scholarly journals Frequency, composition and variation in external food stores constructed by orb-web spiders: Nephila edulis and Nephila plumipes (Araneae : Araneoidea)

2003 ◽  
Vol 51 (2) ◽  
pp. 119 ◽  
Author(s):  
B. V. Griffiths ◽  
G. I. Holwell ◽  
M. E. Herberstein ◽  
M. A. Elgar
Keyword(s):  
Prey Density ◽  
Field Experiments ◽  
Encounter Rate ◽  
Food Stores ◽  
Orb Web ◽  
Animal Material ◽  
Orb Web Spiders ◽  
Nephila Plumipes ◽  
The Web

Few examples of food hoarding have been documented in spiders, yet two Australian species of orb-web spiders, Nephila edulis and N. plumipes, typically incorporate previously captured prey into the web. The effect of prey density and prey-encounter rate on the storage behaviour of adult female N. edulis was tested in the laboratory. Prey density had a significant effect on the propensity to construct external caches: when more food was available, food caches were larger than when the supply of prey was limited. Caching behaviour also differed with the rate of prey encounter, even though the total amount of food supplied was the same. When prey were encountered at constant rates, spiders allocated more food to external storage compared with random encounter rates. Finally, we tested the quality of different prey types for external or internal storage. N. edulis were fed with blow-flies or crickets, and these prey were stored in the web, discarded or totally consumed. Crickets were typically consumed or stored, while flies were more frequently discarded. Field observations of the storage behaviour in N. edulis and N. plumipes found surprising differences in the composition of the cache. While N. plumipes incorporated only animal material, N. edulis also utilised plant material, suggesting that the storage band in N. edulis has other, non-food-storing functions. Field experiments indicated that the presence or absence of external stores in the web of N. plumipes had no influence on mortality, weight gain, or the presence of Argyrodes kleptoparasites.

The silk tuft web decorations of the orb-weaver Gasteracantha cancriformis : testing the prey attraction and the web advertisement hypotheses

Behaviour ◽  
2008 ◽  
Vol 145 (3) ◽  
pp. 277-295 ◽  
Author(s):  
Felipe Gawryszewski ◽  
Paulo Motta
Keyword(s):  
Drosophila Melanogaster ◽  
Foraging Success ◽  
Uv Reflectance ◽  
Web Advertisement ◽  
Orb Web ◽  
Orb Web Spiders ◽  
Large Animals ◽  
And Control ◽  
The Web ◽  
Prey Attraction

AbstractSeveral orb-web spiders build conspicuous decorations in their webs. The prey attraction hypothesis proposes that decorations increase spider foraging success by attracting prey, and that attraction is linked to UV reflectance. Alternatively, the web advertisement hypothesis proposes that decorations are a signal that advertises the presence of the web to large animals. We tested both hypotheses for the web silk tufts of Gasteracantha cancriformis. Even though tufts are UV reflective, we did not find support for the prey attraction hypothesis. In the field, when webs with tufts painted black and control webs were compared, there were no differences in the number of prey captured, number of damaged areas in webs and type of prey captured. In the laboratory, Drosophila melanogaster did not demonstrate preference for tufted silk lines versus non-tufted silk lines. Our data also did not give support for the web advertisement hypothesis. The proportion of web destruction was similar between web with tufts painted black and control webs during four days of experimentation. Therefore, two of the most favoured hypotheses that attempt to explain decorations do not apply for web silk tufts in our study system. Instead we propose that silk tufts might be an aposematic signal.

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.

Drinking behaviour of the orb web spider Argiope bruennichi (Araneae; Araneidae)

Behaviour ◽  
2011 ◽  
Vol 148 (11-13) ◽  
pp. 1295-1309 ◽  
Author(s):  
André Walter ◽  
Constanze Westphal ◽  
Peter Bliss ◽  
Robin F.A. Moritz
Keyword(s):  
Water Budget ◽  
Water Deprivation ◽  
Water Saturation ◽  
Drinking Behaviour ◽  
Water Droplets ◽  
Web Spider ◽  
Orb Web ◽  
Orb Web Spiders ◽  
Water Gain ◽  
The Web

Abstract Water is essential for survival in terrestrial animals. Balancing the water budget can be achieved by avoiding water loss and gaining water. In arthropods drinking as a process of water gain is well investigated in insects. In spiders drinking has only been shown to be present in cursorial spiders but not revealed for web builders. However, some orb web spiders were observed to occasionally ingest water droplets in the web. We here tested whether this reflects drinking. We subjected individual Argiope bruennichi spiders to two different treatments — 'water deprivation' vs. 'water saturation'. We conducted drinking tests by recording the spider's behavioural response to spraying the web with defined amounts of water. After spraying A. bruennichi searched the silk-overstitched web hub for water droplets and ingested them. Individuals that experienced the water deprivation treatment showed significantly more water ingesting behaviours, revealing that this response represents a true drinking mode. All individuals exclusively searched the covered web hubs. We further demonstrated that this structure can retain water for up to 40 min providing an effective substrate for the spiders to drink from. Hence, without the need of leaving the web the silk-covered hubs may help A. bruennichi spiders to balance their water budget.

