scholarly journals Nocturnal foraging enhanced by enlarged secondary eyes in a net-casting spider

2016 ◽  
Vol 12 (5) ◽  
pp. 20160152 ◽  
Author(s):  
Jay A. Stafstrom ◽  
Eileen A. Hebets
Keyword(s):  
Repeated Measures ◽  
Visual Cues ◽  
Prey Capture ◽  
Past Research ◽  
Diet Breadth ◽  
Posterior Median ◽  
Visual Occlusion ◽  
Nocturnal Foraging ◽  
Visually Based ◽  
Median Eyes

Animals that possess extreme sensory structures are predicted to have a related extreme behavioural function. This study focuses on one such extreme sensory structure—the posterior median eyes of the net-casting spider Deinopis spinosa. Although past research has implicated the importance of vision in the nocturnal foraging habits of Deinopis , no direct link between vision in the enlarged eyes and nocturnal foraging has yet been made. To directly test the hypothesis that the enlarged posterior median eyes facilitate visually based nocturnal prey capture, we conducted repeated-measures, visual occlusion trials in both natural and laboratory settings. Our results indicate that D. spinosa relies heavily on visual cues detected by the posterior median eyes to capture cursorial prey items. We suggest that the enlarged posterior median eyes benefit D. spinosa not only through increased diet breadth, but also by allowing spiders to remain active solely at night, thus evading predation by diurnal animals.

THE QUALITY OF VISION IN THE CTENID SPIDER CUPIENNIUS SALEI

1992 ◽  
Vol 164 (1) ◽  
pp. 227-242 ◽  
Author(s):  
M. F. LAND ◽  
F. G. BARTH
Keyword(s):  
Predator Avoidance ◽  
Prey Capture ◽  
Cupiennius Salei ◽  
Quality Of Vision ◽  
Visual Behaviour ◽  
Similar Range ◽  
Retinal Resolution ◽  
Spider Cupiennius Salei ◽  
Median Eyes

Much is known about the mechanosensory behaviour of the spider Cupiennius Keyserling, but much less about its visual capabilities. In this study the quality of the optical image, the retinal resolution and the fields of view were assessed for each of the four pairs of eyes. The image is of good quality in all eyes. The principal (antero-median) eyes lack a tapetum and have an inter-receptor angle of 2.9°. The three secondary eyes (antero-lateral, postero-median and posterolateral) all have ‘gridiron’ tapeta with receptors arranged in rows. The angular separations (along rows × between rows) are 3.6° × 9.3°, 0.9° × 2.3° and 1.0° × 3.0°, respectively. Although the disposition of eyes on the head is similar to that of pisaurid spiders, all other features of the eyes, including the sizes and shapes of the fields of view, resemble those of lycosid spiders. The peripheral visual system of Cupiennius can thus, in principle, support a similar range of visual behaviour to that of lycosids, which includes prey capture, predator avoidance and courtship.

scholarly journals Mechanisms behind the portion size effect-visibility and bite size

2017 ◽  
Author(s):  
Kyle Stanley Burger ◽  
Susan L. Johnson
Keyword(s):  
Size Effect ◽  
Energy Intake ◽  
Repeated Measures ◽  
Visual Cues ◽  
Normal Weight ◽  
Portion Size ◽  
Experimental Conditions ◽  
Bite Size ◽  
Subject Design ◽  
Participant Characteristics

Increases in portion size lead to increases in energy intake, yet the mechanisms behind this ‘portion size effect’ are unclear. This study tested possible mechanisms of the portion size effect i.e., bite size and visual cues in 30 over- and normal-weight individuals (15 men, 15 women). A 2x2 repeated measures, within-subject design was used to test the effects of portion size (410g vs. 820g of a pasta dish) and visual cues (blindfolded vs. visible) on energy intake. At each meal participants were exposed to one of four experimental conditions (small portion/visible; small portion/blindfold; large portion/visible; large portion/blindfold). Participant characteristics, food intake, number of bites, meal duration, palatability measures and hunger and fullness were assessed. In response to a doubling of the portion presented, entrée energy intake increased 26% (220kcal P < 0.001) and mean bite size increased 2.4g/bite (P < 0.05). Overweight individuals consumed 40% (334kcal) more of the entrée in response to the large portion condition (P < 0.05), while lean individuals’ intakes did not differ (P < 0.56). A 12% (122kcal) decrease in entrée intake was observed in the blindfolded condition (P < 0.01), but no portion by visual cue interaction was found; indicating that blindfolding did not attenuate the portion size effect. These data suggest that the portion size effect is greater in overweight individuals and occurs via changes in bite size.

