ORCID Profile
0000-0002-4602-9840
Current Organisation
University of Queensland
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Zoology | Animal Neurobiology | Behavioural Ecology | Biological Adaptation
Expanding Knowledge in the Biological Sciences | Marine Flora, Fauna and Biodiversity |
Publisher: Elsevier BV
Date: 11-2015
Publisher: American Association for the Advancement of Science (AAAS)
Date: 10-05-2019
Abstract: Vertebrates are typically thought to have a consistent system for processing light, in which multiple cone opsins permit color vision during the day, but a single rod opsin provides only monochrome vision in the dark. Musilova et al. analyzed more than 100 deep-sea fish genomes and found a previously unknown proliferation of rod opsin genes that generate rod opsin photopigments that are tuned to different wavelengths of light. These receptors may allow the fish to perceive bioluminescent signals that pervade their deep-sea environment. These results reveal a previously undescribed visual system that allows for color vision in the dark. Science , this issue p. 588
Publisher: S. Karger AG
Date: 2014
DOI: 10.1159/000365960
Abstract: Topographic analyses of retinal ganglion cell density are very useful in providing information about the visual ecology of a species by identifying areas of acute vision within the visual field (i.e. areas of high cell density). In this study, we investigated the neural cell distribution in the ganglion cell layer of a range of lanternfish species belonging to 10 genera. Analyses were performed on wholemounted retinas using stereology. Topographic maps were constructed of the distribution of all neurons and both ganglion and amacrine cell populations in 5 different species from Nissl-stained retinas using cytological criteria. Amacrine cell distribution was also examined immunohistochemically in 2 of the 5 species using anti-parvalbumin antibody. The distributions of both the total neuron and the amacrine cell populations were aligned in all of the species examined, showing a general increase in cell density toward the retinal periphery. However, when the ganglion cell population was topographically isolated from the amacrine cell population, which comprised up to 80% of the total neurons within the ganglion cell layer, a different distribution was revealed. Topographic maps of the true ganglion cell distribution in 18 species of lanternfishes revealed well-defined specializations in different regions of the retina. Different species possessed distinct areas of high ganglion cell density with respect to both peak density and the location and/or shape of the specialized acute zone (i.e. elongated areae ventro-temporales, areae temporales and large areae centrales). The spatial resolving power was calculated to be relatively low (varying from 1.6 to 4.4 cycles per degree), indicating that myctophids may constitute one of the less visually acute groups of deep-sea teleosts. The ersity in retinal specializations and spatial resolving power within the family is assessed in terms of possible ecological functions and evolutionary history.
Publisher: The Company of Biologists
Date: 2019
DOI: 10.1242/JEB.209916
Abstract: Ontogenetic changes of the visual system are often correlated to shifts in habitat and feeding behaviour of animals. Coral reef fishes begin their lives in the pelagic zone and then migrate to the reef. This habitat transition frequently involves a change in diet and light environment as well as major morphological modifications. The spotted unicornfish, Naso brevirostris, is known to shift diet from zooplankton to algae and back to mainly zooplankton when transitioning from larval to juvenile and then to adult stages. Concurrently, N. brevirostris also moves from an open pelagic to a coral-associated habitat before migrating up in the water column when reaching adulthood. Using retinal mapping techniques, we discovered that the distribution and density of ganglion and photoreceptor cells in N. brevirostris mostly changes during the transition from the larval to the juvenile stage, with only minor modifications thereafter. Similarly, visual gene (opsin) expression based on RNA sequencing, although qualitatively similar between stages (all fishes mainly expressed the same three cone opsins SWS2B, RH2B, RH2A), also showed the biggest quantitative difference when transitioning from larvae to juveniles. The juvenile stage in particular seems mismatched with its reef-associated ecology, which may be due to this stage only lasting a fraction of the lifespan of these fishes. Hence, the visual ontogeny found in N. brevirostris is very different from the progressive changes found in other reef fishes calling for a thorough analysis of visual system development of the reef fish community.
