetics, ecological function and origin within P. maculata.
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Hutchinson DA, Savitzky AH, Burghardt GM, Nguyen C, Meinwald J, Schroeder FC, Mori A. Chemical defense of an Asian snake reflects local availability of toxic prey and hatchling diet. J Zool (1987) 2012; 289:270-278. [PMID: 23853424 PMCID: PMC3708106 DOI: 10.1111/jzo.12004] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2012] [Revised: 11/08/2012] [Accepted: 11/10/2012] [Indexed: 12/19/2022]
Abstract
Species that sequester toxins from prey for their own defense against predators may exhibit population-level variation in their chemical arsenal that reflects the availability of chemically defended prey in their habitat. Rhabdophis tigrinus is an Asian snake that possesses defensive glands in the skin of its neck (‘nuchal glands’), which typically contain toxic bufadienolide steroids that the snakes sequester from consumed toads. In this study, we compared the chemistry of the nuchal gland fluid of R. tigrinus from toad-rich and toad-free islands in Japan and determined the effect of diet on the nuchal gland constituents. Our findings demonstrate that captive-hatched juveniles from toad-rich Ishima Island that had not been fed toads possess defensive bufadienolides in their nuchal glands, presumably due to maternal provisioning of these sequestered compounds. Wild-caught juveniles from Ishima possess large quantities of bufadienolides, which could result from a combination of maternal provisioning and sequestration of these defensive compounds from consumed toads. Interestingly, juvenile females from Ishima possess larger quantities of bufadienolides than do juvenile males, whereas a small sample of field-collected snakes suggests that adult males contain larger quantities of bufadienolides than do adult females. Captive-born hatchlings from Kinkasan Island lack bufadienolides in their nuchal glands, reflecting the absence of toads on that island, but they can sequester bufadienolides by feeding on toads (Bufo japonicus) in captivity. The presence of large quantities of bufadienolides in the nuchal glands of R. tigrinus from Ishima may reduce the risk of predation by providing an effective chemical defense, whereas snakes on Kinkasan may experience increased predation due to the lack of defensive compounds in their nuchal glands.
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Affiliation(s)
- D A Hutchinson
- Department of Biology, Coastal Carolina University Conway, SC, USA ; Department of Biological Sciences, Old Dominion University Norfolk, VA, USA
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24
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Microdistribution of tetrodotoxin in two species of blue-ringed octopuses (Hapalochlaena lunulata and Hapalochlaena fasciata) detected by fluorescent immunolabeling. Toxicon 2012; 60:1307-13. [DOI: 10.1016/j.toxicon.2012.08.015] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2012] [Revised: 08/21/2012] [Accepted: 08/29/2012] [Indexed: 11/24/2022]
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25
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Predatory Caddisfly Larvae Sequester Tetrodotoxin from Their Prey, Eggs of the Rough-Skinned Newt (Taricha granulosa). J Chem Ecol 2012; 38:1351-7. [DOI: 10.1007/s10886-012-0213-8] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2012] [Revised: 09/17/2012] [Accepted: 10/22/2012] [Indexed: 01/15/2023]
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26
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Ferrer RP, Zimmer RK. Community ecology and the evolution of molecules of keystone significance. THE BIOLOGICAL BULLETIN 2012; 223:167-177. [PMID: 23111129 DOI: 10.1086/bblv223n2p167] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
Molecules of keystone significance are vital in structuring ecological communities. Select bioactive compounds can cause disproportionately large effects by connecting such seemingly disparate processes as microbial loop dynamics and apex predation. Here, we develop a general theory and propose mechanisms that could lead to the evolution of keystone molecules. Introduced into a respective community by one, or only a few, autotrophic or microbial species, these compounds often originate as chemical defenses. When co-opted by resistant consumer species, however, they are used either in chemical defense against higher-order predators or as chemosensory cues that elicit courtship and mating, alarm, and predatory search. Requisite to these multifunctional properties, biosynthetic capacity evolves along with mechanisms for resistance and/or toxin storage in primary producers. Subsequently, consumers acquire resistances or tolerances, and the toxins are transferred through food webs via trophic interactions. In consumers, mechanisms eventually evolve for recognizing toxins as feeding cues and, ultimately, as signals or pheromones in chemical communication within or between species. One, or a few, active compounds can thus mediate a vast array of physiological traits, expressed differentially across many species in a given community. Through convergent evolution, molecules of keystone significance provide critical information to phylogenetically diverse species, initiate major trophic cascades, and structure communities within terrestrial, freshwater, coastal-ocean and open-ocean habitats.
