Postembryonic Eye Growth in the Seashore Isopod<i>Ligia exotica</i>(Crustacea, Isopoda)

Keskinen, Essi; Takaku, Yasuharu; Meyer‐Rochow, Victor Benno; Hariyama, Takahiko

doi:10.2307/1543472

Cited by 17 publications

(11 citation statements)

References 32 publications

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“…The number and size of ommatidia increase in parallel with the growth of the body during the lifetime of Parhyale . As noted previously for isopod crustaceans [64], these changes are likely to influence both the visual acuity of the eyes (related to ommatidial numbers) and their sensitivity (related to ommatidial size). In the future, it will be interesting to investigate how new ommatidia are incorporated into the eyes, gradually extending the visual field and retinotopic maps in the context of a functioning visual system, and how the changes in visual performance impact visually guided behaviours in juvenile and adult stages.…”

Section: Discussionmentioning

confidence: 79%

Analysis of the genetically tractable crustacean Parhyale hawaiensis reveals the organisation of a sensory system for low-resolution vision

Ramos¹,

Gustafsson²,

N³

et al. 2019

BMC Biol

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Background Arthropod eyes have diversified during evolution to serve multiple needs, such as finding mates, hunting prey and navigating in complex surroundings under varying light conditions. This diversity is reflected in the optical apparatus, photoreceptors and neural circuits that underpin vision. Yet our ability to genetically manipulate the visual system to investigate its function is largely limited to a single species, the fruit fly Drosophila melanogaster . Here, we describe the visual system of Parhyale hawaiensis , an amphipod crustacean for which we have established tailored genetic tools. Results Adult Parhyale have apposition-type compound eyes made up of ~ 50 ommatidia. Each ommatidium contains four photoreceptor cells with large rhabdomeres (R1–4), expected to be sensitive to the polarisation of light, and one photoreceptor cell with a smaller rhabdomere (R5). The two types of photoreceptors express different opsins, belonging to families with distinct wavelength sensitivities. Using the cis- regulatory regions of opsin genes, we established transgenic reporters expressed in each photoreceptor cell type. Based on these reporters, we show that R1–4 and R5 photoreceptors extend axons to the first optic lobe neuropil, revealing striking differences compared with the photoreceptor projections found in related crustaceans and insects. Investigating visual function, we show that Parhyale have a positive phototactic response and are capable of adapting their eyes to different levels of light intensity. Conclusions We propose that the visual system of Parhyale serves low-resolution visual tasks, such as orientation and navigation, based on broad gradients of light intensity and polarisation. Optic lobe structure and photoreceptor projections point to significant divergence from the typical organisation found in other malacostracan crustaceans and insects, which could be associated with a shift to low-resolution vision. Our study provides the foundation for research in the visual system of this genetically tractable species. Electronic supplementary material The online version of this article (10.1186/s12915-019-0676-y) contains supplementary material, which is available to authorized users.

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Section: Discussionmentioning

confidence: 79%

Analysis of the genetically tractable crustacean Parhyale hawaiensis reveals the organisation of a sensory system for low-resolution vision

Ramos¹,

Gustafsson²,

N³

et al. 2019

BMC Biol

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show abstract

“…The number and size of ommatidia increase in parallel with the growth of the body during the lifetime of Parhyale . As noted previously for isopod crustaceans [62], these changes are likely to influence both the visual acuity of the eyes (related to ommatidial numbers) and their sensitivity (related to ommatidial size). In the future, it will be interesting to investigate how new ommatidia are incorporated into the eyes, gradually extending the visual field and retinotopic maps in the context of a functioning visual system, and how the changes in visual performance impact visually-guided behaviours in juvenile and adult stages.…”

Section: Discussion/conclusionmentioning

confidence: 79%

The visual system of the genetically tractable crustaceanParhyale hawaiensis: diversification of eyes and visual circuits associated with low-resolution vision

