scholarly journals Small behavioral adaptations enable more effective prey capture by producing 3D-structured spider threads

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Caroline C. F. Grannemann ◽  
Marco Meyer ◽  
Marian Reinhardt ◽  
Martín J. Ramírez ◽  
Marie E. Herberstein ◽  
...  
Keyword(s):  
Prey Capture ◽  
Behavioral Differences ◽  
Research Attention ◽  
Fiber Alignment ◽  
Web Performance ◽  
Behavioral Adaptations ◽  
Zigzag Pattern ◽  
Orb Web ◽  
The Impact ◽  
The Web

AbstractSpiders 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.

Foraging behaviour in orb-web spiders (Araneidae): do web decorations increase prey capture success in Argiope keyserlingi Karsch, 1878?

2000 ◽  
Vol 48 (2) ◽  
pp. 217 ◽  
Author(s):  
M. E. Herberstein
Keyword(s):  
Foraging Behaviour ◽  
Prey Capture ◽  
Paired Comparison ◽  
Mortality Rates ◽  
Argiope Keyserlingi ◽  
Orb Web ◽  
Orb Web Spiders ◽  
The Web ◽  
Web Size ◽  
Prey Attraction

Orb web spiders in the genus Argiope attach highly visible silk bands called decorations or stabilimenta to their webs. Two different hypotheses regarding the function of these structures were investigated in the field using Argiope keyserlingi: prey attraction and anti-predatory device. The first hypothesis suggests that web decorations attract prey to the web, and webs carrying decorations will capture more prey than those without. A field census of prey capture showed that webs adorned with more decorative bands indeed captured more but similarly sized prey per hour compared with webs carrying fewer decorations. Web height or web size, however, were not related to the rate of prey capture. This pattern was confirmed by a paired comparison of prey-capture rates within individuals that increased or decreased the number of decorative bands on consecutive days. Individuals that used more decorations also captured more prey compared with days when they spun fewer decorations. The second hypothesis suggests that these structures function as anti-predatory devices and, consequently, spiders on decorated webs benefit from a lower rate of mortality than spiders on undecorated webs. A census of the mortality rates of spiders over 19 days revealed that spiders did not disappear from undecorated webs more frequently than from decorated webs. Consequently, the idea that web decorations act as anti-predatory devices in A. keyserlingi was not supported.

scholarly journals The role of capture spiral silk properties in the diversification of orb webs

2012 ◽  
Vol 9 (77) ◽  
pp. 3240-3248 ◽  
Author(s):  
Anna Tarakanova ◽  
Markus J. Buehler
Keyword(s):  
Mechanical Properties ◽  
Prey Capture ◽  
Coarse Grained ◽  
Driving Factor ◽  
Web Performance ◽  
Spider Web ◽  
Orb Web ◽  
System Energy ◽  
Thread Strength

Among a myriad of spider web geometries, the orb web presents a fascinating, exquisite example in architecture and evolution. Orb webs can be divided into two categories according to the capture silk used in construction: cribellate orb webs (composed of pseudoflagelliform silk) coated with dry cribellate threads and ecribellate orb webs (composed of flagelliform silk fibres) coated by adhesive glue droplets. Cribellate capture silk is generally stronger but less-extensible than viscid capture silk, and a body of phylogenic evidence suggests that cribellate capture silk is more closely related to the ancestral form of capture spiral silk. Here, we use a coarse-grained web model to investigate how the mechanical properties of spiral capture silk affect the behaviour of the whole web, illustrating that more elastic capture spiral silk yields a decrease in web system energy absorption, suggesting that the function of the capture spiral shifted from prey capture to other structural roles. Additionally, we observe that in webs with more extensible capture silk, the effect of thread strength on web performance is reduced, indicating that thread elasticity is a dominant driving factor in web diversification.

Prey-capture strategies in sympatric web-building spiders

2006 ◽  
Vol 84 (7) ◽  
pp. 964-973 ◽  
Author(s):  
Samuel Zschokke ◽  
Yann Hénaut ◽  
Suresh P. Benjamin ◽  
J. Alvaro García-Ballinas
Keyword(s):  
Field Experiment ◽  
Prey Capture ◽  
Reaction Times ◽  
Maintenance Costs ◽  
Trade Off ◽  
Orb Web ◽  
Web Building ◽  
The Web

Arthropods in several orders use traps to capture prey. Such trap-building predators expend most of their foraging energy prior to any prey contact. Nevertheless, relative investments in trap construction and actual prey capture may vary among trap builders, and they are likely to face a trade-off between building very effective but energetically costly traps and building less effective traps requiring faster reaction times when attacking prey. We analysed this trade-off in a field experiment by comparing the prey capture behaviour of four different sympatric web-building spiders (Araneae: Araneidae, Nephilidae, Tetragnathidae, Theridiidae) with the retention times of five different prey types in the webs of these spiders. Retention times differed greatly among webs and among prey types. The vertical orb webs retained prey longer than the horizontal orb web and the sheet web, and active prey escaped more quickly than less active prey. Among spiders with orb webs, the spider with the web that retained prey for the shortest time was the fastest to capture prey, thus confirming the expected trade-off between building long-retaining webs and attacking slowly versus building short-retaining webs and attacking more rapidly. The sheet web, however, neither retained prey for an appreciable period of time nor facilitated rapid prey capture. We suggest that this low capture effectiveness of sheet webs is compensated by their lower maintenance costs.

