Visual fields of the compound eyes of four species of Cicindelidae (Coleoptera)

1980 ◽  
Vol 58 (3) ◽  
pp. 326-336 ◽  
Author(s):  
J. E. Kuster ◽  
W. G. Evans
Keyword(s):  
Visual Field ◽  
North American ◽  
Visual Fields ◽  
Morphological Characters ◽  
Head Size ◽  
Compound Eyes ◽  
Eye Size ◽  
Nocturnal Species ◽  
The Relationship ◽  
Diurnal Species

Visual field angles were measured around the circumference of the compound eyes of four species of North American Cicindelidae and plotted on Mollweide homolographs. Areas of monoscopic and stereoscopic visual fields and blind areas were calculated. In contrast to the nocturnal species (Amblycheila schwarzi and Omus californicus), the crepuscular species (Megacephala Carolina) and the diurnal species (Cicindela tranquebarica) have more ommatidia and larger eye size: head size ratios, total visual fields, and stereoscopic visual fields. These characters are considered to be derived and confirm the phylogenetic sequence of the four genera that was previously based on other morphological characters. The relationship between these characters and the biology of each species is also discussed.

The variation of resolution and of ommatidial dimensions in the compound eyes of the fiddler crab Uca lactea annulipes (Ocypodidae, Brachyura, Decapoda)

1996 ◽  
Vol 199 (7) ◽  
pp. 1569-1577 ◽  
Author(s):  
J Zeil ◽  
M Al-Mutairi
Keyword(s):  
Visual Field ◽  
Fiddler Crab ◽  
Visual Fields ◽  
Horizontal Resolution ◽  
Resolving Power ◽  
Compound Eyes ◽  
Vertical Resolution ◽  
Histological Techniques ◽  
Uca Lactea

We studied variations in the optical properties of the compound eyes of Uca lactea annulipes using in vivo optical and histological techniques. The distribution of resolving power in the eyes of this fiddler crab species is typical for arthropods that inhabit flat environments: the eyes possess a panoramic equatorial acute zone for vertical resolution and a steep decrease of resolution away from the eye equator in the dorsal and ventral visual fields. The dimensions of the cellular components of the ommatidia vary accordingly: in the equatorial part of the eyes, facets are larger, and crystalline cones and rhabdoms are longer than in the dorsal and ventral parts of the eyes. Along the eye equator, horizontal resolution is low compared with vertical resolution and varies little throughout the visual field. The eyes of Uca lactea annulipes are unusual in that the gradient of vertical anatomical and optical resolution is steeper in the dorsal than in the ventral visual field. We interpret this difference as indicating that the information content of the world as seen by the crabs differs above and below the horizon line in specific and predictable ways.

Search Performance as a Function of Peripheral Acuity

1965 ◽  
Vol 7 (6) ◽  
pp. 527-537 ◽  
Author(s):  
Dorothy M. Johnston
Keyword(s):  
Visual Field ◽  
Visual Fields ◽  
Search Time ◽  
Apparent Size ◽  
Search Performance ◽  
Small Fields ◽  
Time Required ◽  
The Relationship ◽  
And Training

This study was made to investigate the relationship between the size of visual fields of observers and time required to locate targets on static displays. The findings, which indicate that people with large visual fields can find targets more rapidly than observers with small fields, have practical selection and training application. Equations are presented which can be used to determine search time that can be expected as a function of the size of the visual field of the observer and the apparent size of the area being searched.

The separation of Carex disticha and Carex sartwellii and the status of Carex disticha in North America

1988 ◽  
Vol 66 (11) ◽  
pp. 2323-2330 ◽  
Author(s):  
P. M. Catling ◽  
A. A. Reznicek ◽  
B. S. Brookes
Keyword(s):  
North American ◽  
Principal Component ◽  
Small Region ◽  
Morphological Characters ◽  
Scatter Diagram ◽  
The North ◽  
The Status ◽  
Beak Length ◽  
The Relationship ◽  
Distinguishing Features

