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Balchan NR, Smith CF, Mackessy SP. A plethora of rodents: Rattlesnake predators generate unanticipated patterns of venom resistance in a grassland ecosystem. Toxicon X 2024; 21:100179. [PMID: 38144228 PMCID: PMC10746501 DOI: 10.1016/j.toxcx.2023.100179] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2023] [Revised: 11/05/2023] [Accepted: 11/20/2023] [Indexed: 12/26/2023] Open
Abstract
Predation has the potential to impart strong selective pressures on organisms within their environments, resulting in adaptive changes in prey that minimize risk of predation. Pressures from venomous snakes present an exceptional challenge to prey, as venom represents a unique chemical arsenal evolutionarily tailored to incapacitate prey. In response, venom resistance has been detected in various snake prey species, and to varying degrees. This study analyzes venom resistance in an eastern Colorado grassland habitat, where the Prairie Rattlesnake (Crotalus viridis) and Desert Massasauga Rattlesnake (Sistrurus tergeminus edwardsii) co-occur with a suite of grassland rodents. We test for venom resistance across rodent and snake pairings using two geographically distant field sites to determine the role of 1) predation pressure and trophic ecology, and 2) sympatric and allopatric patterns of venom resistance. Resistance was measured using serum-based metalloproteinase inhibition assays to determine potential inhibition of proteolytic activity, augmented by median lethal dose (LD50) assays on rodent species to assess toxicity of crude venoms. Resistance is present in several rodent species, with strong resistance present in populations of Eastern Woodrat (Neotoma floridana), Ord's Kangaroo Rat (Dipodomys ordii), and Northern Grasshopper Mouse (Onychomys leucogaster). Resistance is less developed in other species, including the House Mouse (Mus musculus) and Plains Pocket Mouse (Perognathus flavescens). An unexpected differential is present, where Lincoln County Kangaroo Rats are highly resistant to venom of co-occurring Prairie Rattlesnakes yet are sensitive to an allopatric population of Prairie Rattlesnakes in Weld County. Lincoln Co. Northern Grasshopper Mice also demonstrate extremely elevated resistance to Weld Co. Prairie Rattlesnake venoms, and they may possess resistance mechanisms for myotoxin a, an abundant component of Weld Co. C. v viridis venoms. This study illustrates the complexity of venom resistance in biological communities that can exist when incorporating multiple species interactions. Future studies aimed at characterizing resistance mechanisms at the molecular level will provide a more detailed physiological context for understanding mechanisms by which resistance to venoms occurs.
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Affiliation(s)
- Neil R. Balchan
- Department of Biological Sciences, University of Northern Colorado, Greeley, CO, 80639, USA
- Department of Integrative Biology, Oklahoma State University, Stillwater, OK, 74078, USA
| | - Cara F. Smith
- Department of Biological Sciences, University of Northern Colorado, Greeley, CO, 80639, USA
- Department of Biochemistry and Molecular Genetics, 12801 East 17th Avenue, University of Colorado Denver, Aurora, CO, 80045, USA
| | - Stephen P. Mackessy
- Department of Biological Sciences, University of Northern Colorado, Greeley, CO, 80639, USA
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2
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Lowe A, Kolmann MA, Paig-Tran EWM. How to Survive a (Juvenile) Piranha Attack: An Integrative Approach to Evaluating Predator Performance. Integr Org Biol 2023; 5:obad032. [PMID: 37818205 PMCID: PMC10561132 DOI: 10.1093/iob/obad032] [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: 03/22/2023] [Revised: 08/01/2023] [Indexed: 10/12/2023] Open
Abstract
