Image formation by a concave reflector in the eye of the scallop, Pecten maximus.

Land, M. F.

doi:10.1113/jphysiol.1965.sp007653

Cited by 152 publications

(148 citation statements)

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“…These mantle eyes contain a lens, two distinct retinas and a concave spherical mirror, morphologically similar to that of previously described scallop eyes (Dakin, 1928;Barber et al, 1966;Morton, 2000). Light reflected off the mirror is thought to form a focused image on the distal retina (Land, 1965), which appears to be wellsuited for the detection of movement (Land, 1966).…”

Section: Introductionmentioning

confidence: 82%

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Scallops visually respond to the size and speed of virtual particles

Speiser

Johnsen

2008

Journal of Experimental Biology

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SUMMARY The unique eyes of scallops are abundant along the right and left valve mantle margins. These eyes form images by reflection off a concave spherical mirror, and give scallops an angular resolution of around 2°, far better than the 13–40° angular resolution provided by the eyes of other bivalves. It has been argued that bivalve mantle eyes primarily act as predator detectors, but behavioral studies have suggested that vision may serve additional purposes in scallops. By placing specimens of the bay scallop Argopecten irradians (Lamarck 1819) in a tank with 5–10 cm s–1 flow, showing them simulated images of moving particles,and recording their behavior, we tested whether visual cues may influence feeding behavior in these animals. We found that scallops opened their anterior mantle gapes significantly more often when they were shown 1.5×1.5 mm virtual particles (with angular sizes of 3.4°) than when they were shown 0.6×0.6 mm particles (1.4°; P<0.001) or no particles at all (P<0.05). We also found that scallops opened their anterior mantle gapes significantly more often when they were shown virtual particles moving at 2.5 cm s–1 (P<0.01)or 5 cm s–1 (P<0.05) than when they were shown particles moving at 10 cm s–1. Because scallops must open their anterior mantle gapes to feed, our findings suggest that these animals may visually detect the size and speed of moving particles and use this information to help identify favorable feeding conditions.

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Section: Introductionmentioning

confidence: 82%

“…Behavioral (von Buddenbrock and Moller-Racke, 1953), morphological (Land, 1965) and physiological (Land, 1966) studies all conclude that scallop eyes have an angular resolution of around 2°. In comparison, the predator-detecting eyes of other bivalves have angular resolutions ranging from 13° to 40° (Nilsson, 1994;Land, 2003).…”

Section: Introductionmentioning

confidence: 99%

Scallops visually respond to the size and speed of virtual particles

Speiser

Johnsen

2008

Journal of Experimental Biology

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“…The animal has fifty or more eyes situated on the ends of short stalks around the edge of its mantle. When the shell is opened the visual field is almost a complete circle of about 3000 of arc in the horizontal plane (Land, 1965). The optimal stimulus for the closure reflex is not total darkness but a shadow in some part of the animal's visual field and thus, under normal conditions, the distal photoreceptors are likely to be subjected to varying degrees of darkness depending on the position and orientation of the individual eye in the field.…”

Section: Effects Of Light Decrement On the Off Responsementioning

confidence: 99%

Contribution of calcium and potassium permeability changes to the off response of scallop hyperpolarizing photoreceptors.

Cornwall¹,

Gorman²

1979

The Journal of Physiology

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SUMMARY1. The membrane response of the distal photoreceptors in the retina of the scallop Pectin irradians to the termination of a bright white light (off response) is shown to be composed of the decay of the hyperpolarizing receptor potential and an action potential with slow kinetics.2. The action potential can be produced in darkness in the absence of external Na+ ions by membrane depolarization.3. The action potential is maintained by replacement of external Ca2+ with Sr2+ or Ba2+, but not by Mg2+. In normal external Ca2+ (9 mM), the action potential is abolished by the addition of the Ca2+ inhibitors, La3+, Co2+, and Mn2+ or the organic Ca2+ antagonist D-600.4. Elevated external Ca2+ concentrations increase the rate of rise and peak amplitude of the action potential as well as the rate of repolarization and after hyperpolarization, but decrease the duration.5. The rate of rise and peak amplitude of the action potential are increased by the K+ antagonists tetraethylammonium (TEA) 4-amino-pyridine (4-AP), Ba2+ and procaine. The antagonists have different effects on subsequent phases of the response, however. External TEA and Ba2+ increase the duration, but decrease the rate of repolarization and abolish the after hyperpolarization, whereas external 4-AP and procaine increase the rate of repolarization, decrease the duration and increase the after hyperpolarization.6. The ratio of the Ca2+ to K+ permeability (PC/0PK) estimated from the constant field equation at the peak of the action potential in different external Ca2+ concentrations is close to 1. 7. The maximum rate of rise and the peak amplitude of the action potential are increased by membrane hyperpolarization and decreased by membrane depolarization. They are decreased by background light intensity relative to their value in the dark.8. In normal ASW the action potential can be identified during the off response as a small overshoot of membrane potential relative to its value in the dark.9. The rate of repolarization of the off response in normal ASW is reduced by agents or conditions which inhibit or reduce Ca2+ permeability changes, e.g. external Co2+ and La2+ or zero external Ca2+.

