Regionally different ommatidial structure in the compound eye of the water-flea Polyphemus (Cladocera, Crustacea)

1983 ◽  
Vol 217 (1207) ◽  
pp. 177-189 ◽  
Keyword(s):  
Compound Eye ◽  
Polarized Light ◽  
Small Animal ◽  
Pigment Cells ◽  
Compound Eyes ◽  
Water Flea ◽  
Edge Type ◽  
Different Types ◽  
Visual Tasks ◽  
Ventral Edge

The two compound eyes of Polyphemus pediculus are completely fused in the midline to form a single integrated unit containing 130 ommatidia with four different types of rhabdoms. The general features of the eye include a cuticle lacking corneal lenses, crystalline cones composed of five cells and the presence of juxtacrystalline cells and distal pigment cells. The rhabdoms are fused and the palisade, when present, is a part of the extracellular space in which the rhabdom is suspended. Four different types of rhabdoms were found zonally arranged in the eye. (i) A foveal type, in the dorsofrontal region of the eye, is characterized by its long and slender shape. (Only five retinula cells contribute to forming this irregularly layered rhabdom, with the first layer composing the distal half of the rhabdom.) (ii) A second type, located ventrally to the fovea, is conventionally layered and is formed by six retinula cells, one of which is aberrant. (iii) A dorsolateral type is continuous (unlayered) and formed by six retinula cells of which one is aberrant. (iv) A dorsal and ventral edge type is wide and short, and lacking palisade. Six retinula cells contribute to the continuous rhabdom and two of these are aberrant with tiny rhabdomeres. The foveal type of rhabdom has a peculiar arrangement of the microvilli, which is thought to depress the sensitivity to vertically polarized light. This mechanism is believed to enhance the ability to detect prey. The zoned eye, with its specialized receptive apparatus, is interpreted as an adaptation for coping with a diversity of visual tasks by a very small animal.

The compound eyes of mantis shrimps (Crustacea, Hoplocarida, Stomatopoda). I. Compound eye structure: the detection of polarized light

1991 ◽  
Vol 334 (1269) ◽  
pp. 33-56 ◽  
Keyword(s):  
Compound Eye ◽  
Polarized Light ◽  
Structural Features ◽  
Polarization Sensitivity ◽  
Compound Eyes ◽  
Visual Tasks ◽  
Retinular Cells ◽  
High Degree ◽  
Structural Adaptations ◽  
Parallel Sampling

Stomatopod crustaceans possess compound eyes divided into three distinct regions: two peripheral retinae - the dorsal and ventral hemispheres — and the mid-band. Throughout the eye, in particular in the midband, there are many structural adaptations that potentially enable different portions of the eye to perform different visual tasks. A high degree of optical overlap between these eye regions allows the parallel sampling of various parameters of light from one direction in space. In consecutive papers, we present structural evidence that stomatopods have the receptors necessary for colour and polarization vision. The first paper describes the retinal structures that suggest the existence of polarization sensitivity in stomatopods. mid-band rows five and six, together with the hemispheres, are probably involved in this visual process. By using two strategies, rhabdomal modification and varying the orientation of similar ommatidial units in the three eye regions, stomatopods have the capacity to analyse polarized light in a very detailed manner. All the species included in this study live in shallow, tropical waters where polarized light signals are abundant. It therefore seems likely that their eyes have evolved to take advantage of such environmental cues. Structural evidence also suggests that all retinular cells in rows one to four of the mid-band, and the distal most retinular cells (R8) over most of the retina, are not sensitive to polarized light. These mid-band rows are instead adapted for colour detection. This function of the stomatopod retina and structural features concerned with colour sensitivity are described in paper II ( Phil. Trans. R. Soc. Lond. B 334, 57—84 (1991)).

scholarly journals Homothorax controls a binary Rhodopsin switch in Drosophila ocelli

PLoS Genetics ◽  
2021 ◽  
Vol 17 (7) ◽  
pp. e1009460
Author(s):  
Abhishek Kumar Mishra ◽  
Cornelia Fritsch ◽  
Roumen Voutev ◽  
Richard S. Mann ◽  
Simon G. Sprecher
Keyword(s):  
Drosophila Melanogaster ◽  
Visual Perception ◽  
Compound Eye ◽  
Polarized Light ◽  
Fruit Fly ◽  
Compound Eyes ◽  
Ancestral Gene ◽  
Evolutionary Diversification ◽  
Opsin Genes ◽  
A Cell