Figures Cory cat panel figureDrawing of bite force measuring equipment and indentation rig Pygocentrus nattereri jaw muscle morphology and skull anatomyBox plot grid of number of Pygocentrus nattereri bites before puncture along different body regions of Corydoras trilineatus during feeding trials resultsDrawing of color-coded Corydoras trilineatus with attack frequencies and average bites until puncture by Pygocentrus nattereriBox plot of average voluntary juvenile Pygocentrus nattereri bite forces to standard lengthPanel of linear ordinary least-squares regressions of Pygocentrus nattereri bite force to adductor mandibulae mass, standard length, and body massOrdinary least-squares regressions of voluntary bites to restrained bites of Pygocentrus nattereriPanel of indentation tests for intact and removed Corydoras trilineatus scutesPanel of indentation tests for Corydoras trilineatus body region. Synopsis There is an evolutionary arms race between predators and prey. In aquatic environments, predatory fishes often use sharp teeth, powerful bites, and/or streamlined bodies to help capture their prey quickly and efficiently. Conversely, prey are often equipped with antipredator adaptations including: scaly armor, sharp spines, and/or toxic secretions. This study focused on the predator-prey interactions between the armored threestripe cory catfish (Corydoras trilineatus) and juvenile red-bellied piranha (Pygocentrus nattereri). Specifically, we investigated how resistant cory catfish armor is to a range of natural and theoretical piranha bite forces and how often this protection translated to survival from predator attacks by Corydoras. We measured the bite force and jaw functional morphology of P. nattereri, the puncture resistance of defensive scutes in C. trilineatus, and the in situ predatory interactions between the two. The adductor mandibulae muscle in juvenile P. nattereri is robust and delivers an average bite force of 1.03 N and maximum bite force of 9.71 N, yet its prey, C. trilineatus, survived 37% of confirmed bites without any damage. The C. trilineatus armor withstood an average of nine bites before puncture by P. nattereri. Predation was successful only when piranhas bit unarmored areas of the body, at the opercular opening and at the caudal peduncle. This study used an integrative approach to understand the outcomes of predator-prey interactions by evaluating the link between morphology and feeding behavior. We found that juvenile P. nattereri rarely used a maximal bite force and displayed a net predation success rate on par with other adult vertebrates. Conversely, C. trilineatus successfully avoided predation by orienting predator attacks toward their resilient, axial armor and behavioral strategies that reduced the predator's ability to bite in less armored regions of the body.
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Affiliation(s)
- A Lowe
- Schmid College of Science and Technology, Chapman University, 1 University Dr, Orange, CA 92866,USA
| | - M A Kolmann
- Department of Biology, University of Louisville, Louisville, KY 40292, USA
| | - E W M Paig-Tran
- Department of Biological Science (MH-282), California State University, Fullerton, 800 N State College Blvd, Fullerton, CA 92834-6850, USA
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3
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Elwood RW. Behavioural Indicators of Pain and Suffering in Arthropods and Might Pain Bite Back? Animals (Basel) 2023; 13:2602. [PMID: 37627393 PMCID: PMC10451332 DOI: 10.3390/ani13162602] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2023] [Revised: 08/07/2023] [Accepted: 08/08/2023] [Indexed: 08/27/2023] Open
Abstract
Pain in response to tissue damage functions to change behaviour so that further damage is minimised whereas healing and survival are promoted. This paper focuses on the behavioural criteria that match the function to ask if pain is likely in the main taxa of arthropods. There is evidence consistent with the idea of pain in crustaceans, insects and, to a lesser extent, spiders. There is little evidence of pain in millipedes, centipedes, scorpions, and horseshoe crabs but there have been few investigations of these groups. Alternative approaches in the study of pain are explored and it is suggested that studies on traumatic mating, agonistic interactions, and defensive venoms might provide clues about pain. The evolution of high cognitive ability, sensory systems, and flexible decision-making is discussed as well as how these might influence the evolution of pain-like states.
