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Gao B, Hu G, Chapman JW. Effects of nocturnal celestial illumination on high-flying migrant insects. Philos Trans R Soc Lond B Biol Sci 2024; 379:20230115. [PMID: 38705175 PMCID: PMC11070249 DOI: 10.1098/rstb.2023.0115] [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: 11/19/2023] [Accepted: 02/27/2024] [Indexed: 05/07/2024] Open
Abstract
Radar networks hold great promise for monitoring population trends of migrating insects. However, it is important to elucidate the nature of responses to environmental cues. We use data from a mini-network of vertical-looking entomological radars in the southern UK to investigate changes in nightly abundance, flight altitude and behaviour of insect migrants, in relation to meteorological and celestial conditions. Abundance of migrants showed positive relationships with air temperature, indicating that this is the single most important variable influencing the decision to initiate migration. In addition, there was a small but significant effect of moonlight illumination, with more insects migrating on full moon nights. While the effect of nocturnal illumination levels on abundance was relatively minor, there was a stronger effect on the insects' ability to orientate close to downwind: flight headings were more tightly clustered on nights when the moon was bright and when cloud cover was sparse. This indicates that nocturnal illumination is important for the navigational mechanisms used by nocturnal insect migrants. Further, our results clearly show that environmental conditions such as air temperature and light levels must be considered if long-term radar datasets are to be used to assess changing population trends of migrants. This article is part of the theme issue 'Towards a toolkit for global insect biodiversity monitoring'.
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Affiliation(s)
- Boya Gao
- Department of Entomology, Nanjing Agricultural University, Nanjing 210095, People's Republic of China
- Centre of Ecology and Conservation, University of Exeter, Penryn, Cornwall TR10 9FE, UK
| | - Gao Hu
- Department of Entomology, Nanjing Agricultural University, Nanjing 210095, People's Republic of China
- Centre of Ecology and Conservation, University of Exeter, Penryn, Cornwall TR10 9FE, UK
| | - Jason W. Chapman
- Department of Entomology, Nanjing Agricultural University, Nanjing 210095, People's Republic of China
- Centre of Ecology and Conservation, University of Exeter, Penryn, Cornwall TR10 9FE, UK
- Environment and Sustainability Institute, University of Exeter, Penryn, Cornwall TR10 9FE, UK
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2
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Kim G, In JH, Lee Y, Rhee H, Park W, Song H, Park J, Jeon JB, Brown TD, Talin AA, Kumar S, Kim KM. Mott neurons with dual thermal dynamics for spatiotemporal computing. NATURE MATERIALS 2024:10.1038/s41563-024-01913-0. [PMID: 38890486 DOI: 10.1038/s41563-024-01913-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/03/2023] [Accepted: 05/05/2024] [Indexed: 06/20/2024]
Abstract
Heat dissipation is a natural consequence of operating any electronic system. In nearly all computing systems, such heat is usually minimized by design and cooling. Here, we show that the temporal dynamics of internally produced heat in electronic devices can be engineered to both encode information within a single device and process information across multiple devices. In our demonstration, electronic NbOx Mott neurons, integrated on a flexible organic substrate, exhibit 18 biomimetic neuronal behaviours and frequency-based nociception within a single component by exploiting both the thermal dynamics of the Mott transition and the dynamical thermal interactions with the organic substrate. Further, multiple interconnected Mott neurons spatiotemporally communicate purely via heat, which we use for graph optimization by consuming over 106 times less energy when compared with the best digital processors. Thus, exploiting natural thermal processes in computing can lead to functionally dense, energy-efficient and radically novel mixed-physics computing primitives.
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Affiliation(s)
- Gwangmin Kim
- Department of Materials Science and Engineering, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, Republic of Korea
| | - Jae Hyun In
- Department of Materials Science and Engineering, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, Republic of Korea
| | - Younghyun Lee
- Department of Materials Science and Engineering, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, Republic of Korea
| | - Hakseung Rhee
- Department of Materials Science and Engineering, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, Republic of Korea
| | - Woojoon Park
- Department of Materials Science and Engineering, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, Republic of Korea
| | - Hanchan Song
- Department of Materials Science and Engineering, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, Republic of Korea
| | - Juseong Park
- Department of Materials Science and Engineering, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, Republic of Korea
| | - Jae Bum Jeon
- Department of Materials Science and Engineering, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, Republic of Korea
| | | | - A Alec Talin
- Sandia National Laboratories, Livermore, CA, USA
| | - Suhas Kumar
- Sandia National Laboratories, Livermore, CA, USA.
| | - Kyung Min Kim
- Department of Materials Science and Engineering, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, Republic of Korea.
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3
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Seymoure B, Dell A, Hölker F, Kalinkat G. A framework for untangling the consequences of artificial light at night on species interactions. Philos Trans R Soc Lond B Biol Sci 2023; 378:20220356. [PMID: 37899016 PMCID: PMC10613547 DOI: 10.1098/rstb.2022.0356] [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: 07/26/2023] [Accepted: 09/08/2023] [Indexed: 10/31/2023] Open
Abstract
Although much evidence exists showing organismal consequences from artificial light at night (ALAN), large knowledge gaps remain regarding ALAN affecting species interactions. Species interactions occur via shared spatio-temporal niches among species, which may be determined by natural light levels. We review how ALAN is altering these spatio-temporal niches through expanding twilight or full Moon conditions and constricting nocturnal conditions as well as creating patches of bright and dark. We review literature from a database to determine if ALAN is affecting species interactions via spatio-temporal dynamics. The literature indicates a growing interest in ALAN and species interactions: 58% of the studies we analysed have been published since 2020. Seventy-five of 79 studies found ALAN altered species interactions. Enhancements and reductions of species interactions were equally documented. Many studies revealed ALAN affecting species interactions spatially, but few revealed temporal alterations. There are biases regarding species interactions and ALAN-most studies investigated predator-prey interactions with vertebrates as predators and invertebrates as prey. Following this literature review, we suggest avenues, such as remote sensing and animal tracking, that can guide future research on the consequences of ALAN on species interactions across spatial and temporal axes. This article is part of the theme issue 'Light pollution in complex ecological systems'.
