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Ghimire A, Xu L, Liu XQ, Rainey JK. A recombinant chimeric spider pyriform-aciniform silk with highly tunable mechanical performance. Mater Today Bio 2024; 26:101073. [PMID: 38711935 PMCID: PMC11070712 DOI: 10.1016/j.mtbio.2024.101073] [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: 01/31/2024] [Revised: 04/11/2024] [Accepted: 04/25/2024] [Indexed: 05/08/2024] Open
Abstract
Spider silks are natural protein-based biomaterials which are renowned for their mechanical properties and hold great promise for applications ranging from high-performance textiles to regenerative medicine. While some spiders can produce several different types of silks, most spider silk types - including pyriform and aciniform silks - are relatively unstudied. Pyriform and aciniform silks have distinct mechanical behavior and physicochemical properties, with materials produced using combinations of these silks currently unexplored. Here, we introduce an engineered chimeric fusion protein consisting of two repeat units of pyriform (Py) silk followed by two repeat units of aciniform (W) silk named Py2W2. This recombinant ∼86.5 kDa protein is amenable to expression and purification from Escherichia coli and exhibits high α-helicity in a fluorinated acid- and alcohol-based solution used to form a dope for wet-spinning. Wet-spinning enables continuous fiber production and post-spin stretching of the wet-spun fibers in air or following submersion in water or ethanol leads to increases in optical anisotropy, consistent with increased molecular alignment along the fiber axis. Mechanical properties of the fibers vary as a function of post-spin stretching condition, with the highest extensibility and strength observed in air-stretched and ethanol-treated fibers, respectively, with mechanics being superior to fibers spun from either constituent protein alone. Notably, the maximum extensibility obtained (∼157 ± 38 %) is of the same magnitude reported for natural flagelliform silks, the class of spider silk most associated with being stretchable. Interestingly, Py2W2 is also water-compatible, unlike its constituent Py2. Fiber-state secondary structure correlates well with the observed mechanical properties, with depleted α-helicity and increased β-sheet content in cases of increased strength. Py2W2 fibers thus provide enhanced materials behavior in terms of their mechanics, tunability, and fiber properties, providing new directions for design and development of biomaterials suitable and tunable for disparate applications.
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Affiliation(s)
- Anupama Ghimire
- Department of Biochemistry & Molecular Biology, Dalhousie University, Halifax, NS, B3H 4R2, Canada
| | - Lingling Xu
- Department of Biochemistry & Molecular Biology, Dalhousie University, Halifax, NS, B3H 4R2, Canada
| | - Xiang-Qin Liu
- Department of Biochemistry & Molecular Biology, Dalhousie University, Halifax, NS, B3H 4R2, Canada
| | - Jan K. Rainey
- Department of Biochemistry & Molecular Biology, Dalhousie University, Halifax, NS, B3H 4R2, Canada
- Department of Chemistry, Dalhousie University, Halifax, NS, B3H 4R2, Canada
- School of Biomedical Engineering, Dalhousie University, Halifax, NS, B3H 4R2, Canada
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2
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Hopfe C, Ospina-Jara B, Schulze T, Tischer M, Morales D, Reinhartz V, Esfahani RE, Valderrama C, Pérez-Rigueiro J, Bleidorn C, Feldhaar H, Cabra-García J, Scheibel T. Impact of environmental factors on spider silk properties. Curr Biol 2024; 34:56-67.e5. [PMID: 38118450 DOI: 10.1016/j.cub.2023.11.043] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2023] [Revised: 10/11/2023] [Accepted: 11/20/2023] [Indexed: 12/22/2023]
Abstract
Spider orb webs have evolved to stop flying prey, fast and slow alike. One of the main web elements dissipating impact energy is the radial fibers, or major ampullate silks, which possess a toughness surpassing most man-made materials. Orb webs are extended phenotypes, and as such their architectural elements, including major ampullate silks, have been selected to optimize prey capture under the respective environmental conditions. In this study, we investigated the correlation of three landscape scales and three microhabitat characteristics with intrinsic silk properties (elastic modulus, yield stress, tensile strength, extensibility, and toughness) to understand underlying ecological patterns. For this purpose, we collected and mechanically tested major ampullate silks from 50 spider species inhabiting large altitudinal and climatic gradients in Colombia. Using regression analysis and model selection, we investigated the environmental drivers of inter- and intra-specific patterns of major ampullate silk properties, taking into account phylogenetic relatedness based on newly sequenced mitochondrial genomes. We found that the total amount of energy absorbed, i.e., toughness and tensile strength, is higher for fibers from species inhabiting regions where heavy rainfall is common. Interestingly, we observe the same general trend between individuals of the same species, stressing the importance of this environmental driver. We also observe a phylogenetic conservation in the relation of environmental variables with silk tensile strength and yield stress. In conclusion, the increase in major ampullate silk tensile strength and toughness may reflect an adaptation to prevent frequent rain damage to orb webs and the associated energetic loss.
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Affiliation(s)
- Charlotte Hopfe
- Department of Biomaterials, Universität Bayreuth, Prof.-Rüdiger-Bormann-Str. 1, Bayreuth 95447, Germany.
| | - Bryan Ospina-Jara
- Department of Biology, Universidad del Valle, Cl. 13 #100-00, Cali 760042, Colombia
| | - Thilo Schulze
- Department of Animal Evolution and Biodiversity, Georg-August-Universität Göttingen, Untere Karspüle 2, Göttingen 37073, Germany
| | - Marta Tischer
- Department of Animal Evolution and Biodiversity, Georg-August-Universität Göttingen, Untere Karspüle 2, Göttingen 37073, Germany
| | - Diego Morales
- Department of Biology, Universidad del Valle, Cl. 13 #100-00, Cali 760042, Colombia
| | - Vivien Reinhartz
- Department of Biomaterials, Universität Bayreuth, Prof.-Rüdiger-Bormann-Str. 1, Bayreuth 95447, Germany
| | - Rashin Eshghi Esfahani
- Department of Biomaterials, Universität Bayreuth, Prof.-Rüdiger-Bormann-Str. 1, Bayreuth 95447, Germany
| | - Carlos Valderrama
- Facultad de Ciencias, Universidad del Rosario, Cl. 12c #6-25, Bogotá 111711, Colombia
| | - José Pérez-Rigueiro
- Center for Biomedical Technology, Universidad Politécnica de Madrid, Crta. M40, Madrid 28223, Spain; Departamento de Ciencia de Materiales, ETSI Caminos, Canales y Puertos, Universidad Politécnica de Madrid, C/Prof. Aranguren 3, Madrid 28040, Spain; Biomedical Research Networking Center in Bioengineering Biomaterials and Nanomedicine (CIBER-BBN), Madrid 28029, Spain; Biomaterials and Regenerative Medicine Group, Instituto de Investigación Sanitaria del Hospital Clínico San Carlos (IdISSC), C/ Prof. Martín Lagos s/n, Madrid 28040, Spain
| | - Christoph Bleidorn
- Department of Animal Evolution and Biodiversity, Georg-August-Universität Göttingen, Untere Karspüle 2, Göttingen 37073, Germany
| | - Heike Feldhaar
- Department of Animal Ecology I, Bayreuth Center of Ecology and Environmental Research (BayCEER), Universität Bayreuth, Universitätsstraße 30, Bayreuth 95440, Germany
| | - Jimmy Cabra-García
- Department of Biology, Universidad del Valle, Cl. 13 #100-00, Cali 760042, Colombia
| | - Thomas Scheibel
- Department of Biomaterials, Universität Bayreuth, Prof.-Rüdiger-Bormann-Str. 1, Bayreuth 95447, Germany; Bayreuther Zentrum für Kolloide und Grenzflächen, Universität Bayreuth, Universitätsstraße 30, Bayreuth 95440, Germany; Bayreuther Materialzentrum, Universität Bayreuth, Universitätsstraße 30, Bayreuth 95440, Germany; Bayreuther Zentrum für Molekulare Biowissenschaften, Universität Bayreuth, Universitätsstraße 30, Bayreuth 95440, Germany; Bayrisches Polymerinstitut, Universität Bayreuth, Universitätsstraße 30, Bayreuth 95440, Germany.
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3
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Agnarsson I. Biomechanics: Rain yields tougher spider silks. Curr Biol 2024; 34:R30-R33. [PMID: 38194927 DOI: 10.1016/j.cub.2023.11.058] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2024]
Abstract
Broad ecological sampling of spider silks from multiple species shows that the biomechanical properties of spider silk reflect the habitat in which their orb webs are built. Silk toughness is highest in habitats with dense rain.
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Affiliation(s)
- Ingi Agnarsson
- Faculty of Life and Environmental Sciences, University of Iceland, Sturlugata 7, 101 Reykjavik, Iceland; Department of Entomology, National Museum of Natural History, Washington, DC 20013-7012, USA; School of Life Sciences, Hubei University, Wuhan, Hubei, China.
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4
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Greco G, Schmuck B, Jalali SK, Pugno NM, Rising A. Influence of experimental methods on the mechanical properties of silk fibers: A systematic literature review and future road map. BIOPHYSICS REVIEWS 2023; 4:031301. [PMID: 38510706 PMCID: PMC10903380 DOI: 10.1063/5.0155552] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/21/2023] [Accepted: 06/20/2023] [Indexed: 03/22/2024]
Abstract
Spider silk fibers are of scientific and industrial interest because of their extraordinary mechanical properties. These properties are normally determined by tensile tests, but the values obtained are dependent on the morphology of the fibers, the test conditions, and the methods by which stress and strain are calculated. Because of this, results from many studies are not directly comparable, which has led to widespread misconceptions in the field. Here, we critically review most of the reports from the past 50 years on spider silk mechanical performance and use artificial spider silk and native silks as models to highlight the effect that different experimental setups have on the fibers' mechanical properties. The results clearly illustrate the importance of carefully evaluating the tensile test methods when comparing the results from different studies. Finally, we suggest a protocol for how to perform tensile tests on silk and biobased fibers.
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Affiliation(s)
| | | | - S. K. Jalali
- Laboratory for Bioinspired, Bionic, Nano, Meta, Materials & Mechanics, Department of Civil, Environmental and Mechanical Engineering, University of Trento, Via Mesiano, 77, 38123 Trento, Italy
| | | | - Anna Rising
- Authors to whom correspondence should be addressed: and
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5
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Han SI, Alicea-Serrano AM, Blackledge TA. Anchor threads can double the insect flight energy absorbed by spider orb webs. J Exp Biol 2023; 226:286587. [PMID: 36633333 PMCID: PMC10086537 DOI: 10.1242/jeb.245123] [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: 10/05/2022] [Accepted: 12/20/2022] [Indexed: 01/13/2023]
Abstract
To successfully capture flying insect prey, a spider's orb web must withstand the energy of impact without the silk breaking. In this study, we examined the anchor threads: the silk lines that anchor the main capture area of the web to the surrounding environment. These anchor threads can account for a large portion of the web, yet are usually excluded from experiments and simulations. We compared projectile capture and kinetic energy absorption between webs with and without access to anchor threads. Webs with anchor threads captured significantly more projectiles and absorbed significantly more energy than those with constrained anchors. This is likely because the anchor threads increase web compliance, resulting in webs with the ability to catch high-energy flying insects without breaking. Anchor threads are one example of how different types of web architecture expand the range of possible prey capture strategies by enabling the web to withstand greater impacts.
