1
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Pandelis GG, Grundler MC, Rabosky DL. Ecological correlates of cranial evolution in the megaradiation of dipsadine snakes. BMC Ecol Evol 2023; 23:48. [PMID: 37679675 PMCID: PMC10485986 DOI: 10.1186/s12862-023-02157-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2023] [Accepted: 08/22/2023] [Indexed: 09/09/2023] Open
Abstract
BACKGROUND Dipsadine snakes represent one of the most spectacular vertebrate radiations that have occurred in any continental setting, with over 800 species in South and Central America. Their species richness is paralleled by stunning ecological diversity, ranging from arboreal snail-eating and aquatic eel-eating specialists to terrestrial generalists. Despite the ecological importance of this clade, little is known about the extent to which ecological specialization shapes broader patterns of phenotypic diversity within the group. Here, we test how habitat use and diet have influenced morphological diversification in skull shape across 160 dipsadine species using micro-CT and 3-D geometric morphometrics, and we use a phylogenetic comparative approach to test the contributions of habitat use and diet composition to variation in skull shape among species. RESULTS We demonstrate that while both habitat use and diet are significant predictors of shape in many regions of the skull, habitat use significantly predicts shape in a greater number of skull regions when compared to diet. We also find that across ecological groupings, fossorial and aquatic behaviors result in the strongest deviations in morphospace for several skull regions. We use simulations to address the robustness of our results and describe statistical anomalies that can arise from the application of phylogenetic generalized least squares to complex shape data. CONCLUSIONS Both habitat and dietary ecology are significantly correlated with skull shape in dipsadines; the strongest relationships involved skull shape in snakes with aquatic and fossorial lifestyles. This association between skull morphology and multiple ecological axes is consistent with a classic model of adaptive radiation and suggests that ecological factors were an important component in driving morphological diversification in the dipsadine megaradiation.
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Affiliation(s)
- Gregory G Pandelis
- Department of Ecology and Evolutionary Biology, University of Michigan, Ann Arbor, Michigan, 48109, USA.
- Museum of Zoology, University of Michigan, Ann Arbor, Michigan, 48109, USA.
- Amphibian and Reptile Diversity Research Center, Department of Biology, University of Texas at Arlington, Arlington, Texas, 76019, USA.
| | - Michael C Grundler
- Department of Ecology and Evolutionary Biology, University of Michigan, Ann Arbor, Michigan, 48109, USA
- Museum of Zoology, University of Michigan, Ann Arbor, Michigan, 48109, USA
| | - Daniel L Rabosky
- Department of Ecology and Evolutionary Biology, University of Michigan, Ann Arbor, Michigan, 48109, USA
- Museum of Zoology, University of Michigan, Ann Arbor, Michigan, 48109, 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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Üveges B, Kalina C, Szabó K, Móricz ÁM, Holly D, Gabor CR, Hettyey A, Bókony V. Does the Glucocorticoid Stress Response Make Toads More Toxic? An Experimental Study on the Regulation of Bufadienolide Toxin Synthesis. Integr Org Biol 2023; 5:obad021. [PMID: 37435008 PMCID: PMC10331804 DOI: 10.1093/iob/obad021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2023] [Revised: 05/15/2023] [Accepted: 06/02/2023] [Indexed: 07/13/2023] Open
Abstract
Chemical defense is a crucial component of fitness in many organisms, yet the physiological regulation of defensive toxin synthesis is poorly understood, especially in vertebrates. Bufadienolides, the main defensive compounds of toads, are toxic to many predators and other natural enemies, and their synthesis can be upregulated by stressors, including predation risk, high conspecific density, and pollutants. Thus, higher toxin content may be the consequence of a general endocrine stress response in toads. Therefore, we hypothesized that bufadienolide synthesis may be stimulated by elevated levels of corticosterone (CORT), the main glucocorticoid hormone of amphibians, or by upstream regulators that stimulate CORT production. To test these alternatives, we treated common toad tadpoles with exogenous CORT (exoCORT) or metyrapone (MTP, a CORT-synthesis inhibitor that stimulates upstream regulators of CORT by negative feedback) in the presence or absence of predation cues for 2 or 6 days, and subsequently measured their CORT release rates and bufadienolide content. We found that CORT release rates were elevated by exoCORT, and to a lesser extent also by MTP, regardless of treatment length. Bufadienolide content was significantly decreased by treatment with exoCORT for 6 days but was unaffected by exposure to exoCORT for 2 days or to MTP for either 6 or 2 days. The presence or absence of predation cues affected neither CORT release rate nor bufadienolide content. Our results suggest that changes in bufadienolide synthesis in response to environmental challenges are not driven by CORT but may rather be regulated by upstream hormones of the stress response.
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Affiliation(s)
| | - C Kalina
- Department of Evolutionary Ecology, Plant Protection Institute, Centre for Agricultural Research, Eötvös Loránd Research Network, Herman Ottó út 15, 1022 Budapest, Hungary
- Department of Ecology, Institute of Biology, University of Veterinary Medicine, István u. 2, 1078 Budapest, Hungary
| | - K Szabó
- Division of Clinical Immunology, Department for Internal Medicine, Faculty of Medicine, University of Debrecen, Móricz Zsigmond út 22, 4032 Debrecen, Hungary
| | - Á M Móricz
- Department of Pathophysiology, Plant Protection Institute, Centre for Agricultural Research, Eötvös Loránd Research Network, Herman Ottó út 15, 1022 Budapest, Hungary
| | - D Holly
- Department of Evolutionary Ecology, Plant Protection Institute, Centre for Agricultural Research, Eötvös Loránd Research Network, Herman Ottó út 15, 1022 Budapest, Hungary
| | - C R Gabor
- Department of Evolutionary Ecology, Plant Protection Institute, Centre for Agricultural Research, Eötvös Loránd Research Network, Herman Ottó út 15, 1022 Budapest, Hungary
- Department of Biology, College of Science and Engineering, Texas State University, 601 University Dr., San Marcos, TX 78666, USA
| | - A Hettyey
- Department of Evolutionary Ecology, Plant Protection Institute, Centre for Agricultural Research, Eötvös Loránd Research Network, Herman Ottó út 15, 1022 Budapest, Hungary
| | - V Bókony
- Department of Evolutionary Ecology, Plant Protection Institute, Centre for Agricultural Research, Eötvös Loránd Research Network, Herman Ottó út 15, 1022 Budapest, Hungary
- Department of Ecology, Institute of Biology, University of Veterinary Medicine, István u. 2, 1078 Budapest, Hungary
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4
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McPeek MA, McPeek SJ, Fu F. Character displacement when natural selection pushes in only one direction. ECOL MONOGR 2022. [DOI: 10.1002/ecm.1547] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
- Mark A. McPeek
- Department of Biological Sciences Dartmouth College Hanover New Hampshire USA
| | | | - Feng Fu
- Department of Mathematics Dartmouth College Hanover New Hampshire USA
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5
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Ferrante L, Najar T, Baccaro F, Kaefer IL. The behavioural ecology behind anti-predator mechanisms: diversity, ontogenetic changes and sexual differences in anuran defence behaviours. ETHOL ECOL EVOL 2022. [DOI: 10.1080/03949370.2021.1967456] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Affiliation(s)
- Lucas Ferrante
- Programa de Pós-Graduação em Ecologia, Instituto Nacional de Pesquisas da Amazônia (INPA), Av. André Araújo 2936, Manaus, AM 69060-001, Brazil
| | - Thainá Najar
- Programa de Iniciação Científica (PIBIC), Instituto Nacional de Pesquisas da Amazônia (INPA), Av. André Araújo 2936, Manaus, AM 69060-001, Brazil
- Curso de Ciências Biológicas, Universidade do Estado do Amazonas (UEA), Av. Djalma Batista 2470, Manaus, AM 69050-010, Brazil
| | - Fabricio Baccaro
- Departamento de Biologia, Universidade Federal do Amazonas (UFAM), Manaus, AM, 69077-000, Brazil
| | - Igor L. Kaefer
- Departamento de Biologia, Universidade Federal do Amazonas (UFAM), Manaus, AM, 69077-000, Brazil
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6
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Grismer J, Scott P, Toffelmier E, Hinds B, Klabacka R, Stewart G, White V, Oaks J, Bradley Shaffer H. Genomic data reveal local endemism in Southern California Rubber Boas (Serpentes: Boidae, Charina) and the critical need for enhanced conservation actions. Mol Phylogenet Evol 2022; 174:107542. [PMID: 35690376 DOI: 10.1016/j.ympev.2022.107542] [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: 08/30/2021] [Revised: 05/25/2022] [Accepted: 05/31/2022] [Indexed: 10/18/2022]
Abstract
The mountains of southern California represent unique, isolated ecosystems that support distinct high-elevation habitats found nowhere else in the area. Analyses of several moisture-dependent species across these sky-islands indicate they exist as locally endemic lineages that occur across these fragmented mountains ranges. The Rubber Boa is a semi-fossorial snake species that is widely distributed in the cooler and more moist ecoregions regions of western North America, including isolated populations across southern California mountain ranges. We developed a genomic and ecological dataset to examine genetic diversity within Rubber Boas and to determine if the endemic Southern Rubber Boa represents a distinct lineage. We quantified current and future habitat suitability under a range of climate change scenarios, and discuss the possible environmental threats facing these unique montane isolates. Our results support four major lineages within Rubber Boas, with genetic breaks that are consistent with biogeographic boundaries observed in other co-distributed, cool-temperature, moisture adapted species. Our data support previous studies that the Southern Rubber Boa is an independent evolutionary unit and now includes multiple locally endemic sky-island populations, restricted to isolated mountain tops and ranges across southern California. Analyses of future habitat suitability indicate that many of these sky-island populations will lose most of their suitable habitat over the next 70 years given predicted increases in drought, rising temperatures, and wildfires. Collectively these data emphasize the critical conservation needs of these montane ecosystems in southern California under current and projected climate change conditions.
