1
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Buffry AD, Currea JP, Franke-Gerth FA, Palavalli-Nettimi R, Bodey AJ, Rau C, Samadi N, Gstöhl SJ, Schlepütz CM, McGregor AP, Sumner-Rooney L, Theobald J, Kittelmann M. Evolution of compound eye morphology underlies differences in vision between closely related Drosophila species. BMC Biol 2024; 22:67. [PMID: 38504308 PMCID: PMC10953123 DOI: 10.1186/s12915-024-01864-7] [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: 09/18/2023] [Accepted: 03/07/2024] [Indexed: 03/21/2024] Open
Abstract
BACKGROUND Insects have evolved complex visual systems and display an astonishing range of adaptations for diverse ecological niches. Species of Drosophila melanogaster subgroup exhibit extensive intra- and interspecific differences in compound eye size. These differences provide an excellent opportunity to better understand variation in insect eye structure and the impact on vision. Here we further explored the difference in eye size between D. mauritiana and its sibling species D. simulans. RESULTS We confirmed that D. mauritiana have rapidly evolved larger eyes as a result of more and wider ommatidia than D. simulans since they recently diverged approximately 240,000 years ago. The functional impact of eye size, and specifically ommatidia size, is often only estimated based on the rigid surface morphology of the compound eye. Therefore, we used 3D synchrotron radiation tomography to measure optical parameters in 3D, predict optical capacity, and compare the modelled vision to in vivo optomotor responses. Our optical models predicted higher contrast sensitivity for D. mauritiana, which we verified by presenting sinusoidal gratings to tethered flies in a flight arena. Similarly, we confirmed the higher spatial acuity predicted for Drosophila simulans with smaller ommatidia and found evidence for higher temporal resolution. CONCLUSIONS Our study demonstrates that even subtle differences in ommatidia size between closely related Drosophila species can impact the vision of these insects. Therefore, further comparative studies of intra- and interspecific variation in eye morphology and the consequences for vision among other Drosophila species, other dipterans and other insects are needed to better understand compound eye structure-function and how the diversification of eye size, shape, and function has helped insects to adapt to the vast range of ecological niches.
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Affiliation(s)
- Alexandra D Buffry
- Department of Biological and Medical Sciences, Oxford Brookes University, Oxford, OX3 0BP, UK
| | - John P Currea
- Integrative Biology and Physiology, UCLA, Los Angeles, CA, 90095, USA
| | - Franziska A Franke-Gerth
- Molecular Evolution and Systematics of Animals, Institute of Biology, University of Leipzig, Talstrasse 33, 04103, Leipzig, Germany
| | - Ravindra Palavalli-Nettimi
- Institute of the Environment and Department of Biological Sciences, Florida International University, Miami, FL, USA
| | - Andrew J Bodey
- Diamond Light Source Ltd, Harwell Science and Innovation Campus, Didcot, UK
| | - Christoph Rau
- Diamond Light Source Ltd, Harwell Science and Innovation Campus, Didcot, UK
| | - Nazanin Samadi
- Swiss Light Source, Paul Scherrer Institute, Forschungsstrasse 111, 5232, Villigen PSI, Switzerland
| | - Stefan J Gstöhl
- Swiss Light Source, Paul Scherrer Institute, Forschungsstrasse 111, 5232, Villigen PSI, Switzerland
| | - Christian M Schlepütz
- Swiss Light Source, Paul Scherrer Institute, Forschungsstrasse 111, 5232, Villigen PSI, Switzerland
| | - Alistair P McGregor
- Department of Biosciences, Durham University, South Road, Durham, DH1 3LE, UK
| | - Lauren Sumner-Rooney
- Museum Für Naturkunde, Leibniz Institute for Evolution and Biodiversity Research, Berlin, 10115, Germany
| | - Jamie Theobald
- Institute of the Environment and Department of Biological Sciences, Florida International University, Miami, FL, USA
| | - Maike Kittelmann
- Department of Biological and Medical Sciences, Oxford Brookes University, Oxford, OX3 0BP, UK.