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Affiliation(s)
- Ryan P Ferrer
- Department of Biology, Seattle Pacific University, 3307 Third Avenue West, Seattle, Washington 98119, USA.
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Savitzky AH, Mori A, Hutchinson DA, Saporito RA, Burghardt GM, Lillywhite HB, Meinwald J. Sequestered defensive toxins in tetrapod vertebrates: principles, patterns, and prospects for future studies. CHEMOECOLOGY 2012; 22:141-158. [PMID: 22904605 PMCID: PMC3418492 DOI: 10.1007/s00049-012-0112-z] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2012] [Accepted: 07/14/2012] [Indexed: 12/16/2022]
Abstract
Chemical defenses are widespread among animals, and the compounds involved may be either synthesized from nontoxic precursors or sequestered from an environmental source. Defensive sequestration has been studied extensively among invertebrates, but relatively few examples have been documented among vertebrates. Nonetheless, the number of described cases of defensive sequestration in tetrapod vertebrates has increased recently and includes diverse lineages of amphibians and reptiles (including birds). The best-known examples involve poison frogs, but other examples include natricine snakes that sequester toxins from amphibians and two genera of insectivorous birds. Commonalities among these diverse taxa include the combination of consuming toxic prey and exhibiting some form of passive defense, such as aposematism, mimicry, or presumptive death-feigning. Some species exhibit passive sequestration, in which dietary toxins simply require an extended period of time to clear from the tissues, whereas other taxa exhibit morphological or physiological specializations that enhance the uptake, storage, and/or delivery of exogenous toxins. It remains uncertain whether any sequestered toxins of tetrapods bioaccumulate across multiple trophic levels, but multitrophic accumulation seems especially likely in cases involving consumption of phytophagous or mycophagous invertebrates and perhaps consumption of poison frogs by snakes. We predict that additional examples of defensive toxin sequestration in amphibians and reptiles will be revealed by collaborations between field biologists and natural product chemists. Candidates for future investigation include specialized predators on mites, social insects, slugs, and toxic amphibians. Comprehensive studies of the ecological, evolutionary, behavioral, and regulatory aspects of sequestration will require teams of ecologists, systematists, ethologists, physiologists, molecular biologists, and chemists. The widespread occurrence of sequestered defenses has important implications for the ecology, evolution, and conservation of amphibians and reptiles.
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Affiliation(s)
- Alan H. Savitzky
- Department of Biology, Utah State University, Logan UT, 84322-5305 USA
| | - Akira Mori
- Department of Zoology, Graduate School of Science, Kyoto University, Sakyo, Kyoto, 606-8502 Japan
| | - Deborah A. Hutchinson
- Department of Biology, Coastal Carolina University, P.O. Box 261954, Conway, SC 29528 USA
| | - Ralph A. Saporito
- Department of Biology, John Carroll University, University Heights, Ohio, 44118 USA
| | - Gordon M. Burghardt
- Department of Psychology, University of Tennessee, Knoxville, TN 37996-0900 USA
| | | | - Jerrold Meinwald
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca NY, 14853-1301 USA
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Takeuchi H, Mori A. Antipredator Displays and Prey Chemical Preference of an Asian Natricine Snake,Macropisthodon rudis(Squamata: Colubridae). CURRENT HERPETOLOGY 2012. [DOI: 10.5358/hsj.31.47] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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29
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The occurrence of defensive alkaloids in non-integumentary tissues of the Brazilian red-belly toad Melanophryniscus simplex (Bufonidae). CHEMOECOLOGY 2012. [DOI: 10.1007/s00049-012-0107-9] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
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Townsend KA, Altvater J, Thomas MC, Schuyler QA, Nette GW. Death in the octopus' garden: fatal blue-lined octopus envenomations of adult green sea turtles. MARINE BIOLOGY 2011; 159:689-695. [PMID: 24391271 PMCID: PMC3873062 DOI: 10.1007/s00227-011-1846-9] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/27/2011] [Accepted: 11/18/2011] [Indexed: 05/12/2023]
Abstract
The blue-lined octopus Hapalochlaena fasciata contains the powerful neuromuscular blocker tetrodotoxin (TTX), which causes muscle weakness and respiratory failure. H. fasciata is regarded as one of the most venomous marine animals in the world, and multiple human fatalities have been attributed to the octopus. To date, there have been no recorded incidents of an envenomation of a wild animal. Here, we present a newly developed, multi-stage tandem mass spectrometry technique that provides unequivocal evidence for two cases of envenomation of two ~110 kg herbivorous green sea turtles by two tiny cryptic blue-lined octopuses (~4 cm body length). These cases of accidental ingestion provide evidence for the first time of the antipredator effect of TTX and highlight a previously unconsidered threat to turtles grazing within seagrass beds.
