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Iwanicki T, Steck M, Bracken-Grissom H, Porter ML. Localization of multiple opsins in ocular and non-ocular tissues of deep-sea shrimps and the first evidence of co-localization in a rhabdomeric R8 cell (Caridea: Oplophoroidea). Vision Res 2024; 219:108403. [PMID: 38581820 DOI: 10.1016/j.visres.2024.108403] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2023] [Revised: 03/14/2024] [Accepted: 03/25/2024] [Indexed: 04/08/2024]
Abstract
Bioluminescence is a prevalent phenomenon throughout the marine realm and is often the dominant source of light in mesophotic and aphotic depth horizons. Shrimp belonging to the superfamily Oplophoroidea are mesopelagic, perform diel vertical migration, and secrete a bright burst of bioluminescent mucous when threatened. Species in the family Oplophoridae also possess cuticular light-emitting photophores presumably for camouflage via counter-illumination. Many species within the superfamily express a single visual pigment in the retina, consistent with most other large-bodied mesopelagic crustaceans studied to date. Photophore-bearing species have an expanded visual opsin repertoire and dual-sensitivity visual systems, as evidenced by transcriptomes and electroretinograms. In this study, we used immunohistochemistry to describe opsin protein localization in the retinas of four species of Oplophoroidea and non-ocular tissues of Janicella spinicauda. Our results show that Acanthephyra purpurea (Acanthephyridae) retinas possess LWS-only photoreceptors, consistent with the singular peak sensitivity previously reported. Oplophoridae retinas contain two opsin clades (LWS and MWS) consistent with dual-sensitivity. Oplophorus gracilirostris and Systellaspis debilis have LWS in the proximal rhabdom (R1-7 cells) and MWS2 localized in the distal rhabdom (R8 cell). Surprisingly, Janicella spinicauda has LWS in the proximal rhabdom (R1-7) and co-localized MWS1 and MWS2 opsin paralogs in the distal rhabdom, providing the first evidence of co-localization of opsins in a crustacean rhabdomeric R8 cell. Furthermore, opsins were found in multiple non-ocular tissues of J. spinicauda, including nerve, tendon, and photophore. These combined data demonstrate evolutionary novelty and opsin duplication within Oplophoridae, with implications for visual ecology, evolution in mesophotic environments, and a mechanistic understanding of adaptive counter-illumination using photophore bioluminescence.
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Affiliation(s)
- Tom Iwanicki
- The Earth Commons Institute, Georgetown University, Washington, DC 20057, United States; School of Life Sciences, University of Hawai'i at Mānoa, Honolulu, HI 96822, United States; Smithsonian Institution, National Museum of Natural History, Department of Invertebrate Zoology, Washington, DC 20013, United States.
| | - Mireille Steck
- School of Life Sciences, University of Hawai'i at Mānoa, Honolulu, HI 96822, United States
| | - Heather Bracken-Grissom
- Smithsonian Institution, National Museum of Natural History, Department of Invertebrate Zoology, Washington, DC 20013, United States; Institute of Environment, Department of Biology, Florida International University, North Miami, FL 33181, United States
| | - Megan L Porter
- School of Life Sciences, University of Hawai'i at Mānoa, Honolulu, HI 96822, United States
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2
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Steck M, Hanscom SJ, Iwanicki T, Sung JY, Outomuro D, Morehouse NI, Porter ML. Secondary not subordinate: Opsin localization suggests possibility for color sensitivity in salticid secondary eyes. Vision Res 2024; 217:108367. [PMID: 38428375 DOI: 10.1016/j.visres.2024.108367] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2023] [Revised: 01/29/2024] [Accepted: 02/13/2024] [Indexed: 03/03/2024]
Abstract
The principal eyes of jumping spiders (Salticidae) integrate a dual-lens system, a tiered retinal matrix with multiple photoreceptor classes and muscular control of retinal movements to form high resolution images, extract color information, and dynamically evaluate visual scenes. While much work has been done to characterize these more complex principal anterior eyes, little work has investigated the three other pairs of simpler secondary eyes: the anterior lateral eye pair and two posterior (lateral and median) pairs of eyes. We investigated the opsin protein component of visual pigments in the eyes of three species of salticid using transcriptomics and immunohistochemistry. Based on characterization and localization of a set of three conserved opsins (Rh1 - green sensitive, Rh2 - blue sensitive, and Rh3 - ultraviolet sensitive) we have identified potential photoreceptors for blue light detection in the eyes of two out of three species: Menemerus bivittatus (Chrysillini) and Habrocestum africanum (Hasarinii). Additionally, the photoreceptor diversity of the secondary eyes exhibits more variation than previous estimates, particularly for the small, posterior median eyes previously considered vestigial in some species. In all three species investigated the lateral eyes were dominated by green-sensitive visual pigments (RH1 opsins), while the posterior median retinas were dominated by opsins forming short-wavelength sensitive visual pigments (e.g. RH2 and/or RH3/RH4). There was also variation among secondary eye types and among species in the distribution of opsins in retinal photoreceptors, particularly for the putatively blue-sensitive visual pigment formed from RH2. Our findings suggest secondary eyes have the potential for color vision, with observed differences between species likely associated with different ecologies and visual tasks.
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Affiliation(s)
| | | | - Tom Iwanicki
- University of Hawai'i at Mānoa, Honolulu HI 96822 USA; The Earth Commons Institute, Georgetown University, Washington DC 20057 USA
| | | | - David Outomuro
- University of Cincinnati, Cincinnati OH 45221; University of Pittsburgh, Pittsburgh PA 15260 USA
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3
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Qian R, Frank TM. Comparative study of spectral sensitivity, irradiance sensitivity, spatial resolution and temporal resolution in the visual systems of Ocypode quadrata and Aratus pisonii. J Exp Biol 2024; 227:jeb246813. [PMID: 38149660 DOI: 10.1242/jeb.246813] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2023] [Accepted: 12/15/2023] [Indexed: 12/28/2023]
Abstract
Early pioneering studies by Autrum on terrestrial arthropods first revealed that the visual systems of arthropods reflected their lifestyles and habitats. Subsequent studies have examined and confirmed Autrum's hypothesis that visual adaptions are driven by predator-prey interactions and activity cycles, with rapidly moving predatory diurnal species generally possessing better temporal resolution than slower moving nocturnal species. However, few studies have compared the vision between diurnal herbivores and nocturnal predators. In this study, the visual physiology of a nocturnal fast-moving predatory crab, the Atlantic ghost crab (Ocypode quadrata) and a diurnal herbivorous crab, the mangrove tree crab (Aratus pisonii), was examined. Spectral sensitivity, irradiance sensitivity and temporal resolution of the crabs were quantified using the electroretinogram (ERG), while the spatial resolution was calculated utilizing morphological methods. Both O. quadrata and A. pisonii had a single dark-adapted spectral sensitivity peak (494 and 499 nm, respectively) and chromatic adaptation had no effect on their spectral sensitivity, indicating that both species have monochromatic visual systems. The temporal resolution of O. quadrata was not significantly different from that of A. pisonii, but O. quadrata did possess a significantly greater spatial resolution and irradiance sensitivity. Both species possess an acute zone in the anterior region of their eyes. The data presented in this study will aid in the current understanding of the correlation between visual physiology and the life history of the animal.