Ramos

Gustafsson

et al. 2019

Preprint

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BackgroundArthropod eyes have diversified during evolution to serve multiple needs, such as finding mates, hunting prey, and navigating in complex surroundings under varying light conditions. This diversity is reflected in the optical apparatus, photoreceptors and neural circuits that underpin vision. While this diversity has been extensively documented, our ability to genetically manipulate the visual system to investigate its function is largely limited to a single species, the fruitfly Drosophila melanogaster. Here, we describe the visual system of Parhyale hawaiensis, an amphipod crustacean for which we have established tailored genetic tools.ResultsAdult Parhyale have apposition-type compound eyes made up of ∼50 ommatidia. Each ommatidium contains four photoreceptor cells with large rhabdomeres (R1-4), expected to be sensitive to the polarisation of light, and one photoreceptor cell with a smaller rhabdomere (R5). The two types of photoreceptors express different opsins, belonging to families with distinct wavelength sensitivities. Using the cis.-regulatory regions of opsin genes, we established transgenic reporters expressed in each photoreceptor cell type. Based on these reporters, we show that R1-4 and R5 photoreceptors extend axons to the first optic lobe neuropil, revealing striking differences compared with the photoreceptor projections found in related crustaceans and insects. Investigating visual function, we show that Parhyale has a positive phototactic response and is capable of adapting its eyes to different levels of light intensity.ConclusionsWe propose that the visual system of Parhyale serves low-resolution visual tasks, such as orientation and navigation, based on broad gradients of light intensity and polarisation. Optic lobe structure and photoreceptor projections point to significant divergence from the conserved visual circuits found in other malacostracan crustaceans and insects, which could be associated with a shift to low-resolution vision. Our study provides the foundation for research in the visual system of this genetically tractable species.

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“…Each cluster produces one whole ommatidium (Hafner & Tokarski 2001). In the eye of Ligia exotica (Roux, 1828) a proliferation zone produces ommatidia but the different components grow at different speeds (Keskinen et al 2002). This also seems to be the case in stomatopod eyes.…”

Section: Discussionmentioning

confidence: 96%

“…Light/dark adaptation involves mechanical changes of the dioptric apparatus and the retina. Crustacean eyes continue to grow through lifetime (Keskinen et al 2002) increasing sizes of eyes and ommatidia. Sizes of ommatidia and skewing both change with the sizes of the animal.…”

Section: Introductionmentioning

confidence: 99%

Morphology of adaptation and morphogenesis in stomatopod eyes

Schiff¹,

Dore²,

Boido³

2007

Italian Journal of Zoology

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Ommatidia of eyes of stomatopods change with adaptation to light or dark. With dark adaptation the crystalline cones shorten and the retina becomes longer. This is due to contractions of myofibrils in veils surrounding the cones, while microtubules within the accessory pigment cells maintain the cytoarchitecture of the ommatidia. Here we describe the changes in Lysiosquillina maculata, a stomatopod living in an extremely bright habitat, which is compared to stomatopods from other ambient light conditions. The postlarval eye of stomatopods grows over the larval eye, gradually substituting it. Growth starts from a morphogenetic furrow at the inner border with the stalk. Similarly, in the adult eye as well at the inner margin between the stalk and the cornea, a morphogenetic furrow is inserted, which at its interior contains a proliferation tissue with clusters of developing ommatidia. At its distal side the proliferation tissue appears to generate the dioptric apparatus, i.e. veils, corneagenous cells and cones, and at its more proximal part the basement membrane, accessory pigment cells and retinular cells. The ommatidial components grow at different speeds.

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Postembryonic Eye Growth in the Seashore IsopodLigia exotica(Crustacea, Isopoda)

Cited by 17 publications

References 32 publications

Analysis of the genetically tractable crustacean Parhyale hawaiensis reveals the organisation of a sensory system for low-resolution vision

Analysis of the genetically tractable crustacean Parhyale hawaiensis reveals the organisation of a sensory system for low-resolution vision

The visual system of the genetically tractable crustaceanParhyale hawaiensis: diversification of eyes and visual circuits associated with low-resolution vision

Morphology of adaptation and morphogenesis in stomatopod eyes

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