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Affiliation(s)
- Jesse Grismer
- Department of Ecology and Evolutionary Biology, La Kretz Center for Californian Conservation Science, and Institute of the Environment and Sustainability, University of California, Los Angeles, CA 90095, USA; Department of Biological Sciences and Museum of Natural History, Auburn University, Auburn, AL 36849, USA; Department of Biology, La Sierra University, Riverside, CA 92515, USA.
| | - Peter Scott
- Department of Ecology and Evolutionary Biology, La Kretz Center for Californian Conservation Science, and Institute of the Environment and Sustainability, University of California, Los Angeles, CA 90095, USA; Department of Life, Earth, and Environmental Sciences, West Texas A&M University, Canyon, TX 79016, USA
| | - Erin Toffelmier
- Department of Ecology and Evolutionary Biology, La Kretz Center for Californian Conservation Science, and Institute of the Environment and Sustainability, University of California, Los Angeles, CA 90095, USA
| | - Brian Hinds
- Department of Biology, La Sierra University, Riverside, CA 92515, USA
| | - Randy Klabacka
- Department of Biological Sciences and Museum of Natural History, Auburn University, Auburn, AL 36849, USA
| | - Glenn Stewart
- Department of Biological Sciences, California State Polytechnic University, Pomona, CA 91768, USA
| | - Virginia White
- Department of Biological Sciences and Museum of Natural History, Auburn University, Auburn, AL 36849, USA
| | - Jamie Oaks
- Department of Biological Sciences and Museum of Natural History, Auburn University, Auburn, AL 36849, USA
| | - H Bradley Shaffer
- Department of Ecology and Evolutionary Biology, La Kretz Center for Californian Conservation Science, and Institute of the Environment and Sustainability, University of California, Los Angeles, CA 90095, USA
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7
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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: 12] [Impact Index Per Article: 6.0] [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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8
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Abstract
The venom glands of reptiles, particularly those of front-fanged advanced snakes, must satisfy conflicting biological demands: rapid synthesis of potentially labile and highly toxic proteins, storage in the gland lumen for long periods, stabilization of the stored secretions, immediate activation of toxins upon deployment and protection of the animal from the toxic effects of its own venom. This dynamic system could serve as a model for the study of a variety of different phenomena involving exocrine gland activation, protein synthesis, stabilization of protein products and secretory mechanisms. However, these studies have been hampered by a lack of a long-term model that can be propagated in the lab (as opposed to whole-animal studies). Numerous attempts have been made to extend the lifetime of venom gland secretory cells, but only recently has an organoid model been shown to have the requisite qualities of recapitulation of the native system, self-propagation and long-term viability (>1 year). A tractable model is now available for myriad cell- and molecular-level studies of venom glands, protein synthesis and secretion. However, venom glands of reptiles are not identical, and many differ very extensively in overall architecture, microanatomy and protein products produced. This Review summarizes the similarities among and differences between venom glands of helodermatid lizards and of rear-fanged and front-fanged snakes, highlighting those areas that are well understood and identifying areas where future studies can fill in significant gaps in knowledge of these ancient, yet fascinating systems.
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Affiliation(s)
- Stephen P Mackessy
- School of Biological Sciences, University of Northern Colorado, 501 20th St., CB 92, Greeley, CO 80639-0017, USA
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9
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Bucciarelli GM, Alsalek F, Kats LB, Green DB, Shaffer HB. Toxic Relationships and Arms-Race Coevolution Revisited. Annu Rev Anim Biosci 2022; 10:63-80. [PMID: 35167315 DOI: 10.1146/annurev-animal-013120-024716] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Toxin evolution in animals is one of the most fascinating and complex subjects of scientific inquiry today. Gaining an understanding of toxins poses a multifaceted challenge given the diverse modes of acquisition, evolutionary adaptations, and abiotic components that affect toxin phenotypes. Here, we highlight some of the main genetic and ecological factors that influence toxin evolution and discuss the role of antagonistic interactions and coevolutionary dynamics in shaping the direction and extent of toxicity and resistance in animals. We focus on toxic Pacific newts (family Salamandridae, genus Taricha) as a system to investigate and better evaluate the widely distributed toxin they possess, tetrodotoxin (TTX), and the hypothesized model of arms-race coevolution with snake predators that is used to explain phenotypic patterns of newt toxicity. Finally, we propose an alternative coevolutionary model that incorporates TTX-producing bacteria and draws from an elicitor-receptor concept to explain TTX evolution and ecology.
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Affiliation(s)
- G M Bucciarelli
- Department of Ecology and Evolutionary Biology, University of California, Los Angeles, California, USA; , , .,La Kretz Center for California Conservation Science, University of California, Los Angeles, California, USA
| | - Farid Alsalek
- Department of Ecology and Evolutionary Biology, University of California, Los Angeles, California, USA; , ,
| | - L B Kats
- Natural Science Division, Pepperdine University, Malibu, California, USA; ,
| | - D B Green
- Natural Science Division, Pepperdine University, Malibu, California, USA; ,
| | - H B Shaffer
- Department of Ecology and Evolutionary Biology, University of California, Los Angeles, California, USA; , , .,La Kretz Center for California Conservation Science, University of California, Los Angeles, California, USA
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10
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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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11
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Hantak MM, Federico NA, Blackburn DC, Guralnick RP. Rapid phenotypic change in a polymorphic salamander over 43 years. Sci Rep 2021; 11:22681. [PMID: 34811418 PMCID: PMC8609024 DOI: 10.1038/s41598-021-02124-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2021] [Accepted: 11/10/2021] [Indexed: 11/30/2022] Open
Abstract
Color polymorphic animals offer a unique system for studying intraspecific phenotypic responses to climate change. Discrete color morphs are easy to identify, and correlated trait responses of morphs can indicate how climate warming may facilitate long-term maintenance of polymorphisms. We use a historical dataset spanning 43 years to examine temporal shifts in color morph frequency and body size in response to climate in the Eastern Red-backed Salamander, Plethodon cinereus, which contains a widespread striped/unstriped color polymorphism. We created a pipeline to extract high-throughput trait data from fluid-preserved museum specimens where we batch-photographed salamanders, de-aggregated individual specimens from photographs, and solicited help of community scientists to score color morphs. We used a linear modeling framework that includes information about spatial population structure to demonstrate that color morph frequency and body size vary in response to climate, elevation, and over time, with an overall trend of higher frequency and decreased body size of the striped morph, but increased size of the unstriped morph. These surprising results suggest that morphs may be responding to multiple climate and geographic drivers through co-adapted morphological changes. This work highlights new practices of extracting trait data from museum specimens to demonstrate species phenotypes response to climate change.
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Affiliation(s)
- Maggie M. Hantak
- grid.15276.370000 0004 1936 8091Florida Museum of Natural History, University of Florida, Gainesville, FL USA
| | - Nicholas A. Federico
- grid.15276.370000 0004 1936 8091Florida Museum of Natural History, University of Florida, Gainesville, FL USA
| | - David C. Blackburn
- grid.15276.370000 0004 1936 8091Florida Museum of Natural History, University of Florida, Gainesville, FL USA
| | - Robert P. Guralnick
- grid.15276.370000 0004 1936 8091Florida Museum of Natural History, University of Florida, Gainesville, FL USA
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12
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Vasconcelos IAD, Souza JOD, de Castro JS, Santana CJCD, Magalhães ACM, Castro MDS, Pires Júnior OR. Salamanders and caecilians, neglected from the chemical point of view. TOXIN REV 2021. [DOI: 10.1080/15569543.2021.1977326] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Affiliation(s)
| | | | | | - Carlos José Correia de Santana
- Department of Physiological Sciences, University of Brasilia, Brasilia, Brazil
- Department of Cell Biology, University of Brasilia, Brasilia, Brazil
| | | | - Mariana de Souza Castro
- Department of Physiological Sciences, University of Brasilia, Brasilia, Brazil
- Department of Cell Biology, University of Brasilia, Brasilia, Brazil
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13
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Robinson KE, Holding ML, Whitford MD, Saviola AJ, Yates JR, Clark RW. Phenotypic and functional variation in venom and venom resistance of two sympatric rattlesnakes and their prey. J Evol Biol 2021; 34:1447-1465. [PMID: 34322920 DOI: 10.1111/jeb.13907] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2021] [Revised: 06/27/2021] [Accepted: 07/13/2021] [Indexed: 12/15/2022]
Abstract
Predator-prey interactions often lead to the coevolution of adaptations associated with avoiding predation and, for predators, overcoming those defences. Antagonistic coevolutionary relationships are often not simple interactions between a single predator and prey but rather a complex web of interactions between multiple coexisting species. Coevolution between venomous rattlesnakes and small mammals has led to physiological venom resistance in several mammalian taxa. In general, viperid venoms contain large quantities of snake venom metalloproteinase toxins (SVMPs), which are inactivated by SVMP inhibitors expressed in resistant mammals. We explored variation in venom chemistry, SVMP expression, and SVMP resistance across four co-distributed species (California Ground Squirrels, Bryant's Woodrats, Southern Pacific Rattlesnakes, and Red Diamond Rattlesnakes) collected from four different populations in Southern California. Our aim was to understand phenotypic and functional variation in venom and venom resistance in order to compare coevolutionary dynamics of a system involving two sympatric predator-prey pairs to past studies that have focused on single pairs. Proteomic analysis of venoms indicated that these rattlesnakes express different phenotypes when in sympatry, with Red Diamonds expressing more typical viperid venom (with a diversity of SVMPs) and Southern Pacifics expressing a more atypical venom with a broader range of non-enzymatic toxins. We also found that although blood sera from both mammals were generally able to inhibit SVMPs from both rattlesnake species, inhibition depended strongly on the snake population, with snakes from one geographic site expressing SVMPs to which few mammals were resistant. Additionally, we found that Red Diamond venom, rather than woodrat resistance, was locally adapted. Our findings highlight the complexity of coevolutionary relationships between multiple predators and prey that exhibit similar offensive and defensive strategies in sympatry.