Publisher: Public Library of Science (PLoS)
Date: 13-06-2014
Publisher: Cold Spring Harbor Laboratory
Date: 05-05-2022
DOI: 10.1101/2022.05.04.490704
Abstract: Developmental changes to the visual systems of animals are often associated with ecological shifts. Reef fishes experience a change in habitat between larval life in the shallow open ocean to juvenile and adult life on the reef. Some species also change their lifestyle over this period and become largely nocturnal. While these ecological transitions are well documented, little is known about the ontogeny of nocturnal reef fish vision. Here, we used histology and transcriptomics to investigate visual development in 12 representative species from both subfamilies, Holocentrinae (squirrelfishes) and Myripristinae (soldierfishes), in the nocturnal coral reef fish family, Holocentridae. Results revealed that the visual systems of holocentrids are initially well-adapted to photopic conditions with pre-settlement larvae having high cone densities, high cone opsin gene expression, a broad cone opsin gene repertoire (8 genes) and a multibank retina ( i . e ., stacked layers of rods) comprising up to two rod banks. At reef settlement, holocentrids started to invest more in their scotopic visual system and upregulated genes involved in cell differentiation roliferation. By adulthood, they had well-developed scotopic vision with a rod-dominated multibank retina comprising 5-17 rod banks, increased summation of rods onto ganglion cells, high rod opsin gene expression, reduced cone opsin gene expression and repertoire (1-4 genes) and upregulated phototransduction genes. Finally, although the two subfamilies shared similar ecologies across development, their visual systems erged after settlement, with Myripristinae investing more in scotopic vision than Holocentrinae. Hence, both ecology and phylogeny likely determine the development of the holocentrid visual system. Coral reef fishes in the family Holocentridae remodel their retina at the cellular and molecular levels to adapt to a nocturnal lifestyle during development.
Publisher: The Company of Biologists
Date: 04-2022
DOI: 10.1242/JEB.243907
Abstract: Vision is used by animals to find food and mates, avoid predators, defend resources and navigate through complex habitats. Behavioural experiments are essential for understanding animals' perception but are often challenging and time-consuming therefore, using species that can be trained easily for complex tasks is advantageous. Picasso triggerfish, Rhinecanthus aculeatus, have been used in many behavioural studies investigating vision and navigation. However, little is known about the molecular and anatomical basis of their visual system. We addressed this knowledge gap here and behaviourally tested achromatic and chromatic acuity. In terms of visual opsins, R. aculeatus possessed one rod opsin gene (RH1) and at least nine cone opsins: one violet-sensitive SWS2B gene, seven duplicates of the blue–green-sensitive RH2 gene (RH2A, RH2B, RH2C1-5) and one red-sensitive LWS gene. However, only five cone opsins were expressed: SWS2B expression was consistent, while RH2A, RH2C-1 and RH2C-2 expression varied depending on whether fish were s led from the field or aquaria. Levels of LWS expression were very low. Using fluorescence in situ hybridisation, we found SWS2B was expressed exclusively in single cones, whereas RH2A and RH2Cs were expressed in opposite double cone members. Anatomical resolution estimated from ganglion cell densities was 6.8 cycles per degree (cpd), which was significantly higher than values obtained from behavioural testing for black-and-white achromatic stimuli (3.9 cpd) and chromatic stimuli (1.7–1.8 cpd). These measures were twice as high as previously reported. This detailed information on their visual system will help inform future studies with this emerging focal species.
Publisher: American Association for the Advancement of Science (AAAS)
Date: 03-11-2017
Abstract: Deep-sea fishes evolved an unconventional visual system to optimize vision in twilight conditions.