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Affiliation(s)
- Kathy A. Townsend
- School of Biological Sciences, The University of Queensland, Moreton Bay Research Station, P.O. Box 138, Dunwich, QLD 4183 Australia
| | - Jens Altvater
- Independent Marine Biochemistry Research, Moreton Bay Research Station, P.O. Box 138, Dunwich, QLD 4183 Australia
| | - Michael C. Thomas
- Independent Marine Biochemistry Research, Moreton Bay Research Station, P.O. Box 138, Dunwich, QLD 4183 Australia
| | - Qamar A. Schuyler
- School of Biological Sciences, The University of Queensland, Moreton Bay Research Station, P.O. Box 138, Dunwich, QLD 4183 Australia
| | - Geoffrey W. Nette
- Independent Marine Biochemistry Research, Moreton Bay Research Station, P.O. Box 138, Dunwich, QLD 4183 Australia
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Williams BL, Hanifin CT, Brodie ED, Brodie ED. Predators usurp prey defenses? Toxicokinetics of tetrodotoxin in common garter snakes after consumption of rough-skinned newts. CHEMOECOLOGY 2011. [DOI: 10.1007/s00049-011-0093-3] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Mooi RD, Wiens JP, Casper GS. Extreme Color Variation within Populations of the Common Gartersnake, Thamnophis sirtalis, in Central North America, with Implications for Subspecies Status. COPEIA 2011. [DOI: 10.1643/ch-10-067] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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Hutchinson DA, Savitzky AH, Mori A, Burghardt GM, Meinwald J, Schroeder FC. Chemical investigations of defensive steroid sequestration by the Asian snake Rhabdophis tigrinus. CHEMOECOLOGY 2011. [DOI: 10.1007/s00049-011-0078-2] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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34
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Williams BL, Hanifin CT, Brodie ED, Brodie III ED. Tetrodotoxin affects survival probability of rough-skinned newts (Taricha granulosa) faced with TTX-resistant garter snake predators (Thamnophis sirtalis). CHEMOECOLOGY 2010. [DOI: 10.1007/s00049-010-0057-z] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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Hanifin CT. The chemical and evolutionary ecology of tetrodotoxin (TTX) toxicity in terrestrial vertebrates. Mar Drugs 2010; 8:577-93. [PMID: 20411116 PMCID: PMC2857372 DOI: 10.3390/md8030577] [Citation(s) in RCA: 115] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2010] [Revised: 03/03/2010] [Accepted: 03/08/2010] [Indexed: 01/05/2023] Open
Abstract
Tetrodotoxin (TTX) is widely distributed in marine taxa, however in terrestrial taxa it is limited to a single class of vertebrates (Amphibia). Tetrodotoxin present in the skin and eggs of TTX-bearing amphibians primarily serves as an antipredator defense and these taxa have provided excellent models for the study of the evolution and chemical ecology of TTX toxicity. The origin of TTX present in terrestrial vertebrates is controversial. In marine organisms the accepted hypothesis is that the TTX present in metazoans results from either dietary uptake of bacterially produced TTX or symbiosis with TTX producing bacteria, but this hypothesis may not be applicable to TTX-bearing amphibians. Here I review the taxonomic distribution and evolutionary ecology of TTX in amphibians with some attention to the origin of TTX present in these taxa.