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Affiliation(s)
- Robert W Elwood
- School of Biological Sciences, Queen's University Belfast, Belfast BT9 5DL, UK
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4
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Ramírez DS, Alzate JF, Simone Y, van der Meijden A, Guevara G, Franco Pérez LM, González-Gómez JC, Prada Quiroga CF. Intersexual Differences in the Gene Expression of Phoneutria depilata (Araneae, Ctenidae) Toxins Revealed by Venom Gland Transcriptome Analyses. Toxins (Basel) 2023; 15:429. [PMID: 37505698 PMCID: PMC10467060 DOI: 10.3390/toxins15070429] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2023] [Revised: 06/17/2023] [Accepted: 06/23/2023] [Indexed: 07/29/2023] Open
Abstract
The wandering spider, Phoneutria depilata, is one of Colombia's most active nocturnal arthropod predators of vertebrates and invertebrates. Its venom has been a relevant subject of study in the last two decades. However, the scarcity of transcriptomic data for the species limits our knowledge of the distinct components present in its venom for linking the mainly neurotoxic effects of the spider venom to a particular molecular target. The transcriptome of the P. depilata venom gland was analyzed to understand the effect of different diets or sex and the impact of these variables on the composition of the venom. We sequenced venom glands obtained from ten males and ten females from three diet treatments: (i) invertebrate: Tenebrio molitor, (ii) vertebrate: Hemidactylus frenatus, and (iii) mixed (T. molitor + H. frenatus). Of 17,354 assembled transcripts from all samples, 65 transcripts relating to venom production differed between males and females. Among them, 36 were classified as neurotoxins, 14 as serine endopeptidases, 11 as other proteins related to venom production, three as metalloprotease toxins, and one as a venom potentiator. There were no differences in transcripts across the analyzed diets, but when considering the effect of diets on differences between the sexes, 59 transcripts were differentially expressed. Our findings provide essential information on toxins differentially expressed that can be related to sex and the plasticity of the diet of P. depilata and thus can be used as a reference for venomics of other wandering spider species.
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Affiliation(s)
- Diego Sierra Ramírez
- Grupo de Investigación Biología y Ecología de Artrópodos (BEA), Facultad de Ciencias, Universidad del Tolima, Altos de Santa Helena, Ibagué 730001, Colombia; (D.S.R.); (J.C.G.-G.)
| | - Juan F. Alzate
- Centro Nacional de Secuenciación Genómica (CNSG), Facultad de Medicina, Universidad de Antioquia, Medellín 050010, Colombia
| | - Yuri Simone
- CIBIO/InBIO/Biopolis, Campus Agrário de Vairão, Rua Padre Armando Quintas 7, 4485-661 Vila do Conde, Portugal; (Y.S.); (A.v.d.M.)
| | - Arie van der Meijden
- CIBIO/InBIO/Biopolis, Campus Agrário de Vairão, Rua Padre Armando Quintas 7, 4485-661 Vila do Conde, Portugal; (Y.S.); (A.v.d.M.)
| | - Giovany Guevara
- Grupo de Investigación en Zoología (GIZ), Facultad de Ciencias, Universidad del Tolima, Altos de Santa Helena, Ibagué 730001, Colombia;
| | - Lida Marcela Franco Pérez
- Facultad de Ciencias Naturales y Matemáticas, Universidad de Ibagué, Carrera 22 Calle 67, Ibagué 730001, Colombia;
| | - Julio César González-Gómez
- Grupo de Investigación Biología y Ecología de Artrópodos (BEA), Facultad de Ciencias, Universidad del Tolima, Altos de Santa Helena, Ibagué 730001, Colombia; (D.S.R.); (J.C.G.-G.)
| | - Carlos F. Prada Quiroga
- Grupo de Investigación Biología y Ecología de Artrópodos (BEA), Facultad de Ciencias, Universidad del Tolima, Altos de Santa Helena, Ibagué 730001, Colombia; (D.S.R.); (J.C.G.-G.)
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Fischer ML, Yepes Vivas SA, Wielsch N, Kirsch R, Vilcinskas A, Vogel H. You are what you eat-ecological niche and microhabitat influence venom activity and composition in aquatic bugs. Proc Biol Sci 2023; 290:20222064. [PMID: 36946119 PMCID: PMC10031423 DOI: 10.1098/rspb.2022.2064] [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: 10/14/2022] [Accepted: 02/27/2023] [Indexed: 03/23/2023] Open
Abstract
True water bugs (Nepomorpha) are mostly predacious insects that live in aquatic habitats. They use their piercing-sucking mouthparts to inject venomous saliva that facilitates the capture and extra-oral digestion of prey animals, but their venom can also be deployed for defence. In Central Europe, nepomorph species representing different families coexist in the same habitat. However, their feeding ecology, including venom composition and deployment, has not been investigated in detail. We used an integrated proteotranscriptomic and bioactivity-based approach to test whether venom composition and activity differ between four water bug species sharing the same habitat but occupying different ecological niches. We found considerable species-dependent differences in the composition of digestive enzymes and venom components that probably evolved as adaptations to particular food sources, foraging strategies and/or microhabitats. The venom of Corixa punctata differed substantially from that of the three strictly predatory species (Ilyocoris cimicoides, Notonecta glauca and Nepa cinerea), and the abundance of herbivory-associated proteins confirms a mostly plant-based diet. Our findings reveal independent adaptations of the digestive and defensive enzyme repertoires accompanied by the evolution of distinct feeding strategies in aquatic bugs.