Publisher: The Company of Biologists
Date: 15-12-2021
DOI: 10.1242/JEB.243420
Abstract: Among fishes in the family Poeciliidae, signals such as colour patterns, ornaments and courtship displays play important roles in mate choice and male–male competition. Despite this, visual capabilities in poeciliids are understudied, in particular, visual acuity, the ability to resolve detail. We used three methods to quantify visual acuity in male and female green swordtails (Xiphophorus helleri), a species in which body size and the length of the male's extended caudal fin (‘sword’) serve as assessment signals during mate choice and agonistic encounters. Topographic distribution of retinal ganglion cells (RGCs) was similar in all in iduals and was characterized by areas of high cell densities located centro-temporally and nasally, as well as a weak horizontal streak. Based on the peak density of RGCs in the centro-temporal area, anatomical acuity was estimated to be approximately 3 cycles per degree (cpd) in both sexes. However, a behavioural optomotor assay found significantly lower mean acuity in males (0.8 cpd) than females (3.0 cpd), which was not explained by differences in eye size between males and females. An additional behavioural assay, in which we trained in iduals to discriminate striped gratings from grey stimuli of the same mean luminance, also showed lower acuity in males (1–2 cpd) than females (2–3 cpd). Thus, although retinal anatomy predicts identical acuity in males and females, two behavioural assays found higher acuity in females than males, a sexual dimorphism that is rare outside of invertebrates. Overall, our results have implications for understanding how poeciliids perceive visual signals during mate choice and agonistic encounters.
Publisher: Wiley
Date: 18-03-2014
DOI: 10.1002/CNE.23495
Abstract: Lanternfishes are one of the most abundant groups of mesopelagic fishes in the world's oceans and play a critical role in biomass vertical turnover. Despite their importance, very little is known about their physiology or how they use their sensory systems to survive in the extreme conditions of the deep sea. In this study, we provide a comprehensive description of the general morphology of the myctophid eye, based on analysis of 53 different species, to understand better their visual capabilities. Results confirm that myctophids possess several visual adaptations for dim-light conditions, including enlarged eyes, an aphakic gap, a tapetum lucidum, and a pure rod retina with high densities of long photoreceptors. Two novel retinal specializations were also discovered. The first specialization is a fundal pigmentation in adult eyes, found within an isolated retinal region (typically central retina) composed of modified pigment epithelial cells, which we hypothesize to be the remnant of a more pronounced visual specialization important in larval stages. The second specialization is an aggregation of extracellular microtubular-like structures found within the sclerad region of the inner nuclear layer of the retina. We hypothesize that the marked interspecific differences in the hypertrophy of these microtubular-like structures may be related to inherent differences in visual function. A general interspecific variability in other parts of the eye is also revealed and examined in this study. The contribution of both ecology and phylogeny to the evolution of ocular specializations and vision in dim light are discussed.
Publisher: Cold Spring Harbor Laboratory
Date: 04-06-2022
DOI: 10.1101/2022.06.02.494615
Abstract: The visual capabilities of fish are optimised for their ecology and light environment over evolutionary time. Similarly, fish vision can adapt to regular changes in light conditions within their lifetime, e . g ., ontogenetic or seasonal variation. However, we do not fully understand how vision responds to irregular short-term changes in the light environment, e . g ., algal blooms and light pollution. In this study, we investigated the effect of short-term exposure to unnatural light conditions on opsin gene expression and retinal cell densities in larval and adult diurnal reef fish (convict surgeonfish Acanthurus triostegus ). Results revealed phenotypic plasticity in the retina across ontogeny, particularly in the larvae. The most substantial differences at both molecular and cellular levels were found under constant dim light, while constant bright light or simulated artificial light at night had a lesser effect. Under dim light, larvae and adults increased expression of the cone opsin genes, sws2a, rh2c and lws , within a few days and larvae also decreased densities of cones, inner nuclear layer cells and ganglion cells. These changes likely enhanced vision under the altered light conditions. Thus, our study suggests that plasticity mainly comes into play when conditions are extremely different to the species’ natural light environment, i . e ., a diurnal fish in ‘constant night’. Finally, in a rescue experiment on adults, shifts in opsin expression were reverted within 24 hours. Overall, our study showed rapid, reversible light-induced changes in the retina of A. triostegus , demonstrating phenotypic plasticity in the visual system of a reef fish throughout life.