To clarify the relationship between the Eurasian Carex disticha and the North American Carex sartwellii, 38 morphological characters were measured in 30 specimens of each. Various qualitative features were also scored. Through analysis of variance (ANOVA), a reduced number of 10 important continuous characters was obtained and the sample of each taxon was increased to 50. ANOVA of these 10 characters revealed that perigynium length and perigynium beak length were the most important discriminating characters, but in a scatter diagram of these two, 15% of the sample occupied a region of overlap. Principal-component analysis and discriminant analysis using the 10 characters resulted in a separation of the two groups, but a small region of overlap existed in both cases. The two taxa are distinct by virtue of accumulation of small morphological and other differences in a number of characters, rather than by sharp differentiation in a few characters. Carex disticha has larger perigynia with beaks (0.8–)1–1.5(–2.3) mm long, whereas C. sartwellii has smaller perigynia with beaks 0.4–1(–1.2) mm long. All distinguishing features are discussed and a key is provided. Immature vouchers for the occurrence of C. disticha in southwestern Quebec are confirmed on the basis of features of the inflorescence. The only other North American station of C. disticha, discovered in Simcoe Co., Ontario, in 1972 and extant in 1986, is also confirmed in the numerical analyses.

scholarly journals Comparative Studies on Dark Adaptation in the Compound Eyes of Nocturnal and Diurnal Lepidoptera

1960 ◽  
Vol 44 (1) ◽  
pp. 195-203 ◽  
Author(s):  
C. G. Bernhard ◽  
D. Ottoson
Keyword(s):  
Comparative Analysis ◽  
Comparative Studies ◽  
Dark Adaptation ◽  
Time Course ◽  
Electrical Response ◽  
Compound Eyes ◽  
Second Phase ◽  
Nocturnal Species ◽  
Two Phases ◽  
Diurnal Species

A comparative analysis has been carried out of the time course and range of dark adaptation in the compound eyes of some common butterflies and noctuid moths (Lepidoptera). The change in sensitivity of the eye during dark adaptation was determined by measurements of the intensity of illumination necessary to elicit an electrical response of a given magnitude of the eye. It was found that the curve for dark adaptation in the diurnal species was smooth. The range of adaptive change varied in different species but usually did not cover more than 1 to 1.5 log units. In the nocturnal species the dark adaptation was found to proceed in two phases. The first phase was usually completed in less than 10 minutes and covered a range of 1 to 1.5 log units. The second phase was more prolonged and covered a range of 2 to 3 log units. In some of the experiments on nocturnal species the second phase failed to appear. Measurements of the size of the response at different intensities showed that the intensity/amplitude relationship was the same in the light-adapted eye as in the dark-adapted eye. In the nocturnal insects the response of the eye in the light-adapted condition was about 20 per cent of that in the dark-adapted eye, while in diurnal insects it was about 60 per cent.

Lateralization Differences for Color-Naming and Color-Matching in Men and Women

1989 ◽  
Vol 69 (2) ◽  
pp. 651-656 ◽  
Author(s):  
David M. Tokar ◽  
Nancy Kubitz Matheson ◽  
Richard H. Haude
Keyword(s):  
Visual Field ◽  
Repeated Measures ◽  
Visual Fields ◽  
Naming Task ◽  
Color Naming ◽  
Matching Task ◽  
Right Visual Field ◽  
Color Matching ◽  
Main Effects ◽  
The Relationship

The relationship between accuracy of color-naming and color-matching in both visual fields (LVF and RVF) as a function of sex was investigated. Subjects were 19 men and 15 women who ranged in age from 18 to 32 yr. Each subject was tested on both a color-naming task and a color-matching task presented tachistoscopically. Accuracy measures for each task were obtained separately for both left and right visual fields. A two-factor analysis of variance with repeated measures on one factor followed by a t test for simple main effects showed significant right visual-field advantage for the color-naming task, a significant sex main effect for the color-matching task (in the left visual field only), and a significant interaction of sex by visual field for the matching task. Men performed in a more strongly lateralized fashion on the color-matching task than did women, supporting the notion of greater lateralization among males.