Visual perception of the environment is mediated by specialized photoreceptor (PR) neurons of the eye. Each PR expresses photosensitive opsins, which are activated by a particular wavelength of light. In most insects, the visual system comprises a pair of compound eyes that are mainly associated with motion, color or polarized light detection, and a triplet of ocelli that are thought to be critical during flight to detect horizon and movements. It is widely believed that the evolutionary diversification of compound eye and ocelli in insects occurred from an ancestral visual organ around 500 million years ago. Concurrently, opsin genes were also duplicated to provide distinct spectral sensitivities to different PRs of compound eye and ocelli. In the fruit fly Drosophila melanogaster, Rhodopsin1 (Rh1) and Rh2 are closely related opsins that originated from the duplication of a single ancestral gene. However, in the visual organs, Rh2 is uniquely expressed in ocelli whereas Rh1 is uniquely expressed in outer PRs of the compound eye. It is currently unknown how this differential expression of Rh1 and Rh2 in the two visual organs is controlled to provide unique spectral sensitivities to ocelli and compound eyes. Here, we show that Homothorax (Hth) is expressed in ocelli and confers proper rhodopsin expression. We find that Hth controls a binary Rhodopsin switch in ocelli to promote Rh2 expression and repress Rh1 expression. Genetic and molecular analysis of rh1 and rh2 supports that Hth acts through their promoters to regulate Rhodopsin expression in the ocelli. Finally, we also show that when ectopically expressed in the retina, hth is sufficient to induce Rh2 expression only at the outer PRs in a cell autonomous manner. We therefore propose that the diversification of rhodpsins in the ocelli and retinal outer PRs occurred by duplication of an ancestral gene, which is under the control of Homothorax.

How small can small be: The compound eye of the parasitoid waspTrichogramma evanescens(Westwood, 1833) (Hymenoptera, Hexapoda), an insect of 0.3- to 0.4-mm total body size

2010 ◽  
Vol 28 (4) ◽  
pp. 295-308 ◽  
Author(s):  
STEFAN FISCHER ◽  
CARSTEN H.G. MÜLLER ◽  
V. BENNO MEYER-ROCHOW
Keyword(s):  
Compound Eye ◽  
Uv Light ◽  
Parasitoid Wasp ◽  
Pigment Cells ◽  
Compound Eyes ◽  
Trichogramma Evanescens ◽  
Cone Cells ◽  
Males And Females ◽  
Total Body ◽  
Effective Use

AbstractWith a body length of only 0.3–0.4 mm, the parasitoid waspTrichogramma evanescens(Westwood) is one of the smallest insects known. Yet, despite its diminutive size, it possesses compound eyes that are of oval shapes, measuring across their long axes in dorsoventral direction 63.39 and 71.11μm in males and females, respectively. The corresponding facet diameters are 5.90μm for males and 6.39μm for females. Owing to the small radii of curvature of the eyes in males (34.59μm) and females (42.82μm), individual ommatidia are short with respective lengths of 24.29 and 34.97μm. The eyes are of the apposition kind, and each ommatidium possesses four cone cells of the eucone type and a centrally fused rhabdom, which throughout its length is formed by no more than eight retinula cells. A ninth cell occupies the place of the eighth retinula cell in the distal third of the rhabdom. The cone is shielded by two primary and six secondary pigment cells, all with no apparent extensions to the basement membrane, unlike the case in larger hymenopterans. The regular and dense packing of the rhabdoms reflects an effective use of space. Calculations on the optics of the eyes ofTrichogrammasuggest that the eyes need not be diffraction limited, provided they use mostly shorter wavelengths, that is, UV light. Publications on the visual behavior of these wasps confirmTrichogramma’s sensitivity to UV radiation. On the basis of our findings, some general functional conclusions for very small compound eyes are formulated.

scholarly journals Homothorax Controls a Binary Rhodopsin Switch in Drosophila Ocelli

2021 ◽  
Author(s):  
Abhishek Kumar Mishra ◽  
Cornelia Fritsch ◽  
Roumen Voutev ◽  
Richard S. Mann ◽  
Simon G. Sprecher
Keyword(s):  
Motion Detection ◽  
Compound Eye ◽  
Polarized Light ◽  
Fruit Fly ◽  
Compound Eyes ◽  
Light Perception ◽  
Ancestral Gene ◽  
Evolutionary Diversification ◽  
Opsin Genes ◽  
A Cell