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Affiliation(s)
- Kelly E Robinson
- Department of Biology, San Diego State University, San Diego, CA, USA.,Department of Biology, University of Nevada, Reno, NV, USA.,Program in Ecology, Evolution and Conservation Biology, University of Nevada, Reno, NV, USA
| | - Matthew L Holding
- Department of Natural Resources and Environmental Science, University of Nevada, Reno, NV, USA.,Department of Biological Science, Florida State University, Tallahassee, FL, USA
| | - Malachi D Whitford
- Department of Biology, San Diego State University, San Diego, CA, USA.,Ecology Graduate Group, University of California, Davis, CA, USA
| | - Anthony J Saviola
- Department of Molecular Medicine and Neurobiology, The Scripps Research Institute, La Jolla, CA, USA.,Department of Biochemistry and Molecular Genetics, University of Colorado Anschutz Medical Campus, Aurora, CO, USA
| | - John R Yates
- Department of Molecular Medicine and Neurobiology, The Scripps Research Institute, La Jolla, CA, USA
| | - Rulon W Clark
- Department of Biology, San Diego State University, San Diego, CA, USA
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14
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Moniz HA, Richard MA, Gienger CM, Feldman CR. Every breath you take: assessing metabolic costs of toxin resistance in garter snakes (Thamnophis). Integr Zool 2021; 17:567-580. [PMID: 34254727 DOI: 10.1111/1749-4877.12574] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Trait specialization often comes at the expense of original trait function, potentially causing evolutionary tradeoffs that may render specialist populations vulnerable to extinction. However, many specialized adaptations evolve repeatedly, suggesting selection favors specialization in specific environments. Some garter snake (Thamnophis) populations possess specialized mutations in voltage-gated sodium channels that allow them to consume Pacific newts (Taricha) defended by a highly potent neurotoxin (tetrodotoxin). These mutations, however, also decrease protein and muscle function, suggesting garter snakes may suffer evolutionary tradeoffs. We measured a key physiological process, standard metabolic rate (SMR), to investigate whether specialized adaptations in toxin-resistant garter snakes affect baseline energy expenditure. In snakes, skeletal muscles influence metabolism and power ventilation, so inefficiencies of sodium channels in these muscles might impact whole-animal energy expenditure. Further, because sodium channels are membrane-bound proteins, inefficiencies of channel kinetics and performance might be exacerbated at suboptimal temperatures. We measured SMR in 2 species, Thamnophis atratus and Thamnophis sirtalis, that independently evolved tetrodotoxin resistance through unique mutations, providing replicate experiments with distinct underlying genetics and potential physiological costs. Despite our expectations, neither resistance phenotype nor sodium channel genotype affected metabolism and resistant snakes did not perform worse under suboptimal body temperature. Instead, T. atratus and T. sirtalis show nearly identical rates of mass-adjusted energy expenditure at both temperatures, despite differing eco-morphologies, life histories, and distant phylogenetic positions. These findings suggest SMR may be a conserved feature of Thamnophis, and that any organismal tradeoffs may be compensated to retain whole-animal function.
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Affiliation(s)
- Haley A Moniz
- Department of Biology, University of Nevada, Reno, Nevada, USA.,Program in Ecology, Evolution and Conservation Biology, University of Nevada, Reno, Nevada, USA
| | - Molly A Richard
- Department of Biology and Center of Excellence for Field Biology, Austin Peay State University, Clarksville, Tennessee, USA
| | - C M Gienger
- Department of Biology and Center of Excellence for Field Biology, Austin Peay State University, Clarksville, Tennessee, USA
| | - Chris R Feldman
- Department of Biology, University of Nevada, Reno, Nevada, USA.,Program in Ecology, Evolution and Conservation Biology, University of Nevada, Reno, Nevada, USA
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15
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Nguyen VAT, Vural DC. Extinction in complex communities as driven by adaptive dynamics. J Evol Biol 2021; 34:1095-1109. [PMID: 33973303 DOI: 10.1111/jeb.13796] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2020] [Revised: 04/08/2021] [Accepted: 04/20/2021] [Indexed: 11/30/2022]
Abstract
In a complex community, species continuously adapt to each other. On rare occasions, the adaptation of a species can lead to the extinction of others, and even its own. 'Adaptive dynamics' is the standard mathematical framework to describe evolutionary changes in community interactions, and in particular, predict adaptation driven extinction. Unfortunately, most authors implement the equations of adaptive dynamics through computer simulations that require assuming a large number of questionable parameters and fitness functions. In this study, we present analytical solutions to adaptive dynamics equations, thereby clarifying how outcomes depend on any computational input. We develop general formulas that predict equilibrium abundances over evolutionary time scales. Additionally, we predict which species will go extinct next, and when this will happen.
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16
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Gendreau KL, Hornsby AD, Hague MTJ, McGlothlin JW. Gene Conversion Facilitates the Adaptive Evolution of Self-Resistance in Highly Toxic Newts. Mol Biol Evol 2021; 38:4077-4094. [PMID: 34129031 PMCID: PMC8476164 DOI: 10.1093/molbev/msab182] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Reconstructing the histories of complex adaptations and identifying the evolutionary mechanisms underlying their origins are two of the primary goals of evolutionary biology. Taricha newts, which contain high concentrations of the deadly toxin tetrodotoxin (TTX) as an antipredator defense, have evolved resistance to self-intoxication, which is a complex adaptation requiring changes in six paralogs of the voltage-gated sodium channel (Nav) gene family, the physiological target of TTX. Here, we reconstruct the origins of TTX self-resistance by sequencing the entire Nav gene family in newts and related salamanders. We show that moderate TTX resistance evolved early in the salamander lineage in three of the six Nav paralogs, preceding the proposed appearance of tetrodotoxic newts by ∼100 My. TTX-bearing newts possess additional unique substitutions across the entire Nav gene family that provide physiological TTX resistance. These substitutions coincide with signatures of positive selection and relaxed purifying selection, as well as gene conversion events, that together likely facilitated their evolution. We also identify a novel exon duplication within Nav1.4 encoding an expressed TTX-binding site. Two resistance-conferring changes within newts appear to have spread via nonallelic gene conversion: in one case, one codon was copied between paralogs, and in the second, multiple substitutions were homogenized between the duplicate exons of Nav1.4. Our results demonstrate that gene conversion can accelerate the coordinated evolution of gene families in response to a common selection pressure.
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Affiliation(s)
- Kerry L Gendreau
- Department of Biological Sciences, Virginia Tech, Blacksburg, United States
| | - Angela D Hornsby
- Department of Biological Sciences, Virginia Tech, Blacksburg, United States.,Philip L. Wright Zoological Museum, Division of Biological Sciences, University of Montana, Missoula, United States
| | - Michael T J Hague
- Division of Biological Sciences, University of Montana, Missoula, MT, United States
| | - Joel W McGlothlin
- Department of Biological Sciences, Virginia Tech, Blacksburg, United States
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17
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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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18
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Hudson SB, Virgin EE, Brodie ED, French SS. Recovery from discrete wound severities in side-blotched lizards (Uta stansburiana): implications for energy budget, locomotor performance, and oxidative stress. J Comp Physiol B 2021; 191:531-543. [PMID: 33582858 DOI: 10.1007/s00360-021-01347-z] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2020] [Revised: 12/22/2020] [Accepted: 01/18/2021] [Indexed: 01/21/2023]
Abstract
Wounding events (predation attempts, competitive combat) result in injuries and/or infections that induce integrated immune responses for the recovery process. Despite the survival benefits of immunity in this context, the costs incurred may require investment to be diverted from traits contributing to immediate and/or future survival, such as locomotor performance and oxidative status. Yet, whether trait constraints manifest likely depends on wound severity and the implications for energy budget. For this study, food intake, body mass, sprint speed, and oxidative indices (reactive oxygen metabolites, antioxidant capacity) were monitored in male side-blotched lizards (Uta stansburiana) healing from cutaneous wounds of discrete sizes (control, small, large). Results indicate that larger wounds induced faster healing, reduced food consumption, and led to greater oxidative stress over time. Granted wounding did not differentially affect body mass or sprint speed overall, small-wounded lizards with greater wound area healed had faster sprint speeds while large-wounded lizards with greater wound area healed had slower sprint speeds. During recovery from either wound severity, however, healing and sprint performance did not correspond with food consumption, body mass loss, nor oxidative status. These findings provide support that energy budget, locomotor performance, and oxidative status of a reptile are linked to wound recovery to an extent, albeit dependent on wound severity.
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Affiliation(s)
- Spencer B Hudson
- Department of Biology, Utah State University, Logan, UT, 84322-5205, USA. .,Ecology Center, Utah State University, Logan, UT, 84322‑5205, USA.
| | - Emily E Virgin
- Department of Biology, Utah State University, Logan, UT, 84322-5205, USA.,Ecology Center, Utah State University, Logan, UT, 84322‑5205, USA
| | - Edmund D Brodie
- Department of Biology, Utah State University, Logan, UT, 84322-5205, USA
| | - Susannah S French
- Department of Biology, Utah State University, Logan, UT, 84322-5205, USA.,Ecology Center, Utah State University, Logan, UT, 84322‑5205, USA
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19
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Cox CL, Logan ML. Using Integrative Biology to Infer Adaptation from Comparisons of Two (or a Few) Species. Physiol Biochem Zool 2021; 94:162-170. [PMID: 33821779 DOI: 10.1086/714018] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
AbstractPhylogenetic comparative methods represent a major advance in integrative and comparative biology and have allowed researchers to rigorously test for adaptation in a macroevolutionary framework. However, phylogenetic comparative methods require trait data for many species, which is impractical for certain taxonomic groups and trait types. We propose that the philosophical principle of severity can be implemented in an integrative framework to generate strong inference of adaptation in studies that compare only a few populations or species. This approach requires (1) ensuring that the study system contains species that are relatively closely related; (2) formulating a specific, clear, overarching hypothesis that can be subjected to integrative testing across levels of biological organization (e.g., ecology, behavior, morphology, physiology, and genetics); (3) collecting data that avoid statistical underdetermination and thus allow severe tests of hypotheses; and (4) systematically refining and refuting alternative hypotheses. Although difficult to collect for more than a few species, detailed, integrative data can be used to differentiate among several potential agents of selection. In this way, integrative studies of small numbers of closely related species can complement and even improve on broadscale phylogenetic comparative studies by revealing the specific drivers of adaptation.