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Affiliation(s)
- Ruchao Qian
- Department of Biological Sciences, Florida International University, Miami, FL 33199, USA
| | - Tamara M Frank
- Halmos College of Natural Sciences and Oceanography, Department of Marine and Environmental Sciences, Nova Southeastern University, Dania Beach, FL 33004, USA
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4
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The diversity of invertebrate visual opsins spanning Protostomia, Deuterostomia, and Cnidaria. Dev Biol 2022; 492:187-199. [PMID: 36272560 DOI: 10.1016/j.ydbio.2022.10.011] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2021] [Revised: 09/28/2022] [Accepted: 10/14/2022] [Indexed: 11/21/2022]
Abstract
Across eumetazoans, the ability to perceive and respond to visual stimuli is largely mediated by opsins, a family of proteins belonging to the G protein-coupled receptor (GPCR) superclass. Lineage-specific gains and losses led to a striking diversity in the numbers, types, and spectral sensitivities conferred by visual opsin gene expression. Here, we review the diversity of visual opsins and differences in opsin gene expression from well-studied protostome, invertebrate deuterostome, and cnidarian groups. We discuss the functional significance of opsin expression differences and spectral tuning among lineages. In some cases, opsin evolution has been linked to the detection of relevant visual signals, including sexually selected color traits and host plant features. In other instances, variation in opsins has not been directly linked to functional or ecological differences. Overall, the array of opsin expression patterns and sensitivities across invertebrate lineages highlight the diversity of opsins in the eumetazoan ancestor and the labile nature of opsins over evolutionary time.
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5
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Palecanda S, Iwanicki T, Steck M, Porter ML. Crustacean conundrums: a review of opsin diversity and evolution. Philos Trans R Soc Lond B Biol Sci 2022; 377:20210289. [PMID: 36058240 PMCID: PMC9441232 DOI: 10.1098/rstb.2021.0289] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2021] [Accepted: 02/06/2022] [Indexed: 11/12/2022] Open
Abstract
Knowledge of crustacean vision is lacking compared to the more well-studied vertebrates and insects. While crustacean visual systems are typically conserved morphologically, the molecular components (i.e. opsins) remain understudied. This review aims to characterize opsin diversity across crustacean lineages for an integrated view of visual system evolution. Using publicly available data from 95 species, we identified opsin sequences and classified them by clade. Our analysis produced 485 putative visual opsins and 141 non-visual opsins. The visual opsins were separated into six clades: long wavelength sensitive (LWS), middle wavelength sensitive (MWS) 1 and 2, short wavelength or ultraviolet sensitive (SWS/UVS) and a clade of thecostracan opsins, with multiple LWS and MWS opsin copies observed. The SWS/UVS opsins were relatively conserved in most species. The crustacean classes Cephalocarida, Remipedia and Hexanauplia exhibited reduced visual opsin diversity compared to others, with the malacostracan decapods having the highest opsin diversity. Non-visual opsins were identified from all investigated classes except Cephalocarida. Additionally, a novel clade of non-visual crustacean-specific, R-type opsins (Rc) was discovered. This review aims to provide a framework for future research on crustacean vision, with an emphasis on the need for more work in spectral characterization and molecular analysis. This article is part of the theme issue 'Understanding colour vision: molecular, physiological, neuronal and behavioural studies in arthropods'.
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Affiliation(s)
- Sitara Palecanda
- School of Life Sciences, University of Hawai'i at Mānoa, Honolulu, HI 96822, USA
| | - Thomas Iwanicki
- School of Life Sciences, University of Hawai'i at Mānoa, Honolulu, HI 96822, USA
| | - Mireille Steck
- School of Life Sciences, University of Hawai'i at Mānoa, Honolulu, HI 96822, USA
| | - Megan L. Porter
- School of Life Sciences, University of Hawai'i at Mānoa, Honolulu, HI 96822, USA
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6
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Meece M, Rathore S, Buschbeck EK. Stark trade-offs and elegant solutions in arthropod visual systems. J Exp Biol 2021; 224:224/4/jeb215541. [PMID: 33632851 DOI: 10.1242/jeb.215541] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Vision is one of the most important senses for humans and animals alike. Diverse elegant specializations have evolved among insects and other arthropods in response to specific visual challenges and ecological needs. These specializations are the subject of this Review, and they are best understood in light of the physical limitations of vision. For example, to achieve high spatial resolution, fine sampling in different directions is necessary, as demonstrated by the well-studied large eyes of dragonflies. However, it has recently been shown that a comparatively tiny robber fly (Holcocephala) has similarly high visual resolution in the frontal visual field, despite their eyes being a fraction of the size of those of dragonflies. Other visual specializations in arthropods include the ability to discern colors, which relies on parallel inputs that are tuned to spectral content. Color vision is important for detection of objects such as mates, flowers and oviposition sites, and is particularly well developed in butterflies, stomatopods and jumping spiders. Analogous to color vision, the visual systems of many arthropods are specialized for the detection of polarized light, which in addition to communication with conspecifics, can be used for orientation and navigation. For vision in low light, optical superposition compound eyes perform particularly well. Other modifications to maximize photon capture involve large lenses, stout photoreceptors and, as has been suggested for nocturnal bees, the neural pooling of information. Extreme adaptations even allow insects to see colors at very low light levels or to navigate using the Milky Way.
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Affiliation(s)
- Michael Meece
- Department of Biological Sciences, University of Cincinnati, Cincinnati, OH 45221, USA
| | - Shubham Rathore
- Department of Biological Sciences, University of Cincinnati, Cincinnati, OH 45221, USA
| | - Elke K Buschbeck
- Department of Biological Sciences, University of Cincinnati, Cincinnati, OH 45221, USA
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7
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Jessop AL, Ogawa Y, Bagheri ZM, Partridge JC, Hemmi JM. Photoreceptors and diurnal variation in spectral sensitivity in the fiddler crab Gelasimus dampieri. J Exp Biol 2020; 223:jeb230979. [PMID: 33097568 DOI: 10.1242/jeb.230979] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2020] [Accepted: 10/16/2020] [Indexed: 11/20/2022]
Abstract
Colour signals, and the ability to detect them, are important for many animals and can be vital to their survival and fitness. Fiddler crabs use colour information to detect and recognise conspecifics, but their colour vision capabilities remain unclear. Many studies have attempted to measure their spectral sensitivity and identify contributing retinular cells, but the existing evidence is inconclusive. We used electroretinogram (ERG) measurements and intracellular recordings from retinular cells to estimate the spectral sensitivity of Gelasimus dampieri and to track diurnal changes in spectral sensitivity. G. dampieri has a broad spectral sensitivity and is most sensitive to wavelengths between 420 and 460 nm. Selective adaptation experiments uncovered an ultraviolet (UV) retinular cell with a peak sensitivity shorter than 360 nm. The species' spectral sensitivity above 400 nm is too broad to be fitted by a single visual pigment and using optical modelling, we provide evidence that at least two medium-wavelength sensitive (MWS) visual pigments are contained within a second blue-green sensitive retinular cell. We also found a ∼25 nm diurnal shift in spectral sensitivity towards longer wavelengths in the evening in both ERG and intracellular recordings. Whether the shift is caused by screening pigment migration or changes in opsin expression remains unclear, but the observation shows the diel dynamism of colour vision in this species. Together, these findings support the notion that G. dampieri possesses the minimum requirement for colour vision, with UV and blue/green receptors, and help to explain some of the inconsistent results of previous research.
