Disturbance behaviors in the spider Uloborus glomosus (Araneae, Uloboridae): possible predator avoidance strategies

1990 ◽  
Vol 68 (6) ◽  
pp. 1090-1097 ◽  
Author(s):  
Paula E. Cushing ◽  
Brent D. Opell
Keyword(s):  
Direct Contact ◽  
Predator Avoidance ◽  
Natural Setting ◽  
Adult Females ◽  
Avoidance Strategies ◽  
Predatory Wasp ◽  
The Web

When disturbed, Uloborus glomosus either remain in position at the hub of their orb webs, jump from the web, move to the edge of the web, or shake the web. Juveniles more frequently exhibited moving and jumping responses, whereas the majority of adults jumped from the web or remained in position. Adults with linear stabilimenta tended to shake their webs in the morning and to jump from their webs in the evening. Juveniles with linear stabilimenta shook their webs in the afternoon and evening, whereas those with circular stabilimenta tended to move to the edge of the web or shake the web during all times of day. Adult females with egg-sac chains were usually aligned with the egg sacs and tended to remain in position when disturbed. Both adults and juveniles lacking stabilimenta or egg-sac chains tended to jump from their webs or move to the edge of their webs. Spiders filmed in a natural setting responded to contact by insects. Predatory wasps repeatedly flew near the spiders without eliciting a response. A tethered predatory wasp held above both juveniles and adults in the laboratory also failed to elicit responses from the spiders. The data agree with the hypothesis that moving to the edge of, shaking, and jumping from the web may be predator avoidance strategies elicited by direct contact.

scholarly journals Microplastic exposure increases predictability of predator avoidance strategies in hermit crabs

2020 ◽  
Vol 1 ◽  
pp. 100005
Author(s):  
Gerrit B. Nanninga ◽  
Cat Horswill ◽  
Sarah M. Lane ◽  
Andrea Manica ◽  
Mark Briffa
Keyword(s):  
Predator Avoidance ◽  
Hermit Crabs ◽  
Avoidance Strategies

Olfactory cues from conspecifics inhibit the web-invasion behavior of Portia, web-invading araneophagic jumping spiders (Araneae: Salticidae)

1993 ◽  
Vol 71 (7) ◽  
pp. 1415-1420 ◽  
Author(s):  
Marianne B. Willey ◽  
Robert R. Jackson
Keyword(s):  
Olfactory Cues ◽  
Adult Males ◽  
Aggressive Mimicry ◽  
Jumping Spiders ◽  
Web Geometry ◽  
Adult Females ◽  
Conspecific Adult ◽  
Invasion Behavior ◽  
Courtship Displays ◽  
The Web

Portia is a genus of web-invading araneophagic spiders that use aggressive mimicry to capture their spider prey. In an experimental study, we demonstrate that adult females of Portia africana, P. fimbriata, P. labiata, and P. schultzi produce olfactory cues that affect the behavior of conspecific adult males, adult females, and juveniles. The olfactory cues of Portia spp. inhibit aggressive mimicry of conspecific spiders that are on a prey spider's web even if the prey spider is visible. This inhibition occurs regardless of the prey spider's web geometry. Prey pursuit by Portia is also inhibited when conspecific females provide olfactory cues in cases where the prey is a spider inhabiting a web. Olfactory cues from adult females elicit courtship displays of conspecific males when males are on the prey spider's web. Portia spp. do not alter their behavior when exposed to olfactory cues of heterospecifics.

scholarly journals Azadirachtin on Oligonychus yothersi in yerba mate Ilex paraguariensis

2016 ◽  
Vol 46 (10) ◽  
pp. 1777-1782
Author(s):  
Luis Francisco Angeli Alves ◽  
Claudecir Castilho Martins ◽  
Ana Paula Mamprim ◽  
Marcos Botton
Keyword(s):  
Direct Contact ◽  
Field Experiments ◽  
Ilex Paraguariensis ◽  
Yerba Mate ◽  
Egg Hatching ◽  
Treated Area ◽  
Adult Females ◽  
Crop Field ◽  
Mite Behavior ◽  
Leaf Disks