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20
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Bury S. Sex-specific growth is mirrored in feeding rate but not moulting frequency in a sexually dimorphic snake. Naturwissenschaften 2021; 108:6. [PMID: 33415456 DOI: 10.1007/s00114-020-01712-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2020] [Revised: 11/06/2020] [Accepted: 11/16/2020] [Indexed: 11/30/2022]
Abstract
Sexual size dimorphism (SSD), commonly observed in snakes, may arise from a different growth rate between the sexes. This indicates a sex-specific resource intake that is in fact observable in free-living snakes. It is not so well known whether the sexes can express differential feeding rates under conditions unconstrained by spatial accessibility, competition, etc. Here, I studied sex-specific variation in growth, its correlate-moulting frequency, and feeding rate in a captive group of sexually dimorphic banded water snakes (Nerodia fasciata) with access to food unconstrained by predation, competition or space. I showed that the sexes did indeed differ in relative mass growth in that females grew faster than males (p = 0.02), but such differences were not apparent in the moulting rate (p = 0.19). Such differential growth was mirrored in the sex-specific feeding rate, with females ingesting a larger number of meals than males (p = 0.004). Such variation in feeding rate may be governed by an individual's energy expenditure and can be interpreted as a behavioural tendency that contributes to SSD development, independently of other behavioural characteristics. Sex-specific resource demands may drive the differential effects of increasing resource scarcity on both sexes.
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Affiliation(s)
- Stanisław Bury
- Department of Comparative Anatomy, Institute of Zoology and Biomedical Research, Jagiellonian University, Gronostajowa 9, 30-387, Kraków, Poland. .,Institute of Environmental Sciences, Jagiellonian University, Gronostajowa 7, 30-387, Kraków, Poland. .,NATRIX Herpetological Association, Legnicka 65, 54-206, Wrocław, Poland.
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21
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Mergler CJ, Gall BG. Has the indestructible insect met its match? Velvet ants as prey to bufonid toads. ETHOL ECOL EVOL 2021. [DOI: 10.1080/03949370.2020.1789747] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Affiliation(s)
- Ciara J. Mergler
- Department of Biology, Hanover College, 517 Ball Drive, Hanover, IN 47243, USA
| | - Brian G. Gall
- Department of Biology, Hanover College, 517 Ball Drive, Hanover, IN 47243, USA
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22
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Whitelaw BL, Cooke IR, Finn J, da Fonseca RR, Ritschard EA, Gilbert MTP, Simakov O, Strugnell JM. Adaptive venom evolution and toxicity in octopods is driven by extensive novel gene formation, expansion, and loss. Gigascience 2020; 9:giaa120. [PMID: 33175168 PMCID: PMC7656900 DOI: 10.1093/gigascience/giaa120] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2020] [Revised: 08/10/2020] [Accepted: 10/06/2020] [Indexed: 01/09/2023] Open
Abstract
BACKGROUND Cephalopods represent a rich system for investigating the genetic basis underlying organismal novelties. This diverse group of specialized predators has evolved many adaptations including proteinaceous venom. Of particular interest is the blue-ringed octopus genus (Hapalochlaena), which are the only octopods known to store large quantities of the potent neurotoxin, tetrodotoxin, within their tissues and venom gland. FINDINGS To reveal genomic correlates of organismal novelties, we conducted a comparative study of 3 octopod genomes, including the Southern blue-ringed octopus (Hapalochlaena maculosa). We present the genome of this species and reveal highly dynamic evolutionary patterns at both non-coding and coding organizational levels. Gene family expansions previously reported in Octopus bimaculoides (e.g., zinc finger and cadherins, both associated with neural functions), as well as formation of novel gene families, dominate the genomic landscape in all octopods. Examination of tissue-specific genes in the posterior salivary gland revealed that expression was dominated by serine proteases in non-tetrodotoxin-bearing octopods, while this family was a minor component in H. maculosa. Moreover, voltage-gated sodium channels in H. maculosa contain a resistance mutation found in pufferfish and garter snakes, which is exclusive to the genus. Analysis of the posterior salivary gland microbiome revealed a diverse array of bacterial species, including genera that can produce tetrodotoxin, suggestive of a possible production source. CONCLUSIONS We present the first tetrodotoxin-bearing octopod genome H. maculosa, which displays lineage-specific adaptations to tetrodotoxin acquisition. This genome, along with other recently published cephalopod genomes, represents a valuable resource from which future work could advance our understanding of the evolution of genomic novelty in this family.
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Affiliation(s)
- Brooke L Whitelaw
- Centre for Sustainable Tropical Fisheries and Aquaculture, James Cook University, 1 James Cook Dr, Douglas QLD 4811 , Australia
- Sciences, Museum Victoria, 11 Nicholson St, Carlton, Victoria 3053, Australia
| | - Ira R Cooke
- College of Public Health, Medical and Vet Sciences, James Cook University,1 James Cook Dr, Douglas QLD 4811 , Australia
- La Trobe Institute of Molecular Science, La Trobe University, Plenty Rd &, Kingsbury Dr, Bundoora, Melbourne, Victoria 3086, Australia
| | - Julian Finn
- Sciences, Museum Victoria, 11 Nicholson St, Carlton, Victoria 3053, Australia
| | - Rute R da Fonseca
- Center for Macroecology, Evolution and Climate (CMEC), GLOBE Institute, University of Copenhagen, Universitetsparken 15, 2100 Copenhagen, Denmark
| | - Elena A Ritschard
- Department of Neurosciences and Developmental Biology, University of Vienna,Universitätsring 1, 1010 Wien, Vienna, Austria
- Department of Biology and Evolution of Marine Organisms, Stazione Zoologica Anton Dohrn, Naples, Italy
| | - M T P Gilbert
- Center for Evolutionary Hologenomics, GLOBE Institute, University of Copenhagen, Øster Voldgade 5–7, 1350 Copenhagen, Denmark
| | - Oleg Simakov
- Department of Neurosciences and Developmental Biology, University of Vienna,Universitätsring 1, 1010 Wien, Vienna, Austria
| | - Jan M Strugnell
- Centre for Sustainable Tropical Fisheries and Aquaculture, James Cook University, 1 James Cook Dr, Douglas QLD 4811 , Australia
- Department of Ecology, Environment and Evolution, La Trobe University, Plenty Rd &, Kingsbury Dr, Bundoora, Melbourne, Victoria 3086, Australia
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23
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Reimche JS, Brodie ED, Stokes AN, Ely EJ, Moniz HA, Thill VL, Hallas JM, Pfrender ME, Brodie ED, Feldman CR. The geographic mosaic in parallel: Matching patterns of newt tetrodotoxin levels and snake resistance in multiple predator-prey pairs. J Anim Ecol 2020; 89:1645-1657. [PMID: 32198924 DOI: 10.1111/1365-2656.13212] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2019] [Accepted: 02/10/2020] [Indexed: 01/12/2023]
Abstract
The Geographic Mosaic Theory of Coevolution predicts that coevolutionary arms races will vary over time and space because of the diverse ecological settings and population histories of interacting species across the landscape. Thus, understanding coevolution may require investigating broad sets of populations sampled across the range of the interaction. In addition, comparing coevolutionary dynamics between similar systems may reveal the importance of specific factors that structure coevolution. Here, we examine geographic patterns of prey traits and predator traits in the relatively unstudied interaction between the Sierra garter snake (Thamnophis couchii) and sympatric prey, the rough-skinned newt (Taricha granulosa), Sierra newt (Ta. sierrae) and California newt (Ta. torosa). This system parallels, in space and phenotypes, a classic example of coevolution between predatory common garter snakes (Th. sirtalis) and their toxic newt prey exhibiting hotspots of newt tetrodotoxin (TTX) levels and matching snake TTX resistance. We quantified prey and predator traits from hundreds of individuals across their distributions, and functional trait matching at sympatric sites. We show strong regional patterns of trait covariation across the shared ranges of Th. couchii and newt prey. Traits differ significantly among localities, with lower newt TTX levels and snake TTX resistance at the northern latitudes, and higher TTX levels and snake resistance at southern latitudes. Newts and snakes in northern populations show the highest degree of functional trait matching despite possessing the least extreme traits. Conversely, newts and snakes in southern populations show the greatest mismatch despite possessing exaggerated traits, with some snakes so resistant to TTX they would be unaffected by any sympatric newt. Nevertheless, individual variation was substantial, and appears to offer the opportunity for continued reciprocal selection in most populations. Overall, the three species of newts appear to be engaged in a TTX-mediated arms race with Th. couchii. These patterns are congruent with those seen between newts and Th. sirtalis, including the same latitudinal gradient in trait covariation, and the potential 'escape' from the arms race by snake predators. Such concordance in broad scale patterns across two distinct systems suggests common phenomena might structure geographic mosaics in similar ways.