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Affiliation(s)
- Anna-Lee Jessop
- School of Biological Sciences, The University of Western Australia, 35 Stirling Highway, Crawley, WA 6009, Australia
- UWA Oceans Institute, The University of Western Australia, 35 Stirling Highway, Crawley, WA 6009, Australia
| | - Yuri Ogawa
- Centre for Neuroscience, Flinders University, GPO Box 2100, Adelaide, SA 5001, Australia
| | - Zahra M Bagheri
- School of Biological Sciences, The University of Western Australia, 35 Stirling Highway, Crawley, WA 6009, Australia
- UWA Oceans Institute, The University of Western Australia, 35 Stirling Highway, Crawley, WA 6009, Australia
| | - Julian C Partridge
- UWA Oceans Institute, The University of Western Australia, 35 Stirling Highway, Crawley, WA 6009, Australia
| | - Jan M Hemmi
- School of Biological Sciences, The University of Western Australia, 35 Stirling Highway, Crawley, WA 6009, Australia
- UWA Oceans Institute, The University of Western Australia, 35 Stirling Highway, Crawley, WA 6009, Australia
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8
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Dyson ML, Perez DM, Curran T, McCullough EL, Backwell PRY. The role of claw color in species recognition and mate choice in a fiddler crab. Behav Ecol Sociobiol 2020. [DOI: 10.1007/s00265-020-02899-w] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Abstract
Many animal signals are brightly colored and convey information about species identity as well as information about individual conspecifics. Colorful bird and lizard signals have received much attention, and many studies have related specific spectral properties of these signals to variation in mating success and territory defense. Far less attention has been given to invertebrates even though there are spectacularly colorful species. The enlarged claw of the male banana fiddler crab Austruca mjoebergi, for example, is bright yellow and contrasts vividly against the mudflat substrate. It is used in waving displays to attract females and in male territory defense and combat. Claw color varies among males in the degree of “yellowness,” ranging very pale yellow to orange. In this study, we examined female responses to claw color variation in two-choice tests using robotic crabs. We found that although females strongly discriminate against colors that fall outside the natural range of intensity, hue, and chroma, they show no consistent preferences for different claw colors within the natural range, and no single component of claw color (hue, chroma, or intensity) independently affected female choices. Using three-choice tests, we also showed that female preferences induce stabilizing selection on male claw color. We conclude that, although claw color is sufficient to facilitate species recognition, it is unlikely to be used in intraspecific mate choice to provide information about male quality.
Significance statement
Fiddler crabs are often brightly colored, are visually orientated animals, and have a highly complex social system. Despite this, there are few studies that have looked at the role of color in species recognition and mate choice in these animals. In this study, we use robotic crabs with painted claws to determine the role of claw color in species recognition and mate choice in the banana fiddler crab, Austruca mjoebergi. We found that color is important in conspecific mate recognition but the variation among males in claw “yellowness” is unlikely to be used by females in intraspecific mate choice decisions.
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9
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Döring CC, Kumar S, Tumu SC, Kourtesis I, Hausen H. The visual pigment xenopsin is widespread in protostome eyes and impacts the view on eye evolution. eLife 2020; 9:55193. [PMID: 32880369 PMCID: PMC7529461 DOI: 10.7554/elife.55193] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2020] [Accepted: 09/01/2020] [Indexed: 12/31/2022] Open
Abstract
Photoreceptor cells in the eyes of Bilateria are often classified into microvillar cells with rhabdomeric opsin and ciliary cells with ciliary opsin, each type having specialized molecular components and physiology. First data on the recently discovered xenopsin point towards a more complex situation in protostomes. In this study, we provide clear evidence that xenopsin enters cilia in the eye of the larval bryozoan Tricellaria inopinata and triggers phototaxis. As reported from a mollusc, we find xenopsin coexpressed with rhabdomeric-opsin in eye photoreceptor cells bearing both microvilli and cilia in larva of the annelid Malacoceros fuliginosus. This is the first organism known to have both xenopsin and ciliary opsin, showing that these opsins are not necessarily mutually exclusive. Compiling existing data, we propose that xenopsin may play an important role in many protostome eyes and provides new insights into the function, evolution, and possible plasticity of animal eye photoreceptor cells.
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Affiliation(s)
| | - Suman Kumar
- Sars International Centre for Marine Molecular Biology, University of Bergen, Bergen, Norway
| | - Sharat Chandra Tumu
- Sars International Centre for Marine Molecular Biology, University of Bergen, Bergen, Norway
| | - Ioannis Kourtesis
- Sars International Centre for Marine Molecular Biology, University of Bergen, Bergen, Norway
| | - Harald Hausen
- Sars International Centre for Marine Molecular Biology, University of Bergen, Bergen, Norway
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10
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DeLeo DM, Bracken-Grissom HD. Illuminating the impact of diel vertical migration on visual gene expression in deep-sea shrimp. Mol Ecol 2020; 29:3494-3510. [PMID: 32748474 DOI: 10.1111/mec.15570] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2020] [Revised: 07/17/2020] [Accepted: 07/20/2020] [Indexed: 12/19/2022]
Abstract
Diel vertical migration (DVM) of marine animals represents one of the largest migrations on our planet. Migrating fauna are subjected to a variety of light fields and environmental conditions that can have notable impacts on sensory mechanisms, including an organism's visual capabilities. Among deep-sea migrators are oplophorid shrimp that vertically migrate hundreds of metres to feed in shallow waters at night. These species also have bioluminescent light organs that emit light during migrations to aid in camouflage. The organs have recently been shown to contain visual proteins (opsins) and genes that infer light sensitivity. Knowledge regarding the impacts of vertical migratory behaviour, and fluctuating environmental conditions, on sensory system evolution is unknown. In this study, the oplophorid Systellaspis debilis was either collected during the day from deep waters or at night from relatively shallow waters to ensure sampling across the vertical distributional range. De novo transcriptomes of light-sensitive tissues (eyes/photophores) from the day/night specimens were sequenced and analysed to characterize opsin diversity and visual/light interaction genes. Gene expression analyses were also conducted to quantify expression differences associated with DVM. Our results revealed an expanded opsin repertoire among the shrimp and differential opsin expression that may be linked to spectral tuning during the migratory process. This study sheds light on the sensory systems of a bioluminescent invertebrate and provides additional evidence for extraocular light sensitivity. Our findings further suggest opsin co-expression and subsequent fluctuations in opsin expression may play an important role in diversifying the visual responses of vertical migrators.