Auditory and Visual Executive Functions in Children and Response to Methylphenidate: A Randomized Controlled Trial

2017 ◽  
Vol 24 (2) ◽  
pp. 235-245
Author(s):  
Yaffa Hadar ◽  
Shraga Hocherman ◽  
Oren Lamm ◽  
Emanuel Tirosh
Keyword(s):  
Executive Functions ◽  
Visual Cues ◽  
Controlled Trial ◽  
Crossover Design ◽  
Control Groups ◽  
Children With Adhd ◽  
Randomized Controlled ◽  
The Difference ◽  
Visually Based ◽  
And Control

Objectives: The aim of the study was to assess auditory and visually based executive functions (EFs) and the effect of methylphenidate (MPH) in children with ADHD. Methods: Thirty-six boys between the ages of 8.3 and 9.7 years with ADHD and 36 matched controls were included. The study group was randomized into MPH and placebo for 7 days each in a crossover design. A Cued Choice Reaction Time (CCRT) test that included incongruent cuing was administered at baseline and following 1 and 2 weeks. Results: The difference between the study and control groups was more evident with visual cues and incongruent cuing. Increased gains by children with predominantly hyperactive–impulsive\combined (HI\C) type of ADHD were observed under MPH. Conclusions: The differences between children with ADHD and typical children are more pronounce under incongruent auditory cuing . The gains attributable to MPH are more specific to tasks involving auditory and visual EFs and in children with HI\C type ADHDs.

scholarly journals Risk assessment and the use of novel shortcuts in spatial detouring tasks in jumping spiders

2019 ◽  
Vol 30 (5) ◽  
pp. 1488-1498 ◽  
Author(s):  
Samuel Aguilar-Argüello ◽  
Daniel Gerhard ◽  
Ximena J Nelson
Keyword(s):  
Spatial Ability ◽  
Visual Cues ◽  
Prey Capture ◽  
Dimensional Space ◽  
A Priori ◽  
Complex Environments ◽  
Environmental Complexity ◽  
3 Dimensional ◽  
Jumping Spiders ◽  
Efficient Route

AbstractSelection on individuals that incorporate risk to quickly and accurately make a priori navigational assessments may lead to increased spatial ability. Jumping spiders (Araneae: Salticidae) are characterized by their highly acute vision, which mediates many behaviors, including prey capture and navigation. When moving to a specific goal (prey, nest, a potential mate, etc.), salticids rely on visual cues and spatial memory to orient in 3-dimensional space. Salticid spatial ability has been studied in homing and detour tasks, with Portia being considered one of the most skillful genera in terms of spatial ability in the family. Commonly living in complex environments, salticids are likely to encounter a wide variety of routes that could lead to a goal, and, as selection favors individuals that can accurately make assessments, they may be able to assess alternative route distances to select the most efficient route. Here, we tested whether 2 salticid species (Portia fimbriata and Trite planiceps) can discriminate and assess between different available routes by their length, and riskiness to escape from a stressful scenario. Results suggest that while Portia is more likely to choose the easiest and shortest escape routes, Trite is faster in both decision making about which route to take, and to escape. However, some individuals were able to use novel shortcuts instead of the routes expected, with Portia containing a higher proportion of shortcut-takers than Trite. These differences in spatial ability seem to correspond with the environmental complexity inhabited by each species.

scholarly journals Myrmarachnine jumping spiders of the new subtribe Levieina from Papua New Guinea (Araneae, Salticidae, Myrmarachnini)

ZooKeys ◽  
2019 ◽  
Vol 842 ◽  
pp. 85-112 ◽  
Author(s):  
Wayne P. Maddison ◽  
Tamás Szűts
Keyword(s):  
Phylogenetic Analysis ◽  
New Species ◽  
Papua New Guinea ◽  
New Guinea ◽  
Coi Gene ◽  
New Genera ◽  
Jumping Spiders ◽  
Posterior Median ◽  
Three New Species ◽  
Median Eyes