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Affiliation(s)
- Jessica S Reimche
- Department of Biology, University of Nevada, Reno, NV, USA.,Program in Ecology, Evolution, and Conservation Biology, University of Nevada, Reno, NV, USA
| | - Edmund D Brodie
- Department of Biology, Utah State University, Logan, UT, USA
| | - Amber N Stokes
- Department of Biology, California State University, Bakersfield, CA, USA
| | - Erica J Ely
- Department of Biology, University of Nevada, Reno, NV, USA.,Department of Herpetology, California Academy of Sciences, San Francisco, CA, USA
| | - Haley A Moniz
- Department of Biology, University of Nevada, Reno, NV, USA.,Program in Ecology, Evolution, and Conservation Biology, University of Nevada, Reno, NV, USA
| | - Vicki L Thill
- Department of Biology, University of Nevada, Reno, NV, USA.,Program in Ecology, Evolution, and Conservation Biology, University of Nevada, Reno, NV, USA
| | - Joshua M Hallas
- Department of Biology, University of Nevada, Reno, NV, USA.,Program in Ecology, Evolution, and Conservation Biology, University of Nevada, Reno, NV, USA
| | - Michael E Pfrender
- Department of Biological Sciences, University of Notre Dame, Notre Dame, IN, USA
| | - Edmund D Brodie
- Mountain Lake Biological Station and Department of Biology, University of Virginia, Charlottesville, VA, USA
| | - Chris R Feldman
- Department of Biology, University of Nevada, Reno, NV, USA.,Program in Ecology, Evolution, and Conservation Biology, University of Nevada, Reno, NV, USA
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24
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Sex linkage of the skeletal muscle sodium channel gene (SCN4A) explains apparent deviations from Hardy-Weinberg equilibrium of tetrodotoxin-resistance alleles in garter snakes (Thamnophis sirtalis). Heredity (Edinb) 2020; 124:647-657. [PMID: 32111979 DOI: 10.1038/s41437-020-0300-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2019] [Revised: 02/13/2020] [Accepted: 02/13/2020] [Indexed: 01/01/2023] Open
Abstract
The arms race between tetrodotoxin-bearing Pacific newts (Taricha) and their garter snake predators (Thamnophis) in western North America has become a classic example of coevolution, shedding light on predator-prey dynamics, the molecular basis of adaptation, and patterns of convergent evolution. Newts are defended by tetrodotoxin (TTX), a neurotoxin that binds to voltage-gated sodium channels (Nav proteins), arresting electrical activity in nerves and muscles and paralyzing would-be predators. However, populations of the common garter snake (T. sirtalis) have overcome this defense, largely through polymorphism at the locus SCN4A, which renders the encoded protein (Nav1.4) less vulnerable to TTX. Previous work suggests that SCN4A commonly shows extreme deviations from Hardy-Weinberg equilibrium (HWE) in these populations, which has been interpreted as the result of intense selection imposed by newts. Here we show that much of this apparent deviation can be attributed to sex linkage of SCN4A. Using genomic data and quantitative PCR, we show that SCN4A is on the Z chromosome in Thamnophis and other advanced snakes. Taking Z-linkage into account, we find that most apparent deviations from HWE can be explained by female hemizygosity rather than low heterozygosity. Sex linkage can affect mutation rates, selection, and drift, and our results suggest that Z-linkage of SCN4A may make significant contributions to the overall dynamics of the coevolutionary arms race between newts and snakes.
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25
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Mailho-Fontana PL, Jared C, Antoniazzi MM, Sciani JM, Pimenta DC, Stokes AN, Grant T, Brodie ED, Brodie ED. Variations in tetrodotoxin levels in populations of Taricha granulosa are expressed in the morphology of their cutaneous glands. Sci Rep 2019; 9:18490. [PMID: 31811169 PMCID: PMC6897900 DOI: 10.1038/s41598-019-54765-z] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2019] [Accepted: 11/15/2019] [Indexed: 12/15/2022] Open
Abstract
Tetrodotoxin (TTX), one of the most toxic substances in nature, is present in bacteria, invertebrates, fishes, and amphibians. Marine organisms seem to bioaccumulate TTX from their food or acquire it from symbiotic bacteria, but its origin in amphibians is unclear. Taricha granulosa can exhibit high TTX levels, presumably concentrated in skin poison glands, acting as an agent of selection upon predatory garter snakes (Thamnophis). This co-evolutionary arms race induces variation in T. granulosa TTX levels, from very high to undetectable. Using morphology and biochemistry, we investigated differences in toxin localization and quality between two populations at the extremes of toxicity. TTX concentration within poison glands is related to the volume of a single cell type in which TTX occurs exclusively in distinctive secretory granules, suggesting a relationship between granule structure and chemical composition. TTX was detected in mucous glands in both populations, contradicting the general understanding that these glands do not secrete defensive chemicals and expanding currently held interpretations of amphibian skin gland functionality. Skin secretions of the two populations differed in low-mass molecules and proteins. Our results demonstrate that interpopulation variation in TTX levels is related to poison gland morphology.
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26
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Hämäläinen L, Mappes J, Thorogood R, Valkonen JK, Karttunen K, Salmi T, Rowland HM. Predators’ consumption of unpalatable prey does not vary as a function of bitter taste perception. Behav Ecol 2019. [DOI: 10.1093/beheco/arz199] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Abstract
Many prey species contain defensive chemicals that are described as tasting bitter. Bitter taste perception is, therefore, assumed to be important when predators are learning about prey defenses. However, it is not known how individuals differ in their response to bitter taste, and how this influences their foraging decisions. We conducted taste perception assays in which wild-caught great tits (Parus major) were given water with increasing concentrations of bitter-tasting chloroquine diphosphate until they showed an aversive response to bitter taste. This response threshold was found to vary considerably among individuals, ranging from chloroquine concentrations of 0.01 mmol/L to 8 mmol/L. We next investigated whether the response threshold influenced the consumption of defended prey during avoidance learning by presenting birds with novel palatable and defended prey in a random sequence until they refused to attack defended prey. We predicted that individuals with taste response thresholds at lower concentrations would consume fewer defended prey before rejecting them, but found that the response threshold had no effect on the birds’ foraging choices. Instead, willingness to consume defended prey was influenced by the birds’ body condition. This effect was age- and sex-dependent, with adult males attacking more of the defended prey when their body condition was poor, whereas body condition did not have an effect on the foraging choices of juveniles and females. Together, our results suggest that even though taste perception might be important for recognizing prey toxicity, other factors, such as predators’ energetic state, drive the decisions to consume chemically defended prey.
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Affiliation(s)
- Liisa Hämäläinen
- Department of Zoology, University of Cambridge, Cambridge, UK
- Department of Biological and Environmental Sciences, University of Jyväskylä, Jyväskylä, Finland
| | - Johanna Mappes
- Department of Biological and Environmental Sciences, University of Jyväskylä, Jyväskylä, Finland
| | - Rose Thorogood
- Department of Zoology, University of Cambridge, Cambridge, UK
- HiLIFE Helsinki Institute of Life Science, University of Helsinki, Helsinki, Finland
- Research Programme in Organismal & Evolutionary Biology, Faculty of Biological and Environmental Sciences, University of Helsinki, Helsinki, Finland
| | - Janne K Valkonen
- Department of Biological and Environmental Sciences, University of Jyväskylä, Jyväskylä, Finland
| | - Kaijamari Karttunen
- Department of Biological and Environmental Sciences, University of Jyväskylä, Jyväskylä, Finland
| | - Tuuli Salmi
- Department of Biological and Environmental Sciences, University of Jyväskylä, Jyväskylä, Finland
| | - Hannah M Rowland
- Department of Zoology, University of Cambridge, Cambridge, UK
- Institute of Zoology, Zoological Society of London, Regent’s Park, London, UK
- Max Planck Institute for Chemical Ecology, Jena, Germany
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27
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Grabowsky ER, Mackessy SP. Predator-prey interactions and venom composition in a high elevation lizard specialist, Crotalus pricei (Twin-spotted Rattlesnake). Toxicon 2019; 170:29-40. [DOI: 10.1016/j.toxicon.2019.09.011] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2019] [Revised: 09/05/2019] [Accepted: 09/09/2019] [Indexed: 01/31/2023]
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28
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Jobe KL, Montaña CG, Schalk CM. Emergent patterns between salamander prey and their predators. FOOD WEBS 2019. [DOI: 10.1016/j.fooweb.2019.e00128] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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29
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Yamamichi M, Lyberger K, Patel S. Antagonistic coevolution between multiple quantitative traits: Matching dynamics can arise from difference interactions. POPUL ECOL 2019. [DOI: 10.1002/1438-390x.12022] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Masato Yamamichi
- Department of General Systems Studies University of Tokyo Tokyo Japan
| | - Kelsey Lyberger
- Department of Evolution and Ecology University of California, Davis Davis California
| | - Swati Patel
- Department of Mathematics Tulane University New Orleans Louisiana
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Potential Invasion Risk of Pet Traded Lizards, Snakes, Crocodiles, and Tuatara in the EU on the Basis of a Risk Assessment Model (RAM) and Aquatic Species Invasiveness Screening Kit (AS-ISK). DIVERSITY 2019. [DOI: 10.3390/d11090164] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Because biological invasions can cause many negative impacts, accurate predictions are necessary for implementing effective restrictions aimed at specific high-risk taxa. The pet trade in recent years became the most important pathway for the introduction of non-indigenous species of reptiles worldwide. Therefore, we decided to determine the most common species of lizards, snakes, and crocodiles traded as pets on the basis of market surveys in the Czech Republic, which is an export hub for ornamental animals in the European Union (EU). Subsequently, the establishment and invasion potential for the entire EU was determined for 308 species using proven risk assessment models (RAM, AS-ISK). Species with high establishment potential (determined by RAM) and at the same time with high potential to significantly harm native ecosystems (determined by AS-ISK) included the snakes Thamnophis sirtalis (Colubridae), Morelia spilota (Pythonidae) and also the lizards Tiliqua scincoides (Scincidae) and Intellagama lesueurii (Agamidae).
