scholarly journals Adhesion enhancement of cribellate capture threads by epicuticular waxes of the insect prey sheds new light on spider web evolution

2017 ◽  
Vol 284 (1855) ◽  
pp. 20170363 ◽  
Author(s):  
Raya A. Bott ◽  
Werner Baumgartner ◽  
Peter Bräunig ◽  
Florian Menzel ◽  
Anna-Christin Joel
Keyword(s):  
Adhesive Force ◽  
Arms Race ◽  
Epicuticular Waxes ◽  
Cuticular Waxes ◽  
Free Surfaces ◽  
Spider Web ◽  
Insect Prey ◽  
Reinforced Composite ◽  
Artificial Surfaces ◽  
Web Building

To survive, web-building spiders rely on their capture threads to restrain prey. Many species use special adhesives for this task, and again the majority of those species cover their threads with viscoelastic glue droplets. Cribellate spiders, by contrast, use a wool of nanofibres as adhesive. Previous studies hypothesized that prey is restrained by van der Waals' forces and entrapment in the nanofibres. A large discrepancy when comparing the adhesive force on artificial surfaces versus prey implied that the real mechanism was still elusive. We observed that insect prey's epicuticular waxes infiltrate the wool of nanofibres, probably induced by capillary forces. The fibre-reinforced composite thus formed led to an adhesion between prey and thread eight times stronger than that between thread and wax-free surfaces. Thus, cribellate spiders employ the originally protective coating of their insect prey as a fatal component of their adhesive and the insect promotes its own capture. We suggest an evolutionary arms race with prey changing the properties of their cuticular waxes to escape the cribellate capture threads that eventually favoured spider threads with viscous glue.

scholarly journals Distinct movement patterns generate stages of spider web building

2021 ◽  
Author(s):  
Abel Corver ◽  
Nicholas Wilkerson ◽  
Jeremiah Miller ◽  
Andrew Gordus
Keyword(s):  
Movement Patterns ◽  
Spider Web ◽  
Web Building

scholarly journals Sequence Capture Phylogenomics of True Spiders Reveals Convergent Evolution of Respiratory Systems

2020 ◽  
Vol 70 (1) ◽  
pp. 14-20 ◽  
Author(s):  
Martín J Ramírez ◽  
Ivan L F Magalhaes ◽  
Shahan Derkarabetian ◽  
Joel Ledford ◽  
Charles E Griswold ◽  
...  
Keyword(s):  
Character Evolution ◽  
Silk Gland ◽  
Published Data ◽  
Spider Web ◽  
Book Lungs ◽  
Character System ◽  
Silk Glands ◽  
Genomic Scale ◽  
Respiratory Systems ◽  
Web Building

Abstract The common ancestor of spiders likely used silk to line burrows or make simple webs, with specialized spinning organs and aerial webs originating with the evolution of the megadiverse “true spiders” (Araneomorphae). The base of the araneomorph tree also concentrates the greatest number of changes in respiratory structures, a character system whose evolution is still poorly understood, and that might be related to the evolution of silk glands. Emphasizing a dense sampling of multiple araneomorph lineages where tracheal systems likely originated, we gathered genomic-scale data and reconstructed a phylogeny of true spiders. This robust phylogenomic framework was used to conduct maximum likelihood and Bayesian character evolution analyses for respiratory systems, silk glands, and aerial webs, based on a combination of original and published data. Our results indicate that in true spiders, posterior book lungs were transformed into morphologically similar tracheal systems six times independently, after the evolution of novel silk gland systems and the origin of aerial webs. From these comparative data, we put forth a novel hypothesis that early-diverging web-building spiders were faced with new energetic demands for spinning, which prompted the evolution of similar tracheal systems via convergence; we also propose tests of predictions derived from this hypothesis.[Book lungs; discrete character evolution; respiratory systems; silk; spider web evolution; ultraconserved elements.]