ABSTRACT: The red mite Oligonychus yothersi is one of the main pests of yerba mate in Brazil The damage this mite causes leads to leaf drop and decreased production. There are no registered acaricides for use in yerba mate; thus, laboratory and field experiments were performed to evaluate the effect of azadirachtin (Azamax(r), 250mL 100L-1) for the control of the red mite in yerba mate. In the laboratory, azadirachtin was applied to yerba mate leaf disks before (residual contact) and after (direct contact) infestation with 15 newly emerged red mite adult females. The effect of azadirachtin on mite behavior was evaluated in arenas with treated and untreated yerba mate leaves, and the number of mites in both areas was recorded. Ovicidal action was evaluated by applying azadirachtin to eggs and recording egg hatching. In the field, two applications of the product were performed (1L spray liquid plant-1) with a 7-day interval. The numbers of living mites were evaluated at 7, 14 and 21 days following the first application on randomly collected leaves. It was observed 86.6 and 91.4% of mortality following 24h of residual and direct contact, respectively. Repellent (62% of individuals leaving the treated area) and ovicidal (98.9% decrease in egg hatching) effects were also observed. The mite population in the yerba mate crop field had decreased by 59.6% at 14 days after the first application of azadirachtin. The results show the potential of azadirachtin for the control of O. yothersi in yerba mate in Brazil.

Trust and Web Interface

2011 ◽  
pp. 191-219
Keyword(s):  
Direct Contact ◽  
Contact Point ◽  
Online Environment ◽  
Web Interface ◽  
Physical Size ◽  
Face To Face ◽  
Physical Cues ◽  
Brick And Mortar ◽  
The Relationship ◽  
The Web

In the brick and mortar world, the trading party makes an assessment of the trustworthiness of the counter party and the trading environment by various physical cues such as physical size of organization, its overall infrastructure, face-to-face interactions, physically examining the product etc. However, in the faceless environment of B2B e-commerce, same physical cues are not available and hence, the trading parties rely on the direct ‘contact point’ - the web-interface or the company’s website/portal to interact and communicate with each other. An effective web interface can induce trust in online environment of B2B e-commerce. The levels of assurance in respect of various dimensions may determine effectiveness of web interface. The present chapter makes an attempt to examine the relationship between the levels of assurance in respect of various dimensions of web interface and the level of trust in B2B e-commerce.

Predator Avoidance Strategies of the Crayfish Orconectes Virilis

Crustaceana ◽  
1996 ◽  
Vol 69 (3) ◽  
pp. 400-412 ◽  
Author(s):  
Brian Mitchell ◽  
Brian A. Hazlett
Keyword(s):  
Predator Avoidance ◽  
Orconectes Virilis ◽  
Avoidance Strategies

scholarly journals Mother Nature in Silko’s Yellow Woman : An Ecofeminist Dimension

2018 ◽  
Vol 7 (3) ◽  
pp. 88-97
Author(s):  
Olfa Gandouz
Keyword(s):  
Direct Contact ◽  
Theoretical Background ◽  
Natural Setting ◽  
The Novel ◽  
Basic Principles ◽  
Her Family ◽  
Mother Nature ◽  
Female Protagonist ◽  
Postmodern Novel ◽  
Shed Light

Abstract Ecofeminism is a term coined by Françoise D’Eubonne in her book Feminism or Death (1974) to show the affinities between ecology and feminism. Both women and nature are perceived as passive elements and like women who complain about patriarchal constraints, ecologists shed light on the impacts of human exploitation over nature which is affected by pollution. Some dimensions of ecofeminism are present in Leslie Marmon Silko’s The Yellow Woman (1981). The postmodern novel contains a female character who forges a link with the natural surroundings and is in a direct contact with some natural elements like plants and animals. What is specific about the heroine is that she escapes her matriarchal society and goes back to nature in order to reconstruct her identity. At the end of the narrative, the female narrator leaves the natural setting and goes back to her family to replay social roles. The present article sets out to study the importance of Mother Nature for the female narrator and to examine the affinities between Earth Mother and the female protagonist. The first part will offer a theoretical background about the basic principles of ecofeminism. Then, my analysis will touch upon the aspects of ecofeminism in the novel. However, the last part will focus on the way the narrator goes beyond her matriarchal culture and reshapes female identity.

scholarly journals Are Minority Opinions Shared Less?