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Affiliation(s)
- Sarah I Han
- The University of Akron, Biology Department, Akron, OH 44325, USA
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Wen R, Wang K, Zan X. Characterization of two full-length tubuliform silk gene sequences from Neoscona theisi reveals intragenic concerted evolution and multiple copies in genome. Int J Biol Macromol 2022; 223:1015-1023. [PMID: 36375671 DOI: 10.1016/j.ijbiomac.2022.11.082] [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: 08/31/2022] [Revised: 10/19/2022] [Accepted: 11/03/2022] [Indexed: 11/12/2022]
Abstract
Orb-web weaving spiders use a variety of silk types for particular tasks, and each silk type is composed of at least two spider silk proteins (spidroins). In the early stage of divergence, however, the molecular evolutionary processes act on spidroin variants are still unclear because of a lack of knowledge for full-length paralogous and orthologous gene sequences among closely related species. Here, we present two complete gene sequences encoding the tubuliform spidroin TuSp1 variants (TuSp1-v2 and TuSp1-v3) from orb-weaving spider Neoscona theisi. Both N. theisi TuSp1-v2 and TuSp1-v3 genes contain a single enormous exon (14,139 bp for TuSp1-v2 and 13,152 bp for TuSp1-v3) and dozens of tandemly arrayed repeats (25 repeats for TuSp1-v2 and 23 repeats for TuSp1-v3) with extreme intragenic homogenization. The pattern of expression for these two spidroins revealed that the level of TuSp1-v3 mRNA is ~3-fold higher than that of TuSp1-v2 in tubuliform gland. Phylogenetic analyses of spidroins not only show the occurrence of a gene duplication event for TuSp1-v2 and TuSp1-v3 in the common ancestor of the Neoscona and Araneus lineage but reinforce the role of concerted evolution for the extreme homogenization of TuSp1 repeats.
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Affiliation(s)
- Rui Wen
- School of Ophthalmology and Optometry, Eye Hospital, School of Biomedical Engineering, Wenzhou Medical University, Wenzhou, Zhejiang Province 325035, China; Oujiang Laboratory, Wenzhou Key Laboratory of Perioperative Medicine, Wenzhou Institute, University of Chinese Academy of Sciences, Wenzhou, Zhejiang 325000, China.
| | - Kangkang Wang
- Oujiang Laboratory, Wenzhou Key Laboratory of Perioperative Medicine, Wenzhou Institute, University of Chinese Academy of Sciences, Wenzhou, Zhejiang 325000, China
| | - Xingjie Zan
- School of Ophthalmology and Optometry, Eye Hospital, School of Biomedical Engineering, Wenzhou Medical University, Wenzhou, Zhejiang Province 325035, China; Oujiang Laboratory, Wenzhou Key Laboratory of Perioperative Medicine, Wenzhou Institute, University of Chinese Academy of Sciences, Wenzhou, Zhejiang 325000, China.
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7
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Rapid molecular diversification and homogenization of clustered major ampullate silk genes in Argiope garden spiders. PLoS Genet 2022; 18:e1010537. [PMID: 36508456 PMCID: PMC9779670 DOI: 10.1371/journal.pgen.1010537] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2022] [Revised: 12/22/2022] [Accepted: 11/18/2022] [Indexed: 12/14/2022] Open
Abstract
The evolutionary diversification of orb-web weaving spiders is closely tied to the mechanical performance of dragline silk. This proteinaceous fiber provides the primary structural framework of orb web architecture, and its extraordinary toughness allows these structures to absorb the high energy of aerial prey impact. The dominant model of dragline silk molecular structure involves the combined function of two highly repetitive, spider-specific, silk genes (spidroins)-MaSp1 and MaSp2. Recent genomic studies, however, have suggested this framework is overly simplistic, and our understanding of how MaSp genes evolve is limited. Here we present a comprehensive analysis of MaSp structural and evolutionary diversity across species of Argiope (garden spiders). This genomic analysis reveals the largest catalog of MaSp genes found in any spider, driven largely by an expansion of MaSp2 genes. The rapid diversification of Argiope MaSp genes, located primarily in a single genomic cluster, is associated with profound changes in silk gene structure. MaSp2 genes, in particular, have evolved complex hierarchically organized repeat units (ensemble repeats) delineated by novel introns that exhibit remarkable evolutionary dynamics. These repetitive introns have arisen independently within the genus, are highly homogenized within a gene, but diverge rapidly between genes. In some cases, these iterated introns are organized in an alternating structure in which every other intron is nearly identical in sequence. We hypothesize that this intron structure has evolved to facilitate homogenization of the coding sequence. We also find evidence of intergenic gene conversion and identify a more diverse array of stereotypical amino acid repeats than previously recognized. Overall, the extreme diversification found among MaSp genes requires changes in the structure-function model of dragline silk performance that focuses on the differential use and interaction among various MaSp paralogs as well as the impact of ensemble repeat structure and different amino acid motifs on mechanical behavior.
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8
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Correa-Garhwal SM, Baker RH, Clarke TH, Ayoub NA, Hayashi CY. The evolutionary history of cribellate orb-weaver capture thread spidroins. BMC Ecol Evol 2022; 22:89. [PMID: 35810286 PMCID: PMC9270836 DOI: 10.1186/s12862-022-02042-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2021] [Accepted: 06/21/2022] [Indexed: 11/19/2022] Open
Abstract
Background Spiders have evolved two types of sticky capture threads: one with wet adhesive spun by ecribellate orb-weavers and another with dry adhesive spun by cribellate spiders. The evolutionary history of cribellate capture threads is especially poorly understood. Here, we use genomic approaches to catalog the spider-specific silk gene family (spidroins) for the cribellate orb-weaver Uloborus diversus. Results We show that the cribellar spidroin, which forms the puffy fibrils of cribellate threads, has three distinct repeat units, one of which is conserved across cribellate taxa separated by ~ 250 Mya. We also propose candidates for a new silk type, paracribellar spidroins, which connect the puffy fibrils to pseudoflagelliform support lines. Moreover, we describe the complete repeat architecture for the pseudoflagelliform spidroin (Pflag), which contributes to extensibility of pseudoflagelliform axial fibers. Conclusions Our finding that Pflag is closely related to Flag, supports homology of the support lines of cribellate and ecribellate capture threads. It further suggests an evolutionary phase following gene duplication, in which both Flag and Pflag were incorporated into the axial lines, with subsequent loss of Flag in uloborids, and increase in expression of Flag in ecribellate orb-weavers, explaining the distinct mechanical properties of the axial lines of these two groups. Supplementary Information The online version contains supplementary material available at 10.1186/s12862-022-02042-5.
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Bergmann F, Stadlmayr S, Millesi F, Zeitlinger M, Naghilou A, Radtke C. The properties of native Trichonephila dragline silk and its biomedical applications. BIOMATERIALS ADVANCES 2022; 140:213089. [PMID: 36037764 DOI: 10.1016/j.bioadv.2022.213089] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/25/2022] [Revised: 08/17/2022] [Accepted: 08/19/2022] [Indexed: 06/15/2023]
Abstract
Spider silk has fascinated mankind for millennia, but it is only in recent decades that scientific research has begun to unravel all its characteristics and applications. The uniqueness of spider silk resides in its versatility, in which a combination of high strength and extensibility results in extraordinary toughness, superior to almost all natural and man-made fibers. Dragline silk consists of proteins with highly repetitive amino acid sequences, which have been correlated with specific secondary structures responsible for its physical properties. The native fiber also shows high cytocompatibility coupled with low immunogenicity, making it a promising natural biomaterial for numerous biomedical applications. Recently, novel technologies have enabled new insights into the material and biomedical properties of silk. Due to the increasing interest in spider silk, as well as the desire to produce synthetic alternatives, we present an update on the current knowledge of silk fibers produced by the spider genus Trichonephila.
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Affiliation(s)
- Felix Bergmann
- Department of Plastic, Reconstructive, and Aesthetic Surgery, Medical University of Vienna, Vienna, Austria; Department of Clinical Pharmacology, Medical University of Vienna, Vienna, Austria
| | - Sarah Stadlmayr
- Department of Plastic, Reconstructive, and Aesthetic Surgery, Medical University of Vienna, Vienna, Austria; Austrian Cluster for Tissue Regeneration, Vienna, Austria
| | - Flavia Millesi
- Department of Plastic, Reconstructive, and Aesthetic Surgery, Medical University of Vienna, Vienna, Austria; Austrian Cluster for Tissue Regeneration, Vienna, Austria
| | - Markus Zeitlinger
- Department of Clinical Pharmacology, Medical University of Vienna, Vienna, Austria
| | - Aida Naghilou
- Department of Plastic, Reconstructive, and Aesthetic Surgery, Medical University of Vienna, Vienna, Austria; Austrian Cluster for Tissue Regeneration, Vienna, Austria.
| | - Christine Radtke
- Department of Plastic, Reconstructive, and Aesthetic Surgery, Medical University of Vienna, Vienna, Austria; Austrian Cluster for Tissue Regeneration, Vienna, Austria
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10
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Opell BD, Elmore HM, Hendricks ML. Adhesive contact and protein elastic modulus tune orb weaving spider glue droplet biomechanics to habitat humidity. Acta Biomater 2022; 151:468-479. [PMID: 35970480 DOI: 10.1016/j.actbio.2022.08.018] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2022] [Revised: 08/02/2022] [Accepted: 08/08/2022] [Indexed: 11/18/2022]
Abstract
Tiny glue droplets along the viscous capture threads of spider orb webs prevent insects from escaping. Each droplet is formed of a protein core surrounded by a hygroscopic aqueous layer, which cause the droplet's adhesion to change with humidity. As an insect struggles to escape the web, a thread's viscoelastic core proteins extend, transferring adhesive forces to the thread's support fibers. Maximum adhesive force is achieved when absorbed atmospheric moisture allows a flattened droplet to establish sufficient adhesive contact while maintaining the core protein cohesion necessary for force transfer. We examined the relationship between these droplet properties and adhesive force and the work of extending droplets at five relative humidities in twelve species that occupy habitats which have different humidities. A regression analysis that included both flattened droplet area and core protein elastic modulus described droplet adhesion, but the model was degraded when core protein area was substituted for droplet. Species from low humidity habitats expressed greater adhesion at lower humidities, whereas species from high humidity habitats expressed greater adhesion at high humidities. Our results suggest a general model of droplet adhesion with two adhesion peaks, one for low humidity species, which occurs when increasing droplet area and decreasing protein cohesion intersect, and another for high humidity species, which occurs when area and cohesion have diverged maximally. These dual peaks in adhesive force explain why some species from intermediate and high humidity habitats express high adhesion at several humidities. STATEMENT OF SIGNIFICANCE: We characterized the effect of humidity on the adhesion of twelve orb weaving spider species' glue droplets and showed how humidity-mediated changes in the contact area of a droplet's outer, hygroscopic aqueous layer and the stiffness of its protein core affect droplet performance. This revealed how droplet adhesion has been tuned to the humidity of a species' habitat and allowed us to revise a model that describes the environmental determinants of droplet biomechanics.
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Affiliation(s)
- Brent D Opell
- Department of Biological Sciences, Virginia Tech, Blacksburg, VA 24061, USA.
| | - Hannah Mae Elmore
- Department of Biological Sciences, Virginia Tech, Blacksburg, VA 24061, USA
| | - Mary L Hendricks
- Department of Biological Sciences, Virginia Tech, Blacksburg, VA 24061, USA
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11
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Kelly SD, Opell BD, Correa-Garwhal SM. Correlated evolution between orb weaver glue droplets and supporting fibres maintains their distinct biomechanical roles in adhesion. J Evol Biol 2022; 35:879-890. [PMID: 35694995 PMCID: PMC9327512 DOI: 10.1111/jeb.14025] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2021] [Revised: 03/31/2022] [Accepted: 05/04/2022] [Indexed: 12/01/2022]
Abstract
Orb weaving spiders employ a 'silken toolkit' to accomplish a range of tasks, including retaining prey that strike their webs. This is accomplished by a viscous capture spiral thread that features tiny glue droplets, supported by a pair of elastic flagelliform fibres. Each droplet contains a glycoprotein core responsible for adhesion. However, prey retention relies on the integrated performance of multiple glue droplets and their supporting fibres, with previous studies demonstrating that a suspension bridge forms, whose biomechanics sum the adhesive forces of multiple droplets while dissipating the energy of the struggling insect. While the interdependence of the droplet's glycoprotein and flagelliform fibres for functional adhesion is acknowledged, there has been no direct test of this hypothesized linkage between the material properties of each component. Spider mass, which differs greatly across orb weaving species, also has the potential to affect flagelliform fibre and glycoprotein material properties. Previous studies have linked spider mass to capture thread performance but have not examined the relationship between spider mass and thread material properties. We extend earlier studies to examine these relationships in 16 orb weaving species using phylogenetic generalized least squares. This analysis revealed that glycoprotein stiffness (elastic modulus) was correlated with flagelliform fibre stiffness, and that spider mass was related to the glycoprotein volume, flagelliform fibre cross-sectional area and droplets per unit thread length. By shaping the elastic moduli of glycoprotein adhesive and flagelliform fibres, natural selection has maintained the biomechanical integration of this adhesive system.