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“…It has been demonstrated mathematically that the image forms on the distal retina, composed of ciliary photoreceptors (Land 1966a), and both physiological and behavioral experiments corroborate this finding (Patten 1886, Land 1966b. Pectinids respond to (1) an overall distribution of brightness in the environment, which determines the direction of swimming behavior via the proximal retina; local changes in (2) light intensity by shadow or (3) movements in the optical environment are involved in defensive responses via the distal retina (original description in Buddenbrock and Moller-Racke 1953, summary in Land 1968).…”

Section: Bivalviamentioning

confidence: 84%

“…Much work has been done on the scallop eye including recent work on optics (Land 1965(Land , 1966a, comparative anatomy (Morton 2000(Morton , 2001 and references therein, Speiser and Johnsen 2008a), electrophysiology (Gorman andMcReynolds 1969, Gomez andNasi 1994), neurophysiology (Spagnola andWilkens 1983, Wilkens 2006), visualmediated behavior (Wilkens and Ache 1977, Hamilton and Koch 1996, Wilkens 2006, Speiser and Johnsen 2008b, phototransduction (Kojima et al 1997), and lens formation and protein evolution (Carosa et al 2002, Piatigorsky 2008.…”

Section: Bivalviamentioning

confidence: 99%

Toward Developing Models to Study the Disease, Ecology, and Evolution of the Eye in Mollusca*

Serb

2008

American Malacological Bulletin

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Several invertebrate systems have been developed to study various aspects of the eye and eye disease including Drosophila, Planaria, Platynereis, and most recently, the cubozoan jellyfish Tripedalia; however, molluscs, the second largest metazoan phylum, so far have been underrepresented in eye research. This is surprising as mollusc systems offer opportunities to study visual processes that may be altered by disease, vision physiology, development of the visual system, behavior, and evolution. Malacologists have labored for over a century as morphologists, systematists, physiologists, and ecologists in order to understand the structural and functional diversity in molluscs at all levels of biological organization. Yet, malacologists have had little opportunity to interact with researchers whose interests are restricted to the biology and development of eyes as model systems as they tend not to publish in the same journals or attend the same meetings. In an effort to highlight the advantages of molluscan eyes as a model system and encourage greater collaboration among researchers, I provide an overview of molluscan eye research from these two perspectives: eye researchers whose interests involve the development, physiology, and disease of the eye and malacologists who study the complete organism in its natural environment. I discuss the developmental and genetic information available for molluscan eyes and the need to place this work in an evolutionary perspective. Finally, I discuss how synergy between these two groups will advance eye research, broaden research in both fields, and aid in developing new molluscan models for eye research. Abstract: Several invertebrate systems have been developed to study various aspects of the eye and eye disease including Drosophila, Planaria, Platynereis, and most recently, the cubozoan jellyfish Tripedalia; however, molluscs, the second largest metazoan phylum, so far have been underrepresented in eye research. This is surprising as mollusc systems offer opportunities to study visual processes that may be altered by disease, vision physiology, development of the visual system, behavior, and evolution. Malacologists have labored for over a century as morphologists, systematists, physiologists, and ecologists in order to understand the structural and functional diversity in molluscs at all levels of biological organization. Yet, malacologists have had little opportunity to interact with researchers whose interests are restricted to the biology and development of eyes as model systems as they tend not to publish in the same journals or attend the same meetings. In an effort to highlight the advantages of molluscan eyes as a model system and encourage greater collaboration among researchers, I provide an overview of molluscan eye research from these two perspectives: eye researchers whose interests involve the development, physiology, and disease of the eye and malacologists who study the complete organism in its natural environment. I discuss the developmental and genet...

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Image formation by a concave reflector in the eye of the scallop, Pecten maximus.

Cited by 152 publications

References 3 publications

Scallops visually respond to the size and speed of virtual particles

Scallops visually respond to the size and speed of virtual particles

Contribution of calcium and potassium permeability changes to the off response of scallop hyperpolarizing photoreceptors.

Toward Developing Models to Study the Disease, Ecology, and Evolution of the Eye in Mollusca*

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