Mobility and electric charge of screening pigment granules in the superposition eye ofEphestia kuehniella Z.

1985 ◽  
Vol 157 (5) ◽  
pp. 667-670
Author(s):  
Erich Weyrauther ◽  
Georg Seitz
Keyword(s):  
Electric Charge ◽  
Pigment Granules ◽  
Screening Pigment ◽  
Superposition Eye

Diurnal changes in retinula cell sensitivities and receptive fields (two-dimensional angular sensitivity functions) in the apposition eyes of Ligia exotica (Crustacea, Isopoda)

2001 ◽  
Vol 204 (2) ◽  
pp. 239-248 ◽  
Author(s):  
T. Hariyama ◽  
V.B. Meyer-Rochow ◽  
T. Kawauchi ◽  
Y. Takaku ◽  
Y. Tsukahara
Keyword(s):  
Receptive Fields ◽  
Resolving Power ◽  
Pigment Cells ◽  
Diurnal Changes ◽  
Two Dimensional ◽  
Angular Sensitivity ◽  
Pigment Granules ◽  
Screening Pigment ◽  
The Difference ◽  
Night And Day

The structural organization of the retinula cells in the eye of Ligia exotica changes diurnally. At night, the microvilli elongate, losing the regular and parallel alignment characteristic of the day condition. Crystalline cones and distal rhabdom tips are not pushed into each other during the day, but at night the rhabdoms protrude into the crystalline cones by up to 5 microm. Screening pigment granules in the retinula cells disperse during the night, but migrate radially towards the vicinity of the rhabdom during the day. No such displacements of the pigment granules of either distal or proximal screening pigment cells were observed. The sensitivity of the eye, monitored by electroretinogram (ERG) recordings, changes diurnally: values at midnight are, on average, 10 times those occurring during the day. However, intracellular recordings from single retinula cells (50 during the day and 50 at night) indicate that the difference between night and day sensitivities is only 2.5-fold. Two-dimensional angular sensitivity curves, indicative of a single unit's spatial sensitivity, had considerably less regular outlines at night than during the day. If based on the 50 % sensitivity level, day and night eyes possessed receptive fields of almost identical width (approximately 2 degrees), but if sensitivities below the 50 % limit were included, then receptive fields at night were significantly more extensive. We suggest that the morphological adaptations and diurnal changes in chromophore content seen in the apposition eye of L. exotica allow this animal to improve its photon capture at night while preserving at least some of the spatial resolving power characteristic of the light-adapted state. This would explain why this animal is capable of performing complex escape behaviours in the presence of predators both in bright and in very dim light.

EFFECT OF DIFFERENT LIGHTING CONDITIONS ON FEEDING ACTIVITY AND EYE ADAPTATION OF POST LARVAE PENAEUS VANNAMEI

2015 ◽  
Vol 77 (33) ◽  
Author(s):  
Noorsyarinah Sanudin ◽  
Audrey Daning Tuzan ◽  
Gunzo Kawamura ◽  
Annita Seok Kian Yong
Keyword(s):  
Feeding Activity ◽  
Light Condition ◽  
Larval Feeding ◽  
Penaeus Vannamei ◽  
Dark Condition ◽  
Clear Zone ◽  
Lighting Conditions ◽  
Pigment Granules ◽  
Screening Pigment ◽  
Dark Conditions

This study was conducted to investigate the effect of light and dark conditions on feeding activity and eye adaptations of post larvae (PL5, PL10, PL20 and PL30) Penaeus vannamei fed with frozen Artemia. Shrimp PL were placed individually in beakers and after acclimatization under the light or dark condition, PL were left to ingest known number of Artemia for 30 minutes. Thereafter, each PL was subsequently anesthetized by putting an ice cube into the beakers followed by adding few drops of paraformaldehyde. The results showed that the PL5 ingested significantly more frozen Artemia under light condition compared to dark condition (P<0.05). The eye structures of PL5 comprises of crystalline cone, rhabdom and fasciculated zone. However, it was incomplete due to the lack of clear zone and no migration of the screening pigment granules was observed under light and dark conditions. On the contrary, the number of frozen Artemia ingested by the latter stages PL10, PL20 and PL30 showed no significant differences (P>0.05) under both light conditions and these PL have complete eye structures with define clear zone. The width of clear zone was found to increase proportionally with the growth of the PL. Besides that, the screening pigment granules were able to migrate under light and dark conditions. The ability of the PL10, PL20 and PL30 to ingest almost similar numbers of Artemia under light and dark conditions suggests that different lighting conditions did not affect the feeding activity of the PL and other sensory organs may play roles in detecting food, while PL5 need light to improve their feeding activity. Based on these results, we suggest that in aquaculture practice, during the rearing of early stage of PL (<PL5), a brighter environment or light should be provided to enhance larval feeding activities. Whereas, later stages of PL (>PL10) can be cultured under any light condition.