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Affiliation(s)
- Sean D Kelly
- Department of Biology, San Diego State University, San Diego, California, USA.,Evolution, Ecology, and Organismal Biology Department, University of California Riverside, Riverside, California, USA
| | - Brent D Opell
- Department of Biological Sciences, Virginia Tech, Blacksburg, Virginia, USA
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12
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Artificial and natural silk materials have high mechanical property variability regardless of sample size. Sci Rep 2022; 12:3507. [PMID: 35241705 PMCID: PMC8894418 DOI: 10.1038/s41598-022-07212-5] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2022] [Accepted: 02/15/2022] [Indexed: 11/29/2022] Open
Abstract
Silk fibres attract great interest in materials science for their biological and mechanical properties. Hitherto, the mechanical properties of the silk fibres have been explored mainly by tensile tests, which provide information on their strength, Young’s modulus, strain at break and toughness modulus. Several hypotheses have been based on these data, but the intrinsic and often overlooked variability of natural and artificial silk fibres makes it challenging to identify trends and correlations. In this work, we determined the mechanical properties of Bombyx mori cocoon and degummed silk, native spider silk, and artificial spider silk, and compared them with classical commercial carbon fibres using large sample sizes (from 10 to 100 fibres, in total 200 specimens per fibre type). The results confirm a substantial variability of the mechanical properties of silk fibres compared to commercial carbon fibres, as the relative standard deviation for strength and strain at break is 10–50%. Moreover, the variability does not decrease significantly when the number of tested fibres is increased, which was surprising considering the low variability frequently reported for silk fibres in the literature. Based on this, we prove that tensile testing of 10 fibres per type is representative of a silk fibre population. Finally, we show that the ideal shape of the stress–strain curve for spider silk, characterized by a pronounced exponential stiffening regime, occurs in only 25% of all tested spider silk fibres.
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13
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Kono N, Ohtoshi R, Malay AD, Mori M, Masunaga H, Yoshida Y, Nakamura H, Numata K, Arakawa K. Darwin's bark spider shares a spidroin repertoire with Caerostris extrusa but achieves extraordinary silk toughness through gene expression. Open Biol 2021; 11:210242. [PMID: 34932907 PMCID: PMC8692038 DOI: 10.1098/rsob.210242] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
Spider silk is a protein-based material whose toughness suggests possible novel applications. A particularly fascinating example of silk toughness is provided by Darwin's bark spider (Caerostris darwini) found in Madagascar. This spider produces extraordinarily tough silk, with an average toughness of 350 MJ m-1 and over 50% extensibility, and can build river-bridging webs with a size of 2.8 m2. Recent studies have suggested that specific spidroins expressed in C. darwini are responsible for the mechanical properties of its silk. Therefore, a more comprehensive investigation of spidroin sequences, silk thread protein contents and phylogenetic conservation among closely related species is required. Here, we conducted genomic, transcriptomic and proteomic analyses of C. darwini and its close relative Caerostris extrusa. A variety of spidroins and low-molecular-weight proteins were found in the dragline silk of these species; all of the genes encoding these proteins were conserved in both genomes, but their genes were more expressed in C. darwini. The potential to produce very tough silk is common in the genus Caerostris, and our results may suggest the existence of plasticity allowing silk mechanical properties to be changed by optimizing related gene expression in response to the environment.
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Affiliation(s)
- Nobuaki Kono
- Institute for Advanced Biosciences, Keio University, 403-1 Nihonkoku, Daihouji, Tsuruoka, Yamagata 997-0017, Japan,Systems Biology Program, Graduate School of Media and Governance, Keio University, 5322 Endo, Fujisawa, Kanagawa 252-0882, Japan
| | - Rintaro Ohtoshi
- RIKEN Center for Sustainable Resource Science, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
| | - Ali D. Malay
- RIKEN Center for Sustainable Resource Science, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
| | - Masaru Mori
- Institute for Advanced Biosciences, Keio University, 403-1 Nihonkoku, Daihouji, Tsuruoka, Yamagata 997-0017, Japan,Systems Biology Program, Graduate School of Media and Governance, Keio University, 5322 Endo, Fujisawa, Kanagawa 252-0882, Japan
| | - Hiroyasu Masunaga
- Japan Synchrotron Radiation Research Institute, 1-1-1, Kouto, Sayo-cho, Sayo-gun, Hyogo 679-5198, Japan,RIKEN SPring-8 Center, 1-1-1 Kouto, Sayo-cho, Sayo-gun, Hyogo 679-5198, Japan
| | - Yuki Yoshida
- Institute for Advanced Biosciences, Keio University, 403-1 Nihonkoku, Daihouji, Tsuruoka, Yamagata 997-0017, Japan,Systems Biology Program, Graduate School of Media and Governance, Keio University, 5322 Endo, Fujisawa, Kanagawa 252-0882, Japan
| | - Hiroyuki Nakamura
- Spiber Inc., 234-1 Mizukami, Kakuganji, Tsuruoka, Yamagata 997-0052, Japan
| | - Keiji Numata
- RIKEN Center for Sustainable Resource Science, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan,Department of Material Chemistry, Kyoto University, Kyotodaigaku-Katsura, Nishikyo-ku, Kyoto 615-8510, Japan
| | - Kazuharu Arakawa
- Institute for Advanced Biosciences, Keio University, 403-1 Nihonkoku, Daihouji, Tsuruoka, Yamagata 997-0017, Japan,Systems Biology Program, Graduate School of Media and Governance, Keio University, 5322 Endo, Fujisawa, Kanagawa 252-0882, Japan
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14
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Xavier GM, Quero A, Moura RR, Vieira C, Meira FA, Gonzaga MO. Influence of web traits, height, and daily periods of exposition on prey captured by orb-weaver spiders. Behav Processes 2021; 193:104536. [PMID: 34728314 DOI: 10.1016/j.beproc.2021.104536] [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: 07/04/2021] [Revised: 09/23/2021] [Accepted: 10/28/2021] [Indexed: 11/16/2022]
Abstract
Orb-webs show diversity in several traits, including silk types, architecture, physical properties, locale, and period of exposition. The investigation of how they determine the identity of intercepted prey is important to functional ecology and to the evaluation of trophic niche partitioning within communities. However, the influence of several of these variables on the composition of intercepted insects remains to be determined. In this study, we evaluated the effects of web architectural traits, height, and daily periods of exposition on the interception of different insects in terms of sizes, masses, and taxa. We conducted observations of prey intercepted by the orb webs of 16 sympatric spider species and artificial webs. We found that all orb webs mainly intercepted small and light insects, sharing the most abundant insect families found in the study area. However, spiders that show nocturnal activity, more radii in their webs, large and high webs captured heavier insects. Other orb-web traits, such as the density of capture threads did not influence the kind of intercepted insects. We discuss why some variables affected prey interceptions in terms of mass. Finally, we discuss the implications of these influential variables to functional ecology, niche differentiation, and how behavioral assessments can complete this investigation in future studies.
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Affiliation(s)
- Gabriel Máximo Xavier
- Pós-graduação em Ecologia e Conservação de Recursos Naturais, Instituto de Biologia, Universidade Federal de Uberlândia, Uberlândia, MG, Brazil.
| | - Adilson Quero
- Pós-graduação em Ecologia e Conservação de Recursos Naturais, Instituto de Biologia, Universidade Federal de Uberlândia, Uberlândia, MG, Brazil
| | - Rafael Rios Moura
- Pós-graduação em Ecologia e Conservação de Recursos Naturais, Instituto de Biologia, Universidade Federal de Uberlândia, Uberlândia, MG, Brazil; Núcleo de Extensão e Pesquisa em Ecologia e Evolução (NEPEE), Departamento de Ciências Agrárias e Naturais, Universidade do Estado de Minas Gerais, Ituiutaba, MG, Brazil
| | - Camila Vieira
- Pós-graduação em Ecologia e Conservação de Recursos Naturais, Instituto de Biologia, Universidade Federal de Uberlândia, Uberlândia, MG, Brazil
| | - Felipe André Meira
- Pós-graduação em Ecologia e Conservação de Recursos Naturais, Instituto de Biologia, Universidade Federal de Uberlândia, Uberlândia, MG, Brazil
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15
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Opell BD, Elmore HM, Hendricks ML. Humidity mediated performance and material properties of orb weaving spider adhesive droplets. Acta Biomater 2021; 131:440-451. [PMID: 34144212 DOI: 10.1016/j.actbio.2021.06.017] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2021] [Revised: 06/05/2021] [Accepted: 06/08/2021] [Indexed: 12/01/2022]
Abstract
Capture thread glue droplets retain insects that strike an orb web and are key to the success of over 4,600 described spider species. Each droplet is a self-assembling adhesive system whose emergent biomechanical properties are centered on its viscoelastic, protein core. This bioadhesive is dependent on its surrounding hygroscopic aqueous layer for hydration and chemical conditioning. Consequently, a droplet's water content and adhesive performance track environmental humidity. We tested the hypothesis that natural selection has tuned a droplet's adhesive performance and material properties to a species' foraging humidity. At 55% relative humidity (RH) the adhesive properties of 12 species ranged from that of PEG-based hydrogels to that of silicone rubber, exhibiting a 1088-fold inter-specific difference in stiffness (0.02-21.76 MPa) and a 147-fold difference in toughness (0.14-20.51 MJ/m3). When tested over a 70% RH range, droplet extension lengths per protein core volume peaked at lower humidities in species from exposed, low humidity habitats, and at higher humidities in nocturnal species and those found in humid habitats. However, at the RH's where these species' maximum extension per protein volume indices were observed, the stiffness of most species' adhesive did not differ, documenting that selection has tuned elastic modulus by adjusting droplet hygroscopicity. This inverse relationship between droplet hygroscopicity and a species' foraging humidity ensures optimal adhesive stiffness. By characterizing the humidity responsiveness and properties of orb spider glue droplets, our study also profiles the range of its biomimetic potential. STATEMENT OF SIGNIFICANCE: Over 4,600 described species of orb weaving spider rely on tiny glue droplets in their webs to retain insect that the web intercepts. The aqueous layer that covers each droplet's core allows this adhesive to remain pliable and to stretch as an insect struggles to escape. The aqueous solution also attracts water from the air, causing the glue droplet's performance to change with humidity. By characterizing the droplet extensions and adhesive material properties of twelve species at relative humidities between of 20 and 90%, this study examined how this unique adhesive system responds to its environment and how it is tuned to the humidity of a species' habitat.