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2
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Perez M, Bagheri ZM, Brown C, Ogawa Y, Partridge JC, Hemmi JM. Contrast sensitivity, visual acuity and the effect of behavioural state on optokinetic gain in fiddler crabs. J Exp Biol 2023; 226:jeb245799. [PMID: 37732387 DOI: 10.1242/jeb.245799] [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: 03/07/2023] [Accepted: 09/14/2023] [Indexed: 09/22/2023]
Abstract
Most animals rely on visual information for a variety of everyday tasks. The information available to a visual system depends in part on its spatial resolving power and contrast sensitivity. Because of their competing demands for physical space within an eye, these traits cannot simultaneously be improved without increasing overall eye size. The contrast sensitivity function is an integrated measure of visual performance that measures both resolution and contrast sensitivity. Its measurement helps us identify how different species have made a trade-off between contrast sensitivity and spatial resolution. It further allows us to identify the evolutionary drivers of sensory processing and visually mediated behaviour. Here, we measured the contrast sensitivity function of the fiddler crab Gelasimus dampieri using its optokinetic responses to wide-field moving sinusoidal intensity gratings of different orientations, spatial frequencies, contrasts and speeds. We further tested whether the behavioural state of the crabs (i.e. whether crabs are actively walking or not) affects their optokinetic gain and contrast sensitivity. Our results from a group of five crabs suggest a minimum perceived contrast of 6% and a horizontal and vertical visual acuity of 0.4 cyc deg-1 and 0.28 cyc deg-1, respectively, in the crabs' region of maximum optomotor sensitivity. Optokinetic gain increased in moving crabs compared with restrained crabs, adding another example of the importance of naturalistic approaches when studying the performance of animals.
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Affiliation(s)
- Monika Perez
- School of Biological Sciences, the University of Western Australia, Perth, WA 6009, Australia
| | - Zahra M Bagheri
- School of Biological Sciences, the University of Western Australia, Perth, WA 6009, Australia
- The UWA Oceans Institute, the University of Western Australia, Perth, WA 6009, Australia
| | - Courtney Brown
- School of Biological Sciences, the University of Western Australia, Perth, WA 6009, Australia
| | - Yuri Ogawa
- School of Biological Sciences, the University of Western Australia, Perth, WA 6009, Australia
| | - Julian C Partridge
- The UWA Oceans Institute, the University of Western Australia, Perth, WA 6009, Australia
| | - Jan M Hemmi
- School of Biological Sciences, the University of Western Australia, Perth, WA 6009, Australia
- The UWA Oceans Institute, the University of Western Australia, Perth, WA 6009, Australia
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3
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Rimniceanu M, Currea JP, Frye MA. Proprioception gates visual object fixation in flying flies. Curr Biol 2023; 33:1459-1471.e3. [PMID: 37001520 PMCID: PMC10133043 DOI: 10.1016/j.cub.2023.03.018] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2022] [Revised: 01/24/2023] [Accepted: 03/07/2023] [Indexed: 04/27/2023]
Abstract
Visual object tracking in animals as diverse as felines, frogs, and fish supports behaviors including predation, predator avoidance, and landscape navigation. Decades of experimental results show that a rigidly body-fixed tethered fly in a "virtual reality" visual flight simulator steers to follow the motion of a vertical bar, thereby "fixating" it on visual midline. This behavior likely reflects a desire to seek natural features such as plant stalks and has inspired algorithms for visual object tracking predicated on robust responses to bar velocity, particularly near visual midline. Using a modified flight simulator equipped with a magnetic pivot to allow frictionless turns about the yaw axis, we discovered that bar fixation as well as smooth steering responses to bar velocity are attenuated or eliminated in yaw-free conditions. Body-fixed Drosophila melanogaster respond to bar oscillation on a stationary ground with frequency-matched wing kinematics and fixate the bar on midline. Yaw-free flies respond to the same stimulus by ignoring the bar and maintaining their original heading. These differences are driven by proprioceptive signals, rather than visual signals, as artificially "clamping" a bar in the periphery of a yaw-free fly has no effect. When presented with a bar and ground oscillating at different frequencies, a yaw-free fly follows the frequency of the ground only, whereas a body-fixed fly robustly steers at the frequencies of both the bar and ground. Our findings support a model in which proprioceptive feedback promote active damping of high-gain optomotor responses to object motion.