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Affiliation(s)
- Brett Seymoure
- Department of Biological Sciences, University of Texas at El Paso, El Paso, TX 79968, USA
| | - Anthony Dell
- National Great Rivers Research and Education Center, Alton, IL 62024, USA
- Department of Biology, WashingtonUniversity in St Louis, St Louis, MO 63130, USA
| | - Franz Hölker
- Leibniz Institute of Freshwater Ecology and Inland Fisheries (IGB), 14195 Berlin, Germany
- Institute of Biology, Freie Universität Berlin, 12587 Berlin, Germany
| | - Gregor Kalinkat
- Leibniz Institute of Freshwater Ecology and Inland Fisheries (IGB), 14195 Berlin, Germany
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4
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Hartbauer M. A Simple Denoising Algorithm for Real-World Noisy Camera Images. J Imaging 2023; 9:185. [PMID: 37754949 PMCID: PMC10532776 DOI: 10.3390/jimaging9090185] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2023] [Revised: 09/12/2023] [Accepted: 09/15/2023] [Indexed: 09/28/2023] Open
Abstract
The noise statistics of real-world camera images are challenging for any denoising algorithm. Here, I describe a modified version of a bionic algorithm that improves the quality of real-word noisy camera images from a publicly available image dataset. In the first step, an adaptive local averaging filter was executed for each pixel to remove moderate sensor noise while preserving fine image details and object contours. In the second step, image sharpness was enhanced by means of an unsharp mask filter to generate output images that are close to ground-truth images (multiple averages of static camera images). The performance of this denoising algorithm was compared with five popular denoising methods: bm3d, wavelet, non-local means (NL-means), total variation (TV) denoising and bilateral filter. Results show that the two-step filter had a performance that was similar to NL-means and TV filtering. Bm3d had the best denoising performance but sometimes led to blurry images. This novel two-step filter only depends on a single parameter that can be obtained from global image statistics. To reduce computation time, denoising was restricted to the Y channel of YUV-transformed images and four image segments were simultaneously processed in parallel on a multi-core processor.
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Vijayan S, Balamurali GS, Johnson J, Kelber A, Warrant EJ, Somanathan H. Dim-light colour vision in the facultatively nocturnal Asian giant honeybee, Apis dorsata. Proc Biol Sci 2023; 290:20231267. [PMID: 37554033 PMCID: PMC10410228 DOI: 10.1098/rspb.2023.1267] [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: 06/07/2023] [Accepted: 07/21/2023] [Indexed: 08/10/2023] Open
Abstract
We discovered nocturnal colour vision in the Asian giant honeybee Apis dorsata-a facultatively nocturnal species-at mesopic light intensities, down to half-moon light levels (approx. 10-2 cd m-2). The visual threshold of nocturnality aligns with their reported nocturnal activity down to the same light levels. Nocturnal colour vision in A. dorsata is interesting because, despite being primarily diurnal, its colour vision capabilities extend into dim light, while the 'model' European honeybee Apis mellifera is reported to be colour-blind at twilight. By employing behavioural experiments with naturally nesting A. dorsata colonies, we show discrimination of the trained colour from other stimuli during the day, and significantly, even at night. Nocturnal colour vision in bees has so far only been reported in the obligately nocturnal carpenter bee Xylocopa tranquebarica. The discovery of colour vision in these two bee species, despite differences in the extent of their nocturnality and the limitations of their apposition compound eye optics, opens avenues for future studies on visual adaptations for dim-light colour vision, their role in pollination of flowers at night, and the effect of light pollution on nocturnal activity in A. dorsata, a ubiquitous pollinator in natural, agricultural and urban habitats in the Asian tropics and sub-tropics.