2021 ◽  
Vol 229 (4) ◽  
pp. 251-256
Author(s):  
Birka Zapf ◽  
Mandy Hütter ◽  
Kai Sassenberg
Keyword(s):  
Product Evaluation ◽  
Natural Setting ◽  
Regression To The Mean ◽  
Excellent Opportunity ◽  
The Mean ◽  
Product Ratings ◽  
The Web

Abstract. Product evaluation portals on the web that collect product ratings provide an excellent opportunity to observe opinion sharing in a natural setting. Evidence across different paradigms shows that minority opinions are shared less than majority opinions. This article reports a study testing whether this effect holds on product evaluation portals. We tracked the ratings of N = 76 products at 12 measurement points. We predicted that the higher (lower) the mean initial rating of a product, the more positive (negative) the newly contributed ratings will differ from this baseline – as an indication of the preferred sharing of majority compared to minority opinions. We found, however, that newly added ratings were on average less extreme than earlier ratings. These results can either be interpreted as regression to the mean or evidence for the preferred sharing of minority opinions.

Drift and activity responses of black flies (Simulium vittatum) in the field: influences of tactile and injury-released stimuli from simulated predation

Behaviour ◽  
2016 ◽  
Vol 153 (2) ◽  
pp. 227-244 ◽  
Author(s):  
Aaron M. Sullivan ◽  
Elyse C. Johnson
Keyword(s):  
Defensive Behavior ◽  
Predator Avoidance ◽  
Chemical Cues ◽  
Black Flies ◽  
Multiple Cues ◽  
Simulium Vittatum ◽  
Tactile Stimuli ◽  
Avoidance Strategies ◽  
Chemical Stimuli ◽  
Sensory Mechanisms

Prey must manage threat from many types of predators; therefore, selection should favor sensory mechanisms that allow the refinement of defensive behavior. To assess responses to tactile and chemical stimuli related to predation, we observed drift and activity of larval black flies (Simulium vittatum) to simulated predator contact intended to imitate benthic and drift predators as well as a combination of tactile and injury-released stimuli. In the field, larvae responded to tactile stimuli applied to the head with a higher frequency of curling and posterior abdominal segments with a higher frequency of drifting. Additionally, chemical cues from injured conspecifics followed by tactile stimuli applied to the head resulted in a higher frequency of drifting than to either cue independently and this effect was more pronounced at night. The results of our study indicate that larval black flies may utilize multiple cues to determine their antipredator and predator avoidance strategies.

Performance level and efficiency of two differing predator-avoidance strategies depend on nutritional state of the prey fish

2009 ◽  
Vol 63 (12) ◽  
pp. 1735-1742 ◽  
Author(s):  
Volker Huckstorf ◽  
Wolf-Christian Lewin ◽  
Thomas Mehner ◽  
Christian Wolter
Keyword(s):  
Predator Avoidance ◽  
Performance Level ◽  
Nutritional State ◽  
Prey Fish ◽  
Avoidance Strategies

Saturn's E, G and F rings: modulated by the plasma sheet

1984 ◽  
Vol 75 ◽  
pp. 597
Author(s):  
E. Grün ◽  
G.E. Morfill ◽  
T.V. Johnson ◽  
G.H. Schwehm
Keyword(s):  
Solar Wind ◽  
Direct Contact ◽  
Transport Processes ◽  
Time Variable ◽  
Dust Particles ◽  
Spatial Diffusion ◽  
Drag Forces ◽  
Orbit Perturbation ◽  
Time Variations ◽  
F Ring

ABSTRACTSaturn's broad E ring, the narrow G ring and the structured and apparently time variable F ring(s), contain many micron and sub-micron sized particles, which make up the “visible” component. These rings (or ring systems) are in direct contact with magnetospheric plasma. Fluctuations in the plasma density and/or mean energy, due to magnetospheric and solar wind processes, may induce stochastic charge variations on the dust particles, which in turn lead to an orbit perturbation and spatial diffusion. It is suggested that the extent of the E ring and the braided, kinky structure of certain portions of the F rings as well as possible time variations are a result of plasma induced electromagnetic perturbations and drag forces. The G ring, in this scenario, requires some form of shepherding and should be akin to the F ring in structure. Sputtering of micron-sized dust particles in the E ring by magnetospheric ions yields lifetimes of 102to 104years. This effect as well as the plasma induced transport processes require an active source for the E ring, probably Enceladus.

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