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Full-Text Articles in Life Sciences
Spider Dragline Silk: Correlated And Mosaic Evolution In High-Performance Biological Materials, Todd Blackledge, Brook Swanson, Cheryl Hayashi, Adam Summers
Spider Dragline Silk: Correlated And Mosaic Evolution In High-Performance Biological Materials, Todd Blackledge, Brook Swanson, Cheryl Hayashi, Adam Summers
Todd A. Blackledge
The evolution of biological materials is a critical, yet poorly understood, component in the generation of biodiversity. For example, the diversification of spiders is correlated with evolutionary changes in the way they use silk, and the material properties of these fibers, such as strength, toughness, extensibility, and stiffness, have profound effects on ecological function. Here, we examine the evolution of the material properties of dragline silk across a phylogenetically diverse sample of species in the Araneomorphae (true spiders). The silks we studied are generally stronger than other biological materials and tougher than most biological or man-made fibers, but their material …
Gumfooted Lines In Black Widow Cobwebs And The Mechanical Properties Of Spider Capture Silk, Todd Blackledge, Adam Summers, Cheryl Hayashi
Gumfooted Lines In Black Widow Cobwebs And The Mechanical Properties Of Spider Capture Silk, Todd Blackledge, Adam Summers, Cheryl Hayashi
Todd A. Blackledge
Orb-weaving spiders produce webs using two types of silk that have radically different mechanical properties. The dragline silk used to construct the supporting frame and radii of the web is stiff and as strong as steel, while the capture spiral is much weaker but more than ten times as extensible. This remarkable divergence in mechanical properties has been attributed to the aqueous glue that coats the capture spiral, which is thought to decrease capture spiral stiffness and increase its extensibility. However, discerning the effect of the aqueous glue on fiber performance is complicated because dragline silk and the capture spiral …
Condition-Dependent Spider Web Architecture In The Western Black Widow, Latrodectus Hesperus, Todd Blackledge, Jacquelyn Zevenbergen
Condition-Dependent Spider Web Architecture In The Western Black Widow, Latrodectus Hesperus, Todd Blackledge, Jacquelyn Zevenbergen
Todd A. Blackledge
Animals use behavioural plasticity to cope with conflicting selective pressures. We investigated how prey availability affects the spinning of cobwebs, whose architecture influences both prey capture and defence. Fed western black widows spun cobwebs containing more silk than did fasted spiders. However, fed spiders invested relatively less silk in the sheets and sticky gumfooted threads of webs and relatively more silk in supporting threads than did fasted spiders. The material properties of silk spun by fed and fasted spiders were relatively similar, but silk threads spun by fed spiders were twice as thick as those of fasted spiders, increasing web …
Spider Silk As A Novel High Performance Muscle Driven By Humidity, Todd Blackledge, Ali Dhinojwala, Ingi Agnarsson, Vasav Sahni
Spider Silk As A Novel High Performance Muscle Driven By Humidity, Todd Blackledge, Ali Dhinojwala, Ingi Agnarsson, Vasav Sahni
Todd A. Blackledge
The abrupt halt of a bumble bee's flight when it impacts the almost invisible threads of an orb web provides an elegant example of the amazing strength and toughness of spider silk. Spiders depend upon these properties for survival, yet the impressive performance of silk is not limited solely to tensile mechanics. Here, we show that silk also exhibits powerful cyclic contractions, allowing it to act as a high performance mimic of biological muscles. These contractions are actuated by changes in humidity alone and repeatedly generate work 50 times greater than the equivalent mass of human muscle. Although we demonstrate …
Spider Orb Webs Rely On Radial Threads To Absorb Prey Energy, Todd Blackledge, Andrew Sensenig, Kimberly Lorentz, Sean Kelly
Spider Orb Webs Rely On Radial Threads To Absorb Prey Energy, Todd Blackledge, Andrew Sensenig, Kimberly Lorentz, Sean Kelly
Todd A. Blackledge
The kinetic energy of flying insect prey is a formidable challenge for orb-weaving spiders. These spiders construct two-dimensional, round webs from a combination of stiff, strong radial silk and highly elastic, glue-coated capture spirals. Orb webs must first stop the flight of insect prey and then retain those insects long enough to be subdued by the spiders. Consequently, spider silks rank among the toughest known biomaterials. The large number of silk threads composing a web suggests that aerodynamic dissipation may also play an important role in stopping prey. Here, we quantify energy dissipation in orb webs spun by diverse species …
Environmentally Induced Post-Spin Property Changes In Spider Silks: Influences Of Web Type, Spidroin Composition And Ecology, Todd Blackledge, Sean Blamires, Chun-Lin Wu, I-Min Tso