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Affiliation(s)
- Maike L. Fischer
- Department of Insect Symbiosis, Max-Planck-Institute for Chemical Ecology, 07745 Jena, Thüringen, Germany
| | - Sol A. Yepes Vivas
- Department of Biochemistry, Max-Planck-Institute for Chemical Ecology, 07745 Jena, Thüringen, Germany
| | - Natalie Wielsch
- Research Group Mass Spectrometry/Proteomics, Max-Planck-Institute for Chemical Ecology, 07745 Jena, Thüringen, Germany
| | - Roy Kirsch
- Department of Insect Symbiosis, Max-Planck-Institute for Chemical Ecology, 07745 Jena, Thüringen, Germany
| | - Andreas Vilcinskas
- Institute for Insect Biotechnology, Justus Liebig Universitat Giessen, 35392 Giessen, Hessen, Germany
| | - Heiko Vogel
- Department of Insect Symbiosis, Max-Planck-Institute for Chemical Ecology, 07745 Jena, Thüringen, Germany
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6
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George K, Lopez-Mateos D, Abd El-Aziz TM, Xiao Y, Kline J, Bao H, Raza S, Stockand JD, Cummins TR, Fornelli L, Rowe MP, Yarov-Yarovoy V, Rowe AH. Structural and Functional Characterization of a Novel Scorpion Toxin that Inhibits NaV1.8 via Interactions With the DI Voltage Sensor and DII Pore Module. Front Pharmacol 2022; 13:846992. [PMID: 35662692 PMCID: PMC9160825 DOI: 10.3389/fphar.2022.846992] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2021] [Accepted: 04/05/2022] [Indexed: 11/30/2022] Open
Abstract
Voltage-gated sodium channel NaV1.8 regulates transmission of pain signals to the brain. While NaV1.8 has the potential to serve as a drug target, the molecular mechanisms that shape NaV1.8 gating are not completely understood, particularly mechanisms that couple activation to inactivation. Interactions between toxin producing animals and their predators provide a novel approach for investigating NaV structure-function relationships. Arizona bark scorpions produce Na+ channel toxins that initiate pain signaling. However, in predatory grasshopper mice, toxins inhibit NaV1.8 currents and block pain signals. A screen of synthetic peptide toxins predicted from bark scorpion venom showed that peptide NaTx36 inhibited Na+ current recorded from a recombinant grasshopper mouse NaV1.8 channel (OtNaV1.8). Toxin NaTx36 hyperpolarized OtNaV1.8 activation, steady-state fast inactivation, and slow inactivation. Mutagenesis revealed that the first gating charge in the domain I (DI) S4 voltage sensor and an acidic amino acid (E) in the DII SS2 – S6 pore loop are critical for the inhibitory effects of NaTx36. Computational modeling showed that a DI S1 – S2 asparagine (N) stabilizes the NaTx36 – OtNaV1.8 complex while residues in the DI S3 – S4 linker and S4 voltage sensor form electrostatic interactions that allow a toxin glutamine (Q) to contact the first S4 gating charge. Surprisingly, the models predicted that NaTx36 contacts amino acids in the DII S5 – SS1 pore loop instead of the SS2 – S6 loop; the DII SS2 – S6 loop motif (QVSE) alters the conformation of the DII S5 – SS1 pore loop, enhancing allosteric interactions between toxin and the DII S5 – SS1 pore loop. Few toxins have been identified that modify NaV1.8 gating. Moreover, few toxins have been described that modify sodium channel gating via the DI S4 voltage sensor. Thus, NaTx36 and OtNaV1.8 provide tools for investigating the structure-activity relationship between channel activation and inactivation gating, and the connection to alternative pain phenotypes.