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31
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Palatability and Predator Avoidance Behavior of Salamanders in Response to the Virginia Opossum (Didelphis Virginiana). AMERICAN MIDLAND NATURALIST 2019. [DOI: 10.1674/0003-0031-181.2.245] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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32
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Goetz SM, Piccolomini S, Hoffman M, Bogan J, Holding ML, Mendonça MT, Steen DA. Serum-based inhibition of pitviper venom by eastern indigo snakes ( Drymarchon couperi). Biol Open 2019; 8:bio.040964. [PMID: 30824421 PMCID: PMC6451346 DOI: 10.1242/bio.040964] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
When organisms possess chemical defenses, their predators may eventually evolve resistance to their toxins. Eastern indigo snakes (Drymarchon couperi; EIS) prey on pitvipers and are suspected to possess physiological resistance to their venom. In this study, we formally investigated this hypothesis using microassays that measured the ability of EIS blood sera to inhibit (A) hemolytic and (B) snake venom metalloproteinase (SVMP) activity of copperhead (Agkistrodon contortrix) venom. To serve as controls, we also tested the inhibitory ability of sera from house mice (Mus musculus) and checkered gartersnakes (Thamnophis marcianus), a snake that does not feed on pitvipers. Sera from both EIS and gartersnakes inhibited over 60% of SVMP activity, while only EIS sera also inhibited venom hemolytic activity (78%). Our results demonstrate that EIS serum is indeed capable of inhibiting two of the primary classes of toxins found in copperhead venom, providing the first empirical evidence suggesting that EIS possess physiological resistance to venom upon injection. Because we documented resistance to hemolytic components of pitviper venom within EIS but not gartersnakes, we speculate this resistance may be driven by selection from feeding on pitvipers while resistance to SVMP may be relatively widespread among snakes. Summary: We confirm eastern indigo snakes possess a physiological resistance to pitviper venom and speculate that venom resistance in snakes may be a product of antagonistic interactions and phylogenetically conserved traits.
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Affiliation(s)
- Scott M Goetz
- Department of Biological Sciences, Auburn University, Auburn, AL 36849, USA
| | - Sara Piccolomini
- Department of Biological Sciences, Auburn University, Auburn, AL 36849, USA
| | - Michelle Hoffman
- Orianne Center for Indigo Conservation, Central Florida Zoo & Botanical Gardens, Eustis, FL 32736, USA
| | - James Bogan
- Orianne Center for Indigo Conservation, Central Florida Zoo & Botanical Gardens, Eustis, FL 32736, USA
| | - Matthew L Holding
- Department of Biological Sciences, Florida State University, Tallahassee, FL 32304, USA
| | - Mary T Mendonça
- Department of Biological Sciences, Auburn University, Auburn, AL 36849, USA
| | - David A Steen
- Georgia Sea Turtle Center, Jekyll Island Authority, Jekyll Island, GA 31527, USA
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33
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Toads phenotypically adjust their chemical defences to anthropogenic habitat change. Sci Rep 2019; 9:3163. [PMID: 30816222 PMCID: PMC6395641 DOI: 10.1038/s41598-019-39587-3] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2018] [Accepted: 01/23/2019] [Indexed: 01/07/2023] Open
Abstract
Despite the well-documented effects of human-induced environmental changes on the morphology, physiology, behaviour and life history of wild animals, next to nothing is known about how anthropogenic habitats influence anti-predatory chemical defence, a crucial fitness component of many species. We investigated the amount and composition of defensive toxins in adult common toads (Bufo bufo) captured in natural, agricultural and urban habitats, and in their offspring raised in a common-garden experiment. We found that, compared to toads captured from natural habitats, adults from both types of anthropogenic habitats had larger toxin glands (parotoids) and their toxin secretion contained higher concentrations of bufagenins, the more potent class of bufadienolide toxins. Furthermore, urban toads had lower concentrations of bufotoxins, the compounds with lower toxicity. None of these differences were present in the captive-raised juveniles; instead, toadlets originating from agricultural habitats had smaller parotoids and lower bufotoxin concentrations. These results suggest that toads' chemical defences respond to the challenges of anthropogenic environments via phenotypic plasticity. These responses may constitute non-adaptive consequences of pollution by endocrine-disrupting chemicals as well as adaptive adjustments to the altered predator assemblages of urban and agricultural habitats.
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Whitelaw BL, Cooke IR, Finn J, Zenger K, Strugnell JM. The evolution and origin of tetrodotoxin acquisition in the blue-ringed octopus (genus Hapalochlaena). AQUATIC TOXICOLOGY (AMSTERDAM, NETHERLANDS) 2019; 206:114-122. [PMID: 30472480 DOI: 10.1016/j.aquatox.2018.10.012] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/08/2018] [Revised: 10/22/2018] [Accepted: 10/22/2018] [Indexed: 06/09/2023]
Abstract
Tetrodotoxin is a potent non-proteinaceous neurotoxin, which is commonly found in the marine environment. Synthesised by bacteria, tetrodotoxin has been isolated from the tissues of several genera including pufferfish, salamanders and octopus. Believed to provide a defensive function, the independent evolution of tetrodotoxin sequestration is poorly understood in most species. Two mechanisms of tetrodotoxin resistance have been identified to date, tetrodotoxin binding proteins in the circulatory system and mutations to voltage gated sodium channels, the binding target of tetrodotoxin with the former potentially succeeding the latter in evolutionary time. This review focuses on the evolution of tetrodotoxin acquisition, in particular how it may have occurred within the blue-ringed octopus genus (Hapalochlaena) and the subsequent impact on venom evolution.
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Affiliation(s)
- Brooke L Whitelaw
- Centre for Sustainable Tropical Fisheries and Aquaculture, James Cook University, Townsville, Queensland, 4811, Australia.
| | - Ira R Cooke
- College of Public Health, Medical and Vet Sciences, James Cook University, Townsville, Queensland, 4811, Australia; La Trobe Institute of Molecular Science, La Trobe University, Melbourne, 3086, Vic. Australia
| | - Julian Finn
- Sciences, Museum Victoria, Carlton, Victoria 3053, Australia
| | - Kyall Zenger
- Centre for Sustainable Tropical Fisheries and Aquaculture, James Cook University, Townsville, Queensland, 4811, Australia
| | - J M Strugnell
- Centre for Sustainable Tropical Fisheries and Aquaculture, James Cook University, Townsville, Queensland, 4811, Australia; Department of Ecology, Environment and Evolution, La Trobe University, Melbourne, 3086, Vic. Australia
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35
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Perry BW, Card DC, McGlothlin JW, Pasquesi GIM, Adams RH, Schield DR, Hales NR, Corbin AB, Demuth JP, Hoffmann FG, Vandewege MW, Schott RK, Bhattacharyya N, Chang BSW, Casewell NR, Whiteley G, Reyes-Velasco J, Mackessy SP, Gamble T, Storey KB, Biggar KK, Passow CN, Kuo CH, McGaugh SE, Bronikowski AM, de Koning APJ, Edwards SV, Pfrender ME, Minx P, Brodie ED, Brodie ED, Warren WC, Castoe TA. Molecular Adaptations for Sensing and Securing Prey and Insight into Amniote Genome Diversity from the Garter Snake Genome. Genome Biol Evol 2018; 10:2110-2129. [PMID: 30060036 PMCID: PMC6110522 DOI: 10.1093/gbe/evy157] [Citation(s) in RCA: 62] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/26/2018] [Indexed: 12/26/2022] Open
Abstract
Colubridae represents the most phenotypically diverse and speciose family of snakes, yet no well-assembled and annotated genome exists for this lineage. Here, we report and analyze the genome of the garter snake, Thamnophis sirtalis, a colubrid snake that is an important model species for research in evolutionary biology, physiology, genomics, behavior, and the evolution of toxin resistance. Using the garter snake genome, we show how snakes have evolved numerous adaptations for sensing and securing prey, and identify features of snake genome structure that provide insight into the evolution of amniote genomes. Analyses of the garter snake and other squamate reptile genomes highlight shifts in repeat element abundance and expansion within snakes, uncover evidence of genes under positive selection, and provide revised neutral substitution rate estimates for squamates. Our identification of Z and W sex chromosome-specific scaffolds provides evidence for multiple origins of sex chromosome systems in snakes and demonstrates the value of this genome for studying sex chromosome evolution. Analysis of gene duplication and loss in visual and olfactory gene families supports a dim-light ancestral condition in snakes and indicates that olfactory receptor repertoires underwent an expansion early in snake evolution. Additionally, we provide some of the first links between secreted venom proteins, the genes that encode them, and their evolutionary origins in a rear-fanged colubrid snake, together with new genomic insight into the coevolutionary arms race between garter snakes and highly toxic newt prey that led to toxin resistance in garter snakes.