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Affiliation(s)
- Sajesh Vijayan
- School of Biology, IISER-TVM Centre for Research and Education in Ecology and Evolution (ICREEE), Indian Institute of Science Education and Research Thiruvananthapuram, Thiruvananthapuram, Kerala, India
| | - G. S. Balamurali
- School of Biology, IISER-TVM Centre for Research and Education in Ecology and Evolution (ICREEE), Indian Institute of Science Education and Research Thiruvananthapuram, Thiruvananthapuram, Kerala, India
- Lund Vision Group, Department of Biology, University of Lund, Sölvegatan 35, Lund 22362, Sweden
| | - Jewel Johnson
- School of Biology, IISER-TVM Centre for Research and Education in Ecology and Evolution (ICREEE), Indian Institute of Science Education and Research Thiruvananthapuram, Thiruvananthapuram, Kerala, India
| | - Almut Kelber
- Lund Vision Group, Department of Biology, University of Lund, Sölvegatan 35, Lund 22362, Sweden
| | - Eric J. Warrant
- Lund Vision Group, Department of Biology, University of Lund, Sölvegatan 35, Lund 22362, Sweden
| | - Hema Somanathan
- School of Biology, IISER-TVM Centre for Research and Education in Ecology and Evolution (ICREEE), Indian Institute of Science Education and Research Thiruvananthapuram, Thiruvananthapuram, Kerala, India
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6
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Hebberecht L, Wainwright JB, Thompson C, Kershenbaum S, McMillan WO, Montgomery SH. Plasticity and genetic effects contribute to different axes of neural divergence in a community of mimetic Heliconius butterflies. J Evol Biol 2023; 36:1116-1132. [PMID: 37341138 DOI: 10.1111/jeb.14188] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2022] [Revised: 03/12/2023] [Accepted: 04/16/2023] [Indexed: 06/22/2023]
Abstract
Changes in ecological preference, often driven by spatial and temporal variation in resource distribution, can expose populations to environments with divergent information content. This can lead to adaptive changes in the degree to which individuals invest in sensory systems and downstream processes, to optimize behavioural performance in different contexts. At the same time, environmental conditions can produce plastic responses in nervous system development and maturation, providing an alternative route to integrating neural and ecological variation. Here, we explore how these two processes play out across a community of Heliconius butterflies. Heliconius communities exhibit multiple Mullerian mimicry rings, associated with habitat partitioning across environmental gradients. These environmental differences have previously been linked to heritable divergence in brain morphology in parapatric species pairs. They also exhibit a unique dietary adaptation, known as pollen feeding, that relies heavily on learning foraging routes, or trap-lines, between resources, which implies an important environmental influence on behavioural development. By comparing brain morphology across 133 wild-caught and insectary-reared individuals from seven Heliconius species, we find strong evidence for interspecific variation in patterns of neural investment. These largely fall into two distinct patterns of variation; first, we find consistent patterns of divergence in the size of visual brain components across both wild and insectary-reared individuals, suggesting genetically encoded divergence in the visual pathway. Second, we find interspecific differences in mushroom body size, a central component of learning and memory systems, but only among wild caught individuals. The lack of this effect in common-garden individuals suggests an extensive role for developmental plasticity in interspecific variation in the wild. Finally, we illustrate the impact of relatively small-scale spatial effects on mushroom body plasticity by performing experiments altering the cage size and structure experienced by individual H. hecale. Our data provide a comprehensive survey of community level variation in brain structure, and demonstrate that genetic effects and developmental plasticity contribute to different axes of interspecific neural variation.
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Affiliation(s)
- Laura Hebberecht
- School of Biological Sciences, University of Bristol, Bristol, UK
- Department of Zoology, University of Cambridge, Cambridge, UK
- Smithsonian Tropical Research Institute, Gamboa, Panama
| | | | | | | | | | - Stephen H Montgomery
- School of Biological Sciences, University of Bristol, Bristol, UK
- Smithsonian Tropical Research Institute, Gamboa, Panama
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7
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Garm A, Hamilton O, Glenner H, Irwin AR, Mah C. Eyes, Vision, and Bioluminescence in Deep-Sea Brisingid Sea Stars. THE BIOLOGICAL BULLETIN 2023; 245:33-44. [PMID: 38820289 DOI: 10.1086/729983] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2024]
Abstract
AbstractSea stars are a major component of the megabenthos in most marine habitats, including those within the deep sea. Being radially symmetric, sea stars have sensory structures that are evenly distributed along the arms, with a compound eye located on each arm tip of most examined species. Surprisingly, eyes with a spatial resolution that rivals the highest acuity known among sea stars so far were recently found in Novodinia americana, a member of the deep-sea sea star order Brisingida. Here, we examined 21 species across 11 brisingid genera for the presence of eyes; where eyes were present, we used morphological characteristics to evaluate spatial resolution and sensitivity. This study found that eyes were present within 43% of the examined species. These brisingid eyes were relatively large compared to those of other deep-sea sea stars, with a high number of densely packed ommatidia. One of the examined species, Brisingaster robillardi, had more than 600 ommatidia per eye, which is the highest number of ommatidia found in any sea star eye so far. Combined, the results indicate that brisingid eyes are adapted for spatial resolution over sensitivity. Together with results showing that many brisingids are bioluminescent, this relatively high spatial resolution suggests that the group may use their eyes to support visually guided intraspecific communication based on bioluminescent signals. Phylogenetic analysis indicated that the common ancestor of brisingids had eyes (P = 0.72) and that eyes were lost once within the clade.
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8
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Ketkar MD, Shao S, Gjorgjieva J, Silies M. Multifaceted luminance gain control beyond photoreceptors in Drosophila. Curr Biol 2023:S0960-9822(23)00619-X. [PMID: 37285845 DOI: 10.1016/j.cub.2023.05.024] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2023] [Revised: 05/10/2023] [Accepted: 05/11/2023] [Indexed: 06/09/2023]
Abstract
Animals navigating in natural environments must handle vast changes in their sensory input. Visual systems, for example, handle changes in luminance at many timescales, from slow changes across the day to rapid changes during active behavior. To maintain luminance-invariant perception, visual systems must adapt their sensitivity to changing luminance at different timescales. We demonstrate that luminance gain control in photoreceptors alone is insufficient to explain luminance invariance at both fast and slow timescales and reveal the algorithms that adjust gain past photoreceptors in the fly eye. We combined imaging and behavioral experiments with computational modeling to show that downstream of photoreceptors, circuitry taking input from the single luminance-sensitive neuron type L3 implements gain control at fast and slow timescales. This computation is bidirectional in that it prevents the underestimation of contrasts in low luminance and overestimation in high luminance. An algorithmic model disentangles these multifaceted contributions and shows that the bidirectional gain control occurs at both timescales. The model implements a nonlinear interaction of luminance and contrast to achieve gain correction at fast timescales and a dark-sensitive channel to improve the detection of dim stimuli at slow timescales. Together, our work demonstrates how a single neuronal channel performs diverse computations to implement gain control at multiple timescales that are together important for navigation in natural environments.