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Affiliation(s)
- Danielle M DeLeo
- Institute of Environment, Department of Biology, Florida International University, North Miami, FL, USA.,Department of Invertebrate Zoology, National Museum of Natural History, Smithsonian Institution, Washington, DC, USA
| | - Heather D Bracken-Grissom
- Institute of Environment, Department of Biology, Florida International University, North Miami, FL, USA
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11
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Exceptional diversity of opsin expression patterns in Neogonodactylus oerstedii (Stomatopoda) retinas. Proc Natl Acad Sci U S A 2020; 117:8948-8957. [PMID: 32241889 DOI: 10.1073/pnas.1917303117] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Stomatopod crustaceans possess some of the most complex animal visual systems, including at least 16 spectrally distinct types of photoreceptive units (e.g., assemblages of photoreceptor cells). Here we fully characterize the set of opsin genes expressed in retinal tissues and determine expression patterns of each in the stomatopod Neogonodactylus oerstedii Using a combination of transcriptome and RACE sequencing, we identified 33 opsin transcripts expressed in each N. oerstedii eye, which are predicted to form 20 long-wavelength-sensitive, 10 middle-wavelength-sensitive, and three UV-sensitive visual pigments. Observed expression patterns of these 33 transcripts were highly unusual in five respects: 1) All long-wavelength and short/middle-wavelength photoreceptive units expressed multiple opsins, while UV photoreceptor cells expressed single opsins; 2) most of the long-wavelength photoreceptive units expressed at least one middle-wavelength-sensitive opsin transcript; 3) the photoreceptors involved in spatial, motion, and polarization vision expressed more transcripts than those involved in color vision; 4) there is a unique opsin transcript that is expressed in all eight of the photoreceptive units devoted to color vision; and 5) expression patterns in the peripheral hemispheres of the eyes suggest visual specializations not previously recognized in stomatopods. Elucidating the expression patterns of all opsin transcripts expressed in the N. oerstedii retina reveals the potential for previously undocumented functional diversity in the already complex stomatopod eye and is a first step toward understanding the functional significance of the unusual abundance of opsins found in many arthropod species' visual systems.
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12
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Caro T, Cluff E, Morgan VM. Colour polymorphism and protective coloration in coconut crabs. ETHOL ECOL EVOL 2019. [DOI: 10.1080/03949370.2019.1626488] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Affiliation(s)
- Tim Caro
- Department of Wildlife, Fish and Conservation Biology, University of California, Davis, CA 95616, USA
| | - Emma Cluff
- Department of Evolution and Ecology, University of California, Davis, CA 95616, USA
| | - Victoria M. Morgan
- Department of Evolution and Ecology, University of California, Davis, CA 95616, USA
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13
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Arikawa K, Iwanaga T, Wakakuwa M, Kinoshita M. Unique Temporal Expression of Triplicated Long-Wavelength Opsins in Developing Butterfly Eyes. Front Neural Circuits 2017; 11:96. [PMID: 29238294 PMCID: PMC5712540 DOI: 10.3389/fncir.2017.00096] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2017] [Accepted: 11/15/2017] [Indexed: 11/13/2022] Open
Abstract
Following gene duplication events, the expression patterns of the resulting gene copies can often diverge both spatially and temporally. Here we report on gene duplicates that are expressed in distinct but overlapping patterns, and which exhibit temporally divergent expression. Butterflies have sophisticated color vision and spectrally complex eyes, typically with three types of heterogeneous ommatidia. The eyes of the butterfly Papilio xuthus express two green- and one red-absorbing visual pigment, which came about via gene duplication events, in addition to one ultraviolet (UV)- and one blue-absorbing visual pigment. We localized mRNAs encoding opsins of these visual pigments in developing eye disks throughout the pupal stage. The mRNAs of the UV and blue opsin are expressed early in pupal development (pd), specifying the type of the ommatidium in which they appear. Red sensitive photoreceptors first express a green opsin mRNA, which is replaced later by the red opsin mRNA. Broadband photoreceptors (that coexpress the green and red opsins) first express the green opsin mRNA, later change to red opsin mRNA and finally re-express the green opsin mRNA in addition to the red mRNA. Such a unique temporal and spatial expression pattern of opsin mRNAs may reflect the evolution of visual pigments and provide clues toward understanding how the spectrally complex eyes of butterflies evolved.
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Affiliation(s)
- Kentaro Arikawa
- Laboratory of Neuroethology, Department of Evolutionary Studies of Biosystems, Graduate University for Advanced Studies (SOKENDAI), Hayama, Japan
| | - Tomoyuki Iwanaga
- Graduate School of Integrated Science, Yokohama City University, Yokohama, Japan
| | - Motohiro Wakakuwa
- Laboratory of Neuroethology, Department of Evolutionary Studies of Biosystems, Graduate University for Advanced Studies (SOKENDAI), Hayama, Japan
| | - Michiyo Kinoshita
- Laboratory of Neuroethology, Department of Evolutionary Studies of Biosystems, Graduate University for Advanced Studies (SOKENDAI), Hayama, Japan
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14
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Nandamuri SP, Dalton BE, Carleton KL. Determination of the Genetic Architecture Underlying Short Wavelength Sensitivity in Lake Malawi Cichlids. J Hered 2017; 108:379-390. [PMID: 28498989 DOI: 10.1093/jhered/esx020] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2016] [Accepted: 02/27/2017] [Indexed: 11/13/2022] Open
Abstract
African cichlids are an exemplary system to study organismal diversity and rapid speciation. Species differ in external morphology including jaw shape and body coloration, but also differ in sensory systems including vision. All cichlids have 7 cone opsin genes with species differing broadly in which opsins are expressed. The differential opsin expression results in closely related species with substantial differences in spectral sensitivity of their photoreceptors. In this work, we take a first step in determining the genetic basis of opsin expression in cichlids. Using a second generation cross between 2 species with different opsin expression patterns, we make a conservative estimate that short wavelength opsin expression is regulated by a few loci. Genetic mapping in 96 F2 hybrids provides clear evidence of a cis-regulatory region for SWS1 opsin that explains 34% of the variation in expression between the 2 species. Additionally, in situ hybridization has shown that SWS1 and SWS2B opsins are coexpressed in individual single cones in the retinas of F2 progeny. Results from this work will contribute to a better understanding of the genetic architecture underlying opsin expression. This knowledge will help answer long-standing questions about the evolutionary processes fundamental to opsin expression variation and how this contributes to adaptive cichlid divergence.
