Color receptors in marine crustaceans: A second spectral class of retinular cell in the compound eyes ofCallinectes andCarcinus

1982 ◽  
Vol 145 (4) ◽  
pp. 549-554 ◽  
Author(s):  
Francis G. Martin ◽  
Michael I. Mote
Keyword(s):  
Compound Eyes ◽  
Retinular Cell ◽  
Marine Crustaceans ◽  
Spectral Class

scholarly journals Localization of the Violet and Yellow Receptor Cells in the Crayfish Retinula

1973 ◽  
Vol 62 (4) ◽  
pp. 355-374 ◽  
Author(s):  
Eisuke Eguchi ◽  
Talbot H. Waterman ◽  
Jiro Akiyama
Keyword(s):  
Light Adaptation ◽  
Selective Adaptation ◽  
Compound Eyes ◽  
Intracellular Recordings ◽  
Intercellular Coupling ◽  
Retinular Cell ◽  
Particle Distributions ◽  
Wavelength Sensitivity ◽  
Retinal Distribution ◽  
Retinular Cells

Cellular identification of color receptors in crayfish compound eyes has been made by selective adaptation at 450 nm and 570 nm, wavelengths near the λmax's of the two retinular cell classes previously demonstrated. By utilizing earlier evidence, the concentration of lysosome-related bodies (LRB) was used to measure relative light adaptation and thus wavelength sensitivity in 665 retinular cells from six eyes. The observed particle distributions demonstrate the following. Both violet and yellow receptors occur ordinarily in each retinula. Of the seven regular retinular cells two (R3 and R4 using Eguchi's numbering [1965]) have mean sensitivities significantly greater to violet and less to yellow than the other five. The latter apparently comprise "pure" yellow receptors (R1 and R7) and mixed yellow and violet receptors (R2, R5, and R6). Explanations of such ambiguity requiring two visual pigments in single retinular cells or intercellular coupling of adjacent neuroreceptors are apparently precluded by previous evidence. Present data imply alternatively some positional variability in the violet pair's location in individual retinulas. Thus R3 and R4 are predominantly the violet receptors but in some retinulas R2 and R3 or R4 and R5 (or rarely some other cell pairs) may be. The retinal distribution of such variations has yet to be determined. In agreement with intracellular recordings the blue and yellow cells here identified belong to both the vertical and horizontal e-vector sensitive channels.

Properties of Single Cells in Posterior Lateral Eyes of Jumping Spiders

1978 ◽  
Vol 33 (1-2) ◽  
pp. 156-158 ◽  
Author(s):  
R. C. Hardie ◽  
P. Duelli
Keyword(s):  
Compound Eye ◽  
Single Cells ◽  
Sensitivity Function ◽  
Compound Eyes ◽  
Angular Sensitivity ◽  
Peak Wavelength ◽  
Jumping Spiders ◽  
Spectral Class ◽  
Single Lens ◽  
Polarised Light

Abstract Properties of single cells in the posterior lateral (PL) eyes of the jum ping spider Plexippus validus are described. Only one spectral class of cells was encountered and the spectra sensitivity was indistinguishable from that measured from the ERG , both peaking at ca. 535 nm. Angular sensi­ tivity (width of angular sensitivity function at the 50% level) averaged .89° ± .12°, the smallest value being .77°. Absolute sensitivity (reciprocal of the number of quanta of peak wavelength, on axis required to generate a 50% response) averaged 1.43 + 2 .5 X 1 0 -11 q-1 ,cm2·s. A ll cells studied were sensitive to the plane of polarised light. The per­ formance of receptors in the PL eyes is compared with that of receptors in the compound eyes of diurnal insects. It is concluded that the single lens eye system of spiders is in ­ herently superior in design to the insect compound eye.

scholarly journals Function of Insect Compound Eyes Containing Crystalline Tracts