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Affiliation(s)
- Madhura D Ketkar
- Institute of Developmental and Neurobiology, Johannes-Gutenberg University Mainz, Hanns-Dieter-Hüsch-Weg 15, 55128 Mainz, Germany
| | - Shuai Shao
- Max Planck Institute for Brain Research, Max-von-Laue-Straße 4, 60438 Frankfurt am Main, Germany; Department of Neurophysiology, Radboud University, Heyendaalseweg 135, 6525 EN Nijmegen, the Netherlands
| | - Julijana Gjorgjieva
- Max Planck Institute for Brain Research, Max-von-Laue-Straße 4, 60438 Frankfurt am Main, Germany; School of Life Sciences, Technical University Munich, Maximus-von-Imhof-Forum 3, 85354 Freising, Germany.
| | - Marion Silies
- Institute of Developmental and Neurobiology, Johannes-Gutenberg University Mainz, Hanns-Dieter-Hüsch-Weg 15, 55128 Mainz, Germany.
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Ogawa Y, Jones L, Ryan LA, Robson SKA, Hart NS, Narendra A. Physiological properties of the visual system in the Green Weaver ant, Oecophylla smaragdina. J Comp Physiol A Neuroethol Sens Neural Behav Physiol 2023:10.1007/s00359-023-01629-7. [PMID: 37055584 DOI: 10.1007/s00359-023-01629-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2022] [Revised: 03/14/2023] [Accepted: 03/29/2023] [Indexed: 04/15/2023]
Abstract
The Green Weaver ants, Oecophylla smaragdina are iconic animals known for their extreme cooperative behaviour where they bridge gaps by linking to each other to build living chains. They are visually oriented animals, build chains towards closer targets, use celestial compass cues for navigation and are visual predators. Here, we describe their visual sensory capacity. The major workers of O. smaragdina have more ommatidia (804) in each eye compared to minor workers (508), but the facet diameters are comparable between both castes. We measured the impulse responses of the compound eye and found their response duration (42 ms) was similar to that seen in other slow-moving ants. We determined the flicker fusion frequency of the compound eye at the brightest light intensity to be 132 Hz, which is relatively fast for a walking insect suggesting the visual system is well suited for a diurnal lifestyle. Using pattern-electroretinography we identified the compound eye has a spatial resolving power of 0.5 cycles deg-1 and reached peak contrast sensitivity of 2.9 (35% Michelson contrast threshold) at 0.05 cycles deg-1. We discuss the relationship of spatial resolution and contrast sensitivity, with number of ommatidia and size of the lens.
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Affiliation(s)
- Yuri Ogawa
- School of Natural Sciences, Macquarie University, Sydney, NSW, 2109, Australia
- Flinders Health and Medical Research Institute, Flinders University, Adelaide, SA, 5001, Australia
| | - Lochlan Jones
- College of Marine and Environmental Sciences, James Cook University, Townsville, QLD, 4814, Australia
| | - Laura A Ryan
- School of Natural Sciences, Macquarie University, Sydney, NSW, 2109, Australia
| | - Simon K A Robson
- College of Science and Sustainability, CQ University Australia, Townsville, QLD, 4812, Australia
| | - Nathan S Hart
- School of Natural Sciences, Macquarie University, Sydney, NSW, 2109, Australia
| | - Ajay Narendra
- School of Natural Sciences, Macquarie University, Sydney, NSW, 2109, Australia.
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10
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Lall AB, Viviani VR, Ventura DF. Spectral tuning of bioluminescence and visual sensitivity in males of Brazilian firefly species inhabiting dim light environments (Coleoptera: Elateroidea: Lampyridae). JOURNAL OF EXPERIMENTAL ZOOLOGY. PART A, ECOLOGICAL AND INTEGRATIVE PHYSIOLOGY 2023; 339:37-45. [PMID: 35971806 DOI: 10.1002/jez.2647] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/16/2021] [Revised: 06/12/2022] [Accepted: 06/21/2022] [Indexed: 01/02/2023]
Abstract
Bioluminescence in fireflies is essential for sexual communication, and each species has evolved a specific bioluminescence emission capable of being detected by its visual system. This spectral "tuning" between visual sensitivity and bioluminescent emission has been established in 14 species of North American fireflies inhabiting diverse photoecological niches. Here we extend that research to three Brazilian species. Macrolampis omissa inhabits the Cerrado (savannas), while Photinus sp1 and Pyrogaster moestus are often sympatric species inhabiting borders of mesophyll rain forests and secondary growth. P. moestus particularly favors humid areas of the forest. M. omissa and Photinus sp1 are twilight-active fireflies emitting yellow bioluminescence. P. moestus is a "twi-night" species emitting green bioluminescence. It initiates flashing at the end of twilight and continues activity into the night. The visual spectral sensitivity of dark-adapted compound eyes in these three species is similar, showing a maximum in the yellow-green wavelengths and a secondary peak in the near-UV, suggesting the presence of two receptors. The bioluminescence emission spectrum in each species is tuned to its yellow-green visual sensitivity peak. Green chromatic adaptation experiments on Photinus sp1 and P. moestus suggest the presence of a blue receptor. The presence of near-UV, blue, and long-wavelength receptors in the compound eyes would enable a trichromatic color vision in Brazilian firefly species active in dim illumination.