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Affiliation(s)
- Brent D Opell
- Department of Biological Sciences, Virginia Tech Blacksburg, VA 24061 United States.
| | - Hannah Mae Elmore
- Department of Biological Sciences, Virginia Tech Blacksburg, VA 24061 United States
| | - Mary L Hendricks
- Department of Biological Sciences, Virginia Tech Blacksburg, VA 24061 United States
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16
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Htut KZ, Alicea-Serrano AM, Singla S, Agnarsson I, Garb JE, Kuntner M, Gregorič M, Haney RA, Marhabaie M, Blackledge TA, Dhinojwala A. Correlation between protein secondary structure and mechanical performance for the ultra-tough dragline silk of Darwin's bark spider. J R Soc Interface 2021; 18:20210320. [PMID: 34129788 PMCID: PMC8205537 DOI: 10.1098/rsif.2021.0320] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2021] [Accepted: 05/24/2021] [Indexed: 11/12/2022] Open
Abstract
The spider major ampullate (MA) silk exhibits high tensile strength and extensibility and is typically a blend of MaSp1 and MaSp2 proteins with the latter comprising glycine-proline-glycine-glycine-X repeating motifs that promote extensibility and supercontraction. The MA silk from Darwin's bark spider (Caerostris darwini) is estimated to be two to three times tougher than the MA silk from other spider species. Previous research suggests that a unique MaSp4 protein incorporates proline into a novel glycine-proline-glycine-proline motif and may explain C. darwini MA silk's extraordinary toughness. However, no direct correlation has been made between the silk's molecular structure and its mechanical properties for C. darwini. Here, we correlate the relative protein secondary structure composition of MA silk from C. darwini and four other spider species with mechanical properties before and after supercontraction to understand the effect of the additional MaSp4 protein. Our results demonstrate that C. darwini MA silk possesses a unique protein composition with a lower ratio of helices (31%) and β-sheets (20%) than other species. Before supercontraction, toughness, modulus and tensile strength correlate with percentages of β-sheets, unordered or random coiled regions and β-turns. However, after supercontraction, only modulus and strain at break correlate with percentages of β-sheets and β-turns. Our study highlights that additional information including crystal size and crystal and chain orientation is necessary to build a complete structure-property correlation model.
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Affiliation(s)
- K Zin Htut
- School of Polymer Science and Polymer Engineering, The University of Akron, Akron, OH 44325, USA
| | - Angela M. Alicea-Serrano
- Department of Biology, Integrated Bioscience Program, The University of Akron, Akron, OH 44325, USA
| | - Saranshu Singla
- School of Polymer Science and Polymer Engineering, The University of Akron, Akron, OH 44325, USA
| | - Ingi Agnarsson
- Department of Biology, University of Vermont, Burlington, VT 05405, USA
| | - Jessica E. Garb
- Department of Biological Sciences, University of Massachusetts Lowell, Lowell, MA 01854, USA
| | - Matjaž Kuntner
- Jovan Hadži Institute of Biology ZRC SAZU, Novi trg 2, 1000 Ljubljana, Slovenia
- Department of Organisms and Ecosystems Research, National Institute of Biology, Večna pot 111, 1000 Ljubljana, Slovenia
| | - Matjaž Gregorič
- Jovan Hadži Institute of Biology ZRC SAZU, Novi trg 2, 1000 Ljubljana, Slovenia
| | - Robert A. Haney
- Department of Biology, Ball State University, Muncie, IN 47306, USA
| | - Mohammad Marhabaie
- The Steve and Cindy Rasmussen Institute for Genomic Medicine, Nationwide Children's Hospital, Columbus, OH 43215, USA
| | - Todd A. Blackledge
- Department of Biology, Integrated Bioscience Program, The University of Akron, Akron, OH 44325, USA
| | - Ali Dhinojwala
- School of Polymer Science and Polymer Engineering, The University of Akron, Akron, OH 44325, USA
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17
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Challita EJ, Alexander SLM, Han SI, Blackledge TA, Coddington JA, Jung S, Bhamla MS. Slingshot spiders build tensed, underdamped webs for ultrafast launches and speedy halts. J Comp Physiol A Neuroethol Sens Neural Behav Physiol 2021; 207:205-217. [PMID: 33723624 DOI: 10.1007/s00359-021-01475-5] [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: 11/30/2020] [Revised: 02/23/2021] [Accepted: 02/26/2021] [Indexed: 10/21/2022]
Abstract
We develop a mathematical model to capture the web dynamics of slingshot spiders (Araneae: Theridiosomatidae), which utilize a tension line to deform their orb webs into conical springs to hunt flying insects. Slingshot spiders are characterized by their ultrafast launch speeds and accelerations (exceeding 1300 [Formula: see text]), however a theoretical approach to characterize the underlying spatiotemporal web dynamics remains missing. To address this knowledge gap, we develop a 2D-coupled damped oscillator model of the web. Our model reveals three key insights into the dynamics of slingshot motion. First, the tension line plays a dual role: enabling the spider to load elastic energy into the web for a quick launch (in milliseconds) to displacements of 10-15 body lengths, but also enabling the spider to halt quickly, attenuating inertial oscillations. Second, the dominant energy dissipation mechanism is viscous drag by the silk lines - acting as a low Reynolds number parachute. Third, the web exhibits underdamped oscillatory dynamics through a finely-tuned balance between the radial line forces, the tension line force and viscous drag dissipation. Together, our work suggests that the conical geometry and tension-line enables the slingshot web to act as both an elastic spring and a shock absorber, for the multi-functional roles of risky predation and self-preservation.
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Affiliation(s)
- Elio J Challita
- Chemical and Biomolecular Engineering, Georgia Institute of Technology, Atlanta, GA, 30311, USA.,Mechanical Engineering, Georgia Institute of Technology, Atlanta, GA, 30311, USA
| | - Symone L M Alexander
- Chemical and Biomolecular Engineering, Georgia Institute of Technology, Atlanta, GA, 30311, USA
| | - Sarah I Han
- Department of Biology, Integrated Bioscience Program, The University of Akron, Akron, OH, 44325, USA
| | - Todd A Blackledge
- Department of Biology, Integrated Bioscience Program, The University of Akron, Akron, OH, 44325, USA
| | - Jonathan A Coddington
- Smithsonian Institution, National Museum of Natural History, 10th and Constitution, NW Washington, DC, 20560, USA
| | - Sunghwan Jung
- Department of Biological and Environmental Engineering, Cornell University, Ithaca, NY, 14853, USA
| | - M Saad Bhamla
- Chemical and Biomolecular Engineering, Georgia Institute of Technology, Atlanta, GA, 30311, USA.
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18
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Shenoy S, Ing K, Barber RP, Rooks EC, Edgerly JS. A Multiscale Characterization of Two Tropical Embiopteran Species: Nano- and Microscale Features of Silk, Silk-Spinning Behavior, and Environmental Correlates of their Distributions. ENVIRONMENTAL ENTOMOLOGY 2020; 49:1242-1251. [PMID: 32696060 DOI: 10.1093/ee/nvaa073] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/21/2020] [Indexed: 06/11/2023]
Abstract
Embioptera display the unique ability to spin silk with their front feet to create protective domiciles. Their body form is remarkably uniform throughout the order, perhaps because they all live within the tight confines of silken tubes. This study contributes to an understanding of the ecology of Embioptera, an order that is rarely studied in the field. We conducted a census to quantify the habitats of two species with overlapping distributions on the tropical island of Trinidad in a search for characteristics that might explain their distinct ecologies. One species, Antipaluria urichi (Saussure) (Embioptera: Clothodidae), lives in larger colonies with more expansive silk in habitats throughout the island, especially in the rainforest of the Northern Range Mountains. The other, Pararhagadochir trinitatis (Saussure) (Embioptera: Scelembiidae), was found only in lowland locations. We quantified silk-spinning behavior and productivity of the two species and found that A. urichi spins thicker silk sheets per individual and emphasizes spin-steps that function to create a domicile that is more expansive than that produced by P. trinitatis. Their silks also interact differently when exposed to water: the smaller-diameter silk fibers of P. trinitatis form more continuous films on the surface of the domicile after being wetted and dried than that seen in A. urichi silk. This tendency gives P. trinitatis silk a shiny appearance in the field compared to the more cloth-like silk of A. urichi. How these silks function in the field and if the differences are partially responsible for the distinct distributions of the two species remain to be determined.
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Affiliation(s)
- Samantha Shenoy
- Department of Biology, Santa Clara University, 500 El Camino Real, Santa Clara, CA
| | - Keilyn Ing
- Department of Biology, Santa Clara University, 500 El Camino Real, Santa Clara, CA
- Center for Nanostructures, Santa Clara University, 500 El Camino Real, Santa Clara, CA
| | - Richard P Barber
- Center for Nanostructures, Santa Clara University, 500 El Camino Real, Santa Clara, CA
- Department of Physics, Santa Clara University, 500 El Camino Real, Santa Clara, CA
| | - Edward C Rooks
- Department of Biology, Santa Clara University, 500 El Camino Real, Santa Clara, CA
| | - Janice S Edgerly
- Department of Biology, Santa Clara University, 500 El Camino Real, Santa Clara, CA
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19
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Fisher DN, Pruitt JN, Yeager J. Orb-weaving spiders show a correlated syndrome of morphology and web structure in the wild. Biol J Linn Soc Lond 2020. [DOI: 10.1093/biolinnean/blaa104] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Abstract
Extended phenotypes are traits that exist outside the physical body of organisms. Despite their role in the lives of the organisms that express them and other organisms influenced by extended phenotypes, the consistency and covariance with morphological and behavioural traits of extended phenotypes has rarely been evaluated. We repeatedly measured an extended phenotype involved in prey acquisition (web structure) of wild orb-weaving spiders (Micrathena vigorsii), which re-build their webs daily. We related web structure to behaviours and spider body length. Web diameter and web density were repeatable among individuals, reaction to a predation threat was very marginally so, and response to a prey stimulus and web evenness were not repeatable. Larger spiders spun wider webs, had webs with increased thread spacing, and the spider possibly tended to react more slowly to a predation threat. When a spider built a relatively larger web it was also a relatively less dense and less even web. The repeatability of web construction and relationship with spider body size we found may be common features of intra-population variation in web structure in spiders. By estimating the consistency and covariances of extended phenotypes we can begin to evaluate what maintains their variation and how they might evolve.
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Affiliation(s)
- David N Fisher
- Department of Psychology, Neuroscience & Behaviour, McMaster University, Hamilton, Ontario, Canada
- School of Biological Sciences, University of Aberdeen, King’s College, Aberdeen, UK
| | - Jonathan N Pruitt
- Department of Psychology, Neuroscience & Behaviour, McMaster University, Hamilton, Ontario, Canada
- Department of Ecology, Evolution & Marine Biology, University of California - Santa Barbara, Santa Barbara, CA, USA
| | - Justin Yeager
- Biodiversidad Medio Ambiente y Salud (BIOMAS), Dirección General de Investigación, Universidad de las Américas, Quito, Ecuador
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20
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Properties of orb weaving spider glycoprotein glue change during Argiope trifasciata web construction. Sci Rep 2019; 9:20279. [PMID: 31889090 PMCID: PMC6937294 DOI: 10.1038/s41598-019-56707-1] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2019] [Accepted: 12/10/2019] [Indexed: 12/24/2022] Open
Abstract
An orb web’s prey capture thread relies on its glue droplets to retain insects until a spider can subdue them. Each droplet’s viscoelastic glycoprotein adhesive core extends to dissipate the forces of prey struggle as it transfers force to stiffer, support line flagelliform fibers. In large orb webs, switchback capture thread turns are placed at the bottom of the web before a continuous capture spiral progresses from the web’s periphery to its interior. To determine if the properties of capture thread droplets change during web spinning, we characterized droplet and glycoprotein volumes and material properties from the bottom, top, middle, and inner regions of webs. Both droplet and glycoprotein volume decreased during web construction, but there was a progressive increase in the glycoprotein’s Young’s modulus and toughness. Increases in the percentage of droplet aqueous material indicated that these increases in material properties are not due to reduced glycoprotein viscosity resulting from lower droplet hygroscopicity. Instead, they may result from changes in aqueous layer compounds that condition the glycoprotein. A 6-fold difference in glycoprotein toughness and a 70-fold difference in Young’s modulus across a web documents the phenotypic plasticity of this natural adhesive and its potential to inspire new materials.