A previously unreported radiation of myrmarachnine jumping spiders from New Guinea is described, which, although having few known species, is remarkably diverse in body forms. This clade is the new subtribe Levieina, represented by seven new species in three new genera. WithinLevieagen. n.are three new species,L.herbertisp. n.,L.lornaesp. n., andL.francesaesp. n., all of which are unusual among the myrmarachnines in appearing as typical salticids, not antlike.Papuamyrgen. n.superficially resemblesLigonipesKarsch, 1878 orRhombonotusL. Koch, 1879 as a compact antlike spider, but lacks their laterally-compressed palp and bears an ectal spur on the paturon of the chelicera. Two species ofPapuamyrgen. n.are described,Papuamyromhifosgasp. n.andP.pandorasp. n.Agorioidesgen. n., containingA.cherubinosp. n.andA.papagenasp. n., is antlike, with the carapace sunken inwards (concave) between the posterior lateral and posterior median eyes. Phylogenetic analysis of data from the 28S, 16SND1, and COI gene regions of 29 species of myrmarachnines shows that the three new genera form a clade that is sister to the subtribe Myrmarachnina (Myrmarachnesensu lato), with the subtribe Ligonipedina less closely related.

Incremental Visual Occlusion During Split-Belt Treadmill Walking Has No Gradient Effect on Adaptation or Retention

2021 ◽  
pp. 003151252110503
Author(s):  
Amanda E. Stone ◽  
Adam C. Hockman ◽  
Jaimie A. Roper ◽  
Chris J. Hass
Keyword(s):  
Visual Field ◽  
Repeated Measures ◽  
Visual Information ◽  
Step Length ◽  
Group Differences ◽  
Lower Visual Field ◽  
Normal Vision ◽  
Locomotor Adaptation ◽  
Visual Occlusion ◽  
Length Standard

Split-belt treadmills have become an increasingly popular means of quantifying ambulation adaptability. Multiple sensory feedback mechanisms, including vision, contribute to task execution and adaptation success. No studies have yet explored visual feedback effects on locomotor adaptability across a spectrum of available visual information. In this study, we sought to better understand the effects of visual information on locomotor adaptation and retention by directly comparing incremental levels of visual occlusion. Sixty healthy young adults completed a split-belt adaptation protocol, including a baseline, asymmetric walking condition (adapt), a symmetric walking condition (de-adapt), and another asymmetric walking condition (re-adapt). We randomly assigned participants into conditions with varied visual occlusion (i.e., complete and lower visual field occlusion, or normal vision). We captured kinematic data, and outcome measures included magnitude of asymmetry, spatial and temporal contributions to step length asymmetry, variability of the final adapted pattern, and magnitude of adaptation. We used repeated measures and four-way MANOVAs to examine the influence of visual occlusion and walking condition. Participants with complete, compared to lower visual field visual occlusion displayed less consistency in their walking pattern, evident via increased step length standard deviation ( p = .007, d = 0.89), and compared to normal vision groups ( p = .003 d = 0.81). We found no other group differences, indicating that varying levels of visual occlusion did not significantly affect locomotor adaptation or retention. This study offers insight into the role vision plays in locomotor adaptation and retention with clinical utility for improving variability in step control.

Moebius Syndrome: Measures of Observer Intelligibility with versus without Visual Cues in Bilateral Facial Paralysis

2007 ◽  
Vol 44 (5) ◽  
pp. 518-522 ◽  
Author(s):  
Shelley Von Berg ◽  
Douglas McColl ◽  
Tami Brancamp
Keyword(s):  
Repeated Measures ◽  
Visual Information ◽  
Speech Intelligibility ◽  
Visual Cues ◽  
Auditory Signal ◽  
Speech Pathology ◽  
Auditory Information ◽  
Moebius Syndrome ◽  
High Predictability ◽  
The University

Objective: This study investigated observers’ intelligibility for the spoken output of an individual with Moebius syndrome (MoS) with and without visual cues. Design: An audiovisual recording of the speaker's output was obtained for 50 Speech Intelligibility in Noise sentences consisting of 25 high predictability and 25 low predictability sentences. Stimuli were presented to observers under two conditions: audiovisual and audio only. Data were analyzed using a multivariate repeated measures model. Observers: Twenty students and faculty affiliated with the Department of Speech Pathology and Audiology at the University of Nevada, Reno. Results: ANOVA mixed design revealed that intelligibility for the audio condition only was significantly greater than intelligibility for the audiovisual condition; and accuracy for high predictability sentences was significantly greater than accuracy for low predictability sentences. Conclusions: The compensatory substitutional placements for phonemes produced by MoS speakers may detract from the intelligibility of speech. This is similar to the McGurk-MacDonald effect, whereby an illusory auditory signal is perceived when visual information from lip movements does not match the auditory information from speech. It also suggests that observers use contextual clues, more than the acoustic signal alone, to arrive at the accurate recognition of the message of the speakers with MoS. Therefore, speakers with MoS should be counseled in the top-down approach of auditory closure. When the speech signal is degraded, predictable messages are more easily understood than unpredictable ones. It is also important to confirm the speaking partner's understanding of the topic before proceeding.