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Affiliation(s)
| | - Brian E Dalton
- National & Environmental Sciences Department, Western State Colorado University, Gunnison, CO 81231
| | - Karen L Carleton
- From the Department of Biology, University of Maryland, College Park, MD 20742
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Vöcking O, Kourtesis I, Tumu SC, Hausen H. Co-expression of xenopsin and rhabdomeric opsin in photoreceptors bearing microvilli and cilia. eLife 2017; 6:23435. [PMID: 28876222 PMCID: PMC5648526 DOI: 10.7554/elife.23435] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2016] [Accepted: 09/01/2017] [Indexed: 12/22/2022] Open
Abstract
Ciliary and rhabdomeric opsins are employed by different kinds of photoreceptor cells, such as ciliary vertebrate rods and cones or protostome microvillar eye photoreceptors, that have specialized structures and molecular physiologies. We report unprecedented cellular co-expression of rhabdomeric opsin and a visual pigment of the recently described xenopsins in larval eyes of a mollusk. The photoreceptors bear both microvilli and cilia and express proteins that are orthologous to transporters in microvillar and ciliary opsin trafficking. Highly conserved but distinct gene structures suggest that xenopsins and ciliary opsins are of independent origin, irrespective of their mutually exclusive distribution in animals. Furthermore, we propose that frequent opsin gene loss had a large influence on the evolution, organization and function of brain and eye photoreceptor cells in bilaterian animals. The presence of xenopsin in eyes of even different design might be due to a common origin and initial employment of this protein in a highly plastic photoreceptor cell type of mixed microvillar/ciliary organization. Animal eyes have photoreceptor cells that contain light-sensitive molecules called opsins. Although all animal photoreceptor cells of this kind share a common origin, the cells found in different organisms can differ considerably. The photoreceptor cells in flies, squids and other invertebrates store a type of opsin called r-opsin in thin projections on the surface known as microvilli. On the other hand, the visual photoreceptor cells in human and other vertebrate eyes transport another type of opsin (known as c-opsin) into more prominent extensions called cilia. It has been suggested that the fly and vertebrate photoreceptor cells represent clearly distinct evolutionary lineages of cells, which diverged early in animal evolution. However, several organisms that are more closely related to flies than to vertebrates have eye photoreceptor cells with cilia. Do all eye photoreceptors with cilia have a common origin in evolution or did they emerge independently in vertebrates and certain invertebrates? The photoreceptor cells of a marine mollusc called Leptochiton asellus, are unusual because they bear both microvilli and cilia, suggesting they have intermediate characteristics between the two well-known types of photoreceptor cells. Previous studies have shown that these photoreceptor cells use r-opsin, but Vöcking et al. have now detected the presence of an additional opsin in the cells. This opsin is a member of the recently discovered xenopsin family of molecules. Further analyses support the findings of previous studies that suggested this type of opsin emerged early on in animal evolution, independently from c-opsin. Other invertebrates that have cilia on their eye photoreceptors also use xenopsin and not c-opsin. The findings of Vöcking et al. suggest that, in addition to c-opsin and r-opsin, xenopsin has also driven the evolution of photoreceptor cells in animals. Eye photoreceptor cells in invertebrates with cilia probably share a common origin with the microvilli photoreceptor cells that is distinct from that of vertebrate visual cells. The observation that two very different types of opsin can be produced within a single cell suggests that the molecular processes that respond to light in photoreceptor cells may be much more complex than previously anticipated. Further work on these processes may help us to understand how animal eyes work and how they are affected by disease.
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Affiliation(s)
- Oliver Vöcking
- Sars International Centre for Marine Molecular Biology, University of Bergen, Bergen, Norway.,Department of Ophthalmology, University of Pittsburgh, Pittsburgh, United States
| | - Ioannis Kourtesis
- Sars International Centre for Marine Molecular Biology, University of Bergen, Bergen, Norway
| | - Sharat Chandra Tumu
- Sars International Centre for Marine Molecular Biology, University of Bergen, Bergen, Norway
| | - Harald Hausen
- Sars International Centre for Marine Molecular Biology, University of Bergen, Bergen, Norway
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Battelle BA. Opsins and Their Expression Patterns in the Xiphosuran Limulus polyphemus. THE BIOLOGICAL BULLETIN 2017; 233:3-20. [PMID: 29182506 DOI: 10.1086/693730] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
The American horseshoe crab Limulus polyphemus (Linnaeus, 1758) is one of four extant species of xiphosuran chelicerates, the sister group to arachnids. Because of their position in the arthropod family tree and because they exhibit many plesiomorphic characteristics, Xiphosura are considered a proxy for the euchelicerate ancestor and therefore important for understanding the evolution and diversification of chelicerates and arthropods. Limulus polyphemus is the most extensively studied xiphosuran, and its visual system has long been a focus of studies critical for our understanding of basic mechanisms of vision and the evolution of visual systems in arthropods. Building upon a wealth of information about the anatomy and physiology of its visual system, advances in genetic approaches have greatly expanded possibilities for understanding its biochemistry. This review focuses on studies of opsin expression in L. polyphemus, which have been significantly advanced by the availability of transcriptomes and a recent high-quality assembly of its genome. These studies show that the repertoire of expressed opsins in L. polyphemus is far larger than anticipated, that the regulation of their expression in rhabdoms is far more complex than anticipated, and that photosensitivity may be distributed widely throughout the L. polyphemus central nervous system. The visual system of L. polyphemus is now arguably the best understood among chelicerates, and as such, it is a critical resource for furthering our understanding of the evolution and diversification of visual systems in arthropods.
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Key Words
- CNS, central nervous system
- LE, lateral eye
- LWS, long wavelength-sensitive
- LpArthOps, Limulus arthropsin
- LpCOps, Limulus C-type opsin
- LpOps, Limulus opsin
- LpPerOps, Limulus peropsin
- ME, median eye
- MWS, medium wavelength-sensitive
- Rh-LpOps, Limulus opsin in rhabdoms
- SWS, short wavelength-sensitive
- VE, ventral eye
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Caves EM, Frank TM, Johnsen S. Spectral sensitivity, spatial resolution and temporal resolution and their implications for conspecific signalling in cleaner shrimp. ACTA ACUST UNITED AC 2016; 219:597-608. [PMID: 26747903 DOI: 10.1242/jeb.122275] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2015] [Accepted: 12/03/2015] [Indexed: 11/20/2022]
Abstract
Cleaner shrimp (Decapoda) regularly interact with conspecifics and client reef fish, both of which appear colourful and finely patterned to human observers. However, whether cleaner shrimp can perceive the colour patterns of conspecifics and clients is unknown, because cleaner shrimp visual capabilities are unstudied. We quantified spectral sensitivity and temporal resolution using electroretinography (ERG), and spatial resolution using both morphological (inter-ommatidial angle) and behavioural (optomotor) methods in three cleaner shrimp species: Lysmata amboinensis, Ancylomenes pedersoni and Urocaridella antonbruunii. In all three species, we found strong evidence for only a single spectral sensitivity peak of (mean ± s.e.m.) 518 ± 5, 518 ± 2 and 533 ± 3 nm, respectively. Temporal resolution in dark-adapted eyes was 39 ± 1.3, 36 ± 0.6 and 34 ± 1.3 Hz. Spatial resolution was 9.9 ± 0.3, 8.3 ± 0.1 and 11 ± 0.5 deg, respectively, which is low compared with other compound eyes of similar size. Assuming monochromacy, we present approximations of cleaner shrimp perception of both conspecifics and clients, and show that cleaner shrimp visual capabilities are sufficient to detect the outlines of large stimuli, but not to detect the colour patterns of conspecifics or clients, even over short distances. Thus, conspecific viewers have probably not played a role in the evolution of cleaner shrimp appearance; rather, further studies should investigate whether cleaner shrimp colour patterns have evolved to be viewed by client reef fish, many of which possess tri- and tetra-chromatic colour vision and relatively high spatial acuity.