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Affiliation(s)
- Martha Rimniceanu
- Department of Integrative Biology and Physiology, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - John P Currea
- Department of Integrative Biology and Physiology, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Mark A Frye
- Department of Integrative Biology and Physiology, University of California, Los Angeles, Los Angeles, CA 90095, USA.
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4
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Currea JP, Sondhi Y, Kawahara AY, Theobald J. Measuring compound eye optics with microscope and microCT images. Commun Biol 2023; 6:246. [PMID: 36882636 PMCID: PMC9992655 DOI: 10.1038/s42003-023-04575-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2021] [Accepted: 02/10/2023] [Indexed: 03/09/2023] Open
Abstract
With a great variety of shapes and sizes, compound eye morphologies give insight into visual ecology, development, and evolution, and inspire novel engineering. In contrast to our own camera-type eyes, compound eyes reveal their resolution, sensitivity, and field of view externally, provided they have spherical curvature and orthogonal ommatidia. Non-spherical compound eyes with skewed ommatidia require measuring internal structures, such as with MicroCT (µCT). Thus far, there is no efficient tool to characterize compound eye optics, from either 2D or 3D data, automatically. Here we present two open-source programs: (1) the ommatidia detecting algorithm (ODA), which measures ommatidia count and diameter in 2D images, and (2) a µCT pipeline (ODA-3D), which calculates anatomical acuity, sensitivity, and field of view across the eye by applying the ODA to 3D data. We validate these algorithms on images, images of replicas, and µCT eye scans from ants, fruit flies, moths, and a bee.
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Affiliation(s)
- John Paul Currea
- Integrative Biology and Physiology, UCLA, Los Angeles, CA, 90095, USA.
| | - Yash Sondhi
- Department of Biological Sciences, Florida International University, Miami, FL, 33199, USA
- McGuire Center for Lepidoptera and Biodiversity, Florida Museum of Natural History, University of Florida, Gainesville, FL, 32611, USA
| | - Akito Y Kawahara
- McGuire Center for Lepidoptera and Biodiversity, Florida Museum of Natural History, University of Florida, Gainesville, FL, 32611, USA
| | - Jamie Theobald
- Department of Biological Sciences, Florida International University, Miami, FL, 33199, USA.
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5
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Stöckl A, Grittner R, Taylor G, Rau C, Bodey AJ, Kelber A, Baird E. Allometric scaling of a superposition eye optimizes sensitivity and acuity in large and small hawkmoths. Proc Biol Sci 2022; 289:20220758. [PMID: 35892218 PMCID: PMC9326294 DOI: 10.1098/rspb.2022.0758] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Animals vary widely in body size within and across species. This has consequences for the function of organs and body parts in both large and small individuals. How these scale, in relation to body size, reveals evolutionary investment strategies, often resulting in trade-offs between functions. Eyes exemplify these trade-offs, as they are limited by their absolute size in two key performance features: sensitivity and spatial acuity. Due to their size polymorphism, insect compound eyes are ideal models for studying the allometric scaling of eye performance. Previous work on apposition compound eyes revealed that allometric scaling led to poorer spatial resolution and visual sensitivity in small individuals, across a range of insect species. Here, we used X-ray microtomography to investigate allometric scaling in superposition compound eyes-the second most common eye type in insects-for the first time. Our results reveal a novel strategy to cope with the trade-off between sensitivity and spatial acuity, as we show that the eyes of the hummingbird hawkmoth retain an optimal balance between these performance measures across all body sizes.