Visual perception of the environment is mediated by specialized photoreceptor (PR) neurons of the eye. Each PR expresses photosensitive opsins, which are activated by a particular wavelength of light. In most insects, the visual system comprises a pair of compound eyes that are mainly associated with motion detection, color or polarized light perception and a triplet of ocelli that are thought to be critical during flight to detect horizon and movements. It is widely believed that evolutionary diversification of compound eye and ocelli in insects occurred from an ancestral visual organ around 500 million years ago. Concurrently, opsin genes were also duplicated to provide distinct spectral sensitivities to different PRs of compound eye and ocelli. In the fruit fly Drosophila melanogaster, Rhodopsin1 (Rh1) and Rh2 are closely related opsins that are originated from the duplication of a single ancestral gene. However, in the visual organs, Rh2 is uniquely expressed in ocelli whereas Rh1 is uniquely expressed in outer PRs of the compound eye. It is currently unknown how this differential expression of Rh1 and Rh2 in the two visual organs is controlled to provide unique spectral sensitivities to ocelli and compound eyes. Here, we show that Homothorax (Hth) is expressed in ocelli and confers proper rhodopsin expression. We find that Hth controls a binary rhodopsin switch in ocelli to promote Rh2 expression and repress Rh1 expression. Genetic and molecular analysis of rh1 and rh2 supports that Hth acts through their promoters to regulate rhodopsin expression in the ocelli. Finally, we also show that when ectopically expressed in the retina, hth is sufficient to induce Rh2 expression only at the outer PRs in a cell autonomous manner. We therefore propose that the diversification of rhodpsins in the ocelli and retinal outer PRs occurred by duplication of an ancestral gene, which is under the control of Homothorax.

scholarly journals A Biomimetic Model of Adaptive Contrast Vision Enhancement from Mantis Shrimp

Sensors ◽  
2020 ◽  
Vol 20 (16) ◽  
pp. 4588
Author(s):  
Binbin Zhong ◽  
Xin Wang ◽  
Xin Gan ◽  
Tian Yang ◽  
Jun Gao
Keyword(s):  
Compound Eye ◽  
Polarized Light ◽  
Field Of View ◽  
Mantis Shrimp ◽  
Adjustment Mechanism ◽  
Pixel Array ◽  
Visual Tasks ◽  
Contrast Vision ◽  
Image Enhance ◽  
Point To Point

Mantis shrimp have complex visual sensors, and thus, they have both color vision and polarization vision, and are adept at using polarization information for visual tasks, such as finding prey. In addition, mantis shrimp, almost unique among animals, can perform three-axis eye movements, such as pitch, yaw, and roll. With this behavior, polarization contrast in their field of view can be adjusted in real time. Inspired by this, we propose a bionic model that can adaptively enhance contrast vision. In this model, a pixel array is used to simulate a compound eye array, and the angle of polarization (AoP) is used as an adjustment mechanism. The polarization information is pre-processed by adjusting the direction of the photosensitive axis point-to-point. Experiments were performed around scenes where the color of the target and the background were similar, or the visibility of the target was low. The influence of the pre-processing model on traditional feature components of polarized light was analyzed. The results show that the model can effectively improve the contrast between the object and the background in the AoP image, enhance the significance of the object, and have important research significance for applications, such as contrast-based object detection.

scholarly journals THE MICROSTRUCTURE OF THE COMPOUND EYES OF INSECTS

1957 ◽  
Vol 3 (3) ◽  
pp. 429-440 ◽  
Author(s):  
Timothy H. Goldsmith ◽  
Delbert E. Philpott
Keyword(s):  
Electron Microscope ◽  
Internal Structure ◽  
Cross Section ◽  
Osmium Tetroxide ◽  
Polarized Light ◽  
Pigment Cells ◽  
Compound Eyes ◽  
Anax Junius ◽  
Sarcophaga Bullata ◽  
Single Structure

The apposition eyes of two diurnal insects, Sarcophaga bullata (Diptera) and Anax junius (Odonata), have been examined with the electron microscope. In the latter case only the rhabdom is described. The rhabdom of the fly consists of a central matrix and seven rhabdomeres, one for each retinula cell. The rhabdomeres show an ordered internal structure built up of transverse tubes, hexagonal in cross-section. These slender compartments running the width of the rhabdomere are 370 A in diameter. After fixation with osmium tetroxide the walls of the compartments are more electron dense than the interiors. The retinula cells contain mitochondria, and pigment granules smaller than those found in the pigment cells. These granules tend to cluster close behind the membranes which separate the retinula cells from their rhabdomeres. The rhabdom of the dragonfly is a single structure which appears to be composed of three fused "rhabdomeres," each similar to a rhabdomere of Sarcophaga. Reasons are given for believing that the rhabdom may be the site of photoreception, as well as the organ for analyzing plane-polarized light, as suggested by other workers.