1969 ◽  
Vol 54 (2) ◽  
pp. 250-267 ◽  
Author(s):  
Kjell B. Døving ◽  
William H. Miller
Keyword(s):  
Point Source ◽  
Theoretical Study ◽  
Visual Fields ◽  
Compound Eyes ◽  
Retinular Cell ◽  
Extended Source ◽  
Microelectrode Recordings ◽  
Extended Sources ◽  
Half Power ◽  
Retinular Cells

Image formation is studied in compound eyes of insects that contain crystalline tracts. In optical experiments the course of light is studied in fresh scalps of dark-adapted eyes using point and extended sources. In the tract region a point source gives a diffusely lighted area within which are punctate spots about 10 times brighter. Because the position of these spots does not change when the source is moved, and because their spacing agrees with estimates based on the known scalp depth, we conclude that these spots represent light radiating from the cut ends of tracts. An extended source gives a dim erect image in the tract region that may come from the pattern of illumination radiating from the cut ends of the tracts. In electrophysiological experiments intracellular microelectrode recordings of responses to illumination are made from single retinular cells of the skipper, Epargyreus clarus, an animal that lacks iris pigment. Measurements of visual fields of single retinular cells by three methods give half-power beam widths of about 2°. Though not conclusive, these experiments suggest that only the light contained in the tract is effective in stimulating the retinular cell. This agrees with the theoretical study of Allen (1968) and is inconsistent with the superposition theory of Exner (1891) as applied to certain moth and skipper eyes.

Differentiation Processes of the Ocellar Retina of the Honeybee (Apis Mellifera L.)

1990 ◽  
Vol 48 (3) ◽  
pp. 430-431
Author(s):  
Maria Anna Pabst
Keyword(s):  
Apis Mellifera ◽  
Distal Part ◽  
Cell Layer ◽  
Single Layer ◽  
Photoreceptor Cells ◽  
Distal Segment ◽  
Compound Eyes ◽  
Thin Sections ◽  
Ultrastructural Studies ◽  
Adult Worker

In addition to the compound eyes, honeybees have three dorsal ocelli on the vertex of the head. Each ocellus has about 800 elongated photoreceptor cells. They are paired and the distal segment of each pair bears densely packed microvilli forming together a platelike fused rhabdom. Beneath a common cuticular lens a single layer of corneagenous cells is present.Ultrastructural studies were made of the retina of praepupae, different pupal stages and adult worker bees by thin sections and freeze-etch preparations. In praepupae the ocellar anlage consists of a conical group of epidermal cells that differentiate to photoreceptor cells, glial cells and corneagenous cells. Some photoreceptor cells are already paired and show disarrayed microvilli with circularly ordered filaments inside. In ocelli of 2-day-old pupae, when a retinogenous and a lentinogenous cell layer can be clearly distinguished, cell membranes of the distal part of two photoreceptor cells begin to interdigitate with each other and so start to form the definitive microvilli. At the beginning the microvilli often occupy the whole width of the developing rhabdom (Fig. 1).

Hematodinium spp. infections in wild and cultured populations of marine crustaceans along the coast of China

2017 ◽  
Vol 124 (3) ◽  
pp. 181-191 ◽  
Author(s):  
JF Wang ◽  
M Li ◽  
J Xiao ◽  
WJ Xu ◽  
CW Li
Keyword(s):  
Marine Crustaceans

New species of bristletails of the genus Lepismachilis (Archaeognatha: Machilidae) from Serbia and Montenegro

2018 ◽  
Vol 58 (2) ◽  
pp. 577-587
Author(s):  
Vladimir Kaplin
Keyword(s):  
New Species ◽  
Balkan Peninsula ◽  
Species Group ◽  
Compound Eyes ◽  
Serbia And Montenegro ◽  
Sensory Field ◽  
Fore Femur ◽  
Three New Species