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Affiliation(s)
- Charles T Hanifin
- Hopkins Marine Station of Stanford University, 120 Oceanview Blvd., Pacific Grove, CA 93950, USA.
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36
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Behavioral and chemical ecology of marine organisms with respect to tetrodotoxin. Mar Drugs 2010; 8:381-98. [PMID: 20411104 PMCID: PMC2857358 DOI: 10.3390/md8030381] [Citation(s) in RCA: 72] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2010] [Revised: 02/24/2010] [Accepted: 02/25/2010] [Indexed: 11/26/2022] Open
Abstract
The behavioral and chemical ecology of marine organisms that possess tetrodotoxin (TTX) has not been comprehensively reviewed in one work to date. The evidence for TTX as an antipredator defense, as venom, as a sex pheromone, and as an attractant for TTX-sequestering organisms is discussed. Little is known about the adaptive value of TTX in microbial producers; thus, I focus on what is known about metazoans that are purported to accumulate TTX through diet or symbioses. Much of what has been proposed is inferred based on the anatomical distribution of TTX. Direct empirical tests of these hypotheses are absent in most cases.
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Abstract
Chemical neuroecology examines the relationships between chemosensory physiology, behavior, and population and community dynamics. A keystone species, for example, is one whose impact on communities is far greater than would be predicted from its relative abundance and biomass. Neurotoxins, then, could function in keystone roles. Rare within natural habitats, they exert strong effects on species interactions at multiple trophic levels. Effects of two guanidine alkaloids, tetrodotoxin (TTX) and saxitoxin (STX), coalesce neurobiological and ecological perspectives. These potent neurotoxins function as chemical defenses by binding to voltage-gated sodium channels on nerve and muscle cells. When borrowed by resistant consumer species, however, they are used in chemical defense against higher-order predators or as chemosensory excitants in mediating critical behavioral interactions. Through a combination of diverse physiological traits, TTX and STX exert profound impacts reverberating across multiple trophic levels and determining a wide range of community-wide attributes. Such traits ultimately render TTX and STX fully functional as keystone molecules, with vast ecological consequences for species assemblages and rates of material exchange.
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Affiliation(s)
- Ryan P Ferrer
- Department of Biology, Seattle Pacific University, Seattle, Washington 98119, USA.
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Williams BL, Caldwell RL. Intra-organismal distribution of tetrodotoxin in two species of blue-ringed octopuses (Hapalochlaena fasciata and H. lunulata). Toxicon 2009; 54:345-53. [DOI: 10.1016/j.toxicon.2009.05.019] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2009] [Revised: 05/01/2009] [Accepted: 05/11/2009] [Indexed: 10/20/2022]
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Llewellyn LE. Sodium channel inhibiting marine toxins. PROGRESS IN MOLECULAR AND SUBCELLULAR BIOLOGY 2009; 46:67-97. [PMID: 19184585 DOI: 10.1007/978-3-540-87895-7_3] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Saxitoxin (STX), tetrodotoxin (TTX) and their many chemical relatives are part of our daily lives. From killing people who eat seafood containing these toxins, to being valuable research tools unveiling the invisible structures of their pharmacological receptor, their global impact is beyond measure. The pharmacological receptor for these toxins is the voltage-gated sodium channel which transports Na ions between the exterior to the interior of cells. The two structurally divergent families of STX and TTX analogues bind at the same location on these Na channels to stop the flow of ions. This can affect nerves, muscles and biological senses of most animals. It is through these and other toxins that we have developed much of our fundamental understanding of the Na channel and its part in generating action potentials in excitable cells.
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Affiliation(s)
- Lyndon E Llewellyn
- Australian Institute of Marine Science, Townsville MC, QLD 4810, Australia.