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21
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Rao D, Tapia-McClung H, Narendra A. Reeling in the prey: fishing behaviour in an orb web spider. J Exp Biol 2019; 222:jeb.213751. [PMID: 31727760 DOI: 10.1242/jeb.213751] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2019] [Accepted: 11/08/2019] [Indexed: 11/20/2022]
Abstract
When an insect is intercepted by a spider web, spiders quickly locate the prey and run towards it. Once they make contact with the prey, they immobilise it and retrieve it to the centre of the web or the retreat for consumption. However, in rare circumstances, the spider can also pull the prey towards itself either while running to the prey or from a stationary position, a behaviour termed as 'reeling'. Reeling is paradoxical as it can lead to web deformation or damage, thereby jeopardising future foraging success. Reeling may increase the retention time for heavier prey or information acquisition with respect to the prey's identity, especially when these prey can cause damage to either the web or the spider itself. We explored the function of reeling behaviour in a neotropical orb web spider Verrucosa arenata We show that spiders performed reeling behaviour irrespective whether they were approaching heavy or light prey, but they changed their trajectories of approach. Spiders approached heavier prey more slowly than light prey and they showed a significantly higher frequency of change in velocity. We discuss these findings in the context of prey capture strategies and prey recognition.
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Affiliation(s)
- Dinesh Rao
- Inbioteca, Universidad Veracruzana, 91090 Xalapa, Veracruz, México
| | - Horacio Tapia-McClung
- Centro de Investigación en Inteligencia Artificial, Universidad Veracruzana, 91000 Xalapa, Veracruz, Mexico
| | - Ajay Narendra
- Department of Biological Sciences, Macquarie University, Sydney, NSW 2109, Australia
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22
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Grannemann CCF, Meyer M, Reinhardt M, Ramírez MJ, Herberstein ME, Joel AC. Small behavioral adaptations enable more effective prey capture by producing 3D-structured spider threads. Sci Rep 2019; 9:17273. [PMID: 31754208 PMCID: PMC6872738 DOI: 10.1038/s41598-019-53764-4] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2019] [Accepted: 10/31/2019] [Indexed: 11/09/2022] Open
Abstract
Spiders are known for producing specialized fibers. The radial orb-web, for example, contains tough silk used for the web frame and the capture spiral consists of elastic silk, able to stretch when prey impacts the web. In concert, silk proteins and web geometry affects the spider's ability to capture prey. Both factors have received considerable research attention, but next to no attention has been paid to the influence of fiber processing on web performance. Cribellate spiders produce a complex fiber alignment as their capture threads. With a temporally controlled spinneret movement, they connect different fibers at specific points to each other. One of the most complex capture threads is produced by the southern house spider, Kukulcania hibernalis (Filistatidae). In contrast to the so far characterized linear threads of other cribellate spiders, K. hibernalis spins capture threads in a zigzag pattern due to a slightly altered spinneret movement. The resulting more complex fiber alignment increased the thread's overall ability to restrain prey, probably by increasing the adhesion area as well as its extensibility. Kukulcania hibernalis' cribellate silk perfectly illustrates the impact of small behavioral differences on the thread assembly and, thus, of silk functionality.
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Affiliation(s)
| | - Marco Meyer
- Institute of Biology II, RWTH Aachen University, Aachen, Germany
| | - Marian Reinhardt
- Museo Argentino de Ciencias Naturales "Bernardino Rivadavia"-CONICET, Buenos Aires, Argentina
| | - Martín J Ramírez
- Museo Argentino de Ciencias Naturales "Bernardino Rivadavia"-CONICET, Buenos Aires, Argentina
| | | | - Anna-Christin Joel
- Institute of Biology II, RWTH Aachen University, Aachen, Germany.
- Department of Biological Sciences, Macquarie University, Sydney, Australia.
- RWTH Aachen University, Institute of Biology II, Worringerweg 3, 52074, Aachen, Germany.
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23
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Opell BD, Burba CM, Deva PD, Kin MHY, Rivas MX, Elmore HM, Hendricks ML. Linking properties of an orb-weaving spider's capture thread glycoprotein adhesive and flagelliform fiber components to prey retention time. Ecol Evol 2019; 9:9841-9854. [PMID: 31534698 PMCID: PMC6745672 DOI: 10.1002/ece3.5525] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2018] [Revised: 07/05/2019] [Accepted: 07/16/2019] [Indexed: 11/07/2022] Open
Abstract
An orb web's adhesive capture spiral is responsible for prey retention. This thread is formed of regularly spaced glue droplets supported by two flagelliform axial lines. Each glue droplet features a glycoprotein adhesive core covered by a hygroscopic aqueous layer, which also covers axial lines between the droplets, making the entire thread responsive to environmental humidity.We characterized the effect of relative humidity (RH) on ability of Argiope aurantia and Argiope trifasciata thread arrays to retain houseflies and characterize the effect of humidity on their droplet properties. Using these data and those of Araneus marmoreus from a previous study, we then develop a regression model that correlated glycoprotein and flagelliform fiber properties with prey retention time. The model selection process included newly determined, humidity-specific Young's modulus and toughness values for the three species' glycoproteins.Argiope aurantia droplets are more hygroscopic than A. trifasciata droplets, causing the glycoprotein within A. aurantia droplets to become oversaturated at RH greater than 55% RH and their extension to decrease, whereas A. trifasciata droplet performance increases to 72% RH. This difference is reflected in species' prey retention times, with that of A. aurantia peaking at 55% RH and that of A. trifasciata at 72% RH.Fly retention time was explained by a regression model of five variables: glue droplet distribution, flagelliform fiber work of extension, glycoprotein volume, glycoprotein thickness, and glycoprotein Young's modulus.The material properties of both glycoprotein and flagelliform fibers appear to be phylogenetically constrained, whereas natural selection can more freely act on the amount of each material invested in a thread and on components of the thread's aqueous layer. Thus, it becomes easier to understand how natural selection can tune the performance of viscous capture threads by directing small changes in these components.
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Affiliation(s)
- Brent D. Opell
- Department of Biological SciencesVirginia TechBlacksburgVAUSA
| | | | - Pritesh D. Deva
- Department of Biological SciencesVirginia TechBlacksburgVAUSA
| | | | - Malik X. Rivas
- Department of Biological SciencesVirginia TechBlacksburgVAUSA
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24
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Orb weaver glycoprotein is a smart biological material, capable of repeated adhesion cycles. Naturwissenschaften 2019; 106:10. [DOI: 10.1007/s00114-019-1607-z] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2018] [Revised: 02/05/2019] [Accepted: 02/08/2019] [Indexed: 12/26/2022]
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25
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Diaz C, Tanikawa A, Miyashita T, Dhinojwala A, Blackledge TA. Silk structure rather than tensile mechanics explains web performance in the moth-specialized spider, Cyrtarachne. JOURNAL OF EXPERIMENTAL ZOOLOGY. PART A, ECOLOGICAL AND INTEGRATIVE PHYSIOLOGY 2018; 329:120-129. [PMID: 29992763 DOI: 10.1002/jez.2212] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/26/2018] [Revised: 06/11/2018] [Accepted: 06/20/2018] [Indexed: 11/08/2022]
Abstract
Orb webs intercept and retain prey so spiders may subdue them. Orb webs are composed of sticky, compliant spirals of capture silk spun across strong, stiff major ampullate silk threads. Interplay between differences in the mechanical properties of these silks is crucial for prey capture. Most orb webs depend upon insects contacting several radial and capture threads for successful retention. Moths, however, escape quickly from most orb webs due to the sacrificial scales covering their bodies. Cyrtarachne orb webs are unusual as they contain a reduced number of capture threads and moths stick unusually well to single threads. We aimed to determine how the tensile properties of the capture spiral and radial threads spun by Cyrtarachne operate in retention of moth prey. A NanoBionix UTM was used to quantify the material properties of flagelliform and major ampullate threads to test if Cyrtarachne's reduced web architecture is accompanied by improvements in tensile performance of its silk. Silk threads showed tensile properties typical of less-specialized orb-weavers, with the exception of high extensibility in radial threads. Radial thread diameters were 62.5% smaller than flagelliform threads, where commonly the two are roughly similar. We utilized our tensile data to create a finite element model of Cyrtarachne's web to investigate energy dissipation during prey impact. Large cross-sectional area of the flagelliform threads played a key role in enabling single capture threads to withstand prey impact. Rather than extraordinary silk, Cyrtarachne utilizes structural changes in the size and attachment of silk threads to facilitate web function.
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Affiliation(s)
- Candido Diaz
- Department of Biology, The University of Akron, Akron, Ohio
| | | | | | - Ali Dhinojwala
- Department of Polymer Science, The University of Akron, Akron, Ohio
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Opell BD, Clouse ME, Andrews SF. Elastic modulus and toughness of orb spider glycoprotein glue. PLoS One 2018; 13:e0196972. [PMID: 29847578 PMCID: PMC5976159 DOI: 10.1371/journal.pone.0196972] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2017] [Accepted: 04/24/2018] [Indexed: 11/19/2022] Open
Abstract
An orb web's prey capture thread features tiny glue droplets, each formed of an adhesive glycoprotein core surrounded by an aqueous layer. Small molecules in the aqueous layer confer droplet hygroscopicity and maintain glycoprotein viscoelasticity, causing droplet volume and glycoprotein performance to track changes in environmental humidity. Droplet extension combines with that of a thread's supporting flagelliform fibers to sum the adhesive forces of multiple droplets, creating an effective adhesive system. We combined measurements of the force on an extending droplet, as gauged by the deflection of its support line, with measurements of glycoprotein volume and droplet extension to determine the Young's modulus (E) and toughness of three species' glycoproteins. We did this at five relative humidities between 20-90% to assess the effect of humidity on these properties. When droplets of a thread span extend, their extensions are constrained and their glycoprotein filaments remain covered by aqueous material. This was also the case during the first extension phase of the individual droplets that we examined. However, as extension progressed, the aqueous layer was progresses disrupted, exposing the glycoprotein. During the first extension phase E ranged from 0.00003 GPa, a value similar to that of fibronectin, a glycoprotein that anchors cells in the extracellular matrix, to 0.00292 GPa, a value similar to that of resilin in insect ligaments. Second phase E increased 4.7-19.4-fold. When compared at the same humidity the E of each species' glycoprotein was less than 5% of the value reported for its flagelliform fibers. This difference may facilitate the coordinated extension of these two capture thread components that is responsible for summing the thread's adhesive forces.