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Affiliation(s)
- Blair W Perry
- Department of Biology, University of Texas at Arlington, Arlington
| | - Daren C Card
- Department of Biology, University of Texas at Arlington, Arlington
| | - Joel W McGlothlin
- Department of Biological Sciences, Virginia Tech, Blacksburg, Virginia
| | | | - Richard H Adams
- Department of Biology, University of Texas at Arlington, Arlington
| | - Drew R Schield
- Department of Biology, University of Texas at Arlington, Arlington
| | - Nicole R Hales
- Department of Biology, University of Texas at Arlington, Arlington
| | - Andrew B Corbin
- Department of Biology, University of Texas at Arlington, Arlington
| | - Jeffery P Demuth
- Department of Biology, University of Texas at Arlington, Arlington
| | - Federico G Hoffmann
- Department of Biochemistry, Molecular Biology, Entomology and Plant Pathology, Mississippi State University, Mississippi State.,Institute for Genomics, Biocomputing and Biotechnology, Mississippi State University, Starkville
| | - Michael W Vandewege
- Department of Biology, Institute for Genomics and Evolutionary Medicine, Temple University
| | - Ryan K Schott
- Department of Ecology and Evolutionary Biology, Department of Cell and Systems Biology, Centre for the Analysis of Genome Evolution & Function, University of Toronto, Ontario, Canada.,Department of Vertebrate Zoology, National Museum of Natural History, Smithsonian Institution, Washington, District of Columbia
| | - Nihar Bhattacharyya
- Department of Cell and Systems Biology, University of Toronto, Ontario, Canada
| | - Belinda S W Chang
- Department of Ecology and Evolutionary Biology, Department of Cell and Systems Biology, Centre for the Analysis of Genome Evolution & Function, University of Toronto, Ontario, Canada
| | - Nicholas R Casewell
- Alistair Reid Venom Research Unit, Parasitology Department, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, United Kingdom
| | - Gareth Whiteley
- Alistair Reid Venom Research Unit, Parasitology Department, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, United Kingdom
| | - Jacobo Reyes-Velasco
- Department of Biology, University of Texas at Arlington, Arlington.,Department of Biology, New York University Abu Dhabi, Saadiyat Island, Abu Dhabi, United Arab Emirates
| | | | - Tony Gamble
- Department of Biological Sciences, Marquette University, Milwaukee, WI 53201, USA.,Bell Museum of Natural History, University of Minnesota, Saint Paul, MN, USA
| | - Kenneth B Storey
- Institute of Biochemistry, Carleton University, Ottawa, Ontario, Canada
| | - Kyle K Biggar
- Institute of Biochemistry, Carleton University, Ottawa, Ontario, Canada
| | | | - Chih-Horng Kuo
- Institute of Plant and Microbial Biology, Academia Sinica, Taipei, Taiwan
| | | | - Anne M Bronikowski
- Department of Ecology, Evolution, and Organismal Biology, Iowa State University
| | - A P Jason de Koning
- Department of Biochemistry and Molecular Biology, Department of Medical Genetics, Alberta Children's Hospital Research Institute, Cumming School of Medicine, University of Calgary, Alberta, Canada
| | - Scott V Edwards
- Department of Organismic and Evolutionary Biology and Museum of Comparative Zoology, Harvard University
| | - Michael E Pfrender
- Department of Biological Sciences and Environmental Change Initiative, University of Notre Dame
| | - Patrick Minx
- The McDonnell Genome Institute, Washington University School of Medicine, St. Louis
| | | | | | - Wesley C Warren
- The McDonnell Genome Institute, Washington University School of Medicine, St. Louis
| | - Todd A Castoe
- Department of Biology, University of Texas at Arlington, Arlington
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36
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Assis BA, Swierk L, Langkilde T. Performance, behavior and offspring morphology may offset reproductive costs of male‐typical ornamentation for female lizards. J Zool (1987) 2018. [DOI: 10.1111/jzo.12599] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- B. A. Assis
- Department of Biology Intercollege Graduate Degree Program in Ecology The Pennsylvania State University University Park PA USA
| | - L. Swierk
- Department of Biology Intercollege Graduate Degree Program in Ecology The Pennsylvania State University University Park PA USA
- School of Forestry and Environmental Studies Yale University New Haven CT USA
- The Center for Brain, Behavior and Cognition The Huck Institutes of the Life Sciences The Pennsylvania State University University Park PA USA
| | - T. Langkilde
- Department of Biology Intercollege Graduate Degree Program in Ecology The Pennsylvania State University University Park PA USA
- The Center for Brain, Behavior and Cognition The Huck Institutes of the Life Sciences The Pennsylvania State University University Park PA USA
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37
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Johnson PTJ, Calhoun DM, Stokes AN, Susbilla CB, McDevitt-Galles T, Briggs CJ, Hoverman JT, Tkach VV, de Roode JC. Of poisons and parasites-the defensive role of tetrodotoxin against infections in newts. J Anim Ecol 2018; 87:1192-1204. [PMID: 29476541 DOI: 10.1111/1365-2656.12816] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2017] [Accepted: 01/17/2018] [Indexed: 11/29/2022]
Abstract
Classical research on animal toxicity has focused on the role of toxins in protection against predators, but recent studies suggest these same compounds can offer a powerful defense against parasites and infectious diseases. Newts in the genus Taricha are brightly coloured and contain the potent neurotoxin, tetrodotoxin (TTX), which is hypothesized to have evolved as a defense against vertebrate predators such as garter snakes. However, newt populations often vary dramatically in toxicity, which is only partially explained by predation pressure. The primary aim of this study was to evaluate the relationships between TTX concentration and infection by parasites. By systematically assessing micro- and macroparasite infections among 345 adult newts (sympatric populations of Taricha granulosa and T. torosa), we detected 18 unique taxa of helminths, fungi, viruses and protozoans. For both newt species, per-host concentrations of TTX, which varied from undetectable to >60 μg/cm2 skin, negatively predicted overall parasite richness as well as the likelihood of infection by the chytrid fungus, Batrachochytrium dendrobatidis, and ranavirus. No such effect was found on infection load among infected hosts. Despite commonly occurring at the same wetlands, T. torosa supported higher parasite richness and average infection load than T. granulosa. Host body size and sex (females > males) tended to positively predict infection levels in both species. For hosts in which we quantified leucocyte profiles, total white blood cell count correlated positively with both parasite richness and total infection load. By coupling data on host toxicity and infection by a broad range of micro- and macroparasites, these results suggest that-alongside its effects on predators-tetrodotoxin may help protect newts against parasitic infections, highlighting the importance of integrative research on animal chemistry, immunological defenses and natural enemy ecology.
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Affiliation(s)
- Pieter T J Johnson
- Department of Ecology and Evolutionary Biology, University of Colorado at Boulder, Boulder, CO, USA
| | - Dana M Calhoun
- Department of Ecology and Evolutionary Biology, University of Colorado at Boulder, Boulder, CO, USA
| | - Amber N Stokes
- Department of Biology, California State University, Bakersfield, CA, USA
| | - Calvin B Susbilla
- Department of Biology, California State University, Bakersfield, CA, USA
| | - Travis McDevitt-Galles
- Department of Ecology and Evolutionary Biology, University of Colorado at Boulder, Boulder, CO, USA
| | - Cheryl J Briggs
- Ecology, Evolution and Marine Biology, University of California, Santa Barbara, Santa Barbara, CA, USA
| | - Jason T Hoverman
- Department of Forestry and Natural Resources, Purdue University, West Lafayette, IN, USA
| | - Vasyl V Tkach
- Department of Biology, University of North Dakota, Grand Forks, ND, USA
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38
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Calhoun DM, Bucciarelli GM, Kats LB, Zimmer RK, Johnson PTJ. Noxious newts and their natural enemies: Experimental effects of tetrodotoxin exposure on trematode parasites and aquatic macroinvertebrates. Toxicon 2017; 137:120-127. [PMID: 28755852 PMCID: PMC5578716 DOI: 10.1016/j.toxicon.2017.07.021] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2017] [Revised: 07/21/2017] [Accepted: 07/23/2017] [Indexed: 01/04/2023]
Abstract
The dermal glands of many amphibian species secrete toxins or other noxious substances as a defense strategy against natural enemies. Newts in particular possess the potent neurotoxin tetrodotoxin (TTX), for which the highest concentrations are found in species within the genus Taricha. Adult Taricha are hypothesized to use TTX as a chemical defense against vertebrate predators such as garter snakes (Thamnophis spp.). However, less is known about how TTX functions to defend aquatic-developing newt larvae against natural enemies, including trematode parasites and aquatic macroinvertebrates. Here we experimentally investigated the effects of exogenous TTX exposure on survivorship of the infectious stages (cercariae) of five species of trematode parasites that infect larval amphibians. Specifically, we used dose-response curves to test the sensitivity of trematode cercariae to progressively increasing concentrations of TTX (0.0 [control], 0.63, 3.13, 6.26, 31.32, and 62.64 nmol L-1) and how this differed among parasite species. We further compared these results to the effects of TTX exposure (0 and 1000 nmolL-1) over 24 h on seven macroinvertebrate taxa commonly found in aquatic habitats with newt larvae. TTX significantly reduced the survivorship of trematode cercariae for all species, but the magnitude of such effects varied among species. Ribeiroia ondatrae - which causes mortality and limb malformations in amphibians - was the least sensitive to TTX, whereas the kidney-encysting Echinostoma trivolvis was the most sensitive. Among the macroinvertebrate taxa, only mayflies (Ephemeroptera) showed a significant increase in mortality following exogenous TTX exposure, despite the use of a concentration 16x higher than the maximum used for trematodes. Our results suggest that maternal investment of TTX into larval newts may provide protection against certain trematode infections and highlight the importance of future work assessing the effects of newt toxicity on both parasite infection success and the palatability of larval newts to invertebrate predators.
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Affiliation(s)
- Dana M Calhoun
- University of Colorado Boulder, Department of Ecology and Evolutionary Biology, Ramaley N122, CB334, Boulder, CO 80309, USA.
| | - Gary M Bucciarelli
- University of California, Los Angeles, Department of Ecology and Evolutionary Biology, 610 Charles E. Young Dr. East, Los Angeles, CA 90095, USA; University of California, Los Angeles, La Kretz Center for California Conservation Science, Institute of the Environmental Sustainability, La Kretz Hall, Los Angeles, CA 90095, USA.
| | - Lee B Kats
- Pepperdine University, Natural Science Division Pacific Coast Highway, Malibu, CA 90263, USA.
| | - Richard K Zimmer
- University of California, Los Angeles, Department of Ecology and Evolutionary Biology, 610 Charles E. Young Dr. East, Los Angeles, CA 90095, USA; University of Queensland, Moreton Bay Research Station, Centre for Marine Sciences, School of Biological Sciences, Dunwich, Queensland 4183, Australia.
| | - Pieter T J Johnson
- University of Colorado Boulder, Department of Ecology and Evolutionary Biology, Ramaley N122, CB334, Boulder, CO 80309, USA.