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Hanifin CT, Brodie ED, Brodie ED. Phenotypic mismatches reveal escape from arms-race coevolution. PLoS Biol 2008; 6:e60. [PMID: 18336073 PMCID: PMC2265764 DOI: 10.1371/journal.pbio.0060060] [Citation(s) in RCA: 144] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2007] [Accepted: 01/24/2008] [Indexed: 11/18/2022] Open
Abstract
Because coevolution takes place across a broad scale of time and space, it is virtually impossible to understand its dynamics and trajectories by studying a single pair of interacting populations at one time. Comparing populations across a range of an interaction, especially for long-lived species, can provide insight into these features of coevolution by sampling across a diverse set of conditions and histories. We used measures of prey traits (tetrodotoxin toxicity in newts) and predator traits (tetrodotoxin resistance of snakes) to assess the degree of phenotypic mismatch across the range of their coevolutionary interaction. Geographic patterns of phenotypic exaggeration were similar in prey and predators, with most phenotypically elevated localities occurring along the central Oregon coast and central California. Contrary to expectations, however, these areas of elevated traits did not coincide with the most intense coevolutionary selection. Measures of functional trait mismatch revealed that over one-third of sampled localities were so mismatched that reciprocal selection could not occur given current trait distributions. Estimates of current locality-specific interaction selection gradients confirmed this interpretation. In every case of mismatch, predators were “ahead” of prey in the arms race; the converse escape of prey was never observed. The emergent pattern suggests a dynamic in which interacting species experience reciprocal selection that drives arms-race escalation of both prey and predator phenotypes at a subset of localities across the interaction. This coadaptation proceeds until the evolution of extreme phenotypes by predators, through genes of large effect, allows snakes to, at least temporarily, escape the arms race. Arms races between natural enemies can lead to the rapid evolution of extreme traits, high degrees of specialization, and the formation of new species. They also serve as the ecological model for the evolution of drug resistance by diseases and for host–pathogen interactions in general. Revealing who wins these arms races and how they do so is critical to our understanding of these processes. Capitalizing on the geographic mosaic of species interactions, we examined the dynamics of the arms race between snakes and their toxic newt prey. Garter snakes in some populations have evolved dramatic resistance to the tetrodotoxin defense of the their local prey. By evaluating the pattern of mismatches between toxicity and resistance, we discovered that predators sometimes escape the arms race through the evolution of extreme resistance, but that prey never come out ahead. The reason for this one-sided outcome appears to depend on the molecular genetic basis of resistance in snakes, wherein changes to a single amino acid residue can confer huge differences in resistance. Who wins in the arms race between predators and prey? In the interaction between snakes and toxic newts, predators sometimes escape the arms race through the evolution of extreme resistance, but prey never come out ahead.
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Affiliation(s)
- Charles T Hanifin
- Department of Biology, Utah State University, Logan, Utah, United States of America.
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Clucas B, Rowe MP, Owings DH, Arrowood PC. Snake scent application in ground squirrels, Spermophilus spp.: a novel form of antipredator behaviour? Anim Behav 2008. [DOI: 10.1016/j.anbehav.2007.05.024] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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Zimmer RK, Ferrer RP. Neuroecology, chemical defense, and the keystone species concept. THE BIOLOGICAL BULLETIN 2007; 213:208-225. [PMID: 18083963 DOI: 10.2307/25066641] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
Neuroecology unifies principles from diverse disciplines, scaling from biophysical properties of nerve and muscle cells to community-wide impacts of trophic interactions. Here, these principles are used as a common fabric, woven from threads of chemosensory physiology, behavior, and population and community ecology. The "keystone species" concept, for example, is seminal in ecological theory. It defines a species whose impacts on communities are far greater than would be predicted from its relative abundance and biomass. Similarly, neurotoxins could function in keystone roles. They are rare within natural habitats but exert strong effects on species interactions at multiple trophic levels. Effects of two guanidine alkaloids, tetrodotoxin (TTX) and saxitoxin (STX), coalesce neurobiological and ecological perspectives. These molecules compose some of the most potent natural poisons ever described, and they are introduced into communities by one, or only a few, host species. Functioning as voltage-gated sodium channel blockers for nerve and muscle cells, TTX and STX serve in chemical defense. When borrowed by resistant consumer species, however, they are used either in chemical defense against higher order predators or for chemical communication as chemosensory excitants. Cascading effects of the compounds profoundly impact community-wide attributes, including species compositions and rates of material exchange. Thus, a diverse array of physiological traits, expressed differentially across many species, renders TTX and STX fully functional as keystone molecules, with vast ecological consequences at multiple trophic levels.