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Affiliation(s)
- Abner B Lall
- Department of Biology, Howard University, Washington, District of Columbia, USA
| | - Vadim R Viviani
- Departamento de Physics, Chemistry and Mathematics, CCTS, Campus of Sorocaba, Universidade Federal de São Carlos, Sorocaba, SP CEP, Brazil
| | - Dora Fix Ventura
- Departamento de Psicologia Experimental, Instituto de Psicologia, Universidade de São Paulo, DFV, São Paulo, SP CEP, Brazil
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11
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Abstract
The ability to see colour at night is known only from a handful of animals. First discovered in the elephant hawk moth Deilephila elpenor, nocturnal colour vision is now known from two other species of hawk moths, a single species of carpenter bee, a nocturnal gecko and two species of anurans. The reason for this rarity—particularly in vertebrates—is the immense challenge of achieving a sufficient visual signal-to-noise ratio to support colour discrimination in dim light. Although no less challenging for nocturnal insects, unique optical and neural adaptations permit reliable colour vision and colour constancy even in starlight. Using the well-studied Deilephila elpenor, we describe the visual light environment at night, the visual challenges that this environment imposes and the adaptations that have evolved to overcome them. We also explain the advantages of colour vision for nocturnal insects and its usefulness in discriminating night-opening flowers. Colour vision is probably widespread in nocturnal insects, particularly pollinators, where it is likely crucial for nocturnal pollination. This relatively poorly understood but vital ecosystem service is threatened from increasingly abundant and spectrally abnormal sources of anthropogenic light pollution, which can disrupt colour vision and thus the discrimination and pollination of flowers. 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)
- Eric Warrant
- Department of Biology, University of Lund, Sölvegatan 35, 22362 Lund, Sweden
| | - Hema Somanathan
- School of Biology, Indian Institute of Science Education and Research, Maruthamala PO, Vithura, Thiruvananthapuram, Kerala 695551, India
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12
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Bagheri ZM, Jessop AL, Partridge JC, Osborn KJ, Hemmi JM. A new computational model illuminates the extraordinary eyes of Phronima. PLoS Comput Biol 2022; 18:e1010545. [PMID: 36251706 PMCID: PMC9576097 DOI: 10.1371/journal.pcbi.1010545] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2022] [Accepted: 09/05/2022] [Indexed: 11/07/2022] Open
Abstract
Vision in the midwater of the open ocean requires animals to perform visual tasks quite unlike those of any other environment. These tasks consist of detecting small, low contrast objects and point sources against a relatively dim and uniform background. Deep-sea animals have evolved many extraordinary visual adaptations to perform these tasks. Linking eye anatomy to specific selective pressures, however, is challenging, not least because of the many difficulties of studying deep-sea animals. Computational modelling of vision, based on detailed morphological reconstructions of animal eyes, along with underwater optics, offers a chance to understand the specific visual capabilities of individual visual systems. Prior to the work presented here, comprehensive models for apposition compound eyes in the mesopelagic, the dominant eye form of crustaceans, were lacking. We adapted a model developed for single-lens eyes and used it to examine how different parameters affect the model’s ability to detect point sources and extended objects. This new model also allowed us to examine spatial summation as a means to improve visual performance. Our results identify a trade-off between increased depth range over which eyes function effectively and increased distance at which extended objects can be detected. This trade-off is driven by the size of the ommatidial acceptance angle. We also show that if neighbouring ommatidia have overlapping receptive fields, spatial summation helps with all detection tasks, including the detection of bioluminescent point sources. By applying our model to the apposition compound eyes of Phronima, a mesopelagic hyperiid amphipod, we show that the specialisations of the large medial eyes of Phronima improve both the detection of point sources and of extended objects. The medial eyes outperformed the lateral eyes at every modelled detection task. We suggest that the small visual field size of Phronima’s medial eyes and the strong asymmetry between the medial and lateral eyes reflect Phronima’s need for effective vision across a large depth range and its habit of living inside a barrel. The barrel’s narrow aperture limits the usefulness of a large visual field and has allowed a strong asymmetry between the medial and lateral eyes. The model provides a useful tool for future investigations into the visual abilities of apposition compound eyes in the deep sea. How do animals see the world? This is particularly an interesting question when the animal’s eyes look very different from our own, or if they inhabit an environment that is visually very different from ours. Biologists approach this question by seeking to determine not only how animal eyes function but also what selective pressures led to the evolution of their eyes. Understanding the eyes of deep-sea animals is particularly intriguing and more challenging than usual because their visual world is so dramatically different from our own and they are inaccessible and therefore hard to study. Understanding their visual capabilities by behavioural or physiological experiments is at best extremely challenging and often impossible. However, modelling of their visual abilities, by combining knowledge about ocular anatomy with information about the way light propagates in the deep sea, is comparatively tractable. Here we present a computational model that predicts the ability of apposition compound eyes (eyes that are widely found in many arthropod invertebrates) to detect salient visual targets in the deep sea between 200 and 700 m below the surface. We use this model specifically to examine the extraordinary ‘double eyes’ of the midwater hyperiid amphipod Phronima that have perplexed scientists for decades. This allowed us to put forward a new hypothesis about the selective pressures that have led to Phronima’s unusual eyes. The predictive model we present here also provides a framework for future assessments of visual performance of apposition compound eyes in other deep-sea animals.