Publisher: The Company of Biologists
Date: 09-2022
DOI: 10.1242/JEB.244513
Abstract: Developmental changes to the visual systems of animals are often associated with ecological shifts. Reef fishes experience a change in habitat between larval life in the shallow open ocean to juvenile and adult life on the reef. Some species also change their lifestyle over this period and become nocturnal. While these ecological transitions are well documented, little is known about the ontogeny of nocturnal reef fish vision. Here, we used transcriptomics to investigate visual development in 12 representative species from both subfamilies, Holocentrinae (squirrelfishes) and Myripristinae (soldierfishes), in the nocturnal coral reef fish family, Holocentridae. Results revealed that the visual systems of holocentrids are initially well adapted to photopic conditions with pre-settlement larvae having high levels of cone opsin gene expression and a broad cone opsin gene repertoire (8 genes). At reef settlement, holocentrids started to invest more in their scotopic visual system, and compared with adults, showed upregulation of genes involved in cell differentiation roliferation. By adulthood, holocentrids had well developed scotopic vision with high levels of rod opsin gene expression, reduced cone opsin gene expression and repertoire (1–4 genes) and upregulated phototransduction genes. Finally, although the two subfamilies shared similar ecologies across development, their visual systems erged after settlement, with Myripristinae investing more in scotopic vision than Holocentrinae. Hence, both ecology and phylogeny are likely to determine the development of the holocentrid visual system.
Publisher: Cold Spring Harbor Laboratory
Date: 25-05-2020
DOI: 10.1101/2020.05.24.113811
Abstract: The visual systems of teleost fishes usually match their habitats and lifestyles. Since coral reefs are bright and colourful environments, the visual systems of their diurnal inhabitants have been more extensively studied than those of nocturnal species. In order to fill this knowledge gap, we conducted a detailed investigation of the visual systems of the coral reef fish family Holocentridae (squirrelfish and soldierfish). In addition to their nocturnality, this family is particularly interesting for dim-light vision studies due to its ecological and evolutionary connection to deeper habitats. Results showed that the visual system of holocentrids is well adapted to their nocturnal lifestyle with a rod-dominated retina. Surprisingly, rods in all species were arranged into 6-17 well-defined banks, a feature most commonly found in deep-sea fishes, that may increase the light sensitivity of the eye and/or allow colour discrimination in dim-light. Holocentrids also have the potential for dichromatic colour vision during the day with the presence of at least two spectrally different cone types: single cones expressing the blue-sensitive SWS2A gene, and double cones expressing one or two green-sensitive RH2 genes. Some differences were observed between the two subfamilies, with Holocentrinae having a slightly more developed photopic visual system than Myripristinae. Moreover, retinal topography of both ganglion cells and cone photoreceptors showed specific patterns for each cell type, likely highlighting different visual demands at different times of the day, such as feeding. Overall, their well-developed scotopic visual systems and the ease of catching and maintaining holocentrids in aquaria, make them ideal models to investigate teleost dim-light vision and more particularly shed light on the function of multibank retina and its potential for dim-light colour vision.
Publisher: The Royal Society
Date: 05-04-2017
Abstract: Ecological and behavioural constraints play a major role in shaping the visual system of different organisms. In the mesopelagic zone of the deep- sea, between 200 and 1000 m, very low intensities of downwelling light remain, creating one of the dimmest habitats in the world. This ambient light is, however, enhanced by a multitude of bioluminescent signals emitted by its inhabitants, but these are generally dim and intermittent. As a result, the visual system of mesopelagic organisms has been pushed to its sensitivity limits in order to function in this extreme environment. This review covers the current body of knowledge on the visual system of one of the most abundant and intensely studied groups of mesopelagic fishes: the lanternfish (Myctophidae). We discuss how the plasticity, performance and novelty of its visual adaptations, compared with other deep-sea fishes, might have contributed to the ersity and abundance of this family. This article is part of the themed issue ‘Vision in dim light’.