Epicuticular Waxes from Leaves and Stems of Jojoba (Simmondsia chinensis [Link] Schneider)

1983 ◽  
Vol 38 (9-10) ◽  
pp. 679-682
Author(s):  
Paul-Gerhard Gülz ◽  
Claudia Eich
Keyword(s):  
Distribution Patterns ◽  
Quantitative Composition ◽  
Similar Distribution ◽  
Epicuticular Waxes ◽  
Cuticular Waxes ◽  
Aerial Parts ◽  
Branched Alkanes ◽  
Organ Specific ◽  
Seed Coats ◽  
Long Chain

Abstract Epicuticular waxes were extracted with chloroform from air dried Jojoba leaves and stems. These cuticular waxes consisted of homologues of n-alkanes, branched alkanes, alkenes, wax esters, aldehydes, acetates, esters, free long chain fatty acids and alcohols. Both leaves and stems showed the same qualitative and quantitative composition with similar distribution patterns. Very long chain and in most cases saturated compounds are dominating. The composition of epicuticular waxes from Jojoba leaves and stems is quite different from that of Jojoba pericarp and seed coats and demonstrates an organ specific wax composition of different aerial parts of this plant.

scholarly journals Deer herbivory reduces web-building spider abundance by simplifying forest vegetation structure

2016 ◽  
Author(s):  
Elizabeth J Roberson ◽  
Michael J Chips ◽  
Walter P Carson ◽  
Thomas P Rooney
Keyword(s):  
Vegetation Structure ◽  
Prey Availability ◽  
Forest Disturbance ◽  
Geographic Region ◽  
Spider Webs ◽  
Spider Web ◽  
Food Web Interactions ◽  
Closed Canopy ◽  
Availability Index ◽  
Web Building

Indirect effects are a common feature of ecological systems, arising when one species affects interactions among two or more other species. We examined how browsing by white-tailed deer (Odocoileus virginianus) affected the abundance and composition of a web-building spider guild through their effects on the structure of the ground and shrub layers of northern hardwood forests. We examined paired plots consisting of deer-free and control plots in Pennsylvania and Wisconsin. We recorded the abundance of seven types of webs, each corresponding to a family of web-building spiders. We quantified vegetation structure and habitat suitability for the spiders by computing a web scaffold availability index (WSAI) at 0.5 m and 1.0 m above the ground. At Wisconsin sites, we recorded prey availability. Spider webs were twice as abundant in deer-free plots compared to control plots, while WSAI was 7-12 times greater in deer-free plots. Prey availability was also higher in deer-free plots. With the exception of funnel web-builders, all spider web types were significantly more abundant in deer-free plots. Both deer exclusion and the geographic region of plots were significant predictors of spider community structure. In closed canopy forests with high browsing pressure, the low density of tree saplings and shrubs provides few locations for web-building spiders to anchor webs. Recruitment of these spiders may become coupled with forest disturbance events that increase tree and shrub recruitment. By modifying habitat structure, deer indirectly modify arthropod food web interactions. As deer populations have increased in eastern North America over the past several decades, the effects of deer on web-building spiders may be widespread throughout the region.

Using spider web types as a substitute for assessing web-building spider biodiversity and the success of habitat restoration

2010 ◽  
Vol 19 (11) ◽  
pp. 3141-3155 ◽  
Author(s):  
John R. Gollan ◽  
Helen M. Smith ◽  
Matthew Bulbert ◽  
Andrew P. Donnelly ◽  
Lance Wilkie
Keyword(s):  
Habitat Restoration ◽  
Spider Web ◽  
Web Building

scholarly journals Dynamic environments do not appear to constrain spider web building behaviour

2021 ◽  
Vol 108 (3) ◽  
Author(s):  
Tom Mulder ◽  
Lucas Wilkins ◽  
Beth Mortimer ◽  
Fritz Vollrath
Keyword(s):  
Wind Loading ◽  
Spider Webs ◽  
Spider Web ◽  
Thread Tension ◽  
In The Wild ◽  
Orb Web ◽  
Araneus Diadematus ◽  
Orb Web Spiders ◽  
Building Behaviour ◽  
Web Building