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Affiliation(s)
- Zahra M. Bagheri
- School of Biological Sciences, The University of Western Australia, Crawley, Western Australia, Australia
- UWA Oceans Institute, The University of Western Australia, Crawley, Western Australia, Australia
- * E-mail: (ZMB); (A-LJ)
| | - Anna-Lee Jessop
- School of Biological Sciences, The University of Western Australia, Crawley, Western Australia, Australia
- UWA Oceans Institute, The University of Western Australia, Crawley, Western Australia, Australia
- * E-mail: (ZMB); (A-LJ)
| | - Julian C. Partridge
- UWA Oceans Institute, The University of Western Australia, Crawley, Western Australia, Australia
| | - Karen J. Osborn
- Department of Invertebrate Zoology, Smithsonian National Museum of Natural History, Washington, DC, United States of America
- Monterey Bay Aquarium Research Institute, Moss Landing, California, United States of America
| | - Jan M. Hemmi
- School of Biological Sciences, The University of Western Australia, Crawley, Western Australia, Australia
- UWA Oceans Institute, The University of Western Australia, Crawley, Western Australia, Australia
- Department of Invertebrate Zoology, Smithsonian National Museum of Natural History, Washington, DC, United States of America
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13
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Stöckl AL, Foster JJ. Night skies through animals' eyes-Quantifying night-time visual scenes and light pollution as viewed by animals. Front Cell Neurosci 2022; 16:984282. [PMID: 36274987 PMCID: PMC9582234 DOI: 10.3389/fncel.2022.984282] [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] [Received: 07/01/2022] [Accepted: 09/09/2022] [Indexed: 11/13/2022] Open
Abstract
A large proportion of animal species enjoy the benefits of being active at night, and have evolved the corresponding optical and neural adaptations to cope with the challenges of low light intensities. However, over the past century electric lighting has introduced direct and indirect light pollution into the full range of terrestrial habitats, changing nocturnal animals' visual worlds dramatically. To understand how these changes affect nocturnal behavior, we here propose an animal-centered analysis method based on environmental imaging. This approach incorporates the sensitivity and acuity limits of individual species, arriving at predictions of photon catch relative to noise thresholds, contrast distributions, and the orientation cues nocturnal species can extract from visual scenes. This analysis relies on just a limited number of visual system parameters known for each species. By accounting for light-adaptation in our analysis, we are able to make more realistic predictions of the information animals can extract from nocturnal visual scenes under different levels of light pollution. With this analysis method, we aim to provide context for the interpretation of behavioral findings, and to allow researchers to generate specific hypotheses for the behavior of nocturnal animals in observed light-polluted scenes.
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Affiliation(s)
- Anna Lisa Stöckl
- Department of Biology, University of Konstanz, Konstanz, Germany
- Centre for the Advanced Study of Collective Behaviour, University of Konstanz, Konstanz, Germany
- Zukunftskolleg, Universität Konstanz, Konstanz, Germany
| | - James Jonathan Foster
- Department of Biology, University of Konstanz, Konstanz, Germany
- Centre for the Advanced Study of Collective Behaviour, University of Konstanz, Konstanz, Germany
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14
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Menz MHM, Scacco M, Bürki-Spycher HM, Williams HJ, Reynolds DR, Chapman JW, Wikelski M. Individual tracking reveals long-distance flight-path control in a nocturnally migrating moth. Science 2022; 377:764-768. [PMID: 35951704 DOI: 10.1126/science.abn1663] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
Each year, trillions of insects make long-range seasonal migrations. These movements are relatively well understood at a population level, but how individual insects achieve them remains elusive. Behavioral responses to conditions en route are little studied, primarily owing to the challenges of tracking individual insects. Using a light aircraft and individual radio tracking, we show that nocturnally migrating death's-head hawkmoths maintain control of their flight trajectories over long distances. The moths did not just fly with favorable tailwinds; during a given night, they also adjusted for head and crosswinds to precisely hold course. This behavior indicates that the moths use a sophisticated internal compass to maintain seasonally beneficial migratory trajectories independent of wind conditions, illuminating how insects traverse long distances to take advantage of seasonal resources.