Environmentally Induced Post-Spin Property Changes In Spider Silks: Influences Of Web Type, Spidroin Composition And Ecology, Todd Blackledge, Sean Blamires, Chun-Lin Wu, I-Min Tso
Todd A. Blackledge
Many spiders use silk to construct webs that must function for days at a time, whereas many other species renew their webs daily. The mechanical properties of spider silk can change after spinning under environmental stress, which could influence web function. We hypothesize that spiders spinning longer-lasting webs produce silks composed of proteins that are more resistant to environmental stresses. The major ampullate (MA) silks of orb web spiders are principally composed of a combination of two proteins (spidroins) called MaSp1 and MaSp2. We expected spider MA silks dominated by MaSp1 to have the greatest resistance to post-spin property change …
Silken Toolkits: Biomechanics Of Silk Fibers Spun By The Orb Web Spider Argiope Argentata (Fabricius 1775), Todd Blackledge, Cheryl Hayashi
Silken Toolkits: Biomechanics Of Silk Fibers Spun By The Orb Web Spider Argiope Argentata (Fabricius 1775), Todd Blackledge, Cheryl Hayashi
Todd A. Blackledge
Orb-weaving spiders spin five fibrous silks from differentiated glands that contain unique sets of proteins. Despite diverse ecological functions, the mechanical properties of most of these silks are not well characterized. Here, we quantify the mechanical performance of this toolkit of silks for the silver garden spider Argiope argentata. Four silks exhibit viscoelastic behaviour typical of polymers, but differ statistically from each other by up to 250% in performance, giving each silk a distinctive suite of material properties. Major ampullate silk is 50% stronger than other fibers, but also less extensible. Aciniform silk is almost twice as tough as other …
Quasistatic And Continuous Dynamic Characterization Of The Mechanical Properties Of Silk From The Cobweb Of The Black Widow Spider Latrodectus Hesperus, Todd Blackledge, John Swindeman, Cheryl Hayashi
Quasistatic And Continuous Dynamic Characterization Of The Mechanical Properties Of Silk From The Cobweb Of The Black Widow Spider Latrodectus Hesperus, Todd Blackledge, John Swindeman, Cheryl Hayashi
Todd A. Blackledge
Spider silks are among the strongest and toughest known materials, but investigation of these remarkable properties has been confined largely to orb-weaving spiders. We investigated the mechanical performance of silk from the cobweb-weaving spider Latrodectus hesperus. Both silk from the scaffolding region of the web and sticky gumfooted capture lines had material properties similar to the major ampullate silk that orb weavers use as the framework for their orb webs. Major ampullate fibers obtained from anaesthetized Latrodectus spiders were similar, but exhibited increased stiffness and reduced extensibility. Novel continuous dynamic analysis of the silks revealed that the loss tangent (tanδ) …
Unraveling The Mechanical Properties Of Composite Silk Threads Spun By Cribellate Orb-Weaving Spiders, Todd Blackledge, Cheryl Hayashi
Unraveling The Mechanical Properties Of Composite Silk Threads Spun By Cribellate Orb-Weaving Spiders, Todd Blackledge, Cheryl Hayashi
Todd A. Blackledge
Orb-web weaving spiders depend upon the mechanical performance of capture threads to absorb the energy of flying prey. Most orb-weavers spin wet capture threads with core fibers of flagelliform silk. These threads are extremely compliant and extensible due to the folding of their constituent proteins into molecular nanosprings and hydration by a surrounding coating of aqueous glue. In contrast, other orb-weavers use cribellate capture threads, which are composite structures consisting of core fibers of pseudoflagelliform silk surrounded by a matrix of fine dry cribellar fibrils. Based on phylogenetic evidence, cribellate capture threads predate the use of viscid capture threads. To …
Damping Capacity Is Evolutionarily Conserved In The Radial Silk Of Orb-Weaving Spiders, Todd Blackledge, Sean Kelly, Andrew Sensenig, Kimberly Lorentz
Damping Capacity Is Evolutionarily Conserved In The Radial Silk Of Orb-Weaving Spiders, Todd Blackledge, Sean Kelly, Andrew Sensenig, Kimberly Lorentz
Todd A. Blackledge
Orb-weaving spiders depend upon their two-dimensional silk traps to stop insects in mid flight. While the silks used to construct orb webs must be extremely tough to absorb the tremendous kinetic energy of insect prey, webs must also minimize the return of that energy to prey to prevent insects from bouncing out of oscillating webs. We therefore predict that the damping capacity of major ampullate spider silk, which forms the supporting frames and radial threads of orb webs, should be evolutionarily conserved among orb-weaving spiders. We test this prediction by comparing silk from six diverse species of orb spiders. Silk …