Eco-localization of a prey in a spider orb web

2021 ◽  
pp. 107754632199354
Author(s):  
Ramón Zaera ◽  
Óscar Serrano ◽  
José Fernández-Sáez ◽  
Antonino Morassi
Keyword(s):  
Time History ◽  
Transverse Displacement ◽  
Control Points ◽  
Axially Symmetric ◽  
Large Interval ◽  
Highly Sensitive ◽  
Orb Web ◽  
Orb Web Spiders ◽  
Transverse Deflection ◽  
The Web

Orb web spiders locate the position of a perturbation in the web because of a prey impact through highly sensitive slit sensilla at the tip of their legs. Thus, the web serves as a self-made extension of its sensory space which transmits vibrations from the perturbation point to the spider location. These vibrations may contain the information required by the spider to rapidly identify the position where the prey has impacted and approach to it before it flies away. For axially symmetric orb webs supported at the boundary and for a spider which stays at the center of the web, it was shown that the knowledge of the transverse deflection time history at the eight spider legs, for a sufficiently large interval of time, contains enough information to localize the position of the prey. In this article, we address the same inverse problem of localization of the prey, but we suppose that the spider knows only a small number of selected information of the transverse displacement, such as, for example, the maxima of the response of the time history at the eight control points. We show how this reduced information still allows the spider to obtain a fairly accurate angular localization of the prey, for different prey and orb web characteristics.

scholarly journals The effect of predator-prey distance and prey profitability on the attack behaviour of the orb-web spider Argiope keyserlingi (Araneidae)

2001 ◽  
Vol 49 (3) ◽  
pp. 213 ◽  
Author(s):  
F. E. Champion de Crespigny ◽  
M. E. Herberstein ◽  
M. A. Elgar
Keyword(s):  
Foraging Behaviour ◽  
Physiological Condition ◽  
Web Design ◽  
Central Place ◽  
Predator Prey ◽  
Web Spider ◽  
Argiope Keyserlingi ◽  
Orb Web ◽  
Orb Web Spiders ◽  
The Web

The foraging behaviour of central-place foragers is thought to be strongly influenced by the distance between the forager and the food source (predator–prey distance). Orb-web spiders are uniquely suited for investigating this idea because they make active foraging decisions towards prey entangled in the web, and they define the dimensions of their foraging arena when they construct the web. Here we manipulate the physiological condition of Argiope keyserlingi and present the spiders with prey of varying quality, in terms of size and accessibility (location within the web and distance from the spider). We found that these spiders adjust their foraging behaviour primarily in response to their physiological condition but, in contrast to other central-place foragers, are indiscriminant of predator–prey distance or the likelihood of escape of the prey. We suggest that these factors are incorporated into the design of the web, and thus increase foraging success through efficient web design.

THE STABILIMENTUM OF THE ORB WEB SPIDER, ARGIOPE ARGENTATA: AN IMPROBABLE DEFENCE AGAINST PREDATORS

1970 ◽  
Vol 102 (6) ◽  
pp. 641-655 ◽  
Author(s):  
Michael H. Robinson ◽  
Barbara Robinson
Keyword(s):  
Wild Birds ◽  
Mechanical Function ◽  
Mechanical State ◽  
Web Spider ◽  
Prey Location ◽  
Orb Web ◽  
Final Adjustment ◽  
Orb Web Spiders ◽  
The Web

AbstractThe stabilimentum of orb web spiders is a structure for which several functions, both mechanical and defensive, have been suggested. Argiope argentata (Fabricius) builds a stabilimentum in the form of a white diagonal cross. Analysis of over 2500 webs of this species shows that the perfect cross is seldom built and nearly two thirds of the webs contain no stabilimentum at all. Experiments with wild birds as predators show that they can use stabilimentum-like models in prey location. From these data, and a review of the defensive adaptations of orb web spiders, it is argued that the A. argentata stabilimentum is not an anti-predator device. The evidence for a mechanical function is reviewed and discussed. It is suggested that the stabilimentum provides the spider with a means of making a final adjustment to the mechanical state of the web when this is necessary.

Positioning at the hub: does it matter on which side of the web orb-web spiders sit?

2001 ◽  
Vol 255 (2) ◽  
pp. 157-163 ◽  
Author(s):  
M. E. Herberstein ◽  
A. M. Heiling
Keyword(s):  
Orb Web ◽  
Orb Web Spiders ◽  
The Web

scholarly journals A novel property of spider silk: chemical defence against ants

2011 ◽  
Vol 279 (1734) ◽  
pp. 1824-1830 ◽  
Author(s):  
Shichang Zhang ◽  
Teck Hui Koh ◽  
Wee Khee Seah ◽  
Yee Hing Lai ◽  
Mark A. Elgar ◽  
...  
Keyword(s):  
Adaptive Response ◽  
Nutritional Value ◽  
Spider Silk ◽  
Chemical Defence ◽  
Spider Webs ◽  
Small Juvenile ◽  
Web Spider ◽  
Orb Web ◽  
Orb Web Spiders ◽  
The Web