Publisher: The Company of Biologists
Date: 2016
DOI: 10.1242/JEB.149211
Abstract: The distinct behaviors and varied habitats where animals live place different requirements on their visual systems. A trade-off exists between resolution and sensitivity, with these properties varying across the retina. Spectral sensitivity, which affects both achromatic and chromatic (colour) vision, also varies across the retina, though the function of this inhomogeneity is less clear. We previously demonstrated spatially varying spectral sensitivity of double cones in the cichlid fish Metriaclima zebra due to coexpression of different opsins. Here, we map the distributions of ganglion cells and cone cells and quantify opsin coexpression in single cones to show these also vary across the retina. We identify an area centralis with peak acuity and infrequent coexpression, which may be suited for tasks such as foraging and detecting male signals. The peripheral retina has reduced ganglion cell densities and increased opsin coexpression. Modeling of cichlid visual tasks indicates that coexpression might hinder colour discrimination of foraging targets and some fish colours. But, coexpression might improve contrast detection of dark objects against bright backgrounds, which might be useful for detecting predators or zooplankton. This suggests a trade off between acuity and colour discrimination in the central retina versus lower resolution but more sensitive contrast detection in the peripheral retina. Significant variation in the pattern of coexpression among in iduals, however, raises interesting questions about the selective forces at work.
Publisher: Public Library of Science (PLoS)
Date: 05-03-2013
Publisher: Cold Spring Harbor Laboratory
Date: 27-11-2022
DOI: 10.1101/2022.11.27.518067
Abstract: Multibank retinas have rod photoreceptors stacked into multiple layers. They are found in many species of fish that inhabit dim environments and are one of the most common visual adaptations in the deep-sea. Despite its prevalence, the function of multibank retinas remained unknown. Two predominant theories, neither of which has been tested, have emerged: 1) they enhance sensitivity in dim light, and 2) they allow colour vision in dim light. To investigate the sensitivity hypothesis, we performed electrophysiological recordings and compared the rod pigments of three species of nocturnal reef fishes, two with a multibank retina ( Neoniphon sammara and Myripristis violacea ) and a control species with a single rod bank ( Ostorhinchus compressus ). Results indicated that nocturnal reef fishes with a multibank retina have higher temporal resolution of vision, as indicated by electrophysiology, and that their rhodopsin proteins likely also have faster retinal release kinetics, as suggested by amino acid substitutions. Electrophysiology also showed that the multibank retina conferred greater sensitivity to both dim and bright intensities than a single rod bank and this occurred at times when rod-derived signals usually dominate the visual response. This study provides the first functional evidence for enhanced dim-light sensitivity using a multibank retina while also suggesting novel roles for the adaptation in enhancing bright-light sensitivity and the speed of vision. Most vertebrates have one layer of the dim-light active rod photoreceptors however, some species have multiple layers, known as a multibank retina. We used electrophysiology on nocturnal reef fishes with and without multibank retinas to evaluate the sensory advantage of having multiple rod layers. We show that fish with multibank retinas have both faster vision and enhanced sensitivity to bright and dim light intensities. Thus, we resolve for the first time the function of multibank retinas – one of the most common visual adaptations in the deep sea. Our findings highlight an unconventional vertebrate visual system as well as the visual capabilities of fishes from the most vast (deep sea) and vibrant (reefs) ecosystems on the planet.
Publisher: S. Karger AG
Date: 2015
DOI: 10.1159/000371652
Abstract: Deep-sea fishes possess several adaptations to facilitate vision where light detection is pushed to its limit. Lanternfishes (Myctophidae), one of the world's most abundant groups of mesopelagic fishes, possess a novel and unique visual specialisation, a sexually dimorphic photostable yellow pigmentation, constituting the first record of a visual sexual dimorphism in any non-primate vertebrate. The topographic distribution of the yellow pigmentation across the retina is species specific, varying in location, shape and size. Spectrophotometric analyses reveal that this new retinal specialisation differs between species in terms of composition and acts as a filter, absorbing maximally between 356 and 443 nm. Microspectrophotometry and molecular analyses indicate that the species containing this pigmentation also possess at least 2 spectrally distinct rod visual pigments as a result of a duplication of the i Rh1 /i opsin gene. After modelling the effect of the yellow pigmentation on photoreceptor spectral sensitivity, we suggest that this unique specialisation acts as a filter to enhance contrast, thereby improving the detection of bioluminescent emissions and possibly fluorescence in the extreme environment of the deep sea. The fact that this yellow pigmentation is species specific, sexually dimorphic and isolated within specific parts of the retina indicates an evolutionary pressure to visualise prey redators/mates in a particular part of each species' visual field.