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Affiliation(s)
- Brent D. Opell
- Department of Biological Sciences, Virginia Tech, Blacksburg, Virginia, United States of America
| | - Mary E. Clouse
- Department of Biological Sciences, Virginia Tech, Blacksburg, Virginia, United States of America
| | - Sheree F. Andrews
- Department of Biological Sciences, Virginia Tech, Blacksburg, Virginia, United States of America
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Lacava M, Camargo A, Garcia LF, Benamú MA, Santana M, Fang J, Wang X, Blamires SJ. Web building and silk properties functionally covary among species of wolf spider. J Evol Biol 2018; 31:968-978. [DOI: 10.1111/jeb.13278] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2017] [Revised: 02/18/2018] [Accepted: 04/04/2018] [Indexed: 01/09/2023]
Affiliation(s)
- Mariángeles Lacava
- Centro Universitario de Rivera Universidad de la República Rivera Uruguay
- Centro Universitario Regional del Este (CURE) Universidad de la República Treinta y Tres Uruguay
| | - Arley Camargo
- Centro Universitario de Rivera Universidad de la República Rivera Uruguay
| | - Luis F. Garcia
- Centro Universitario Regional del Este (CURE) Universidad de la República Treinta y Tres Uruguay
- Laboratorio Ecología del Comportamiento (IIBCE) Montevideo Uruguay
| | - Marco A. Benamú
- Centro Universitario de Rivera Universidad de la República Rivera Uruguay
- Laboratorio Ecología del Comportamiento (IIBCE) Montevideo Uruguay
| | - Martin Santana
- Laboratorio Ecología del Comportamiento (IIBCE) Montevideo Uruguay
| | - Jian Fang
- Institute for Frontier Materials (IFM) Deakin University Geelong Vic. Australia
| | - Xungai Wang
- Institute for Frontier Materials (IFM) Deakin University Geelong Vic. Australia
| | - Sean J. Blamires
- Evolution & Ecology Research Centre School of Biological, Earth & Environmental Sciences The University of New South Wales Sydney NSW Australia
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Piorkowski D, Blackledge TA, Liao C, Doran NE, Wu C, Blamires SJ, Tso I. Humidity‐dependent mechanical and adhesive properties of
Arachnocampa tasmaniensis
capture threads. J Zool (1987) 2018. [DOI: 10.1111/jzo.12562] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- D. Piorkowski
- Department of Life Science Tunghai University Taichung Taiwan
| | - T. A. Blackledge
- Department of Biology Integrated Bioscience Program The University of Akron Akron OH USA
| | - C.‐P. Liao
- Department of Life Science Tunghai University Taichung Taiwan
| | | | - C.‐L. Wu
- Center for Measurement Standards Industrial Technology Research Institute Hsinchu Taiwan
| | - S. J. Blamires
- Evolution and Ecology Research Centre University of New South Wales Sydney NSW Australia
| | - I.‐M. Tso
- Department of Life Science Tunghai University Taichung Taiwan
- Center for Tropical Ecology and Biodiversity Tunghai University Taichung Taiwan
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29
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Opell BD, Jain D, Dhinojwala A, Blackledge TA. Tuning orb spider glycoprotein glue performance to habitat humidity. J Exp Biol 2018; 221:221/6/jeb161539. [DOI: 10.1242/jeb.161539] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
ABSTRACT
Orb-weaving spiders use adhesive threads to delay the escape of insects from their webs until the spiders can locate and subdue the insects. These viscous threads are spun as paired flagelliform axial fibers coated by a cylinder of solution derived from the aggregate glands. As low molecular mass compounds (LMMCs) in the aggregate solution attract atmospheric moisture, the enlarging cylinder becomes unstable and divides into droplets. Within each droplet an adhesive glycoprotein core condenses. The plasticity and axial line extensibility of the glycoproteins are maintained by hygroscopic LMMCs. These compounds cause droplet volume to track changes in humidity and glycoprotein viscosity to vary approximately 1000-fold over the course of a day. Natural selection has tuned the performance of glycoprotein cores to the humidity of a species' foraging environment by altering the composition of its LMMCs. Thus, species from low-humidity habits have more hygroscopic threads than those from humid forests. However, at their respective foraging humidities, these species' glycoproteins have remarkably similar viscosities, ensuring optimal droplet adhesion by balancing glycoprotein adhesion and cohesion. Optimal viscosity is also essential for integrating the adhesion force of multiple droplets. As force is transferred to a thread's support line, extending droplets draw it into a parabolic configuration, implementing a suspension bridge mechanism that sums the adhesive force generated over the thread span. Thus, viscous capture threads extend an orb spider's phenotype as a highly integrated complex of large proteins and small molecules that function as a self-assembling, highly tuned, environmentally responsive, adhesive biomaterial. Understanding the synergistic role of chemistry and design in spider adhesives, particularly the ability to stick in wet conditions, provides insight in designing synthetic adhesives for biomedical applications.
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Affiliation(s)
- Brent D. Opell
- Department of Biological Sciences, Virginia Tech, Blacksburg, VA 24061, USA
| | - Dharamdeep Jain
- Department of Polymer Science, Integrated Bioscience Program, The University of Akron, Akron, OH 44325, USA
| | - Ali Dhinojwala
- Department of Polymer Science, Integrated Bioscience Program, The University of Akron, Akron, OH 44325, USA
| | - Todd A. Blackledge
- Department of Biology, Integrated Bioscience Program, The University of Akron, Akron, OH 44325, USA
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Kerr GG, Nahrung HF, Wiegand A, Kristoffersen J, Killen P, Brown C, Macdonald J. Mechanical properties of silk of the Australian golden orb weavers Nephila pilipes and Nephilaplumipes. Biol Open 2018; 7:bio.029249. [PMID: 29437044 PMCID: PMC5861357 DOI: 10.1242/bio.029249] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Silks from orb-weaving spiders are exceptionally tough, producing a model polymer for biomimetic fibre development. The mechanical properties of naturally spun silk threads from two species of Australian orb-weavers, Nephila pilipes and Nephilaplumipes, were examined here in relation to overall thread diameter, the size and number of fibres within threads, and spider size. N. pilipes, the larger of the two species, had significantly tougher silk with higher strain capacity than its smaller congener, producing threads with average toughness of 150 MJ m−3, despite thread diameter, mean fibre diameter and number of fibres per thread not differing significantly between the two species. Within N. pilipes, smaller silk fibres were produced by larger spiders, yielding tougher threads. In contrast, while spider size was correlated with thread diameter in N. plumipes, there were no clear patterns relating to silk toughness, which suggests that the differences in properties between the silk of the two species arise through differing molecular structure. Our results support previous studies that found that the mechanical properties of silk differ between distantly related spider species, and extends on that work to show that the mechanical and physical properties of silk from more closely related species can also differ remarkably. Summary: Spider silk is a remarkably tough and extensible biomaterial. We identified macrostuctural and mechanical differences in outer web frame silk of two Australian orb-weaving spiders.
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Affiliation(s)
- Genevieve G Kerr
- Genecology Research Centre and School of Science, Engineering and Education, University of the Sunshine Coast, Sippy Downs, Queensland 4556, Australia
| | - Helen F Nahrung
- Genecology Research Centre and School of Science, Engineering and Education, University of the Sunshine Coast, Sippy Downs, Queensland 4556, Australia
| | - Aaron Wiegand
- Genecology Research Centre and School of Science, Engineering and Education, University of the Sunshine Coast, Sippy Downs, Queensland 4556, Australia
| | - Joanna Kristoffersen
- Genecology Research Centre and School of Science, Engineering and Education, University of the Sunshine Coast, Sippy Downs, Queensland 4556, Australia
| | - Peter Killen
- Genecology Research Centre and School of Science, Engineering and Education, University of the Sunshine Coast, Sippy Downs, Queensland 4556, Australia
| | - Cameron Brown
- Botnar Research Centre, Nuffield Department of Orthopaedics, Rheumatology and Musculoskeletal Sciences, University of Oxford, Oxford, OX3 7LD, UK.,Institute of Health and Biomedical Innovation and School of Chemistry, Physics and Mechanical Engineering, Queensland University of Technology, Brisbane, Queensland 4000, Australia
| | - Joanne Macdonald
- Genecology Research Centre and School of Science, Engineering and Education, University of the Sunshine Coast, Sippy Downs, Queensland 4556, Australia .,Division of Experimental Therapeutics, Columbia University, New York, NY 10032, USA
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Piorkowski D, Blamires SJ, Doran NE, Liao CP, Wu CL, Tso IM. Ontogenetic shift toward stronger, tougher silk of a web-building, cave-dwelling spider. J Zool (1987) 2017. [DOI: 10.1111/jzo.12507] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Affiliation(s)
- D. Piorkowski
- Department of Life Science; Tunghai University; Taichung Taiwan
| | - S. J. Blamires
- Evolution and Ecology Research Centre; University of New South Wales; Sydney NSW Australia
| | - N. E. Doran
- Bookend Trust and the School of Biological Sciences; University of Tasmania; Sandy Bay Tasmania Australia
| | - C.-P. Liao
- Department of Life Science; Tunghai University; Taichung Taiwan
| | - C.-L. Wu
- Center for Measurement Standards; Industrial Technology Research Institute; Hsinchu Taiwan
| | - I.-M. Tso
- Department of Life Science; Tunghai University; Taichung Taiwan
- Center for Tropical Ecology and Biodiversity; Tunghai University; Taichung Taiwan
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Dahirel M, Dierick J, De Cock M, Bonte D. Intraspecific variation shapes community-level behavioral responses to urbanization in spiders. Ecology 2017; 98:2379-2390. [PMID: 28585743 DOI: 10.1002/ecy.1915] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/22/2017] [Revised: 05/09/2017] [Accepted: 05/24/2017] [Indexed: 01/08/2023]
Abstract
Urban areas are an extreme example of human-changed environments, exposing organisms to multiple and strong selection pressures. Adaptive behavioral responses are thought to play a major role in animals' success or failure in such new environments. Approaches based on functional traits have proven especially valuable to understand how species communities respond to environmental gradients. Until recently, they have, however, often ignored the potential consequences of intraspecific trait variation (ITV). When ITV is prevalent, it may highly impact ecological processes and resilience against stressors. This may be especially relevant in animals, in which behavioral traits can be altered very flexibly at the individual level to track environmental changes. We investigated how species turnover and ITV influenced community-level behavioral responses in a set of 62 sites of varying levels of urbanization, using orb web spiders and their webs as models of foraging behavior. ITV alone explained around one-third of the total trait variation observed among communities. Spider web structure changed according to urbanization, in ways that increase the capture efficiency of webs in a context of smaller urban prey. These trait shifts were partly mediated by species turnover, but ITV increased their magnitude, potentially helping to buffer the effects of environmental changes on communities. The importance of ITV varied depending on traits and on the spatial scale at which urbanization was considered. Despite being neglected from community-level analyses in animals, our results highlight the importance of accounting for intraspecific trait variation to fully understand trait responses to (human-induced) environmental changes and their impact on ecosystem functioning.
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Affiliation(s)
- Maxime Dahirel
- Terrestrial Ecology Unit, Department of Biology, Ghent University, Ghent, Belgium.,UMR 6553 Ecobio, Université de Rennes 1/CNRS, Rennes, France
| | - Jasper Dierick
- Terrestrial Ecology Unit, Department of Biology, Ghent University, Ghent, Belgium
| | - Maarten De Cock
- Terrestrial Ecology Unit, Department of Biology, Ghent University, Ghent, Belgium
| | - Dries Bonte
- Terrestrial Ecology Unit, Department of Biology, Ghent University, Ghent, Belgium
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33
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Piorkowski D, Blackledge TA. Punctuated evolution of viscid silk in spider orb webs supported by mechanical behavior of wet cribellate silk. Naturwissenschaften 2017; 104:67. [DOI: 10.1007/s00114-017-1489-x] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2017] [Revised: 07/01/2017] [Accepted: 07/04/2017] [Indexed: 01/09/2023]
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Blamires SJ, Blackledge TA, Tso IM. Physicochemical Property Variation in Spider Silk: Ecology, Evolution, and Synthetic Production. ANNUAL REVIEW OF ENTOMOLOGY 2017; 62:443-460. [PMID: 27959639 DOI: 10.1146/annurev-ento-031616-035615] [Citation(s) in RCA: 65] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
The unique combination of great stiffness, strength, and extensibility makes spider major ampullate (MA) silk desirable for various biomimetic and synthetic applications. Intensive research on the genetics, biochemistry, and biomechanics of this material has facilitated a thorough understanding of its properties at various levels. Nevertheless, methods such as cloning, recombination, and electrospinning have not successfully produced materials with properties as impressive as those of spider silk. It is nevertheless becoming clear that silk properties are a consequence of whole-organism interactions with the environment in addition to genetic expression, gland biochemistry, and spinning processes. Here we assimilate the research done and assess the techniques used to determine distinct forms of spider silk chemical and physical property variability. We suggest that more research should focus on testing hypotheses that explain spider silk property variations in ecological and evolutionary contexts.