Spider webs are made of silk, the properties of which ensure remarkable efficiency at capturing prey. However, remaining on, or near, the web exposes the resident spiders to many potential predators, such as ants. Surprisingly, ants are rarely reported foraging on the webs of orb-weaving spiders, despite the formidable capacity of ants to subdue prey and repel enemies, the diversity and abundance of orb-web spiders, and the nutritional value of the web and resident spider. We explain this paradox by reporting a novel property of the silk produced by the orb-web spider Nephila antipodiana (Walckenaer). These spiders deposit on the silk a pyrrolidine alkaloid (2-pyrrolidinone) that provides protection from ant invasion. Furthermore, the ontogenetic change in the production of 2-pyrrolidinone suggests that this compound represents an adaptive response to the threat of natural enemies, rather than a simple by-product of silk synthesis: while 2-pyrrolidinone occurs on the silk threads produced by adult and large juvenile spiders, it is absent on threads produced by small juvenile spiders, whose threads are sufficiently thin to be inaccessible to ants.

Does decoration building influence antipredator responses in an orb-web spider (Argiope keyserlingi) in its natural habitat?

2007 ◽  
Vol 55 (1) ◽  
pp. 1 ◽  
Author(s):  
Sean J. Blamires ◽  
Dieter F. Hochuli ◽  
Michael B. Thompson
Keyword(s):  
Wind Speed ◽  
Body Condition ◽  
Natural Habitat ◽  
Antipredator Behaviour ◽  
Web Spider ◽  
Antipredator Responses ◽  
Argiope Keyserlingi ◽  
Orb Web ◽  
Orb Web Spiders ◽  
The Web

Antipredator strategies adopted by animals need to compensate for temporal changes. Many orb-web spiders add silk decorations to their webs, which principally attract prey but may attract some predators. To identify their influence on antipredator behaviour in adult female St Andrew’s cross spiders (Argiope keyserlingi) we measured: spider body condition, web characteristics (area, spiral length and decoration building), environmental variables (air temperature, humidity, wind speed, relative prey abundance) and antipredator responses (remaining at the hub, dropping, shifting to the web periphery, or pumping the web) at three distinct periods (July–August, September–October and January–February) in the field. We developed path models from multiple regression analyses to distinguish between factors having direct and indirect effects. We found that even though both antipredator responses and decoration building change over time, antipredator responses and decoration investment are independent. Body condition and wind speed are directly positively associated with pumping frequency, and decoration building is negatively associated with the frequency of remaining at the hub because the likelihood that an object approaching the web is a predator increases if decorations are added. Wind speed is positively associated with antipredator behaviour and decoration building, due to an increased rate of feeding affecting body condition.

THE INFLUENCE OF TILLAGE SYSTEMS ON THE GROWTH, DEVELOPMENT AND YIELD OF LONG-FLAX

2020 ◽  
Author(s):  
V. Dumych ◽  
Keyword(s):  
Growth And Development ◽  
Field Experiments ◽  
Conservation Tillage ◽  
Mineral Fertilizers ◽  
Tillage Systems ◽  
Yield And Quality ◽  
Tillage System ◽  
The Difference ◽  
Flax Seeds

The purpose of research: to improve the technology of growing flax in the Western region of Ukraine on the basis of the introduction of systems for minimizing tillage, which will increase the yield of trusts and seeds. Research methods: field, laboratory, visual and comparative calculation method. Research results: Field experiments included the study of three tillage systems (traditional, canning and mulching) and determining their impact on growth and development and yields of trusts and flax seeds. The traditional tillage system included the following operations: plowing with a reversible plow to a depth of 27 cm, cultivation with simultaneous harrowing and pre-sowing tillage. The conservation system is based on deep shelfless loosening of the soil and provided for chiseling to a depth of 40 cm, disking to a depth of 15 cm, cultivation with simultaneous harrowing, pre-sowing tillage. During the implementation of the mulching system, disking to a depth of 15 cm, cultivation with simultaneous harrowing and pre-sowing tillage with a combined unit was carried out. Tillage implements and machines were used to perform tillage operations: disc harrow BDVP-3,6, reversible plow PON-5/4, chisel PCh-3, cultivator KPSP-4, pre-sowing tillage unit LK-4. The SZ-3,6 ASTPA grain seeder was used for sowing long flax of the Kamenyar variety. Simultaneously with the sowing of flax seeds, local application of mineral fertilizers (nitroammophoska 2 c/ha) was carried out. The application of conservation tillage allows to obtain the yield of flax trust at the level of 3,5 t/ha, which is 0,4 t/ha (12.9 %) more than from the area of traditional tillage and 0,7 t/ha (25 %) in comparison with mulching. In the area with canning treatment, the seed yield was the highest and amounted to 0,64 t/ha. The difference between this option and traditional and mulching tillage reaches 0,06 t/ha (10,3 %) and 0.10 t/ha (18.5 %), respectively. Conclusions. Preservation tillage, which is based on shelf-free tillage to a depth of 40 cm and disking to a depth of 15 cm has a positive effect on plant growth and development, yield and quality of flax.

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