scholarly journals Males of the orb-web spider Argiope bruennichi sacrifice themselves to unrelated females

2010 ◽  
Vol 6 (5) ◽  
pp. 585-588 ◽  
Author(s):  
Klaas W. Welke ◽  
Jutta M. Schneider
Keyword(s):  
Paternal Care ◽  
Genetic Relatedness ◽  
Selective Pressure ◽  
Mating Behaviour ◽  
Copulation Duration ◽  
Female Fecundity ◽  
Web Spider ◽  
Orb Web ◽  
Cannibalism Rate ◽  
Orb Web Spiders

Costs of inbreeding can lead to total reproductive failure and inbreeding avoidance is, therefore, common. In classical sex roles with no paternal care, the selective pressure to avoid inbreeding is mostly on the female, which carries the higher costs. In some orb-web spiders, this situation is very different because females are polyandrous and males are monogynous or at most bigynous. Additionally, females of many entelegyne orb weavers are thought to bias paternity post-copulatorily towards a desired mate. This increases the selective pressure on males to adjust their investment in a mating with regard to the compatibility to a female. Here, we examine whether genetic relatedness influences mating behaviour in the orb-web spider Argiope bruennichi . We mated either a sibling or a non-sibling male to a female in single copulation trials and compared copulation duration, cannibalism rate and female fecundity. Our experiment revealed that males prolonged their copulation duration and were cannibalized more frequently when mating with a non-sibling female. Males mating with a sibling female were more likely to escape cannibalism by copulating briefly, thus presumably increasing their chances of re-mating with a more compatible female. This suggests that males can adaptively adjust their investment relating to the compatibility of a female.

scholarly journals Spatial learning affects thread tension control in orb-web spiders

2013 ◽  
Vol 9 (4) ◽  
pp. 20130052 ◽  
Author(s):  
Kensuke Nakata
Keyword(s):  
Spatial Learning ◽  
Tension Control ◽  
Web Spider ◽  
The Future ◽  
Thread Tension ◽  
Orb Web ◽  
Orb Web Spiders ◽  
The Way

Although it is well known that spatial learning can be important in the biology of predators that actively move around in search for food, comparatively little is known about ways in which spatial learning might function in the strategies of sit-and-wait predators. In this study, Cyclosa octotuberculata , an orb-web spider that uses its legs to contract radial threads of its web to increase thread tension, was trained to capture prey in limited web sectors. After training, spiders that had captured prey in horizontal web sectors applied more tension on radial threads connected to horizontal sectors than spiders that had captured prey in vertical sectors. This result suggests that the effect of experience on C. octotuberculata 's behaviour is not expressed in the way the trained spider responds to prey-derived stimuli and is instead expressed in behaviour by which the spider anticipates the likely direction from which prey will arrive in the future. This illustrates that learning can be important even when the predator remains in one location during foraging bouts.

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.

scholarly journals Remote copulation: male adaptation to female cannibalism

2012 ◽  
Vol 8 (4) ◽  
pp. 512-515 ◽  
Author(s):  
Daiqin Li ◽  
Joelyn Oh ◽  
Simona Kralj-Fišer ◽  
Matjaž Kuntner
Keyword(s):  
Sexual Conflict ◽  
Sperm Transfer ◽  
Copulation Duration ◽  
Sexual Cannibalism ◽  
Empirical Testing ◽  
Web Spider ◽  
Maladaptive Behaviour ◽  
Orb Web ◽  
Male Organ

Sexual cannibalism by females and associated male behaviours may be driven by sexual conflict. One such male behaviour is the eunuch phenomenon in spiders, caused by total genital emasculation, which is a seemingly maladaptive behaviour. Here, we provide the first empirical testing of an adaptive hypothesis to explain this behaviour, the remote copulation, in a highly sexually cannibalistic orb-web spider Nephilengys malabarensis . We demonstrate that sperm transfer continues from the severed male organ into female genitals after the male has been detached from copula. Remote copulation increases the total amount of sperm transferred, and thus probably enhances paternity. We conclude that the mechanism may have evolved in response to sexual cannibalism and female-controlled short copulation duration.

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.

scholarly journals Orb-web spider color polymorphism through the eyes of multiple prey and predators

2017 ◽  
Author(s):  
Nathalia Ximenes ◽  
Felipe M. Gawryszewski
Keyword(s):  
Color Vision ◽  
Warning Signal ◽  
Sensory Systems ◽  
Color Polymorphism ◽  
Avian Predators ◽  
Web Spider ◽  
Color Morphs ◽  
Orb Web ◽  
Distinct Color ◽  
Orb Web Spiders

ABSTRACTThe sensory drive theory predicts that signals, sensory systems, and signaling behavior should coevolve. Variation in the sensory systems of prey and predators may explain the diversity of color signals, such as color polymorphism. The spider Gasteracantha cancriformis (Araneidae) possesses several conspicuous color morphs. The aim of the present study was to assess whether the color polymorphism of G. cancriformis may be maintained by pressure from multiple signal receivers, such as prey and predators with distinct color vision systems. Although, the multiple receivers world is a more realistic scenario, it has received little attention. In orb-web spiders, the prey attraction hypothesis states that conspicuous colors are prey lures that increase spider foraging success via flower mimicry. However, in highly defended species, conspicuous colors could also be a warning signal to predators. We used color vision modelling to estimate chromatic and achromatic contrast of G. cancriformis morphs as perceived by potential prey and predator taxa. Our results revealed that individual prey and predator taxa perceive the conspicuousness of morphs differently. For instance, the red morph is perceived as quite conspicuous to lepidopteran prey and avian predators, but not by other insects. Therefore, the multiple prey and predator hypotheses may explain the evolution of color polymorphism in G. cancriformis. However, flower mimicry hypothesis was weakly corroborated. Other parameters that are not evaluated by color vision models, such as distance, shape, angle, and pattern geometry could also affect the perception of color morphs by both prey and predators and thereby influence morph survival.

scholarly journals Shaped by the Sun: the effect of exposure to sunlight on the evolution of spider bodies

2021 ◽  
Vol 17 (11) ◽  
Author(s):  
Leonardo Ferreira-Sousa ◽  
Pedro N. Rocha ◽  
Paulo C. Motta ◽  
Felipe M. Gawryszewski
Keyword(s):  
Meteorological Data ◽  
Sun Exposure ◽  
The Body ◽  
Protected Species ◽  
Body Area ◽  
Web Spider ◽  
Model Combining ◽  
Orb Web ◽  
Orb Web Spiders ◽  
Body Shapes

Body temperature can strongly influence fitness. Some Sun-exposed ectotherms thermoregulate by adjusting body posture according to the Sun's position. In these species, body elongation should reduce the risk of heat stress by allowing the exposure of a smaller body area to sunlight. Therefore, selection should favour more elongated bodies in Sun-exposed than in Sun-protected species. Diurnal orb-web spider species that sit on their webs are more likely to be Sun-exposed, on average, than nocturnal or diurnal shelter-building species. We measured the body elongation of orb-web spiders (Araneae, Araneidae) across 1024 species and classified them as Sun-protected or exposed based on the literature. We found that Sun-exposed species evolved more elongate bodies than Sun-protected ones. Further, we built a model combining traditional heat transfer models with models of thermoregulatory postures in orb-web spiders and meteorological data. The model indicates that body elongation in large orb-web spiders decreases the risk of high body temperatures. Overall, our results suggest that Sun exposure influenced the evolution of body shapes of orb-web spiders.

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.

Sign in / Sign up

Export Citation Format

Share Document