scholarly journals Extensive Variation in the Activities of Pseudocerastes and Eristicophis Viper Venoms Suggests Divergent Envenoming Strategies Are Used for Prey Capture

Toxins ◽  
2021 ◽  
Vol 13 (2) ◽  
pp. 112
Author(s):  
Bianca op den Brouw ◽  
Francisco C. P. Coimbra ◽  
Lachlan A. Bourke ◽  
Tam Minh Huynh ◽  
Danielle H. W. Vlecken ◽  
...  
Keyword(s):  
Prey Capture ◽  
Anticoagulant Activity ◽  
Protein Composition ◽  
Coagulation Factors ◽  
Arid Environments ◽  
Factor X ◽  
Venom Protein ◽  
Research Attention ◽  
Future Assessment ◽  
Viper Venoms

Snakes of the genera Pseudocerastes and Eristicophis (Viperidae: Viperinae) are known as the desert vipers due to their association with the arid environments of the Middle East. These species have received limited research attention and little is known about their venom or ecology. In this study, a comprehensive analysis of desert viper venoms was conducted by visualising the venom proteomes via gel electrophoresis and assessing the crude venoms for their cytotoxic, haemotoxic, and neurotoxic properties. Plasmas sourced from human, toad, and chicken were used as models to assess possible prey-linked venom activity. The venoms demonstrated substantial divergence in composition and bioactivity across all experiments. Pseudocerastes urarachnoides venom activated human coagulation factors X and prothrombin and demonstrated potent procoagulant activity in human, toad, and chicken plasmas, in stark contrast to the potent neurotoxic venom of P. fieldi. The venom of E. macmahonii also induced coagulation, though this did not appear to be via the activation of factor X or prothrombin. The coagulant properties of P. fieldi and P. persicus venoms varied among plasmas, demonstrating strong anticoagulant activity in the amphibian and human plasmas but no significant effect in that of bird. This is conjectured to reflect prey-specific toxin activity, though further ecological studies are required to confirm any dietary associations. This study reinforces the notion that phylogenetic relatedness of snakes cannot readily predict venom protein composition or function. The significant venom variation between these species raises serious concerns regarding antivenom paraspecificity. Future assessment of antivenom is crucial.

scholarly journals Are Bacterio- and Phytoplankton Community Compositions Related in Lakes Differing in Their Cyanobacteria Contribution and Physico-Chemical Properties?

Genes ◽  
2021 ◽  
Vol 12 (6) ◽  
pp. 855
Author(s):  
Mikołaj Kokociński ◽  
Dariusz Dziga ◽  
Adam Antosiak ◽  
Janne Soininen
Keyword(s):  
Environmental Factors ◽  
Community Composition ◽  
Phytoplankton Community ◽  
Heterotrophic Bacteria ◽  
Bacterial Community Composition ◽  
Physical Factors ◽  
Research Attention ◽  
Phytoplankton Community Composition ◽  
The Impact ◽  
Bacteria Communities

Bacterioplankton community composition has become the center of research attention in recent years. Bacteria associated with toxic cyanobacteria blooms have attracted considerable interest. However, little is known about the environmental factors driving the bacteria community, including the impact of invasive cyanobacteria. Therefore, our aim has been to determine the relationships between heterotrophic bacteria and phytoplankton community composition across 24 Polish lakes with different contributions of cyanobacteria including the invasive species Raphidiopsis raciborskii. This analysis revealed that cyanobacteria were present in 16 lakes, while R. raciborskii occurred in 14 lakes. Our results show that bacteria communities differed between lakes dominated by cyanobacteria and lakes with minor contributions of cyanobacteria but did not differ between lakes with R. raciborskii and other lakes. Physical factors, including water and Secchi depth, were the major drivers of bacteria and phytoplankton community composition. However, in lakes dominated by cyanobacteria, bacterial community composition was also influenced by biotic factors such as the amount of R. raciborskii, chlorophyll-a and total phytoplankton biomass. Thus, our study provides novel evidence on the influence of environmental factors and R. raciborskii on lake bacteria communities.

scholarly journals Estimation of Determinants of Farmland Abandonment and Its Data Problems

Land ◽  
2021 ◽  
Vol 10 (6) ◽  
pp. 596
Author(s):  
Shinichi Kitano
Keyword(s):  
Census Data ◽  
Evaluation Research ◽  
Developed Countries ◽  
Third Party ◽  
Objective Data ◽  
Farmland Abandonment ◽  
Subjective Data ◽  
Research Attention ◽  
Abandoned Farmland ◽  
The Impact