Publisher: Wiley
Date: 11-11-2022
DOI: 10.1111/MEC.16744
Abstract: The visual capabilities of fish are optimized for their ecology and light environment over evolutionary time. Similarly, fish vision can adapt to regular changes in light conditions within their lifetime, e.g. , ontogenetic or seasonal variation. However, we do not fully understand how vision responds to irregular short‐term changes in the light environment, e.g., algal blooms and light pollution. In this study, we investigated the effect of short‐term exposure to unnatural light conditions on opsin gene expression and retinal cell densities in juvenile and adult diurnal reef fish (convict surgeonfish Acanthurus triostegus ). Results revealed phenotypic plasticity in the retina across ontogeny, particularly during development. The most substantial differences at both molecular and cellular levels were found under constant dim light, while constant bright light and simulated artificial light at night had a lesser effect. Under dim light, juveniles and adults increased absolute expression of the cone opsin genes, sws2a, rh2c and lws, within a few days and juveniles also decreased densities of cones, inner nuclear layer cells and ganglion cells. These changes potentially enhanced vision under the altered light conditions. Thus, our study suggests that plasticity mainly comes into play when conditions are extremely different to the species' natural light environment, i.e., a diurnal fish in “constant night”. Finally, in a rescue experiment on adults, shifts in opsin expression were reverted within 24 h. Overall, our study showed rapid, reversible light‐induced changes in the retina of A. triostegus , demonstrating phenotypic plasticity in the visual system of a reef fish throughout life.
Publisher: Wiley
Date: 16-02-2020
Publisher: Elsevier BV
Date: 09-2009
Publisher: Cold Spring Harbor Laboratory
Date: 23-09-2018
DOI: 10.1101/424895
Abstract: Vertebrate vision is accomplished through a set of light-sensitive photopigments, which are located in the photoreceptors of the retina and consist of a visual opsin protein bound to a chromophore. In dim-light, vertebrates generally rely upon a single rod opsin (RH1) for obtaining visual information. By inspecting 101 fish genomes, we found that three deep-sea teleost lineages have independently expanded their RH1 gene repertoires. Amongst these, the silver spinyfin ( Diretmus argenteus Johnson 1863) stands out as having the highest number of visual opsins known for animals to date (2 cone and 38 rod opsins). Spinyfins simultaneously express up to 14 RH1s encoding for photopigments with different peak spectral sensitivities (λ max =448-513 nm) that cover the range of the residual daylight, as well as the bioluminescence spectrum present in the deep-sea. Our findings present novel molecular and functional evidence for the recurrent evolution of multiple rod opsin-based vision in vertebrates. Contrary to the single rod opsin used by most vertebrates, some fishes use multiple rod opsins for vision in the dimly lit deep-sea.
Publisher: The Company of Biologists
Date: 09-2022
DOI: 10.1242/JEB.244740
Abstract: Ontogenetic changes in the habitats and lifestyles of animals are often reflected in their visual systems. Coral reef fishes start life in the shallow open ocean but inhabit the reef as juveniles and adults. Alongside this change in habitat, some species also change lifestyles and become nocturnal. However, it is not fully understood how the visual systems of nocturnal reef fishes develop and adapt to these significant ecological shifts over their lives. Therefore, we used a histological approach to examine visual development in the nocturnal coral reef fish family, Holocentridae. We examined 7 representative species spanning both subfamilies, Holocentrinae (squirrelfishes) and Myripristinae (soldierfishes). Pre-settlement larvae showed strong adaptation for photopic vision with high cone densities and had also started to develop a multibank retina (i.e. multiple rod layers), with up to two rod banks present. At reef settlement, holocentrids showed greater adaptation for scotopic vision, with higher rod densities and higher summation of rods onto the ganglion cell layer. By adulthood, they had well-developed scotopic vision with a highly rod-dominated multibank retina comprising 5–17 rod banks and enhanced summation of rods onto the ganglion cell layer. Although the ecological demands of the two subfamilies were similar throughout their lives, their visual systems differed after settlement, with Myripristinae showing more pronounced adaptation for scotopic vision than Holocentrinae. Thus, it is likely that both ecology and phylogeny contribute to the development of the holocentrid visual system.