AbstractMany laboratory experiments demonstrate how orb-web spiders change the architecture of their webs in response to prey, surroundings and wind loading. The overall shape of the web and a range of other web parameters are determined by frame and anchor threads. In the wild, unlike the lab, the anchor threads are attached to branches and leaves that are not stationary but move, which affects the thread tension field. Here we experimentally test the effect of a moving support structure on the construction behaviour and web-parameters of the garden cross spider Araneus diadematus. We found no significant differences in building behaviour between rigid and moving anchors in total time spent and total distance covered nor in the percentage of the total time spent and distance covered to build the three major web components: radials, auxiliary and capture spirals. Moreover, measured key parameters of web-geometry were equally unaffected. These results call for re-evaluation of common understanding of spider webs as thread tensions are often considered to be a major factor guiding the spider during construction and web-operation.

scholarly journals Studies on the Geometrical Design of Spider Webs for Reinforced Composite Structures

2021 ◽  
Vol 5 (2) ◽  
pp. 57
Author(s):  
Yohannes Regassa ◽  
Hirpa G. Lemu ◽  
Belete Sirabizuh ◽  
Samuel Rahimeto
Keyword(s):  
Fiber Orientation ◽  
Composite Structures ◽  
Spider Silk ◽  
Pressure Vessels ◽  
Aviation Industry ◽  
Measurement Tool ◽  
Spider Webs ◽  
Spider Web ◽  
Reinforced Composite ◽  
Structural Applications

Spider silk is an astonishingly tough biomaterial that consists almost entirely of large proteins. Studying the secrets behind the high strength nature of spider webs is very challenging due to their miniature size. In spite of their complex nature, researchers have always been inspired to mimic Nature for developing new products or enhancing the performance of existing technologies. Accordingly, the spider web can be taken as a model for optimal fiber orientation for composite materials to be used in critical structural applications. In this study an attempt is made to analyze the geometrical characteristics of the web construction building units such as spirals and radials. As a measurement tool, we have used a developed MATLAB algorithm code for measuring the node to node of rings and radials angle of orientation. Spider web image samples were collected randomly from an ecological niche with black background sample collection tools. The study shows that the radial angle of orientation is 12.7 degrees with 5 mm distance for the spirals’ mesh size. The extracted geometrical numeric values from the spider web show moderately skewed statistical data. The study sheds light on spider web utilization to develop an optimized fiber orientation reinforced composite structure for constructing, for instance, shell structures, pressure vessels and fuselage cones for the aviation industry.

Epicuticular Waxes and Flavonol Aglycones of the European Mistletoe, Viscum album L.

2000 ◽  
Vol 55 (5-6) ◽  
pp. 314-317 ◽  
Author(s):  
Eckhard Wollenweber ◽  
Anja Wieland ◽  
Klaus Haas
Keyword(s):  
Oleanolic Acid ◽  
Seasonal Changes ◽  
Viscum Album ◽  
Epicuticular Waxes ◽  
Main Constituent ◽  
Primary Alcohols ◽  
Cuticular Waxes ◽  
Aliphatic Compounds

Cuticular waxes of Viscum album ssp. album contain oleanolic acid as main constituent, accompanied by aliphatic compounds like alkanes, esters and primary alcohols. A number of flavonol aglycones (methyl ethers of quercetin and kaempferol) have also been identified. Seasonal changes in amount and composition of cuticular waxes and the presence of flavonol aglycones are described and the ecophysiological significance of flavonoids on the surface of the mistletoe is briefly discussed.

Composition of Epicuticular Waxes from Fruits of Jojoba (Simmondsia chinensis [Link] Schneider)

1982 ◽  
Vol 37 (11-12) ◽  
pp. 1053-1056 ◽  
Author(s):  
Paul-Gerhard Gülz
Keyword(s):  
Homologous Series ◽  
Cuticular Wax ◽  
Wax Esters ◽  
Hydrocarbon Fraction ◽  
Simmondsia Chinensis ◽  
Epicuticular Waxes ◽  
Cuticular Waxes ◽  
Branched Alkanes ◽  
Seed Coats ◽  
Long Chain

Abstract Epicuticular waxes were extracted with hexane from dry Jojoba pericarp and seed. These cuticular waxes consisted of hydrocarbons, wax esters, free acids, free alcohols and sterols; additionally aldehydes were found in the wax obtained from seed coats. The hydrocarbon fraction contained a homologous series of n-alkanes and branched alkanes but no alkenes. The composition of the wax esters of the cuticular wax was similar to that of the cotyledons. The esters are composed of monounsaturated long chain acids and alcohols.

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