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Affiliation(s)
- Richard K Zimmer
- Department of Ecology and Evolutionary Biology, University of California, Los Angeles, California 90095-1606, USA.
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Hutchinson DA, Mori A, Savitzky AH, Burghardt GM, Wu X, Meinwald J, Schroeder FC. Dietary sequestration of defensive steroids in nuchal glands of the Asian snake Rhabdophis tigrinus. Proc Natl Acad Sci U S A 2007; 104:2265-70. [PMID: 17284596 PMCID: PMC1892995 DOI: 10.1073/pnas.0610785104] [Citation(s) in RCA: 77] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The Asian snake Rhabdophis tigrinus possesses specialized defensive glands on its neck that contain steroidal toxins known as bufadienolides. We hypothesized that R. tigrinus does not synthesize these defensive steroids but instead sequesters the toxins from toads it consumes as prey. To test this hypothesis, we conducted chemical analyses on the glandular fluid from snakes collected in toad-free and toad-present localities. We also performed feeding experiments in which hatchling R. tigrinus were reared on controlled diets that either included or lacked toads. We demonstrate that the cardiotonic steroids in the nuchal glands of R. tigrinus are obtained from dietary toads. We further show that mothers containing high levels of bufadienolides can provision their offspring with toxins. Hatchlings had bufadienolides in their nuchal glands only if they were fed toads or were born to a dam with high concentrations of these compounds. Because geographic patterns in the availability of toxic prey are reflected in the chemical composition of the glandular fluid, snakes in toad-free regions are left undefended by steroidal toxins. Our findings confirm that the sequestration of dietary toxins underlies geographic variation in antipredatory behavior in this species and provide a unique example of sequestered defensive compounds in a specialized vertebrate structure.
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Affiliation(s)
- Deborah A. Hutchinson
- *Department of Biological Sciences, Old Dominion University, Norfolk, VA 23529
- To whom correspondence may be addressed. E-mail:
or
| | - Akira Mori
- Department of Zoology, Graduate School of Science, Kyoto University, Sakyo, Kyoto 606-8502, Japan
| | - Alan H. Savitzky
- *Department of Biological Sciences, Old Dominion University, Norfolk, VA 23529
| | - Gordon M. Burghardt
- Departments of Psychology and Ecology and Evolutionary Biology, University of Tennessee, Knoxville, TN 37996; and
| | - Xiaogang Wu
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, NY 14853
| | - Jerrold Meinwald
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, NY 14853
- To whom correspondence may be addressed. E-mail:
or
| | - Frank C. Schroeder
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, NY 14853
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Ritson-Williams R, Yotsu-Yamashita M, Paul VJ. Ecological functions of tetrodotoxin in a deadly polyclad flatworm. Proc Natl Acad Sci U S A 2006; 103:3176-9. [PMID: 16492790 PMCID: PMC1413867 DOI: 10.1073/pnas.0506093103] [Citation(s) in RCA: 66] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The deadly neurotoxin tetrodotoxin (TTX) is found in a variety of animal phyla and, because of its toxicity, is most often assumed to deter predation. On the tropical Pacific island of Guam, we found an undescribed flatworm (planocerid sp. 1) that contains high levels of TTX and its analogs. Through ecological experiments, we show that TTXs do not protect these flatworms from some predators but instead are used to capture mobile prey. TTX is known to have multiple ecological functions, which has probably led to its widespread presence among prokaryotes and at least 10 metazoan phyla.
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