scholarly journals Histological and histochemical investigation of the compound eye of the whiteleg shrimp (Litopenaeus vannamei)

2017 ◽  
Author(s):  
Hao-Kai Chang ◽  
Cheng-Chung Lin ◽  
Shih-Ling Hsuan
Keyword(s):  
Optic Nerve ◽  
Litopenaeus Vannamei ◽  
Compound Eye ◽  
Histochemical Staining ◽  
Pigment Cells ◽  
Histological Structure ◽  
Cell Clusters ◽  
Different Types ◽  
Staining Methods ◽  
Medulla Terminalis

The compound eye is the primary visual system in crustaceans. Although the histological structure and histochemical characteristics of compound eyes of some insect and crab species are now well understood, no such studies have been undertaken in the whiteleg shrimp (Litopenaeus vannamei). In this study, eye samples from L. vannamei were fixed and paraffin sections were stained using several histochemical methods. The histological structure of each layer of the compound eye was examined and compared using different histochemical staining methods. It was found that the compound eye of L. vannamei consisted of cuticle, cornea, ommatidia, optic nerve layer, lamina ganglionaris, and medulla in an outside-in order. The cuticle of L. vannamei eyes was very thin, composed of a single epicuticle layer, as confirmed by Masson’s trichrome stain. The screening pigments produced by screening pigment cells were arranged at the junction of the ommatidia and optic nerve layer; these pigments stained differentially after different histochemical staining methods suggesting the screening pigment cells can be classified into different types. Notably, clusters of foamy glandular cells (FGCs) were observed in the optic nerve layer; these stained positively with periodic acid-Schiff and toluidine blue, and appeared blue after Masson’s trichrome stain. Immunohistochemical (IHC) staining was used to further define the origin and characteristics of FGCs. The IHC analysis showed that FGCs were positive for vimentin and synaptophysin (SYN), suggesting their neuroendocrine nature. In the medulla internalis and medulla terminalis, the neural clusters that surround the neurophil could be divided into three types by differences in morphology: the largest and the smallest cell clusters were neuron clusters and neurosecretory cells, respectively; the middle-sized cell clusters appeared SYN-positive and have not previously been described. Overall, this study is the first to provide a detailed description of the normal features of the compound eye of L. vannamei. The identification of different types of screening pigments in the ommatidia, the endocrine nature of FGcs in the optic nerve layer, and the novel neural clusters between the medulla internalis and medulla terminalis, will be important information for further study into the compound eye of L. vannamei.

Stomatopod Vision

2017 ◽  
Author(s):  
Thomas W. Cronin ◽  
N. Justin Marshall ◽  
Roy L. Caldwell
Keyword(s):  
Compound Eye ◽  
Visual Fields ◽  
Polarized Light ◽  
Image Features ◽  
Compound Eyes ◽  
Circularly Polarized Light ◽  
Circularly Polarized ◽  
Mantis Shrimp ◽  
Single Compound ◽  
Unique Capability

The predatory stomatopod crustaceans, or mantis shrimp, are among the most attractive and dynamic creatures living in the sea. Their special features include their powerful raptorial appendages, used to kill, stun, or disable other animals (whether predators, prey, or competitors), and their highly specialized compound eyes. Mantis shrimp vision is unlike that of any other animal and has several unique features. Their compound eyes are optically triple, each having three separate regions that produce overlapping visual fields viewing certain regions of space. They have the most diverse set of spectral classes of receptors ever described in animals, with as many as 16 types in a single compound eye. These receptors are based on a highly duplicated set of opsin molecules paired with strongly absorbing photostable filters in some photoreceptor types. The receptor set includes six ultraviolet types, all spectrally distinct, many themselves tuned by photostable filters. There are as many as eight types of polarization receptors of up to three spectral classes (including an ultraviolet class). In some species, two sets of these receptors analyze circularly polarized light, another unique capability. Stomatopod eyes move independently, each capable of visual field stabilization, image foveation and tracking, or scanning of image features. Stomatopods are known to recognize colors and polarization features and evidently use these in predation and communication. Altogether, mantis shrimps have perhaps the most unusual vision of any animal.