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Affiliation(s)
- Sean J Blamires
- Department of Life Science, Tunghai University, Taichung 40704, Taiwan;
- Evolution & Ecology Research Centre, School of Biological, Earth & Environmental Sciences, The University of New South Wales, Sydney 2052, Australia;
| | - Todd A Blackledge
- Department of Biology, Integrated Bioscience Program, The University of Akron, Akron, Ohio 44325;
| | - I-Min Tso
- Department of Life Science, Tunghai University, Taichung 40704, Taiwan;
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35
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Zheng L, Behrooz M, Gordaninejad F. A bioinspired adaptive spider web. BIOINSPIRATION & BIOMIMETICS 2017; 12:016012. [PMID: 28094244 DOI: 10.1088/1748-3190/12/1/016012] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
This work presents an adaptive structure inspired by spider webs' behavior. To investigate the dynamic properties and performance of this system, numerical models are developed to examine the effects of pretension in radial strings, and Young's modulus, and damping ratio on the natural frequency and total energy of the system. An experimental study was conducted to validate theoretical results. Stepper motors controlled by a microcontroller are utilized to increase the pretension in the radial strings of the web in order to tune the web's energy absorption ability. It is demonstrated that the pretension, Young's modulus, and damping ratio in the radial strings can significantly affect the natural frequency and total energy of full and damaged webs. It is also shown that increasing the pretension in the radial strings compensates for the loss of stiffness due to the damaged strings. Finally, it is shown that controlling the pretension in radial strings can provide higher energy absorption capability for the spider web.
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Affiliation(s)
- L Zheng
- Department of Mechanical Engineering, Composite and Intelligent Materials Laboratory, University of Nevada, Reno, NV 89557, USA
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36
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Roberts L, Pérez-Domínguez R, Elliott M. Use of baited remote underwater video (BRUV) and motion analysis for studying the impacts of underwater noise upon free ranging fish and implications for marine energy management. MARINE POLLUTION BULLETIN 2016; 112:75-85. [PMID: 27622927 DOI: 10.1016/j.marpolbul.2016.08.039] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/23/2016] [Revised: 08/15/2016] [Accepted: 08/18/2016] [Indexed: 06/06/2023]
Abstract
Free-ranging individual fish were observed using a baited remote underwater video (BRUV) system during sound playback experiments. This paper reports on test trials exploring BRUV design parameters, image analysis and practical experimental designs. Three marine species were exposed to playback noise, provided as examples of behavioural responses to impulsive sound at 163-171dB re 1μPa (peak-to-peak SPL) and continuous sound of 142.7dB re 1μPa (RMS, SPL), exhibiting directional changes and accelerations. The methods described here indicate the efficacy of BRUV to examine behaviour of free-ranging species to noise playback, rather than using confinement. Given the increasing concern about the effects of water-borne noise, for example its inclusion within the EU Marine Strategy Framework Directive, and the lack of empirical evidence in setting thresholds, this paper discusses the use of BRUV, and short term behavioural changes, in supporting population level marine noise management.
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Affiliation(s)
- Louise Roberts
- Institute of Estuarine and Coastal Studies (IECS), University of Hull, Hull HU6 7RX, United Kingdom.
| | - Rafael Pérez-Domínguez
- Institute of Estuarine and Coastal Studies (IECS), University of Hull, Hull HU6 7RX, United Kingdom
| | - Michael Elliott
- Institute of Estuarine and Coastal Studies (IECS), University of Hull, Hull HU6 7RX, United Kingdom
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37
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Dionne J, Lefèvre T, Auger M. Major Ampullate Spider Silk with Indistinguishable Spidroin Dope Conformations Leads to Different Fiber Molecular Structures. Int J Mol Sci 2016; 17:E1353. [PMID: 27548146 PMCID: PMC5000749 DOI: 10.3390/ijms17081353] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2016] [Revised: 08/11/2016] [Accepted: 08/15/2016] [Indexed: 11/17/2022] Open
Abstract
To plentifully benefit from its properties (mechanical, optical, biological) and its potential to manufacture green materials, the structure of spider silk has to be known accurately. To this aim, the major ampullate (MA) silk of Araneus diadematus (AD) and Nephila clavipes (NC) has been compared quantitatively in the liquid and fiber states using Raman spectromicroscopy. The data show that the spidroin conformations of the two dopes are indistinguishable despite their specific amino acid composition. This result suggests that GlyGlyX and GlyProGlyXX amino acid motifs (X = Leu, Glu, Tyr, Ser, etc.) are conformationally equivalent due to the chain flexibility in the aqueous environment. Species-related sequence specificity is expressed more extensively in the fiber: the β-sheet content is lower and width of the orientation distribution of the carbonyl groups is broader for AD (29% and 58°, respectively) as compared to NC (37% and 51°, respectively). β-Sheet content values are close to the proportion of polyalanine segments, suggesting that β-sheet formation is mainly dictated by the spidroin sequence. The extent of molecular alignment seems to be related to the presence of proline (Pro) that may decrease conformational flexibility and inhibit chain extension and alignment upon drawing. It appears that besides the presence of Pro, secondary structure and molecular orientation contribute to the different mechanical properties of MA threads.
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Affiliation(s)
- Justine Dionne
- Regroupement québécois de Recherche sur la Fonction, l'Ingénierie et les Applications des Protéines (PROTEO), Centre de Recherche sur les Matériaux Avancés (CERMA), Centre Québécois sur les Matériaux Fonctionnels (CQMF), Département de Chimie, Université Laval, Pavillon Alexandre-Vachon, Ville de Québec, QC G1V 0A6, Canada.
| | - Thierry Lefèvre
- Regroupement québécois de Recherche sur la Fonction, l'Ingénierie et les Applications des Protéines (PROTEO), Centre de Recherche sur les Matériaux Avancés (CERMA), Centre Québécois sur les Matériaux Fonctionnels (CQMF), Département de Chimie, Université Laval, Pavillon Alexandre-Vachon, Ville de Québec, QC G1V 0A6, Canada.
| | - Michèle Auger
- Regroupement québécois de Recherche sur la Fonction, l'Ingénierie et les Applications des Protéines (PROTEO), Centre de Recherche sur les Matériaux Avancés (CERMA), Centre Québécois sur les Matériaux Fonctionnels (CQMF), Département de Chimie, Université Laval, Pavillon Alexandre-Vachon, Ville de Québec, QC G1V 0A6, Canada.
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Stellwagen SD, Opell BD, Clouse ME. The impact of UVB radiation on the glycoprotein glue of orb-weaving spider capture thread. ACTA ACUST UNITED AC 2016; 218:2675-84. [PMID: 26333924 DOI: 10.1242/jeb.123067] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Many spider orb-webs are exposed to sunlight and the potentially damaging effects of ultraviolet B (UVB) radiation. We examined the effect of UVB on the viscoelastic glycoprotein core of glue droplets deposited on the prey capture threads of these webs, hypothesizing that webs built by species that occupy sunny habitats are less susceptible to UVB damage than are webs built by species that prefer shaded forest habitats or by nocturnal species. Threads were tested shortly after being collected in the early morning and after being exposed to UVB energy equivalent to a day of summer sun and three times this amount. Droplets kept in a dark chamber allowed us to evaluate post-production changes. Droplet volume was unaffected by treatments, indicating that UVB did not damage the hygroscopic compounds in the aqueous layer that covers droplets. UVB exposure did not affect energies of droplet extension for species from exposed and partially to mostly shaded habitats (Argiope aurantia, Leucauge venusta and Verrucosa arenata). However, UVB exposure reduced the energy of droplet extension in Micrathena gracilis from shaded forests and Neoscona crucifera, which forages at night. Only in L. venusta did the energy of droplet extension increase after the dark treatment, suggesting endogenous molecular alignment. This study adds UVB irradiation to the list of factors (humidity, temperature and strain rate) known to affect the performance of spider glycoprotein glue, factors that must be more fully understood if adhesives that mimic spider glycoprotein glue are to be produced.
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Affiliation(s)
- Sarah D Stellwagen
- Department of Biological Sciences, Virginia Tech, Blacksburg, VA 24061, USA
| | - Brent D Opell
- Department of Biological Sciences, Virginia Tech, Blacksburg, VA 24061, USA
| | - Mary E Clouse
- Department of Biological Sciences, Virginia Tech, Blacksburg, VA 24061, USA
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The effect of ageing on the mechanical properties of the silk of the bridge spider Larinioides cornutus (Clerck, 1757). Sci Rep 2016; 6:24699. [PMID: 27156712 PMCID: PMC4860589 DOI: 10.1038/srep24699] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2015] [Accepted: 03/23/2016] [Indexed: 12/04/2022] Open
Abstract
Spider silk is regarded as one of the best natural polymer fibers especially in terms of low density, high tensile strength and high elongation until breaking. Since only a few bio-engineering studies have been focused on spider silk ageing, we conducted nano-tensile tests on the vertical naturally spun silk fibers of the bridge spider Larinioides cornutus (Clerck, 1757) (Arachnida, Araneae) to evaluate changes in the mechanical properties of the silk (ultimate stress and strain, Young’s modulus, toughness) over time. We studied the natural process of silk ageing at different time intervals from spinning (20 seconds up to one month), comparing silk fibers spun from adult spiders collected in the field. Data were analyzed using Linear Mixed Models. We detected a positive trend versus time for the Young’s modulus, indicating that aged silks are stiffer and possibly less effective in catching prey. Moreover, we observed a negative trend for the ultimate strain versus time, attesting a general decrement of the resistance force. These trends are interpreted as being due to the drying of the silk protein chains and the reorientation among the fibers.
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40
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Tietsch V, Alencastre J, Witte H, Torres F. Exploring the shock response of spider webs. J Mech Behav Biomed Mater 2016; 56:1-5. [DOI: 10.1016/j.jmbbm.2015.11.007] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2015] [Revised: 11/02/2015] [Accepted: 11/09/2015] [Indexed: 10/22/2022]
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41
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McMillan D, Hohu K, Edgerly JS. Choreography of silk spinning by webspinners (Insecta: Embioptera) reflects lifestyle and hints at phylogeny. Biol J Linn Soc Lond 2016. [DOI: 10.1111/bij.12749] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- David McMillan
- Department of Biology; Santa Clara University; Santa Clara CA USA
| | - Kyle Hohu
- Department of Biology; Santa Clara University; Santa Clara CA USA
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42
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Large orb-webs adapted to maximise total biomass not rare, large prey. Sci Rep 2015; 5:14121. [PMID: 26374379 PMCID: PMC4570981 DOI: 10.1038/srep14121] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2015] [Accepted: 08/18/2015] [Indexed: 11/24/2022] Open
Abstract
Spider orb-webs are the ultimate anti-ballistic devices, capable of dissipating the relatively massive kinetic energy of flying prey. Increased web size and prey stopping capacity have co-evolved in a number orb-web taxa, but the selective forces driving web size and performance increases are under debate. The rare, large prey hypothesis maintains that the energetic benefits of rare, very large prey are so much greater than the gains from smaller, more common prey that smaller prey are irrelevant for reproduction. Here, we integrate biophysical and ecological data and models to test a major prediction of the rare, large prey hypothesis, that selection should favour webs with increased stopping capacity and that large prey should comprise a significant proportion of prey stopped by a web. We find that larger webs indeed have a greater capacity to stop large prey. However, based on prey ecology, we also find that these large prey make up a tiny fraction of the total biomass (=energy) potentially captured. We conclude that large webs are adapted to stop more total biomass, and that the capacity to stop rare, but very large, prey is an incidental consequence of the longer radial silks that scale with web size.