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Affiliation(s)
- Eleanor M Caves
- Department of Biology, Box 90338, Duke University, Durham, NC 27708, USA
| | - Tamara M Frank
- Halmos College of Natural Sciences and Oceanography, Department of Marine and Environmental Sciences, Nova Southeast University, 8000 North Ocean Drive, Dania Beach, FL 33004, USA
| | - Sönke Johnsen
- Department of Biology, Box 90338, Duke University, Durham, NC 27708, USA
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18
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Henze MJ, Oakley TH. The Dynamic Evolutionary History of Pancrustacean Eyes and Opsins. Integr Comp Biol 2015; 55:830-42. [DOI: 10.1093/icb/icv100] [Citation(s) in RCA: 71] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
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19
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Marshall J, Carleton KL, Cronin T. Colour vision in marine organisms. Curr Opin Neurobiol 2015; 34:86-94. [PMID: 25725325 DOI: 10.1016/j.conb.2015.02.002] [Citation(s) in RCA: 57] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2015] [Revised: 02/02/2015] [Accepted: 02/05/2015] [Indexed: 12/18/2022]
Abstract
Colour vision in the marine environment is on average simpler than in terrestrial environments with simple or no colour vision through monochromacy or dichromacy. Monochromacy is found in marine mammals and elasmobranchs, including whales and sharks, but not some rays. Conversely, there is also a greater diversity of colour vision in the ocean than on land, examples being the polyspectral stomatopods and the many colour vision solutions found among reef fish. Recent advances in sequencing reveal more opsin (visual pigment) types than functionally useful at any one time. This diversity arises through opsin duplication and conversion. Such mechanisms allow pick-and-mix adaptation that tunes colour vision on a variety of very short non-evolutionary timescales. At least some of the diversity in marine colour vision is best explained as unconventional colour vision or as neutral drift.
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Affiliation(s)
- Justin Marshall
- Queensland Brain Institute, University of Queensland, Brisbane, Queensland 4070, Australia.
| | - Karen L Carleton
- Department of Biology, University of Maryland, College Park, MD 20742, USA
| | - Thomas Cronin
- Department of Biological Sciences, University of Maryland Baltimore County, Baltimore, MD 21250, USA
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20
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Comparative transcriptomic analysis provides insights into the molecular basis of brachyurization and adaptation to benthic lifestyle in Eriocheir sinensis. Gene 2015; 558:88-98. [DOI: 10.1016/j.gene.2014.12.048] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2014] [Revised: 12/20/2014] [Accepted: 12/22/2014] [Indexed: 01/29/2023]
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21
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Abstract
Dragonflies are colorful and large-eyed animals strongly dependent on color vision. Here we report an extraordinary large number of opsin genes in dragonflies and their characteristic spatiotemporal expression patterns. Exhaustive transcriptomic and genomic surveys of three dragonflies of the family Libellulidae consistently identified 20 opsin genes, consisting of 4 nonvisual opsin genes and 16 visual opsin genes of 1 UV, 5 short-wavelength (SW), and 10 long-wavelength (LW) type. Comprehensive transcriptomic survey of the other dragonflies representing an additional 10 families also identified as many as 15-33 opsin genes. Molecular phylogenetic analysis revealed dynamic multiplications and losses of the opsin genes in the course of evolution. In contrast to many SW and LW genes expressed in adults, only one SW gene and several LW genes were expressed in larvae, reflecting less visual dependence and LW-skewed light conditions for their lifestyle under water. In this context, notably, the sand-burrowing or pit-dwelling species tended to lack SW gene expression in larvae. In adult visual organs: (i) many SW genes and a few LW genes were expressed in the dorsal region of compound eyes, presumably for processing SW-skewed light from the sky; (ii) a few SW genes and many LW genes were expressed in the ventral region of compound eyes, probably for perceiving terrestrial objects; and (iii) expression of a specific LW gene was associated with ocelli. Our findings suggest that the stage- and region-specific expressions of the diverse opsin genes underlie the behavior, ecology, and adaptation of dragonflies.
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Battelle BA, Kempler KE, Saraf SR, Marten CE, Dugger DR, Speiser DI, Oakley TH. Opsins in Limulus eyes: characterization of three visible light-sensitive opsins unique to and co-expressed in median eye photoreceptors and a peropsin/RGR that is expressed in all eyes. J Exp Biol 2015; 218:466-79. [PMID: 25524988 PMCID: PMC4317242 DOI: 10.1242/jeb.116087] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2014] [Accepted: 12/09/2014] [Indexed: 11/20/2022]
Abstract
The eyes of the horseshoe crab Limulus polyphemus have long been used for studies of basic mechanisms of vision, and the structure and physiology of Limulus photoreceptors have been examined in detail. Less is known about the opsins Limulus photoreceptors express. We previously characterized a UV opsin (LpUVOps1) that is expressed in all three types of Limulus eyes (lateral compound eyes, median ocelli and larval eyes) and three visible light-sensitive rhabdomeric opsins (LpOps1, -2 and -5) that are expressed in Limulus lateral compound and larval eyes. Physiological studies showed that visible light-sensitive photoreceptors are also present in median ocelli, but the visible light-sensitive opsins they express were unknown. In the current study we characterize three newly identified, visible light-sensitive rhabdomeric opsins (LpOps6, -7 and -8) that are expressed in median ocelli. We show that they are ocellar specific and that all three are co-expressed in photoreceptors distinct from those expressing LpUVOps1. Our current findings show that the pattern of opsin expression in Limulus eyes is much more complex than previously thought and extend our previous observations of opsin co-expression in visible light-sensitive Limulus photoreceptors. We also characterize a Limulus peropsin/RGR (LpPerOps1). We examine the phylogenetic relationship of LpPerOps1 with other peropsins and RGRs, demonstrate that LpPerOps1 transcripts are expressed in each of the three types of Limulus eyes and show that the encoded protein is expressed in membranes of cells closely associated with photoreceptors in each eye type. These finding suggest that peropsin was in the opsin repertoire of euchelicerates.