A new fossil evaniid wasp from Eocene Baltic amber, with highly modified compound eyes unique within the Hymenoptera

2017 ◽  
Vol 92 (2) ◽  
pp. 189-195 ◽  
Author(s):  
John T. Jennings ◽  
David D. O’Carroll ◽  
Priya ◽  
Lars Krogmann ◽  
Andrew D. Austin
Keyword(s):  
New Species ◽  
Compound Eye ◽  
Surface Modifications ◽  
Curved Surface ◽  
Baltic Amber ◽  
Compound Eyes ◽  
Old World ◽  
Different Types ◽  
Surface Discontinuity ◽  
Eocene Amber

AbstractEvaniid wasps develop as solitary egg predators within the oothecae of cockroaches. Fossil evaniids are relatively common compared with most other parasitoid Hymenoptera, undoubtedly due to their searching for host cockroaches on tree trunks and thus an increased chance of being trapped in tree resin. The genusParevaniaKieffer, 1907 is widely distributed through the Old World and is also known from a small number of rather unremarkable fossil taxa. Here we add to this extinct faunaParevania oculiseparataJennings, Krogmann, and Austin new species from Baltic Eocene amber, a species that has highly modified compound eyes that are unique among the Hymenoptera, and possibly among insects as a whole.Parevania oculiseparatan. sp. possesses a prominent acute ridge extending across the entire dorso-ventral elongation of the eye surface. Modifications to the regular curved surface of the eyes are extremely rare among Hymenoptera and previously were only known from two species ofInostemmaHaliday, 1833 (Platygastridae s. s.) and the three known species ofIsomeralaShipp, 1894 (Eucharitidae). In describing this unusual fossil evaniid species, we also analyze the optical consequences of the eye surface discontinuity, and discuss different types of compound eye modifications that occur in other Hymenoptera and other insects.

scholarly journals Histological and histochemical investigation of the compound eye of the whiteleg shrimp (Litopenaeus vannamei)

2017 ◽  
Author(s):  
Hao-Kai Chang ◽  
Cheng-Chung Lin ◽  
Shih-Ling Hsuan
Keyword(s):  
Optic Nerve ◽  
Litopenaeus Vannamei ◽  
Compound Eye ◽  
Histochemical Staining ◽  
Pigment Cells ◽  
Histological Structure ◽  
Cell Clusters ◽  
Different Types ◽  
Staining Methods ◽  
Medulla Terminalis

The compound eye is the primary visual system in crustaceans. Although the histological structure and histochemical characteristics of compound eyes of some insect and crab species are now well understood, no such studies have been undertaken in the whiteleg shrimp (Litopenaeus vannamei). In this study, eye samples from L. vannamei were fixed and paraffin sections were stained using several histochemical methods. The histological structure of each layer of the compound eye was examined and compared using different histochemical staining methods. It was found that the compound eye of L. vannamei consisted of cuticle, cornea, ommatidia, optic nerve layer, lamina ganglionaris, and medulla in an outside-in order. The cuticle of L. vannamei eyes was very thin, composed of a single epicuticle layer, as confirmed by Masson’s trichrome stain. The screening pigments produced by screening pigment cells were arranged at the junction of the ommatidia and optic nerve layer; these pigments stained differentially after different histochemical staining methods suggesting the screening pigment cells can be classified into different types. Notably, clusters of foamy glandular cells (FGCs) were observed in the optic nerve layer; these stained positively with periodic acid-Schiff and toluidine blue, and appeared blue after Masson’s trichrome stain. Immunohistochemical (IHC) staining was used to further define the origin and characteristics of FGCs. The IHC analysis showed that FGCs were positive for vimentin and synaptophysin (SYN), suggesting their neuroendocrine nature. In the medulla internalis and medulla terminalis, the neural clusters that surround the neurophil could be divided into three types by differences in morphology: the largest and the smallest cell clusters were neuron clusters and neurosecretory cells, respectively; the middle-sized cell clusters appeared SYN-positive and have not previously been described. Overall, this study is the first to provide a detailed description of the normal features of the compound eye of L. vannamei. The identification of different types of screening pigments in the ommatidia, the endocrine nature of FGcs in the optic nerve layer, and the novel neural clusters between the medulla internalis and medulla terminalis, will be important information for further study into the compound eye of L. vannamei.

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