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Affiliation(s)
- Myles H M Menz
- Department of Migration, Max Planck Institute of Animal Behavior, 78315 Radolfzell, Germany.,College of Science and Engineering, James Cook University, Townsville, QLD 4811, Australia.,Department of Biology, University of Konstanz, 78464 Konstanz, Germany
| | - Martina Scacco
- Department of Migration, Max Planck Institute of Animal Behavior, 78315 Radolfzell, Germany.,Department of Biology, University of Konstanz, 78464 Konstanz, Germany
| | | | - Hannah J Williams
- Department of Migration, Max Planck Institute of Animal Behavior, 78315 Radolfzell, Germany.,Department of Biology, University of Konstanz, 78464 Konstanz, Germany
| | - Don R Reynolds
- Natural Resources Institute, University of Greenwich, Chatham, Kent ME4 4TB, UK.,Rothamsted Research, Harpenden, Hertfordshire AL5 2JQ, UK
| | - Jason W Chapman
- Centre for Ecology and Conservation, University of Exeter, Penryn, Cornwall TR10 9FE, UK.,Environment and Sustainability Institute, University of Exeter, Penryn, Cornwall TR10 9FE, UK.,Department of Entomology, College of Plant Protection, Nanjing Agricultural University, Nanjing 210095, China
| | - Martin Wikelski
- Department of Migration, Max Planck Institute of Animal Behavior, 78315 Radolfzell, Germany.,Department of Biology, University of Konstanz, 78464 Konstanz, Germany.,Centre for the Advanced Study of Collective Behaviour, University of Konstanz, 78464 Konstanz, Germany
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15
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Brodrick EA, How MJ, Hemmi JM. Fiddler crab electroretinograms reveal vast circadian shifts in visual sensitivity and temporal summation in dim light. J Exp Biol 2022; 225:274663. [PMID: 35156128 PMCID: PMC8976941 DOI: 10.1242/jeb.243693] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2021] [Accepted: 02/04/2022] [Indexed: 11/20/2022]
Abstract
Many animals with compound eyes undergo major optical changes to adjust visual sensitivity from day to night, often under control of a circadian clock. In fiddler crabs, this presents most conspicuously in the huge volume increase of photopigment-packed rhabdoms and the widening of crystalline cone apertures at night. These changes are hypothesised to adjust the light flux to the photoreceptors and to alter optical sensitivity as the eye moves between light- and dark-adapted states. Here, we compare optical sensitivity in fiddler crab eyes (Gelasimus dampieri) during daytime and night via three electroretinogram (ERG) experiments performed on light- and dark-adapted crabs.
1) Light intensity required to elicit a threshold ERG response varied over six orders of magnitude, allowing more sensitive vision for discriminating small contrasts in dim light after dusk. During daytime, the eyes remained relatively insensitive, which would allow effective vision on bright mudflats, even after prolonged dark adaptation.
2) Flicker fusion frequency (FFF) experiments indicated that temporal summation is employed in dim light to increase light-gathering integration times and enhance visual sensitivity during both night and day.
3) ERG responses to flickering lights during 60 mins of dark adaptation increased at a faster rate and greater extent after sunset compared to daytime. However, even brief, dim and intermittent light exposure strongly disrupted dark-adaptation processes.
Together, these findings demonstrate effective light adaptation to optimise vision over the large range of light intensities that these animals experience.
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Affiliation(s)
| | - Martin J. How
- School of Biological Sciences, University of Bristol, Bristol, BS8 1TQ, UK
| | - Jan M. Hemmi
- School of Biological Sciences & UWA Oceans Institute, University of Western Australia, Perth, WA 6009, Australia
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16
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Henning M, Ramos-Traslosheros G, Gür B, Silies M. Populations of local direction-selective cells encode global motion patterns generated by self-motion. SCIENCE ADVANCES 2022; 8:eabi7112. [PMID: 35044821 PMCID: PMC8769539 DOI: 10.1126/sciadv.abi7112] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/10/2023]
Abstract
Self-motion generates visual patterns on the eye that are important for navigation. These optic flow patterns are encoded by the population of local direction–selective cells in the mouse retina, whereas in flies, local direction–selective T4/T5 cells are thought to be uniformly tuned. How complex global motion patterns can be computed downstream is unclear. We show that the population of T4/T5 cells in Drosophila encodes global motion patterns. Whereas the mouse retina encodes four types of optic flow, the fly visual system encodes six. This matches the larger number of degrees of freedom and the increased complexity of translational and rotational motion patterns during flight. The four uniformly tuned T4/T5 subtypes described previously represent a local subset of the population. Thus, a population code for global motion patterns appears to be a general coding principle of visual systems that matches local motion responses to modes of the animal’s movement.
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Affiliation(s)
- Miriam Henning
- Institute of Developmental Biology and Neurobiology, Johannes-Gutenberg University Mainz, Mainz 55128, Germany
- Göttingen Graduate School for Neurosciences, Biophysics, and Molecular Biosciences (GGNB) and International Max Planck Research School (IMPRS) for Neurosciences at the University of Göttingen, Göttingen 37077, Germany
| | - Giordano Ramos-Traslosheros
- Institute of Developmental Biology and Neurobiology, Johannes-Gutenberg University Mainz, Mainz 55128, Germany
- Göttingen Graduate School for Neurosciences, Biophysics, and Molecular Biosciences (GGNB) and International Max Planck Research School (IMPRS) for Neurosciences at the University of Göttingen, Göttingen 37077, Germany
| | - Burak Gür
- Institute of Developmental Biology and Neurobiology, Johannes-Gutenberg University Mainz, Mainz 55128, Germany
- Göttingen Graduate School for Neurosciences, Biophysics, and Molecular Biosciences (GGNB) and International Max Planck Research School (IMPRS) for Neurosciences at the University of Göttingen, Göttingen 37077, Germany
| | - Marion Silies
- Institute of Developmental Biology and Neurobiology, Johannes-Gutenberg University Mainz, Mainz 55128, Germany
- Corresponding author.