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Affiliation(s)
- Kiran George
- Department of Biology, University of Oklahoma, Norman, OK, United States
| | - Diego Lopez-Mateos
- Department of Physiology and Membrane Biology, University of California, Davis, Davis, CA, United States
- Biophysics Graduate Group, University of California, Davis, Davis, CA, United States
| | - Tarek Mohamed Abd El-Aziz
- Department of Cellular and Integrative Physiology, University of Texas Health Science Center San Antonio, San Antonio, TX, United States
- Zoology Department, Faculty of Science, Minia University, El-Minia, Egypt
- Amsaal Venom Farm L.L.C., Abu Dhabi, United Arab Emirates
| | - Yucheng Xiao
- Department of Biology, School of Science, Indiana University-Purdue University Indianapolis, Indianapolis, IN, United States
| | - Jake Kline
- Department of Biology, University of Oklahoma, Norman, OK, United States
| | - Hong Bao
- Department of Biology, University of Oklahoma, Norman, OK, United States
| | - Syed Raza
- Department of Biology, University of Oklahoma, Norman, OK, United States
| | - James D. Stockand
- Department of Cellular and Integrative Physiology, University of Texas Health Science Center San Antonio, San Antonio, TX, United States
| | - Theodore R. Cummins
- Department of Biology, School of Science, Indiana University-Purdue University Indianapolis, Indianapolis, IN, United States
| | - Luca Fornelli
- Department of Biology, University of Oklahoma, Norman, OK, United States
| | - Matthew P. Rowe
- Department of Biology, University of Oklahoma, Norman, OK, United States
| | - Vladimir Yarov-Yarovoy
- Department of Physiology and Membrane Biology, University of California, Davis, Davis, CA, United States
- Biophysics Graduate Group, University of California, Davis, Davis, CA, United States
- Department of Anesthesiology and Pain Medicine, University of California, Davis, Davis, CA, United States
| | - Ashlee H. Rowe
- Department of Biology, University of Oklahoma, Norman, OK, United States
- Graduate Program in Cellular and Behavioral Neurobiology, University of Oklahoma, Norman, OK, United States
- *Correspondence: Ashlee H. Rowe,
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7
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Forde A, Jacobsen A, Dugon MM, Healy K. Scorpion Species with Smaller Body Sizes and Narrower Chelae Have the Highest Venom Potency. Toxins (Basel) 2022; 14:219. [PMID: 35324715 PMCID: PMC8951363 DOI: 10.3390/toxins14030219] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2022] [Revised: 03/10/2022] [Accepted: 03/14/2022] [Indexed: 02/04/2023] Open
Abstract
Scorpionism is a global health concern, with an estimation of over one million annual envenomation cases. Despite this, little is known regarding the drivers of scorpion venom potency. One widely held view is that smaller scorpions with less-developed chelae possess the most potent venoms. While this perception is often used as a guide for medical intervention, it has yet to be tested in a formal comparative framework. Here, we use a phylogenetic comparative analysis of 36 scorpion species to test whether scorpion venom potency, as measured using LD50, is related to scorpion body size and morphology. We found a positive relationship between LD50 and scorpion total length, supporting the perception that smaller scorpions possess more potent venoms. We also found that, independent of body size, scorpion species with long narrow chelae have higher venom potencies compared to species with more robust chelae. These results not only support the general perception of scorpion morphology and potency, but also the presence of an ecology trade-off with scorpions either selected for well-developed chelae or more potent venoms. Testing the patterns of venom variations in scorpions aids both our ecological understanding and our ability to address the global health burden of scorpionism.