Motor and Cognitive Testing of Bone Marrow Transplant Patients after Chemoradiotherapy

1989 ◽  
Vol 68 (3_suppl) ◽  
pp. 1227-1241 ◽  
Author(s):  
Pia Earth ◽  
Robert S. Kennedy ◽  
Norman E. Lane ◽  
William P. Dunlap ◽  
J. Mark Ordy
Keyword(s):  
Bone Marrow ◽  
Bone Marrow Transplant ◽  
Repeated Measures ◽  
High Reliability ◽  
Past Research ◽  
Marrow Transplant ◽  
Cognitive Testing ◽  
Single Individual ◽  
Performance Deficits ◽  
Transplant Patients

Assessment of cognitive and motor performance of bone marrow transplant patients prior to, during, and following intensive toxic chemoradiotherapy may provide an important adjunct to measures of physiological and medical status. The present study is an attempt to assess whether, as side-effects, these aggressive treatments result in cognitive performance deficits, and if so, whether such changes recover posttreatment. Measurement of cognitive ability in this situation presents special problems not encountered with one-time tests intended for healthy adults. Such tests must be sensitive to changes within a single individual, which emphasizes the crucial importance of high reliability, stability across repeated-measures, and resistance to confounding factors such as motivation and fatigue. The present research makes use of a microbased portable test battery developed to have reliable and sensitive tests which were adapted to study the special requirements of transplant patients who may suffer cognitive deficits as a result of treatment. The results showed slight but significant changes in neuropsychological capacity when compared to baseline levels and controls, particularly near the beginning of treatment. The sensitivity of the battery in detecting such subtle temporary changes is discussed in terms of past research showing effects of other stressors, such as simulated high altitude and ingestion of alcohol, on these measures.

Effects of Text Enhancement, Identical Prescription-Package Names, Visual Cues, and Verbal Provocation on Visual Searches of Look-Alike Drug Names: A Simulation and Eye-Tracking Study

2019 ◽  
Vol 62 (7) ◽  
pp. 1102-1116
Author(s):  
Hailiang Wang ◽  
Calvin K. L. Or
Keyword(s):  
Eye Tracking ◽  
Repeated Measures ◽  
Visual Cues ◽  
Eye Gaze ◽  
Visual Cue ◽  
Repeated Measures Design ◽  
Target Drug ◽  
Drug Names ◽  
Text Enhancement ◽  
Visual Searches

Objective Simulation and eye tracking were used to examine the effects of text enhancement, identical prescription-package names, visual cues, and verbal provocation on visual searches of look-alike drug names. Background Look-alike drug names can cause confusion and medication errors, which jeopardize patient safety. The effectiveness of many strategies that may prevent these problems requires evaluation. Method We conducted two experiments that were based on a four-way, repeated-measures design. The within-subject factors were text enhancement, identical prescription-package names, visual cues, and verbal provocation. In Experiment 1, 40 nurses searched for and selected a target drug from an array of drug packages on a pharmacy shelf mock-up. In Experiment 2, the eye movements of another 40 nurses were tracked while they performed a computer-based drug search task. Results Text enhancement had no significant effect on the drug search. Nurses selected the target drugs more quickly and easily when the prescriptions and drug packages shared identical drug name formats. The use of a visual cue to direct nurses’ attention facilitated their visual searches and improved their eye gaze behaviors. The nurses reported greater mental effort if they were provoked verbally during the drug search. Conclusion Efficient and practical strategies should be adopted for designs that facilitate accurate drug search. Among these strategies are using identical name appearances on drug prescriptions and packages, using a visual cue to direct nurses’ attention, and avoiding rushing nurses while they are concentrating. Application The findings aim to inspire recommendations for work system designs that will improve the visual search of look-alike drug names.

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