SEXUAL DIMORPHISM IN THE SWEET POTATO WEEVIL, CYLAS FORMICARIUS (F.) (COLEOPTERA: BRENTIDAE)

1997 ◽  
Vol 129 (1) ◽  
pp. 61-69 ◽  
Author(s):  
Christopher K. Starr ◽  
David D. Wilson ◽  
Ray F. Severson ◽  
Stanley J. Kays
Keyword(s):  
Sexual Dimorphism ◽  
Sweet Potato ◽  
Relative Size ◽  
Compound Eyes ◽  
Cylas Formicarius ◽  
Eye Size ◽  
Sensory Hairs ◽  
Sweet Potato Weevil ◽  
Different Types ◽  
The Relationship

AbstractCylas formicarius (F.) shows a strong overall sexual monomorophism, with external differences noted in only three organs: (a) relative size of the hind wings; (b) form of the antennal club and numbers of its different types of sensillum; and (c) size of the compound eyes and their individual facets. We relate these to known or predicted behavioural differences. Eye dimorphism is used to test a theoretical rule on the relationship between differences in overall eye size and in the size of individual ommatidia. Some sexually monomorphic features are briefly discussed, including two types of putatively sensory hairs not found on the antennae.

scholarly journals Optical scaling in conspecific Cataglyphis ants

1995 ◽  
Vol 198 (8) ◽  
pp. 1637-1646 ◽  
Author(s):  
C Zollikofer ◽  
R Wehner ◽  
T Fukushi
Keyword(s):  
Visual Acuity ◽  
Visual Field ◽  
Cross Sections ◽  
Compound Eye ◽  
Size Variation ◽  
Vertical Direction ◽  
Head Size ◽  
Radius Of Curvature ◽  
Optical Parameters ◽  
Eye Size

This study examines the effects of body size variation on the optical properties of the compound eyes of visually guided desert ants belonging to the genus Cataglyphis. Although linear head size may vary by a factor of 2 within conspecific workers and most optical parameters change accordingly, the extent of the visual field remains constant. Comparative measurements carried out on workers of three species (C. albicans, C. bicolor and C. fortis) and on reproductive females and males of one species (C. bicolor) show that the form (size and shape) of the visual field is highly characteristic for each caste/species. A constant visual field is realised by reciprocal scaling rules for the number of ommatidia and the angular spacing of ommatidia. While larger ants have more ommatidia per compound eye, interommatidial angles are reduced accordingly, thus giving rise to a constant visual field. Among conspecific ant workers, the relationship between spatial visual acuity and eye size is similar to that found in interspecific comparisons and reflects optical constraints imposed on the design of the compound eye. Mapping of spatial visual directions onto the compound eye surface reveals a characteristic, inhomogeneous distribution of interommatidial spacing, particularly a foveal band with increased visual acuity in the vertical direction. This 'visual stretch' viewing the horizon is similar to that found in a variety of flying insects. Although, among conspecific workers, both the number of ommatidia and the interommatidial angles vary with varying head size, the overall pattern of interommatidial spacing is maintained so that corresponding positions on the compound eye of small and large individuals look in equivalent directions in space. These findings are in accordance with the observation that the shape of the compound eye surface, as expressed by the radius of curvature along cross sections, is similar in small and large ants.

Cottus specus, a new troglomorphic species of sculpin (Cottidae) from southeastern Missouri.

Zootaxa ◽  
2013 ◽  
Vol 3609 (5) ◽  
pp. 484-494 ◽  
Author(s):  
GINNY L. ADAMS ◽  
BROOKS M. BURR ◽  
DAVID E. STARKEY
Keyword(s):  
New Species ◽  
Pore Size ◽  
North American ◽  
Morphological Characters ◽  
Fresh Waters ◽  
Eye Size ◽  
A New Species

Cottus specus, a new species, is described from the karst regions of the Bois Brule drainage in eastern Missouri, USA. Cottus specus is distinguishable from all members of the genus Cottus using both genetic and morphological characters, including eye size and cephalic pore size. Cottus specus represents the first description of a cave species within Cottus. The addition of C. specus brings the total number of recognized species of Cottus to 33 in North American fresh waters.