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Affiliation(s)
- Anna Stöckl
- Behavioral Physiology and Sociobiology (Zoology II), University of Würzburg, Würzburg, Germany
| | - Rebecca Grittner
- Behavioral Physiology and Sociobiology (Zoology II), University of Würzburg, Würzburg, Germany
| | - Gavin Taylor
- Institute for Globally Distributed Open Research and Education (IGDORE), Ribeirão Preto, Brazil
| | - Christoph Rau
- Diamond Light Source, Harwell Science and Innovation Campus, Didcot, UK
| | - Andrew J. Bodey
- Diamond Light Source, Harwell Science and Innovation Campus, Didcot, UK
| | - Almut Kelber
- Department of Biology, Lund University, Lund, Sweden
| | - Emily Baird
- Department of Zoology, Stockholm University, Stockholm, Sweden
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6
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Currea JP, Frazer R, Wasserman SM, Theobald J. Acuity and summation strategies differ in vinegar and desert fruit flies. iScience 2022; 25:103637. [PMID: 35028530 PMCID: PMC8741510 DOI: 10.1016/j.isci.2021.103637] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2021] [Revised: 09/16/2021] [Accepted: 12/14/2021] [Indexed: 11/11/2022] Open
Abstract
An animal's vision depends on terrain features that limit the amount and distribution of available light. Approximately 10,000 years ago, vinegar flies (Drosophila melanogaster) transitioned from a single plant specialist into a cosmopolitan generalist. Much earlier, desert flies (D. mojavensis) colonized the New World, specializing on rotting cactuses in southwest North America. Their desert habitats are characteristically flat, bright, and barren, implying environmental differences in light availability. Here, we demonstrate differences in eye morphology and visual motion perception under three ambient light levels. Reducing ambient light from 35 to 18 cd/m2 causes sensitivity loss in desert but not vinegar flies. However, at 3 cd/m2, desert flies sacrifice spatial and temporal acuity more severely than vinegar flies to maintain contrast sensitivity. These visual differences help vinegar flies navigate under variably lit habitats around the world and desert flies brave the harsh desert while accommodating their crepuscular lifestyle.
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Affiliation(s)
- John P. Currea
- Department of Psychology, Florida International University, Miami, FL 33199, USA
| | - Rachel Frazer
- Division of Neurobiology and Behavior, Columbia University, New York, NY 10027, USA
| | - Sara M. Wasserman
- Department of Neuroscience, Wellesley College, Wellesley, MA 02481, USA
| | - Jamie Theobald
- Department of Biological Sciences, Florida International University, Miami, FL 33199, USA
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7
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Grittner R, Baird E, Stöckl A. Spatial tuning of translational optic flow responses in hawkmoths of varying body size. J Comp Physiol A Neuroethol Sens Neural Behav Physiol 2021; 208:279-296. [PMID: 34893928 PMCID: PMC8934765 DOI: 10.1007/s00359-021-01530-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2021] [Revised: 11/28/2021] [Accepted: 11/30/2021] [Indexed: 11/12/2022]
Abstract
To safely navigate their environment, flying insects rely on visual cues, such as optic flow. Which cues insects can extract from their environment depends closely on the spatial and temporal response properties of their visual system. These in turn can vary between individuals that differ in body size. How optic flow-based flight control depends on the spatial structure of visual cues, and how this relationship scales with body size, has previously been investigated in insects with apposition compound eyes. Here, we characterised the visual flight control response limits and their relationship to body size in an insect with superposition compound eyes: the hummingbird hawkmoth Macroglossum stellatarum. We used the hawkmoths’ centring response in a flight tunnel as a readout for their reception of translational optic flow stimuli of different spatial frequencies. We show that their responses cut off at different spatial frequencies when translational optic flow was presented on either one, or both tunnel walls. Combined with differences in flight speed, this suggests that their flight control was primarily limited by their temporal rather than spatial resolution. We also observed strong individual differences in flight performance, but no correlation between the spatial response cutoffs and body or eye size.
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Affiliation(s)
- Rebecca Grittner
- Behavioral Physiology and Sociobiology (Zoology II), University of Würzburg, Würzburg, Germany
| | - Emily Baird
- Department of Zoology, Stockholm University, Stockholm, Sweden
| | - Anna Stöckl
- Behavioral Physiology and Sociobiology (Zoology II), University of Würzburg, Würzburg, Germany.