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Affiliation(s)
- Barbara-Anne Battelle
- Whitney Laboratory for Marine Bioscience and Departments of Neuroscience and Biology, 9505 Ocean Shore Blvd, University of Florida, St Augustine, FL 32080, USA
| | - Karen E Kempler
- Whitney Laboratory for Marine Bioscience and Departments of Neuroscience and Biology, 9505 Ocean Shore Blvd, University of Florida, St Augustine, FL 32080, USA
| | - Spencer R Saraf
- Whitney Laboratory for Marine Bioscience and Departments of Neuroscience and Biology, 9505 Ocean Shore Blvd, University of Florida, St Augustine, FL 32080, USA
| | - Catherine E Marten
- Whitney Laboratory for Marine Bioscience and Departments of Neuroscience and Biology, 9505 Ocean Shore Blvd, University of Florida, St Augustine, FL 32080, USA
| | - Donald R Dugger
- Department of Ophthalmology, University of Florida, Gainesville, FL 32080, USA
| | - Daniel I Speiser
- Department of Ecology, Evolution and Marine Biology, University of California, Santa Barbara, CA 93106, USA Department of Biological Sciences, University of South Carolina, Columbia, SC 29208, USA
| | - Todd H Oakley
- Department of Ecology, Evolution and Marine Biology, University of California, Santa Barbara, CA 93106, USA
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How aquatic water-beetle larvae with small chambered eyes overcome challenges of hunting under water. J Comp Physiol A Neuroethol Sens Neural Behav Physiol 2014; 200:911-22. [PMID: 25261360 DOI: 10.1007/s00359-014-0944-9] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2014] [Revised: 09/12/2014] [Accepted: 09/15/2014] [Indexed: 10/24/2022]
Abstract
A particularly unusual visual system exists in the visually guided aquatic predator, the Sunburst Diving Beetle, Thermonectus marmoratus (Coleoptera: Dytiscidae). The question arises: how does this peculiar visual system function? A series of experiments suggests that their principal eyes (E1 and E2) are highly specialized for hunting. These eyes are tubular and have relatively long focal lengths leading to high image magnification. Their retinae are linear, and are divided into distinct green-sensitive distal and UV and polarization-sensitive proximal portions. Each distal retina, moreover, has many tiers of photoreceptors with rhabdomeres the long axis of which are peculiarly oriented perpendicular to the light path. Based on detailed optical investigations, the lenses of these eyes are bifocal and project focused images onto specific retinal tiers. Behavioral experiments suggest that these larvae approach prey within their eyes' near-fields, and that they can correctly gauge prey distances even when conventional distance-vision mechanisms are unavailable. In the near-field of these eyes object distance determines which of the many retinal layers receive the best-focused images. This retinal organization could facilitate an unusual distance-vision mechanism. We here summarize past findings and discuss how these eyes allow Thermonectus larvae to be such successful predators.
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24
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Alkaladi A, Zeil J. Functional anatomy of the fiddler crab compound eye (Uca vomeris: Ocypodidae, Brachyura, Decapoda). J Comp Neurol 2014; 522:1264-83. [DOI: 10.1002/cne.23472] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2013] [Revised: 09/16/2013] [Accepted: 09/17/2013] [Indexed: 11/06/2022]
Affiliation(s)
- Ali Alkaladi
- ARC Centre of Excellence in Vision Science, Research School of Biology; Australian National University; Canberra Australia
| | - Jochen Zeil
- ARC Centre of Excellence in Vision Science, Research School of Biology; Australian National University; Canberra Australia
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25
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Stowasser A, Buschbeck EK. Multitasking in an eye: How the unusual organization of the principal larval eyes of Thermonectus marmoratus allows for far and near vision and might aid in depth perception. J Exp Biol 2014; 217:2509-16. [DOI: 10.1242/jeb.098624] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Abstract
Very few visual systems diverge fundamentally from the basic plans of well-studied animal eyes. However, investigating those that do can provide novel insights into visual system function. A particularly unusual system exists in the principal larval eyes of a visually guided aquatic predator, the Sunburst Diving Beetle, Thermonectus marmoratus (Coleoptera: Dystiscidae). These eyes are characterized by complex layered distal and proximal retinas. We previously reported that their principal eye E2 has a bifocal lens, and previous behavioral experiments suggested that these larvae have a unilateral range finding mechanism that may involve their bizarre eye organization. In our present study, we expanded our optical measurements and found that: 1) E1 also has a bifocal lens, 2) E1 is best suited for far vision while E2 is best suited for near vision and 3) throughout their typical hunting range, the positions of focused images shift across specific retinal layers. This anatomical and optical organization in principal could support unilateral range finding. Taken together, our findings outline an unusual visual mechanism that probably is essential for the extraordinary hunting ability of these larvae.
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The Antarctic krill Euphausia superba shows diurnal cycles of transcription under natural conditions. PLoS One 2013; 8:e68652. [PMID: 23874706 PMCID: PMC3714250 DOI: 10.1371/journal.pone.0068652] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2013] [Accepted: 05/30/2013] [Indexed: 12/20/2022] Open
Abstract
BACKGROUND Polar environments are characterized by extreme seasonal changes in day length, light intensity and spectrum, the extent of sea ice during the winter, and food availability. A key species of the Southern Ocean ecosystem, the Antarctic krill (Euphausia superba) has evolved rhythmic physiological and behavioral mechanisms to adapt to daily and seasonal changes. The molecular organization of the clockwork underlying these biological rhythms is, nevertheless, still only partially understood. METHODOLOGY/PRINCIPAL FINDINGS The genome sequence of the Antarctic krill is not yet available. A normalized cDNA library was produced and pyrosequenced in the attempt to identify large numbers of transcripts. All available E. superba sequences were then assembled to create the most complete existing oligonucleotide microarray platform with a total of 32,217 probes. Gene expression signatures of specimens collected in the Ross Sea at five different time points over a 24-hour cycle were defined, and 1,308 genes differentially expressed were identified. Of the corresponding transcripts, 609 showed a significant sinusoidal expression pattern; about 40% of these exibithed a 24-hour periodicity while the other 60% was characterized by a shorter (about 12-hour) rhythm. We assigned the differentially expressed genes to functional categories and noticed that those concerning translation, proteolysis, energy and metabolic process, redox regulation, visual transduction and stress response, which are most likely related to daily environmental changes, were significantly enriched. Two transcripts of peroxiredoxin, thought to represent the ancestral timekeeping system that evolved about 2.5 billion years ago, were also identified as were two isoforms of the EsRh1 opsin and two novel arrestin1 sequences involved in the visual transduction cascade. CONCLUSIONS Our work represents the first characterization of the krill diurnal transcriptome under natural conditions and provides a first insight into the genetic regulation of physiological changes, which occur around the clock during an Antarctic summer day.
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Porter ML, Speiser DI, Zaharoff AK, Caldwell RL, Cronin TW, Oakley TH. The evolution of complexity in the visual systems of stomatopods: insights from transcriptomics. Integr Comp Biol 2013; 53:39-49. [PMID: 23727979 DOI: 10.1093/icb/ict060] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Stomatopod crustaceans have complex visual systems containing up to 16 different spectral classes of photoreceptors, more than described for any other animal. A previous molecular study of this visual system focusing on the expression of opsin genes found many more transcripts than predicted on the basis of physiology, but was unable to fully document the expressed opsin genes responsible for this diversity. Furthermore, questions remain about how other components of phototransduction cascades are involved. This study continues prior investigations by examining the molecular function of stomatopods' visual systems using new whole eye 454 transcriptome datasets from two species, Hemisquilla californiensis and Pseudosquilla ciliata. These two species represent taxonomic diversity within the order Stomatopoda, as well as variations in the anatomy and physiology of the visual system. Using an evolutionary placement algorithm to annotate the transcriptome, we identified the presence of nine components of the stomatopods' G-protein-coupled receptor (GPCR) phototransduction cascade, including two visual arrestins, subunits of the heterotrimeric G-protein, phospholipase C, transient receptor potential channels, and opsin transcripts. The set of expressed transduction genes suggests that stomatopods utilize a Gq-mediated GPCR-signaling cascade. The most notable difference in expression between the phototransduction cascades of the two species was the number of opsin contigs recovered, with 18 contigs found in retinas of H. californiensis, and 49 contigs in those of P. ciliata. Based on phylogenetic placement and fragment overlap, these contigs were estimated to represent 14 and 33 expressed transcripts, respectively. These data expand the known opsin diversity in stomatopods to clades of arthropod opsins that are sensitive to short wavelengths and ultraviolet wavelengths and confirm the results of previous studies recovering more opsin transcripts than spectrally distinct types of photoreceptors. Many of the recovered transcripts were phylogenetically placed in an evolutionary clade of crustacean opsin sequences that is rapidly expanding as the visual systems from more species are investigated. We discuss these results in relation to the emerging pattern, particularly in crustacean visual systems, of the expression of multiple opsin transcripts in photoreceptors of the same spectral class, and even in single photoreceptor cells.