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39
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A comparison of genetic diversity and population structure of the endangered scaleshell mussel (Leptodea leptodon), the fragile papershell (Leptodea fragilis) and their host-fish the freshwater drum (Aplodinotus grunniens). CONSERV GENET 2017. [DOI: 10.1007/s10592-017-1015-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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40
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Goetz SM, Guyer C, Boback SM, Romagosa CM. Toxic, invasive treefrog creates evolutionary trap for native gartersnakes. Biol Invasions 2017. [DOI: 10.1007/s10530-017-1554-6] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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41
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Smith GD, French SS. Physiological Trade-Offs in Lizards: Costs for Individuals and Populations. Integr Comp Biol 2017; 57:344-351. [DOI: 10.1093/icb/icx062] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
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42
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Bucciarelli GM, Green DB, Shaffer HB, Kats LB. Individual fluctuations in toxin levels affect breeding site fidelity in a chemically defended amphibian. Proc Biol Sci 2017; 283:rspb.2016.0468. [PMID: 27194704 DOI: 10.1098/rspb.2016.0468] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2016] [Accepted: 04/19/2016] [Indexed: 11/12/2022] Open
Abstract
Behaviours that influence habitat selection strongly determine species movement patterns. One component of animal behaviour that largely influences movement patterns and habitat choice is site fidelity. California newts (family Salamandridae) demonstrate remarkable site fidelity, typically homing to the same pool of a stream each breeding season. Individuals often occupy a specific pool throughout the breeding season, but some males shift among breeding pools, altering their set of potential mates, competitors, and predators. In this study, we measured dermal concentrations of the chemical defence compound tetrodotoxin (TTX) in recaptured male California newts (Taricha torosa) over five breeding seasons to evaluate whether relative TTX concentrations are associated with breeding site fidelity in the field. Our five years of field sampling indicates that TTX concentrations of individuals and group means fluctuate tremendously, implying that TTX is not a stable phenotypic trait. Despite such fluctuations, we found that an individual's relative TTX concentration explains fidelity to a breeding pool and suggests that newts may be able to assess both their own concentrations of TTX and that of conspecifics to make decisions about remaining in or abandoning a breeding pool. These results provide us a novel dimension to chemical defence phenotypes in nature and their ecological consequences, potentially requiring a re-evaluation of the coevolutionary dynamics of predation pressure on toxin-laden organisms.
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Affiliation(s)
- Gary M Bucciarelli
- Department of Ecology and Evolutionary Biology, University of California, Los Angeles, CA 90095, USA UCLA La Kretz Center for California Conservation Science, Institute of the Environment and Sustainability, Los Angeles, CA 90095, USA
| | - David B Green
- Natural Science Division, Pepperdine University, 24255 Pacific Coast Highway, Malibu, CA 90263, USA
| | - H Bradley Shaffer
- Department of Ecology and Evolutionary Biology, University of California, Los Angeles, CA 90095, USA UCLA La Kretz Center for California Conservation Science, Institute of the Environment and Sustainability, Los Angeles, CA 90095, USA
| | - Lee B Kats
- Natural Science Division, Pepperdine University, 24255 Pacific Coast Highway, Malibu, CA 90263, USA
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43
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Neuman-Lee LA, Brodie ED, Hansen T, Brodie ED, French SS. To stress or not to stress: Physiological responses to tetrodotoxin in resistant gartersnakes vary by sex. Comp Biochem Physiol A Mol Integr Physiol 2017; 209:34-40. [DOI: 10.1016/j.cbpa.2015.11.017] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2015] [Revised: 10/10/2015] [Accepted: 11/05/2015] [Indexed: 01/08/2023]
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44
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Brodie ED, Brodie ED. COSTS OF EXPLOITING POISONOUS PREY: EVOLUTIONARY TRADE‐OFFS IN A PREDATOR‐PREY ARMS RACE. Evolution 2017; 53:626-631. [DOI: 10.1111/j.1558-5646.1999.tb03798.x] [Citation(s) in RCA: 79] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/1998] [Accepted: 12/14/1998] [Indexed: 11/30/2022]
Affiliation(s)
- Edmund D. Brodie
- Department of Biology Indiana University Bloomington Indiana 47405
| | - Edmund D. Brodie
- Department of Biology Utah State University Logan Utah 84322‐5305
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Brodie ED. HOMOGENEITY OF THE GENETIC VARIANCE‐COVARIANCE MATRIX FOR ANTIPREDATOR TRAITS IN TWO NATURAL POPULATIONS OF THE GARTER SNAKE
THAMNOPHIS ORDINOIDES. Evolution 2017; 47:844-854. [DOI: 10.1111/j.1558-5646.1993.tb01238.x] [Citation(s) in RCA: 49] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/1991] [Accepted: 09/04/1992] [Indexed: 11/28/2022]
Affiliation(s)
- Edmund D. Brodie
- Department of Ecology and Evolution University of Chicago Chicago Illinois 60637
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46
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Brodie ED, Brodie ED. EVOLUTIONARY RESPONSE OF PREDATORS TO DANGEROUS PREY-REDUCTION OF TOXICITY OF NEWTS AND RESISTANCE OF GARTER SNAKES IN ISLAND POPULATIONS. Evolution 2017; 45:221-224. [PMID: 28564068 DOI: 10.1111/j.1558-5646.1991.tb05280.x] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/1990] [Accepted: 04/12/1990] [Indexed: 11/28/2022]
Affiliation(s)
- Edmund D Brodie
- Department of Ecology and Evolution, University of Chicago, 940 E 57th Street, Chicago, IL, 60637, USA
| | - Edmund D Brodie
- Department of Biology, The University of Texas at Arlington, Arlington, TX, 76019, USA
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47
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Hague MT, Feldman CR, Brodie ED, Brodie ED. Convergent adaptation to dangerous prey proceeds through the same first‐step mutation in the garter snake
Thamnophis sirtalis. Evolution 2017; 71:1504-1518. [DOI: 10.1111/evo.13244] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2017] [Accepted: 03/24/2017] [Indexed: 12/28/2022]
Affiliation(s)
- Michael T.J. Hague
- Department of Biology University of Virginia Charlottesville Virginia 22904
| | | | | | - Edmund D. Brodie
- Department of Biology University of Virginia Charlottesville Virginia 22904
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48
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Herr MW, Graham SP, Langkilde T. Stressed snakes strike first: Hormone levels and defensive behavior in free ranging cottonmouths (Agkistrodon piscivorus). Gen Comp Endocrinol 2017; 243:89-95. [PMID: 27823955 DOI: 10.1016/j.ygcen.2016.11.003] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/24/2016] [Revised: 10/29/2016] [Accepted: 11/03/2016] [Indexed: 01/02/2023]
Abstract
Stress is believed to be an important factor mediating animal behavior. Here we explore the relationship between concentrations of a stress hormone and defensive behavior of a snake. The cottonmouth (Agkistrodon piscivorus) is an abundant, large-bodied pitviper that is well known for its intense defensive behaviors. The defensive behaviors and hormonal ecology of cottonmouths have been studied extensively, but the interaction between these is not well understood. We conducted field trials, recording the snake's behavior and obtaining blood samples to quantify plasma CORT concentrations, both upon first encountering a snake and after a 30min standardized confinement stressor. We found that snakes with elevated levels of baseline CORT at first encounter were more likely to strike than exhibit a threat display when approached in the field. However, this behavior was not related to the magnitude of the snake's CORT increase following confinement, suggesting that more stress-prone snakes are not more defensive. Post-stressor antipredator behavior was also not related to any of our CORT measures. This study suggests that baseline CORT levels can be important correlates of defensive behavior. If this is a causative relationship, environmental challenges that increase baseline stress levels of populations may elevate cottonmouth defensive behavior. This would increase costs associated with defensive behavior (energetic, lost opportunity, etc.) and have important consequences for animal-human interactions.
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Affiliation(s)
- Mark W Herr
- Department of Biology, The Pennsylvania State University, USA.
| | - Sean P Graham
- Department of Biology, Geology, and Physical Sciences, Sul Ross State University, USA
| | - Tracy Langkilde
- Department of Biology, The Pennsylvania State University, USA; Intercollege Graduate Degree Program in Ecology, and The Center for Brain, Behavior and Cognition, The Pennsylvania State University, USA
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49
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Coevolution in sexually reproducing populations of predators and prey. Ecol Modell 2016. [DOI: 10.1016/j.ecolmodel.2016.06.017] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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50
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Feldman CR, Durso AM, Hanifin CT, Pfrender ME, Ducey PK, Stokes AN, Barnett KE, Brodie III ED, Brodie Jr ED. Is there more than one way to skin a newt? Convergent toxin resistance in snakes is not due to a common genetic mechanism. Heredity (Edinb) 2016; 116:84-91. [PMID: 26374236 PMCID: PMC4675877 DOI: 10.1038/hdy.2015.73] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2015] [Revised: 06/07/2015] [Accepted: 06/08/2015] [Indexed: 02/08/2023] Open
Abstract
Convergent evolution of tetrodotoxin (TTX) resistance, at both the phenotypic and genetic levels, characterizes coevolutionary arms races between amphibians and their snake predators around the world, and reveals remarkable predictability in the process of adaptation. Here we examine the repeatability of the evolution of TTX resistance in an undescribed predator-prey relationship between TTX-bearing Eastern Newts (Notophthalmus viridescens) and Eastern Hog-nosed Snakes (Heterodon platirhinos). We found that that local newts contain levels of TTX dangerous enough to dissuade most predators, and that Eastern Hog-nosed Snakes within newt range are highly resistant to TTX. In fact, these populations of Eastern Hog-nosed Snakes are so resistant to TTX that the potential for current reciprocal selection might be limited. Unlike all other cases of TTX resistance in vertebrates, H. platirhinos lacks the adaptive amino acid substitutions in the skeletal muscle sodium channel that reduce TTX binding, suggesting that physiological resistance in Eastern Hog-nosed Snakes is conferred by an alternate genetic mechanism. Thus, phenotypic convergence in this case is not due to parallel molecular evolution, indicating that there may be more than one way for this adaptation to arise, even among closely related species.
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Affiliation(s)
- C R Feldman
- Department of Biology, University of Nevada Reno, Reno, NV, USA
| | - A M Durso
- Department of Biology, Utah State University, Logan, UT, USA
| | - C T Hanifin
- Department of Biology, Utah State University, Logan, UT, USA
- Department of Biology, Utah State University, Uintah Basin, Vernal, UT, USA
| | - M E Pfrender
- Department of Biological Sciences, University of Notre Dame, Notre Dame, IN, USA
| | - P K Ducey
- Department of Biological Sciences, State University of New York–Cortland, Cortland, NY, USA
| | - A N Stokes
- Department of Biology, California State University Bakersfield, Bakersfield, CA, USA
| | - K E Barnett
- New York State Department of Environmental Conservation, Albany, NY, USA
| | - E D Brodie III
- Mountain Lake Biological Station and Department of Biology, University of Virginia, Charlottesville, VA, USA
| | - E D Brodie Jr
- Department of Biology, Utah State University, Logan, UT, USA
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