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Affiliation(s)
- Alannah Forde
- Venom Systems & Proteomics Lab, School of Natural Sciences, Ryan Institute, National University of Ireland Galway, H91 TK33 Galway, Ireland; (A.F.); (A.J.); (M.M.D.)
| | - Adam Jacobsen
- Venom Systems & Proteomics Lab, School of Natural Sciences, Ryan Institute, National University of Ireland Galway, H91 TK33 Galway, Ireland; (A.F.); (A.J.); (M.M.D.)
| | - Michel M. Dugon
- Venom Systems & Proteomics Lab, School of Natural Sciences, Ryan Institute, National University of Ireland Galway, H91 TK33 Galway, Ireland; (A.F.); (A.J.); (M.M.D.)
| | - Kevin Healy
- Macroecology Lab, School of Natural Sciences, Ryan Institute, National University of Ireland Galway, H91 TK33 Galway, Ireland
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8
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Arroyave-Muñoz A, Meijden AVD, Estrada-Gómez S, García LF. Linking toxicity and predation in a venomous arthropod: the case of Tityus fuhrmanni (Scorpiones: Buthidae), a generalist predator scorpion. J Venom Anim Toxins Incl Trop Dis 2022; 28:e20210036. [PMID: 35082841 PMCID: PMC8747031 DOI: 10.1590/1678-9199-jvatitd-2021-0036] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2021] [Accepted: 07/12/2021] [Indexed: 11/21/2022] Open
Abstract
Background: Scorpions are arachnids that have a generalist diet, which use venom to
subdue their prey. The study of their trophic ecology and capture behavior
is still limited compared to other organisms, and aspects such as trophic
specialization in this group have been little explored. Methods: In order to determine the relationship between feeding behavior and venom
toxicity in the scorpion species Tityus fuhrmanni, 33
specimens were offered prey with different morphologies and defense
mechanisms: spiders, cockroaches and crickets. In each of the experiments we
recorded the following aspects: acceptance rate, immobilization time and the
number of capture attempts. The median lethal dose of T.
fuhrmanni venom against the three different types of prey was
also evaluated. Results: We found that this species does not have a marked difference in acceptance
for any of the evaluated prey, but the number of capture attempts of spiders
is higher when compared to the other types of prey. The immobilization time
is shorter in spiders compared to other prey and the LD50 was
higher for cockroaches. Conclusions: These results indicate that T. fuhrmanni is a scorpion with
a generalist diet, has a venom with a different potency among prey and is
capable of discriminating between prey types and employing distinct
strategies to subdue them.
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9
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OUP accepted manuscript. Syst Biol 2022; 71:1281-1289. [DOI: 10.1093/sysbio/syac021] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2020] [Revised: 03/01/2022] [Accepted: 03/05/2022] [Indexed: 11/14/2022] Open
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10
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Simone Y, van der Meijden A. Armed stem to stinger: a review of the ecological roles of scorpion weapons. J Venom Anim Toxins Incl Trop Dis 2021; 27:e20210002. [PMID: 34527038 PMCID: PMC8425188 DOI: 10.1590/1678-9199-jvatitd-2021-0002] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2021] [Accepted: 03/18/2021] [Indexed: 12/24/2022] Open
Abstract
Scorpions possess two systems of weapons: the pincers (chelae) and the stinger (telson). These are placed on anatomically and developmentally well separated parts of the body, that is, the oral appendages and at the end of the body axis. The otherwise conserved body plan of scorpions varies most in the shape and relative dimensions of these two weapon systems, both across species and in some cases between the sexes. We review the literature on the ecological function of these two weapon systems in each of three contexts of usage: (i) predation, (ii) defense and (iii) sexual contests. In the latter context, we will also discuss their usage in mating. We first provide a comparative background for each of these contexts of usage by giving examples of other weapon systems from across the animal kingdom. Then, we discuss the pertinent aspects of the anatomy of the weapon systems, particularly those aspects relevant to their functioning in their ecological roles. The literature on the functioning and ecological role of both the chelae and the telson is discussed in detail, again organized by context of usage. Particular emphasis is given on the differences in morphology or usage between species or higher taxonomic groups, or between genders, as such cases are most insightful to understand the roles of each of the two distinct weapon systems of the scorpions and their evolutionary interactions. We aimed to synthesize the literature while minimizing conjecture, but also to point out gaps in the literature and potential future research opportunities.