Abstract The fauna of bristletails of the genus Lepismachilis Verhoeff, 1910 in Montenegro and Serbia includes only one species L. (Berlesilis) targionii (Grassi, 1887) with 2 + 2 eversible vesicles on abdominal urocoxites II–VI. Three new species of this genus are described: L. (Lepismachilis) prijepolja sp. nov., L. (Lepismachilis) limensa sp. nov. from Serbia, and L. (Lepismachilis) alexandrae sp. nov. from Montenegro. All described new species belong to the species group of the subgenus Lepismachilis s. str. with 2 + 2 eversible vesicles on abdominal urocoxites II–V. Lepismachilis prijepolja sp. nov. differs from L. y-signata Kratochvíl, 1945 and L. notata Stach, 1919 by the color, drawings and ratios of the compound eyes; ratios of sensory field on fore femur of male, number of divisions of ovipositor. Lepismachilis limensa sp. nov. differs from L. hauseri Bitsch, 1974 and L. abchasica Kaplin, 2017 by ratios of paired ocelli, sensory field on fore femur of male; ratios and chaetotaxy of maxillary and labial palps. Lepismachilis alexandrae sp. nov. differs from L. abchasica by the drawings of the compound eyes; ratios of paired ocelli, sensory field on fore femur of male; number of divisions of the parameres and gonapophyses. A list of the Machilidae occurring in Balkan Peninsula is also provided.

scholarly journals Revisiting the Planet Mass and Stellar Metallicity Relation for Low-Mass Exoplanets Orbiting GKM Class Stars

Universe ◽  
2021 ◽  
Vol 7 (4) ◽  
pp. 88
Author(s):  
Jonathan H. Jiang ◽  
Daniel Zhao ◽  
Xuan Ji ◽  
Bohan Xie ◽  
Kristen A. Fahy
Keyword(s):  
Uncertainty Analysis ◽  
Stellar Mass ◽  
Observational Evidence ◽  
Statistical Characteristics ◽  
Stellar Disk ◽  
Exponential Law ◽  
Spectral Class ◽  
Low Mass ◽  
M Stars

The growing database of exoplanets has shown us the statistical characteristics of various exoplanet populations, providing insight towards their origins. Observational evidence suggests that the process by which gas giants are conceived in the stellar disk may be disparate from that of smaller planets. Using NASA’s Exoplanet Archive, we analyzed the relationships between planet mass and stellar metallicity, as well as planet mass and stellar mass for low-mass exoplanets (MP < 0.13 MJ) orbiting spectral class G, K, and M stars. We performed further uncertainty analysis to confirm that the exponential law relationships found between the planet mass, stellar mass, and the stellar metallicity cannot be fully explained by observation biases alone.

scholarly journals In search of the spectral composition of an effective light trap for the mushroom pest Lycoriella ingenua (Diptera: Sciaridae)

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Sándor Kecskeméti ◽  
András Geösel ◽  
József Fail ◽  
Ádám Egri
Keyword(s):  
Light Intensity ◽  
Spectral Sensitivity ◽  
Fungal Pathogens ◽  
Light Trap ◽  
Spectral Composition ◽  
Wavelength Dependence ◽  
Crop Damage ◽  
Photon Flux ◽  
Compound Eyes ◽  
Behavioural Experiments

AbstractCertain fungus gnats, like Lycoriella ingenua are notorious pests in agriculture, especially in mushroom production. While larvae cause mainly direct crop damage, adults are vectors of several dangerous fungal pathogens. To promote the development of pesticide-free management methods, such as light trapping, we measured the spectral sensitivity of L. ingenua compound eyes with electroretinography and performed two different behavioural experiments to reveal the wavelength dependence of phototaxis in this species. The spectral sensitivity of the compound eyes is bimodal with peaks at 370 nm (UV) and 526 nm (green). Behavioural experiments showed that attraction to light as a function of wavelength depends on light intensity. In our first experiment, where the minimal photon flux (105–109 photons/cm2/s) needed for eliciting a phototactic response was determined wavelength by wavelength, phototaxis was strongest in the green spectral range (~526 nm). In the other behavioural experiment, where wavelength preference was tested under a higher but constant light intensity (~1013 photons/cm2/s), the highest attraction was elicited by UV wavelengths (398 nm). Our results suggest that both UV and green are important spectral regions for L. ingenua thus we recommend to use both UV (~370-398 nm) and green (~526 nm) for trapping these insects.

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