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8
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Buschbeck E, Warrant E. Editorial. ARTHROPOD STRUCTURE & DEVELOPMENT 2021; 63:101073. [PMID: 34052786 DOI: 10.1016/j.asd.2021.101073] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
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9
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Interplay between sex determination cascade and major signaling pathways during Drosophila eye development: Perspectives for future research. Dev Biol 2021; 476:41-52. [PMID: 33745943 DOI: 10.1016/j.ydbio.2021.03.005] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2020] [Revised: 02/07/2021] [Accepted: 03/01/2021] [Indexed: 12/15/2022]
Abstract
Understanding molecular mechanisms of sexually dimorphic organ growth is a fundamental problem of developmental biology. Recent quantitative studies showed that the Drosophila compound eye is a convenient model to study the determination of the final organ size. In Drosophila, females have larger eyes than males and this is evident even after correction for the larger body size. Moreover, female eyes include more ommatidia (photosensitive units) than male eyes and this difference is specified at the third larval instar in the eye primordia called eye imaginal discs. This may result in different visual capabilities between the two sexes and have behavioral consequences. Despite growing evidence on the genetic bases of eye size variation between different Drosophila species and strains, mechanisms responsible for within-species sexual dimorphism still remain elusive. Here, we discuss a presumptive crosstalk between the sex determination cascade and major signaling pathways during dimorphic eye development. Male- and female-specific isoforms of Doublesex (Dsx) protein are known to control sex-specific differentiation in the somatic tissues. However, no data on Dsx function during eye disc growth and patterning are currently available. Remarkably, Sex lethal (Sxl), the sex determination switch protein, was shown to directly affect Hedgehog (Hh) and Notch (N) signaling in the Drosophila wing disc. The similarity of signaling pathways involved in the wing and eye disc growth suggests that Sxl might be integrated into regulation of eye development. Dsx role in the eye disc requires further investigation. We discuss currently available data on sex-biased gene expression in the Drosophila eye and highlight perspectives for future studies.
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10
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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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11
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Rospars JP, Meyer-Vernet N. How fast do mobile organisms respond to stimuli? Response times from bacteria to elephants and whales. Phys Biol 2021; 18:026002. [PMID: 33232948 DOI: 10.1088/1478-3975/abcd88] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Quick responses to fast changes in the environment are crucial in animal behaviour and survival, for example to seize prey, escape predators, or negotiate obstacles. Here, we study the 'simple response time' that is the time elapsed between receptor stimulation and motor activation as typically shown in escape responses, for mobile organisms of various taxa ranging from bacteria to large vertebrates. We show that 95% of these simple response times lie within one order of magnitude of the overall geometric mean of about 25 ms, which is similar to that of a well-studied sensory time scale, the inverse of the critical flicker fusion frequency in vision, also lying within close bounds for all the organisms studied. We find that this time scale is a few times smaller than the minimum time to move by one body length, which is known to lie also within a relatively narrow range for all moving organisms. The remarkably small 102-fold range of the simple response time among so disparate life forms varying over 1020-fold in body mass suggests that it is determined by basic physicochemical constraints, independently on the structure and scale of the organism. We thus propose first-principle estimates of the simple response and sensory time scales in terms of physical constants and a few basic biological properties common to mobile organisms and constraining their responses.
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Affiliation(s)
- Jean-Pierre Rospars
- Institute of Ecology and Environmental Sciences of Paris, INRAE, Route de Saint-Cyr, 78000 Versailles, France
| | - Nicole Meyer-Vernet
- LESIA, Observatoire de Paris, Université PSL, CNRS, Sorbonne Université, Université de Paris, 5 place Jules Janssen, 92195 Meudon, France
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12
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Kaushik PK, Olsson SB. Using virtual worlds to understand insect navigation for bio-inspired systems. CURRENT OPINION IN INSECT SCIENCE 2020; 42:97-104. [PMID: 33010476 DOI: 10.1016/j.cois.2020.09.010] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/14/2020] [Revised: 09/18/2020] [Accepted: 09/22/2020] [Indexed: 06/11/2023]
Abstract
Insects perform a wide array of intricate behaviors over large spatial and temporal scales in complex natural environments. A mechanistic understanding of insect cognition has direct implications on how brains integrate multimodal information and can inspire bio-based solutions for autonomous robots. Virtual Reality (VR) offers an opportunity assess insect neuroethology while presenting complex, yet controlled, stimuli. Here, we discuss the use of insects as inspiration for artificial systems, recent advances in different VR technologies, current knowledge gaps, and the potential for application of insect VR research to bio-inspired robots. Finally, we advocate the need to diversify our model organisms, behavioral paradigms, and embrace the complexity of the natural world. This will help us to uncover the proximate and ultimate basis of brain and behavior and extract general principles for common challenging problems.