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Affiliation(s)
- Yuri Simone
- CIBIO Research Centre in Biodiversity and Genetic Resources, InBIO, Porto, Portugal
| | - Arie van der Meijden
- CIBIO Research Centre in Biodiversity and Genetic Resources, InBIO, Porto, Portugal
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11
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Electric Eels Wield a Functional Venom Analogue. Toxins (Basel) 2021; 13:toxins13010048. [PMID: 33435184 PMCID: PMC7826911 DOI: 10.3390/toxins13010048] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2020] [Revised: 12/30/2020] [Accepted: 01/07/2021] [Indexed: 12/23/2022] Open
Abstract
In this paper, I draw an analogy between the use of electricity by electric eels (Electrophorus electricus) to paralyze prey muscles and the use of venoms that paralyze prey by disrupting the neuromuscular junction. The eel’s strategy depends on the recently discovered ability of eels to activate prey motor neuron efferents with high-voltage pulses. Usually, eels use high voltage to cause brief, whole-body tetanus, thus preventing escape while swallowing prey whole. However, when eels struggle with large prey, or with prey held precariously, they often curl to bring their tail to the opposite side. This more than doubles the strength of the electric field within shocked prey, ensuring maximal stimulation of motor neuron efferents. Eels then deliver repeated volleys of high-voltage pulses at a rate of approximately 100 Hz. This causes muscle fatigue that attenuates prey movement, thus preventing both escape and defense while the eel manipulates and swallows the helpless animal. Presumably, the evolution of enough electrical power to remotely activate ion channels in prey efferents sets the stage for the selection of eel behaviors that functionally “poison” prey muscles.
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12
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Klompen AML, Macrander J, Reitzel AM, Stampar SN. Transcriptomic Analysis of Four Cerianthid (Cnidaria, Ceriantharia) Venoms. Mar Drugs 2020; 18:md18080413. [PMID: 32764303 PMCID: PMC7460484 DOI: 10.3390/md18080413] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2020] [Revised: 07/16/2020] [Accepted: 07/22/2020] [Indexed: 12/18/2022] Open
Abstract
Tube anemones, or cerianthids, are a phylogenetically informative group of cnidarians with complex life histories, including a pelagic larval stage and tube-dwelling adult stage, both known to utilize venom in stinging-cell rich tentacles. Cnidarians are an entirely venomous group that utilize their proteinaceous-dominated toxins to capture prey and defend against predators, in addition to several other ecological functions, including intraspecific interactions. At present there are no studies describing the venom for any species within cerianthids. Given their unique development, ecology, and distinct phylogenetic-placement within Cnidaria, our objective is to evaluate the venom-like gene diversity of four species of cerianthids from newly collected transcriptomic data. We identified 525 venom-like genes between all four species. The venom-gene profile for each species was dominated by enzymatic protein and peptide families, which is consistent with previous findings in other cnidarian venoms. However, we found few toxins that are typical of sea anemones and corals, and furthermore, three of the four species express toxin-like genes closely related to potent pore-forming toxins in box jellyfish. Our study is the first to provide a survey of the putative venom composition of cerianthids and contributes to our general understanding of the diversity of cnidarian toxins.
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Affiliation(s)
- Anna M. L. Klompen
- Department of Ecology and Evolutionary Biology, University of Kansas, 1200 Sunnyside Ave., Lawrence, KS 66045, USA
- Correspondence:
| | - Jason Macrander
- Department of Biological Sciences, University of North Carolina at Charlotte, 9201 University City Blvd, Charlotte, NC 28262, USA; (J.M.); (A.M.R.)
- Department of Biology, Florida Southern College, 111 Lake Hollingsworth, Drive Lakeland, FL 33801, USA
| | - Adam M. Reitzel
- Department of Biological Sciences, University of North Carolina at Charlotte, 9201 University City Blvd, Charlotte, NC 28262, USA; (J.M.); (A.M.R.)
| | - Sérgio N. Stampar
- Department of Biological Sciences, Universidade Estadual Paulista “Júlio de Mesquita Filho” (UNESP), FCL, Assis, SP 19806, Brazil;
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