scholarly journals Trilobite vision: a comparison of schizochroal and holochroal eyes with the compound eyes of modern arthropods

1992 ◽  
Vol 6 ◽  
pp. 103-103
Author(s):  
David. Fordyce ◽  
Thomas W. Cronin
Keyword(s):  
Visual Field ◽  
National Science Foundation ◽  
Compound Eye ◽  
Visual Fields ◽  
Visual Space ◽  
Compound Eyes ◽  
Central Processing ◽  
Corneal Lens ◽  
Bright Sunlight ◽  
Parameter Values

The compound eyes of trilobites provide the best examples of fossilized sensory organs for which the function in life can be worked out today, because the optical array of their corneal lenses preserves the geometry with which the eye originally sampled the visual world. An analysis of trilobite vision is strengthened by the use of new mathematical approaches to compound eye design. In particular, the product of the facet diameter (D) and the interommatidial angle (Δϕ) gives the value of the eye parameter, DΔϕ, which is a reliable indicator of the photic conditions in which the eye was used. In modern arthropods, DΔϕ values range from 0.3 for animals active in bright sunlight to 20 or more for nocturnal or deep-sea animals.Three types of compound eyes existed in trilobites: schizochroal, holochroal, and abathochroal. We examined the schizochroal and holochroal types. Schizochroal eyes were studied in the phacopid species Phacops rana crassituberculata and Phacops rana milleri. We measured the diameter of every corneal lens, and estimated its optical axis by taking the normal to the plane of the lens's diameter. In both species, each eye covered almost exactly 180° of visual space in azimuth with no binocular overlap, from directly anterior to directly posterior. Vertically, the visual field extended from the horizon to about 40° in elevation. Facet diameters and interommatidial angles were large, giving eye parameter values ranging from 10 to > 150. These are much greater than in any living arthropod, implying that modern compound eye theory does not apply to schizochroal eyes. We believe that each ommatidium of the schizochroal eye served as a miniature lens eye. If so, phacopid vision must have been unique, with multiply overlapping visual fields. Such a design would have required considerable central processing, but could have provided exceptional opportunities for spatial, spectral, and polarizational analysis.We examined holochroal compound eyes in Asaphus cornutus and Isotelus “gigas”. Here, visual field coverage was greater than in the schizochroal eye type, with a small amount of frontal binocular overlap. Holochroal eyes contain far more ommatidia than do schizochroal types, reducing both facet diameter (D) and interommatidial angle (Δϕ). Thus, DΔϕ values in these species fall into the same range as in modern compound eyes. This implies that function of the holochroal eye was similar to that of modern crustaceans and insects.This material is based on research supported by the National Science Foundation under Grants No. BNS-8518769 and BNS-8917183.

scholarly journals A Risk-Based Approach to Assess the Operational Resilience of Transmission Grids

2020 ◽  
Vol 10 (14) ◽  
pp. 4761
Author(s):  
Milorad Papic ◽  
Svetlana Ekisheva ◽  
Eduardo Cotilla-Sanchez
Keyword(s):  
Power System ◽  
North American ◽  
Response Times ◽  
Transmission System ◽  
Energy Delivery ◽  
The North ◽  
System Components ◽  
Bulk Power ◽  
Definition Of ◽  
The Relationship

Modern risk analysis studies of the power system increasingly rely on big datasets, either synthesized, simulated, or real utility data. Particularly in the transmission system, outage events have a strong influence on the reliability, resilience, and security of the overall energy delivery infrastructure. In this paper we analyze historical outage data for transmission system components and discuss the implications of nearby overlapping outages with respect to resilience of the power system. We carry out a risk-based assessment using North American Electric Reliability Corporation (NERC) Transmission Availability Data System (TADS) for the North American bulk power system (BPS). We found that the quantification of nearby unscheduled outage clusters would improve the response times for operators to readjust the system and provide better resilience still under the standard definition of N-1 security. Finally, we propose future steps to investigate the relationship between clusters of outages and their electrical proximity, in order to improve operator actions in the operation horizon.

Sign in / Sign up

Export Citation Format

Share Document