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43
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Gregorič M, Agnarsson I, Blackledge TA, Kuntner M. Phylogenetic position and composition of Zygiellinae andCaerostris, with new insight into orb-web evolution and gigantism. Zool J Linn Soc 2015. [DOI: 10.1111/zoj.12281] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Affiliation(s)
- Matjaž Gregorič
- Institute of Biology; Scientific Research Centre; Slovenian Academy of Sciences and Arts; Novi trg 2 P. O. Box 306 SI-1001 Ljubljana Slovenia
- Integrated Bioscience Program; Department of Biology; University of Akron; Akron OH 44325-3908 USA
| | - Ingi Agnarsson
- Department of Biology; University of Vermont; Burlington VT USA
- Department of Entomology; National Museum of Natural History; Smithsonian Institution; Washington, DC USA
| | - Todd A. Blackledge
- Integrated Bioscience Program; Department of Biology; University of Akron; Akron OH 44325-3908 USA
| | - Matjaž Kuntner
- Institute of Biology; Scientific Research Centre; Slovenian Academy of Sciences and Arts; Novi trg 2 P. O. Box 306 SI-1001 Ljubljana Slovenia
- Department of Entomology; National Museum of Natural History; Smithsonian Institution; Washington, DC USA
- Centre for Behavioural Ecology and Evolution; College of Life Sciences; Hubei University; Wuhan Hubei China
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44
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Structural optimization of 3D-printed synthetic spider webs for high strength. Nat Commun 2015; 6:7038. [PMID: 25975372 PMCID: PMC4479035 DOI: 10.1038/ncomms8038] [Citation(s) in RCA: 81] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2014] [Accepted: 03/25/2015] [Indexed: 11/08/2022] Open
Abstract
Spiders spin intricate webs that serve as sophisticated prey-trapping architectures that simultaneously exhibit high strength, elasticity and graceful failure. To determine how web mechanics are controlled by their topological design and material distribution, here we create spider-web mimics composed of elastomeric filaments. Specifically, computational modelling and microscale 3D printing are combined to investigate the mechanical response of elastomeric webs under multiple loading conditions. We find the existence of an asymptotic prey size that leads to a saturated web strength. We identify pathways to design elastomeric material structures with maximum strength, low density and adaptability. We show that the loading type dictates the optimal material distribution, that is, a homogeneous distribution is better for localized loading, while stronger radial threads with weaker spiral threads is better for distributed loading. Our observations reveal that the material distribution within spider webs is dictated by the loading condition, shedding light on their observed architectural variations. Spider webs have some intriguing mechanical properties, but understanding of the properties is limited to individual silk fibres. Here, the authors create mimics of spider web using 3D techniques, which enables them to acquire knowledge of mechanical strength of the entire synthetic web.
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45
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Meyer A, Pugno NM, Cranford SW. Compliant threads maximize spider silk connection strength and toughness. J R Soc Interface 2015; 11:20140561. [PMID: 25008083 DOI: 10.1098/rsif.2014.0561] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
Millions of years of evolution have adapted spider webs to achieve a range of functionalities, including the well-known capture of prey, with efficient use of material. One feature that has escaped extensive investigation is the silk-on-silk connection joints within spider webs, particularly from a structural mechanics perspective. We report a joint theoretical and computational analysis of an idealized silk-on-silk fibre junction. By modifying the theory of multiple peeling, we quantitatively compare the performance of the system while systematically increasing the rigidity of the anchor thread, by both scaling the stress-strain response and the introduction of an applied pre-strain. The results of our study indicate that compliance is a virtue-the more extensible the anchorage, the tougher and stronger the connection becomes. In consideration of the theoretical model, in comparison with rigid substrates, a compliant anchorage enormously increases the effective adhesion strength (work required to detach), independent of the adhered thread itself, attributed to a nonlinear alignment between thread and anchor (contact peeling angle). The results can direct novel engineering design principles to achieve possible load transfer from compliant fibre-to-fibre anchorages, be they silk-on-silk or another, as-yet undeveloped, system.
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Affiliation(s)
- Avery Meyer
- Laboratory for Nanotechnology in Civil Engineering (NICE), Department of Civil and Environmental Engineering, Northeastern University, 400 Snell Engineering, 360 Huntington Avenue, Boston, MA 02115, USA
| | - Nicola M Pugno
- Laboratory of Bio-Inspired and Graphene Nanomechanics, Department of Civil, Environmental and Mechanical Engineering, Università di Trento, via Mesiano 77, 38123 Trento, Italy Center for Materials and Microsystems, Fondazione Bruno Kessler, Via Sommarive 18, 38123 Povo (Trento), Italy
| | - Steven W Cranford
- Laboratory for Nanotechnology in Civil Engineering (NICE), Department of Civil and Environmental Engineering, Northeastern University, 400 Snell Engineering, 360 Huntington Avenue, Boston, MA 02115, USA
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46
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Gregorič M, Kuntner M, Blackledge TA. Does body size predict foraging effort? Patterns of material investment in spider orb webs. J Zool (1987) 2015. [DOI: 10.1111/jzo.12219] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Affiliation(s)
- M. Gregorič
- Institute of Biology Scientific Research Centre Slovenian Academy of Sciences and Arts Ljubljana Slovenia
- Department of Biology and Integrated Bioscience Program University of Akron Akron OH USA
| | - M. Kuntner
- Institute of Biology Scientific Research Centre Slovenian Academy of Sciences and Arts Ljubljana Slovenia
- Department of Entomology National Museum of Natural History Smithsonian Institution Washington DC USA
- College of Life Sciences Hubei University Wuhan Hubei China
| | - T. A. Blackledge
- Department of Biology and Integrated Bioscience Program University of Akron Akron OH USA
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47
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Correa-Garhwal SM, Garb JE. Diverse Formulas for Spider Dragline Fibers Demonstrated by Molecular and Mechanical Characterization of Spitting Spider Silk. Biomacromolecules 2014; 15:4598-605. [DOI: 10.1021/bm501409n] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Affiliation(s)
- Sandra M. Correa-Garhwal
- Department of Biological
Sciences, University of Massachusetts—Lowell, Lowell, Massachusetts 01854, United States
| | - Jessica E. Garb
- Department of Biological
Sciences, University of Massachusetts—Lowell, Lowell, Massachusetts 01854, United States
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48
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Pan WJ, Fang HY, Zhang P, Pan HC. The complete mitochondrial genome of striped lynx spider Oxyopes sertatus (Araneae: Oxyopidae). Mitochondrial DNA A DNA Mapp Seq Anal 2014; 27:1616-7. [PMID: 25208169 DOI: 10.3109/19401736.2014.958695] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
The complete mitochondrial genome of Oxyopes sertatus is a circular molecule of 14,442 bp in length, containing 13 protein-coding genes, 2 ribosomal RNAs, 22 transfer RNAs, and a control region. The A + T content of the overall base composition of H-strand is 75.9% (T: 42.9%; C: 8.2%; A: 33.0%; G: 15.9%). COII, COIII and ND4 genes begin with TTG as start codon; ATP6, COI, ND1 and ND5 genes begin with ATA as start codon, ATP8, Cyt b, ND2 and ND3 genes begin with ATT as start codon, ND6 gene begins with GTG as start codon, while ND4L gene start with a typical ATG initiation codon. ND2 gene is terminated with TAG as stop codon, Cyt b and ND5 end with TA, COI, ND1 and ND4L end with T, ATP6, ATP8, COII, COIII, ND3, ND4 and ND6 end with TAA.
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Affiliation(s)
- Wen-Jian Pan
- a Laboratory of Molecular Evolution and Biodiversity , College of Life Sciences, Anhui Normal University , Wuhu , P. R. China
| | - Hong-Yan Fang
- a Laboratory of Molecular Evolution and Biodiversity , College of Life Sciences, Anhui Normal University , Wuhu , P. R. China
| | - Peng Zhang
- a Laboratory of Molecular Evolution and Biodiversity , College of Life Sciences, Anhui Normal University , Wuhu , P. R. China
| | - Hong-Chun Pan
- a Laboratory of Molecular Evolution and Biodiversity , College of Life Sciences, Anhui Normal University , Wuhu , P. R. China
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49
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Zaera R, Soler A, Teus J. Uncovering changes in spider orb-web topology owing to aerodynamic effects. J R Soc Interface 2014; 11:20140484. [PMID: 24966235 DOI: 10.1098/rsif.2014.0484] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
An orb-weaving spider's likelihood of survival is influenced by its ability to retain prey with minimum damage to its web and at the lowest manufacturing cost. This set of requirements has forced the spider silk to evolve towards extreme strength and ductility to a degree that is rare among materials. Previous studies reveal that the performance of the web upon impact may not be based on the mechanical properties of silk alone, aerodynamic drag could play a role in the dissipation of the prey's energy. Here, we present a thorough analysis of the effect of the aerodynamic drag on wind load and prey impact. The hypothesis considered by previous authors for the evaluation of the drag force per unit length of thread has been revisited according to well-established principles of fluid mechanics, highlighting the functional dependence on thread diameter that was formerly ignored. Theoretical analysis and finite-element simulations permitted us to identify air drag as a relevant factor in reducing deterioration of the orb web, and to reveal how the spider can take greater-and not negligible-advantage of drag dissipation. The study shows the beneficial air drag effects of building smaller and less dense webs under wind load, and larger and denser webs under prey impact loads. In essence, it points out why the aerodynamics need to be considered as an additional driving force in the evolution of silk threads and orb webs.
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Affiliation(s)
- Ramón Zaera
- Department of Continuum Mechanics and Structural Analysis, University Carlos III of Madrid, 28911 Leganés, Madrid, Spain
| | - Alejandro Soler
- Department of Continuum Mechanics and Structural Analysis, University Carlos III of Madrid, 28911 Leganés, Madrid, Spain
| | - Jaime Teus
- Department of Continuum Mechanics and Structural Analysis, University Carlos III of Madrid, 28911 Leganés, Madrid, Spain
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50
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Stellwagen SD, Opell BD, Short KG. Temperature mediates the effect of humidity on the viscoelasticity of glycoprotein glue within the droplets of an orb-weaving spider's prey capture threads. ACTA ACUST UNITED AC 2014; 217:1563-9. [PMID: 24501134 DOI: 10.1242/jeb.097816] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Sticky viscous prey capture threads retain insects that strike araneoid orb-webs. The threads' two axial fibers support a series of glue droplets, each featuring a core of adhesive viscoelastic glycoprotein covered by an aqueous solution. After sticking, the glue extends, summing the adhesion of multiple droplets, and dissipates some of the energy of a struggling prey. As a day progresses, threads experience a drop in humidity and an increase in temperature, environmental variables that have the potential to alter thread and web function. We hypothesize that thread droplets respond to these opposing environmental changes in a manner that stabilizes their performance, and test this by examining threads spun by Argiope aurantia, a species that occupies exposed, weedy habitats. We confirmed that decreased humidity increases glycoprotein viscosity and found that increased temperature had the opposite effect. To evaluate the combined effect of temperature and humidity on a droplet's ability to transfer adhesive force and dissipate energy, we extended a droplet and measured both the deflection of the axial line supporting the droplet and the duration of its tensive load. The cumulative product of these two indices, which reflects the energy required to extend a droplet, was greatest under afternoon (hot and dry) conditions, less under morning (cool and humid) conditions, and least under hot and humid afternoon conditions. Although the opposing effects of temperature and humidity tend to stabilize glycoprotein performance, A. aurantia thread droplets appear to function optimally during the afternoon, equipping this species to capture large orthopterans, which are most active at this time.
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Affiliation(s)
- Sarah D Stellwagen
- Department of Biological Sciences, Virginia Tech, Blacksburg, VA 24061, USA
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