Abandoned farmland is particularly problematic in developed countries where agriculture has a comparative disadvantage in terms of effective use of land resources invested over time. While many studies have estimated the causes of these problems, few have discussed in detail the impact of data characteristics and accuracy on the estimation results. In this study, issues related to the underlying data and the estimation of the determinants of farmland abandonment were examined. Most previous studies on farmland abandonment in Japan have used census data as the basis of their analyses. However, census data are recorded subjectively by farmers. To address this, surveys of abandoned farmland are being conducted by a third party, and the results are compiled into a geographic information system (GIS) database. Two types of datasets (subjective census data and objective GIS data) were examined for their estimation performance. Although the two sets of data are correlated, there are considerable differences between them. Subjective variables are compatible with subjective data, and objective variables are compatible with objective data (meaning that parameters are easily identified). Original data for analysis, such as policy variables, are compatible with objective data. In policy evaluation research, attention should be paid to objective data collection.

scholarly journals Big Data Analytics for Search Engine Optimization

2020 ◽  
Vol 4 (2) ◽  
pp. 5 ◽  
Author(s):  
Ioannis C. Drivas ◽  
Damianos P. Sakas ◽  
Georgios A. Giannakopoulos ◽  
Daphne Kyriaki-Manessi
Keyword(s):  
Big Data ◽  
Cultural Heritage ◽  
Search Engine ◽  
Data Analytics ◽  
User Behavior ◽  
Big Data Analytics ◽  
Data Types ◽  
Search Engine Optimization ◽  
The Impact ◽  
The Web

In the Big Data era, search engine optimization deals with the encapsulation of datasets that are related to website performance in terms of architecture, content curation, and user behavior, with the purpose to convert them into actionable insights and improve visibility and findability on the Web. In this respect, big data analytics expands the opportunities for developing new methodological frameworks that are composed of valid, reliable, and consistent analytics that are practically useful to develop well-informed strategies for organic traffic optimization. In this paper, a novel methodology is implemented in order to increase organic search engine visits based on the impact of multiple SEO factors. In order to achieve this purpose, the authors examined 171 cultural heritage websites and their retrieved data analytics about their performance and user experience inside them. Massive amounts of Web-based collections are included and presented by cultural heritage organizations through their websites. Subsequently, users interact with these collections, producing behavioral analytics in a variety of different data types that come from multiple devices, with high velocity, in large volumes. Nevertheless, prior research efforts indicate that these massive cultural collections are difficult to browse while expressing low visibility and findability in the semantic Web era. Against this backdrop, this paper proposes the computational development of a search engine optimization (SEO) strategy that utilizes the generated big cultural data analytics and improves the visibility of cultural heritage websites. One step further, the statistical results of the study are integrated into a predictive model that is composed of two stages. First, a fuzzy cognitive mapping process is generated as an aggregated macro-level descriptive model. Secondly, a micro-level data-driven agent-based model follows up. The purpose of the model is to predict the most effective combinations of factors that achieve enhanced visibility and organic traffic on cultural heritage organizations’ websites. To this end, the study contributes to the knowledge expansion of researchers and practitioners in the big cultural analytics sector with the purpose to implement potential strategies for greater visibility and findability of cultural collections on the Web.

Behind the Web Store: The Organisational and Spatial Evolution of Multichannel Retailing in Toronto

10.1068/a3562 ◽  
2002 ◽  
Vol 34 (8) ◽  
pp. 1411-1441 ◽  
Author(s):  
Andrew Currah
Keyword(s):  
Urban Space ◽  
Economic Geography ◽  
Information Technologies ◽  
Urban Landscape ◽  
Commodity Chain ◽  
Multichannel Retailing ◽  
Business To Consumer ◽  
Economic Landscape ◽  
The Impact ◽  
The Web

In this paper I address two issues of general relevance to contemporary debates in economic geography: first, the organisational and spatial implications of new information technologies for the economic landscape; and, second, the enduring role of place to digital capitalism. Specifically, I examine the organisational evolution of multichannel retailing in Toronto from a geographical perspective. Bricks-and-mortar retailers are increasingly pursuing a multichannel strategy by operating an Internet-based web store alongside the existing network of physical retail outlets. I therefore evaluate the organisational implications of the adoption of business-to-consumer e-commerce (e-tailing) technology for six Canadian bricks-and-mortar retailers based in Toronto and assess how the associated changes in business structure have been inscribed upon the urban landscape. The argument is developed in three sections. First, I discuss how the formula for competitive advantage in the new (r)etail markets of the developed world has shifted from a pure play to a multichannel organisational paradigm. Second, I provide a background to the development of Canadian e-commerce and an overview of the empirical methodologies employed during the research. Third, the focus of the paper moves ‘behind the web store’ to spatialise the physical places that constitute the fulfilment infrastructure of e-tailing as sequentially linked stages in Internet commodity chains. I evaluate the impact of the Internet commodity chain upon the geographical organisation of each retailer, and, in particular, consider whether the unique logistical requirements of e-tailing have stimulated spatial processes of disintermediation and reintermediation. It is argued that, when read through the lens of Toronto, e-tailing has incurred limited organisational disruption and is characterised by a distinctive geography of integration between online and offline retailing services within the urban space of the city. I conclude the paper by contextualising the findings within themes for conceptual debate in economic geography.

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