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Affiliation(s)
- Pavan Kumar Kaushik
- National Centre for Biological Sciences, Tata Institute of Fundamental Research, GKVK Campus, Bellary Road, Bengaluru, 560064, India.
| | - Shannon B Olsson
- National Centre for Biological Sciences, Tata Institute of Fundamental Research, GKVK Campus, Bellary Road, Bengaluru, 560064, India.
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13
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Casares F, McGregor AP. The evolution and development of eye size in flies. WILEY INTERDISCIPLINARY REVIEWS-DEVELOPMENTAL BIOLOGY 2020; 10:e380. [PMID: 32400100 DOI: 10.1002/wdev.380] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/01/2019] [Revised: 03/08/2020] [Accepted: 03/12/2020] [Indexed: 01/19/2023]
Abstract
The compound eyes of flies exhibit striking variation in size, which has contributed to the adaptation of these animals to different habitats and their evolution of specialist behaviors. These differences in size are caused by differences in the number and/or size of ommatidia, which are specified during the development of the retinal field in the eye imaginal disc. While the genes and developmental mechanisms that regulate the formation of compound eyes are understood in great detail in the fruit fly Drosophila melanogaster, we know very little about the genetic changes and mechanistic alterations that lead to natural variation in ommatidia number and/or size, and thus overall eye size, within and between fly species. Understanding the genetic and developmental bases for this natural variation in eye size not only has great potential to help us understand adaptations in fly vision but also determine how eye size and organ size more generally are regulated. Here we explore the genetic and developmental mechanisms that could underlie natural differences in compound eye size within and among fly species based on our knowledge of eye development in D. melanogaster and the few cases where the causative genes and mechanisms have already been identified. We suggest that the fly eye provides an evolutionary and developmental framework to better understand the regulation and diversification of this crucial sensory organ globally at a systems level as well as the gene regulatory networks and mechanisms acting at the tissue, cellular and molecular levels. This article is categorized under: Establishment of Spatial and Temporal Patterns > Regulation of Size, Proportion, and Timing Invertebrate Organogenesis > Flies Comparative Development and Evolution > Regulation of Organ Diversity.
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Affiliation(s)
| | - Alistair P McGregor
- Department of Biological and Medical Sciences, Oxford Brookes University, Oxford, UK
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14
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Small eyes in dim light: Implications to spatio-temporal visual abilities in Drosophila melanogaster. Vision Res 2020; 169:33-40. [DOI: 10.1016/j.visres.2020.02.007] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2019] [Revised: 02/27/2020] [Accepted: 02/27/2020] [Indexed: 02/07/2023]
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15
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Ryan LA, Cunningham R, Hart NS, Ogawa Y. The buzz around spatial resolving power and contrast sensitivity in the honeybee, Apis mellifera. Vision Res 2020; 169:25-32. [PMID: 32145455 DOI: 10.1016/j.visres.2020.02.005] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2019] [Revised: 02/17/2020] [Accepted: 02/18/2020] [Indexed: 10/24/2022]
Abstract
Most animals rely on vision to perform a range of behavioural tasks and variations in the anatomy and physiology of the eye likely reflect differences in habitat and life history. Moreover, eye design represents a balance between often conflicting requirements for gathering different forms of visual information. The trade-off between spatial resolving power and contrast sensitivity is common to all visual systems, and European honeybees (Apis mellifera) present an important opportunity to better understand this trade-off. Vision has been studied extensively in A. mellifera as it is vital for foraging, navigation and communication. Consequently, spatial resolving power and contrast sensitivity in A. mellifera have been measured using several methodologies; however, there is considerable variation in estimates between methodologies. We assess pattern electroretinography (pERG) as a new method for assessing the trade-off between visual spatial and contrast information in A.mellifera. pERG has the benefit of measuring spatial contrast sensitivity from higher order visual processing neurons in the eye. Spatial resolving power of A.mellifera estimated from pERG was 0.54 cycles per degree (cpd), and contrast sensitivity was 16.9. pERG estimates of contrast sensitivity were comparable to previous behavioural studies. Estimates of spatial resolving power reflected anatomical estimates in the frontal region of the eye, which corresponds to the region stimulated by pERG. Apis mellifera has similar spatial contrast sensitivity to other hymenopteran insects with similar facet diameter (Myrmecia ant species). Our results support the idea that eye anatomy has a substantial effect on spatial contrast sensitivity in compound eyes.