Investigation of the Screening Pigment System in the Compound Eye of the Moth Agrotis segetum (fam. Noctuidae) by Visible Reflectometry

1987 ◽  
Vol 42 (1-2) ◽  
pp. 152-156 ◽  
Author(s):  
Trond Nordtug ◽  
Thor Bernt Melø
Keyword(s):  
Light Adaptation ◽  
Compound Eye ◽  
Extinction Spectrum ◽  
Light Extinction ◽  
Agrotis Segetum ◽  
Lag Phase ◽  
Reflection Spectroscopy ◽  
Screening Pigment ◽  
Reflected Light ◽  
Superposition Eye

Abstract The functional properties of the light adaptation system in the superposition eye of the moth Agrotis segetum have been investigated by reflection spectroscopy. The spectrum of the reflected light from the tapetum of dark adapted eyes had a peak at about 580 nm corresponding to a spacing between the reflecting layers in the tapetum of 145 nm. During light adaptation of the eye the observed reflectance changes could be explained by light extinction in one screening pigment. The shape of the extinction spectrum of the screening was constant throughout the adaptation process and after a lag phase the optical density of the pigment in the light path increased linearly with time. The screening pigment caused light extinction both by absorption and to some degree also by scattering. The absorption spectrum of the screening pigment had a broad maximum about 590 nm and the scattering efficiency of the pigment particles seemed to be nearly independent of the wavelength.

scholarly journals Screening pigment of the camera eyes of stalkeyed mollusks (Pulmonata, Stylommatophora) with different light preferences

2017 ◽  
Vol 27 (3) ◽  
pp. 133-140
Author(s):  
I. P. Shepeleva
Keyword(s):  
Electron Density ◽  
Morphological Properties ◽  
Light Conditions ◽  
Pigment Granules ◽  
Screening Pigment ◽  
Gastropod Mollusks

Morphological properties of the granules of the screening pigment in the retinae of camera eyes of gastropod mollusks with different light preferences were studied. It was demonstrated that the pigment granules of mollusks can differ by color and size but do not differ by structure, electron density and form. Light conditions of mollusks’ habitats can influence on the amount of the screening pigment, which in its turn does not affect resolving ability of the eyes.

Spectral absorption by screening pigment granules in the compound eyes of a moth and a wasp

1970 ◽  
Vol 67 (3) ◽  
pp. 238-242 ◽  
Author(s):  
G. H�glund ◽  
H. Langer ◽  
G. Struwe ◽  
B. Thorell
Keyword(s):  
Compound Eyes ◽  
Spectral Absorption ◽  
Pigment Granules ◽  
Screening Pigment

Evidence for a Pathway of Distal Screening Pigment Granules across the Basement Membrane of the Crayfish Photoreceptor

1992 ◽  
Vol 47 (5-6) ◽  
pp. 453-464
Author(s):  
Ulrich Schraermeyer
Keyword(s):  
Basement Membrane ◽  
Light Adaptation ◽  
Procambarus Clarkii ◽  
Pigment Cell ◽  
Dense Material ◽  
Pigment Cells ◽  
Electron Dense Material ◽  
Orconectes Limosus ◽  
Pigment Granules ◽  
Screening Pigment

The distal pigment cells of Orconectes limosus contain two layers of large electron lucent vacuoles that are separated by layers of small right-angled platelets adjacent to the crystalline cones. The crystalline cones of the dioptric apparatus of this species have evaginations into the distal pigment cell cytoplasm. In photoreceptors of Orconectes limosus and Procambarus clarkii a dark pigment accumulation site was detected just distal to the basement membrane at the edges of each retina. These pigment accumulations occurred independent of the state of light adaptation. Ultrastructurally the pigment granules at this accumulation site resemble distal screening pigment granules according to their size (up to 1.2 μm in diameter) and fibrous structure. Distal screening pigment granules were also found in tube-like cell processes or extracellularly within and proximal to the retinal basement membrane, indicating pigment transport to and across the basement membrane. Proximal to the basement membrane screening pigment granules were also observed disintegrated to a gravel-like electron dense material in widely branched cells. Evidence was found that an electron dense material, probably resulting from disintegrating screening pigment granules, was incorporated in the integument of the eyestalk. Four hours after injection of gold particles into the eye stalk distal to the retina they were detected inside and proximal to the retinal basement membrane.

Sign in / Sign up

Export Citation Format

Share Document