Publisher: Elsevier BV
Date: 12-2012
DOI: 10.1016/J.MARENVRES.2012.09.001
Abstract: In the past few decades, hydrothermal vent research has progressed immensely, resulting in higher-quality s les and long-term studies. With time, scientists are becoming more aware of the impacts of s ling on the faunal communities and are looking for less invasive ways to investigate the vent ecosystems. In this perspective, imagery analysis plays a very important role. With this study, we test which factors can be quantitatively and accurately assessed based on imagery, through comparison with faunal s ling. Twelve instrumented chains were deployed on the Atlantic Eiffel Tower hydrothermal edifice and the corresponding study sites were subsequently s led. Discrete, quantitative s les were compared to the imagery recorded during the experiment. An observer-effect was tested, by comparing imagery data gathered by different scientists. Most factors based on image analyses concerning Bathymodiolus azoricus mussels were shown to be valid representations of the corresponding s les. Additional ecological assets, based exclusively on imagery, were included.
Publisher: Springer Science and Business Media LLC
Date: 11-11-2019
DOI: 10.1038/S41598-019-52297-0
Abstract: Vision plays a major role in the life of most teleosts, and is assumingly well adapted to each species ecology and behaviour. Using a multidisciplinary approach, we scrutinised several aspects of the visual system and ecology of the Great Barrier Reef anemonefish, Amphiprion akindynos , including its orange with white patterning, retinal anatomy and molecular biology, its symbiosis with anemones and sequential hermaphroditism. Amphiprion akindynos possesses spectrally distinct visual pigments and opsins: one rod opsin, RH1 (498 nm), and five cone opsins, SWS1 (370 nm), SWS2B (408 nm), RH2B (498 nm), RH2A (520 nm), and LWS (554 nm). Cones were arranged in a regular mosaic with each single cone surrounded by four double cones. Double cones mainly expressed RH2B (53%) in one member and RH2A (46%) in the other, matching the prevailing light. Single cones expressed SWS1 (89%), which may serve to detect zooplankton, conspecifics and the host anemone. Moreover, a segregated small fraction of single cones coexpressed SWS1 with SWS2B (11%). This novel visual specialisation falls within the region of highest acuity and is suggested to increase the chromatic contrast of Amphiprion akindynos colour patterns, which might improve detection of conspecifics.
Publisher: Cold Spring Harbor Laboratory
Date: 03-07-2019
DOI: 10.1101/691774
Abstract: Ontogenetic changes of the visual system are often correlated to shifts in habitat and feeding behaviour of animals. Coral reef fishes begin their lives in the pelagic zone and then migrate to the reef. This transition of habitat frequently involves a change in diet and light environment as well as major morphological modifications. The spotted unicornfish, Naso brevirostris , is known to shift diet from zooplankton to algae and back to zooplankton when transitioning from larval to juvenile and then to adult stages. Concurrently, N. brevirostris also moves from an open pelagic to a coral-associated habitat before migrating up in the water column when reaching adulthood. Using retinal mapping techniques, we discovered that the distribution and density of ganglion and photoreceptor cells in N. brevirostris do not change with the habitat or the feeding habits of each developmental stage. Instead, fishes showed a neotenic development with a slight change from larval to juvenile stages and not many modifications thereafter. Visual gene expression based on RNA sequencing mirrored this pattern independent of stage, fishes mainly expressed three cone opsin genes ( SWS2B, RH2B, RH2A ), with a quantitative difference in the expression of the green opsin genes ( RH2A and RH2B ) when transitioning from larvae to juveniles. Hence, contrary to the ontogenetic changes found in many animals, the visual system is fixed early on in N. brevirostris development calling for a thorough analysis of visual system development of the reef fish community.
Location: Saudi Arabia
Start Date: 2018
End Date: 05-2022
Amount: $365,058.00
Funder: Australian Research Council
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