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Affiliation(s)
- Laura A Ryan
- Department of Biological Sciences, Macquarie University, Sydney, New South Wales 2109, Australia.
| | - Rhianon Cunningham
- Department of Biological Sciences, Macquarie University, Sydney, New South Wales 2109, Australia
| | - Nathan S Hart
- Department of Biological Sciences, Macquarie University, Sydney, New South Wales 2109, Australia
| | - Yuri Ogawa
- Department of Biological Sciences, Macquarie University, Sydney, New South Wales 2109, Australia
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Characterization of the Genetic Architecture Underlying Eye Size Variation Within Drosophila melanogaster and Drosophila simulans. G3-GENES GENOMES GENETICS 2020; 10:1005-1018. [PMID: 31919111 DOI: 10.1534/g3.119.400877] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
The compound eyes of insects exhibit striking variation in size, reflecting adaptation to different lifestyles and habitats. However, the genetic and developmental bases of variation in insect eye size is poorly understood, which limits our understanding of how these important morphological differences evolve. To address this, we further explored natural variation in eye size within and between four species of the Drosophila melanogaster species subgroup. We found extensive variation in eye size among these species, and flies with larger eyes generally had a shorter inter-ocular distance and vice versa We then carried out quantitative trait loci (QTL) mapping of intra-specific variation in eye size and inter-ocular distance in both D. melanogaster and D. simulans This revealed that different genomic regions underlie variation in eye size and inter-ocular distance in both species, which we corroborated by introgression mapping in D. simulans This suggests that although there is a trade-off between eye size and inter-ocular distance, variation in these two traits is likely to be caused by different genes and so can be genetically decoupled. Finally, although we detected QTL for intra-specific variation in eye size at similar positions in D. melanogaster and D. simulans, we observed differences in eye fate commitment between strains of these two species. This indicates that different developmental mechanisms and therefore, most likely, different genes contribute to eye size variation in these species. Taken together with the results of previous studies, our findings suggest that the gene regulatory network that specifies eye size has evolved at multiple genetic nodes to give rise to natural variation in this trait within and among species.
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Growing tiny eyes: How juvenile jumping spiders retain high visual performance in the face of size limitations and developmental constraints. Vision Res 2019; 160:24-36. [DOI: 10.1016/j.visres.2019.04.006] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2019] [Revised: 04/18/2019] [Accepted: 04/18/2019] [Indexed: 11/21/2022]
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Taylor GJ, Tichit P, Schmidt MD, Bodey AJ, Rau C, Baird E. Bumblebee visual allometry results in locally improved resolution and globally improved sensitivity. eLife 2019; 8:40613. [PMID: 30803484 PMCID: PMC6391067 DOI: 10.7554/elife.40613] [Citation(s) in RCA: 47] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2018] [Accepted: 12/23/2018] [Indexed: 12/19/2022] Open
Abstract
The quality of visual information that is available to an animal is limited by the size of its eyes. Differences in eye size can be observed even between closely related individuals, yet we understand little about how this affects vision. Insects are good models for exploring the effects of size on visual systems because many insect species exhibit size polymorphism. Previous work has been limited by difficulties in determining the 3D structure of eyes. We have developed a novel method based on x-ray microtomography to measure the 3D structure of insect eyes and to calculate predictions of their visual capabilities. We used our method to investigate visual allometry in the bumblebee Bombus terrestris and found that size affects specific aspects of vision, including binocular overlap, optical sensitivity, and dorsofrontal visual resolution. This reveals that differential scaling between eye areas provides flexibility that improves the visual capabilities of larger bumblebees. Bees fly through complex environments in search of nectar from flowers. They are aided in this quest by excellent eyesight. Scientists have extensively studied the eyesight of honeybees to learn more about how such tiny eyes work and how they process and learn visual information. Less is known about the honeybee’s larger cousins, the bumblebees, which are also important pollinators. Bumblebees come in different sizes and one question scientists have is how eye size affects