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Affiliation(s)
- Megan L Porter
- Department of Biology, University of South Dakota, Vermillion, SD 57069, USA.
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Systematic variations in microvilli banding patterns along fiddler crab rhabdoms. J Comp Physiol A Neuroethol Sens Neural Behav Physiol 2012; 199:99-113. [DOI: 10.1007/s00359-012-0771-9] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2012] [Revised: 10/12/2012] [Accepted: 10/16/2012] [Indexed: 11/25/2022]
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Ogawa Y, Awata H, Wakakuwa M, Kinoshita M, Stavenga DG, Arikawa K. Coexpression of three middle wavelength-absorbing visual pigments in sexually dimorphic photoreceptors of the butterfly Colias erate. J Comp Physiol A Neuroethol Sens Neural Behav Physiol 2012; 198:857-67. [PMID: 22972231 DOI: 10.1007/s00359-012-0756-8] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2012] [Revised: 08/29/2012] [Accepted: 08/29/2012] [Indexed: 01/18/2023]
Abstract
The tiered ommatidia of the Eastern Pale Clouded yellow butterfly, Colias erate, contain nine photoreceptor cells, four of which contribute their rhabdomeral microvilli to the distal tier of the rhabdom. We analyzed the visual pigments and spectral sensitivities of these distal photoreceptors in both sexes of Colias erate. A subset of photoreceptor cells expresses a newly discovered middle wavelength-absorbing opsin, Colias erate Blue (CeB), in addition to two previously described middle wavelength-absorbing opsins, CeV1 and CeV2. The other photoreceptors either coexpress CeV1 and CeV2, or exclusively express a short wavelength-absorbing opsin, CeUV, or a long wavelength-absorbing opsin, CeL. Males and females have the same visual pigment expression patterns, but the photoreceptor spectral sensitivities are sexually dimorphic. The photoreceptors coexpressing three middle wavelength-absorbing opsins are broad-blue receptors in males, but in females they are narrow-blue receptors. Those with CeV1 and CeV2 are violet receptors in females, while they are shouldered-blue receptors in males. The sexual dimorphism in spectral sensitivity is caused by a sex-specific distribution of fluorescent pigment that functions as a spectral filter.
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Affiliation(s)
- Yuri Ogawa
- Laboratory of Neuroethology, Sokendai-Hayama (The Graduate University for Advanced Studies), Hayama, 240-0193, Japan
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Henze MJ, Dannenhauer K, Kohler M, Labhart T, Gesemann M. Opsin evolution and expression in arthropod compound eyes and ocelli: insights from the cricket Gryllus bimaculatus. BMC Evol Biol 2012; 12:163. [PMID: 22935102 PMCID: PMC3502269 DOI: 10.1186/1471-2148-12-163] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2012] [Accepted: 08/24/2012] [Indexed: 11/28/2022] Open
Abstract
Background Opsins are key proteins in animal photoreception. Together with a light-sensitive group, the chromophore, they form visual pigments which initiate the visual transduction cascade when photoactivated. The spectral absorption properties of visual pigments are mainly determined by their opsins, and thus opsins are crucial for understanding the adaptations of animal eyes. Studies on the phylogeny and expression pattern of opsins have received considerable attention, but our knowledge about insect visual opsins is still limited. Up to now, researchers have focused on holometabolous insects, while general conclusions require sampling from a broader range of taxa. We have therefore investigated visual opsins in the ocelli and compound eyes of the two-spotted cricket Gryllus bimaculatus, a hemimetabolous insect. Results Phylogenetic analyses place all identified cricket sequences within the three main visual opsin clades of insects. We assign three of these opsins to visual pigments found in the compound eyes with peak absorbances in the green (515 nm), blue (445 nm) and UV (332 nm) spectral range. Their expression pattern divides the retina into distinct regions: (1) the polarization-sensitive dorsal rim area with blue- and UV-opsin, (2) a newly-discovered ventral band of ommatidia with blue- and green-opsin and (3) the remainder of the compound eye with UV- and green-opsin. In addition, we provide evidence for two ocellar photopigments with peak absorbances in the green (511 nm) and UV (350 nm) spectral range, and with opsins that differ from those expressed in the compound eyes. Conclusions Our data show that cricket eyes are spectrally more specialized than has previously been assumed, suggesting that similar adaptations in other insect species might have been overlooked. The arrangement of spectral receptor types within some ommatidia of the cricket compound eyes differs from the generally accepted pattern found in holometabolous insect taxa and awaits a functional explanation. From the opsin phylogeny, we conclude that gene duplications, which permitted differential opsin expression in insect ocelli and compound eyes, occurred independently in several insect lineages and are recent compared to the origin of the eyes themselves.
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Affiliation(s)
- Miriam J Henze
- Department of Biology, Lund University, Sölvegatan 35, 22362 Lund, Sweden.
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Baldwin J, Johnsen S. The male blue crab, Callinectes sapidus, uses both chromatic and achromatic cues during mate choice. J Exp Biol 2012; 215:1184-91. [DOI: 10.1242/jeb.067512] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
SUMMARY
In the blue crab, Callinectes sapidus, claw color varies by sex, sexual maturity and individual. Males rely in part on color cues to select appropriate mates, and these chromatic cues may be perceived through an opponent interaction between two photoreceptors with maximum wavelength sensitivities at 440 and 508 nm. The range of color discrimination of this dichromatic visual system may be limited, however, and it is unclear whether male blue crabs are capable of discriminating the natural variations in claw color that may be important in mate choice. By testing males’ innate color preferences in binary choice tests between photographs of red-clawed females and six variations of orange-clawed females, we examined both the chromatic (opponent interaction) and achromatic (relative luminance) cues used in male mate choice. Males significantly preferred red-clawed females to orange-clawed females, except when the test colors were similar in both opponency and relative luminance. Our results are unusual in that they indicate that male mate choice in the blue crab is not guided solely by achromatic or chromatic mechanisms, suggesting that both color and intensity are used to evaluate female claw color.
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Affiliation(s)
- Jamie Baldwin
- Department of Biology, Duke University, Durham, NC 27708, USA
| | - Sönke Johnsen
- Department of Biology, Duke University, Durham, NC 27708, USA
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Friedrich M, Wood EJ, Wu M. Developmental evolution of the insect retina: insights from standardized numbering of homologous photoreceptors. JOURNAL OF EXPERIMENTAL ZOOLOGY PART B-MOLECULAR AND DEVELOPMENTAL EVOLUTION 2011; 316:484-99. [DOI: 10.1002/jez.b.21424] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/23/2011] [Revised: 05/26/2011] [Indexed: 11/09/2022]
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