vision. Bigger bumblebees are known to have bigger eyes, and bigger eyes are usually better. But which aspects of vision are improved in larger eyes is not clear. For example, does the size of a bee’s eyes affect how large their field of view is, or how sensitive they are to light? Or does it impact their visual acuity, a measurement of the smallest objects the eye can see? Scaling up an eye would likely improve all these aspects of sight slightly, but changes in a small area of the eye might more drastically improve some parts of vision. Now, Taylor et al. show that larger bumblebees with bigger eyes have better vision than their smaller counterparts. In the experiments, a technique called microtomography was used to measure the 3D structure of bumblebee eyes. The measurements were then applied to build 3D models of the bumblebee eyes, and computational geometry was used to calculate the sensitivity, acuity, and viewing direction across the entire surface of each model eye. Taylor et al. found that larger bees had improved ability to see small objects in front or slightly above them. They had a bigger area of overlap between the sight in both eyes when they looked forward and up. They were also more sensitive to light across the eye. The experiments show that improvements in eyesight with larger size are very specific and likely help larger bees to adapt to their environment. Behavioral studies could help scientists better understand how these changes help bigger bees and how the traits evolved. These findings might also help engineers trying to design miniature cameras to help small, flying autonomous vehicles navigate. Bees fly through complex environments and face challenges similar to those small flying vehicles would face. Emulating the design of bee eyes and how they change with size might lead to the development of better cameras for these vehicles.
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Affiliation(s)
| | - Pierre Tichit
- Department of Biology, Lund University, Lund, Sweden
| | - Marie D Schmidt
- Department of Biology, Lund University, Lund, Sweden.,Westphalian University of Applied Sciences, Bocholt, Germany
| | | | | | - Emily Baird
- Department of Biology, Lund University, Lund, Sweden.,Department of Zoology, Stockholm University, Stockholm, Sweden
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Palavalli-Nettimi R, Ogawa Y, Ryan LA, Hart NS, Narendra A. Miniaturisation reduces contrast sensitivity and spatial resolving power in ants. J Exp Biol 2019; 222:jeb.203018. [DOI: 10.1242/jeb.203018] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2019] [Accepted: 05/17/2019] [Indexed: 12/30/2022]
Abstract
Vision is crucial for animals to find prey, locate conspecifics, and to navigate within cluttered landscapes. Animals need to discriminate objects against a visually noisy background. However, the ability to detect spatial information is limited by eye size. In insects, as individuals become smaller, the space available for the eyes reduces, which affects the number of ommatidia, the size of the lens and the downstream information processing capabilities. The evolution of small body size in a lineage, known as miniaturisation, is common in insects. Here, using pattern electroretinography with vertical sinusoidal gratings as stimuli, we studied how miniaturisation affects spatial resolving power and contrast sensitivity in four diurnal ants that live in a similar environment but varied in their body and eye size. We found that ants with fewer and smaller ommatidial facets had lower spatial resolving power and contrast sensitivity. The spatial resolving power was maximum in the largest ant Myrmecia tarsata at 0.60 cycles per degree (cpd) compared to the ant with smallest eyes Rhytidoponera inornata that had 0.48 cpd. Maximum contrast sensitivity (minimum contrast threshold) in M. tarsata (2627 facets) was 15.51 (6.4% contrast detection threshold) at 0.1 cpd, while the smallest ant R. inornata (227 facets) had a maximum contrast sensitivity of 1.34 (74.1% contrast detection threshold) at 0.05 cpd. This is the first study to physiologically investigate contrast sensitivity in the context of insect allometry. Miniaturisation thus dramatically decreases maximum contrast sensitivity and also reduces spatial resolution, which could have implications for visually guided behaviours.
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Affiliation(s)
| | - Yuri Ogawa
- Department of Biological Sciences, Macquarie University, Sydney, NSW 2109, Australia
| | - Laura A. Ryan
- Department of Biological Sciences, Macquarie University, Sydney, NSW 2109, Australia
| | - Nathan S. Hart
- Department of Biological Sciences, Macquarie University, Sydney, NSW 2109, Australia
| | - Ajay Narendra
- Department of Biological Sciences, Macquarie University, Sydney, NSW 2109, Australia
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