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17
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Avilés JM, Cruz-Miralles Á, Parejo D. Moonlight influence on quality of nestlings of scops owls depends on paternal coloration. Behav Ecol 2021. [DOI: 10.1093/beheco/arab139] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Abstract
Lunar phases might favor the maintenance of color polymorphism via disruptive selection if the different color variants performed differently in terms of prey capture under different moonlight levels. Moonlight, however, may affect prey capture as a side effect of its influence on prey behavior. Here we combine data of parental provisioning and quality of owlets with one ex-situ study of grasshopper activity to test whether Eurasian scops owls (Otus scops) with different plumage color and their prey are differently affected by moonlight. Food provisioning increased from new- to full-moon. However, the effect of moonlight on owlet mass gain and immune response depended on paternal coloration. On the one hand, body mass gain of nestlings of the greyest fathers increased from nights with new- to full-moon, whereas it did not change with moonlight for the brownest fathers. On the other hand, PHA response of nestlings of the brownest fathers increased with high moonlight levels during the first week of life, whereas it did not change with moonlight levels for the greyest fathers. Grasshoppers were more active at new moon than at full or waning moon. Our study provides supporting evidence that moonlight influences the behavior of both scops owls and its prey and suggests that fluctuations in environmental conditions can modulate the advantages of morphs. These results are important because they provide a general insight into a little appreciated mechanism for the maintenance of color polymorphism in natural populations based on the interactive effect of different environmental factors.
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Affiliation(s)
- Jesús M Avilés
- Departamento de Ecología Funcional y Evolutiva, EEZA-CSIC, La Cañada de San Urbano, Almería E-04001, España
- Unidad Asociada (UNEX-CSIC): Ecología en el Antropoceno, Facultad de Ciencias, Universidad de Extremadura, Badajoz E-06006, España
| | - Ángel Cruz-Miralles
- Departamento de Anatomía, Biología Celular y Zoología, Facultad de Ciencias, Universidad de Extremadura, Badajoz E-04001, España
| | - Deseada Parejo
- Departamento de Ecología Funcional y Evolutiva, EEZA-CSIC, La Cañada de San Urbano, Almería E-04001, España
- Departamento de Anatomía, Biología Celular y Zoología, Facultad de Ciencias, Universidad de Extremadura, Badajoz E-04001, España
- Unidad Asociada (UNEX-CSIC): Ecología en el Antropoceno, Facultad de Ciencias, Universidad de Extremadura, Badajoz E-06006, España
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18
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Leibbrandt R, Nicholas S, Nordström K. The impulse response of optic flow-sensitive descending neurons to roll m-sequences. J Exp Biol 2021; 224:273641. [PMID: 34870706 PMCID: PMC8714074 DOI: 10.1242/jeb.242833] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2021] [Accepted: 11/05/2021] [Indexed: 11/23/2022]
Abstract
When animals move through the world, their own movements generate widefield optic flow across their eyes. In insects, such widefield motion is encoded by optic lobe neurons. These lobula plate tangential cells (LPTCs) synapse with optic flow-sensitive descending neurons, which in turn project to areas that control neck, wing and leg movements. As the descending neurons play a role in sensorimotor transformation, it is important to understand their spatio-temporal response properties. Recent work shows that a relatively fast and efficient way to quantify such response properties is to use m-sequences or other white noise techniques. Therefore, here we used m-sequences to quantify the impulse responses of optic flow-sensitive descending neurons in male Eristalis tenax hoverflies. We focused on roll impulse responses as hoverflies perform exquisite head roll stabilizing reflexes, and the descending neurons respond particularly well to roll. We found that the roll impulse responses were fast, peaking after 16.5–18.0 ms. This is similar to the impulse response time to peak (18.3 ms) to widefield horizontal motion recorded in hoverfly LPTCs. We found that the roll impulse response amplitude scaled with the size of the stimulus impulse, and that its shape could be affected by the addition of constant velocity roll or lift. For example, the roll impulse response became faster and stronger with the addition of excitatory stimuli, and vice versa. We also found that the roll impulse response had a long return to baseline, which was significantly and substantially reduced by the addition of either roll or lift. Summary: The impulse response of hoverfly optic flow-sensitive descending neurons to roll m-sequences reaches its time to peak within 20 ms and slowly returns to baseline over the next 100 ms.
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Affiliation(s)
- Richard Leibbrandt
- Neuroscience, Flinders Health and Medical Research Institute, Flinders University, GPO Box 2100, 5001 Adelaide, SA, Australia
| | - Sarah Nicholas
- Neuroscience, Flinders Health and Medical Research Institute, Flinders University, GPO Box 2100, 5001 Adelaide, SA, Australia
| | - Karin Nordström
- Neuroscience, Flinders Health and Medical Research Institute, Flinders University, GPO Box 2100, 5001 Adelaide, SA, Australia.,Department of Neuroscience, Uppsala University, Box 593, 751 24 Uppsala, Sweden
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19
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Deora T, Ahmed MA, Brunton BW, Daniel TL. Learning to feed in the dark: how light level influences feeding in the hawkmoth Manduca sexta. Biol Lett 2021; 17:20210320. [PMID: 34520685 PMCID: PMC8440038 DOI: 10.1098/rsbl.2021.0320] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
Nocturnal insects like moths are essential for pollination, providing resilience to the diurnal pollination networks. Moths use both vision and mechanosensation to locate the nectary opening in the flowers with their proboscis. However, increased light levels due to artificial light at night (ALAN) pose a serious threat to nocturnal insects. Here, we examined how light levels influence the efficacy by which the crepuscular hawkmoth Manduca sexta locates the nectary. We used three-dimensional-printed artificial flowers fitted with motion sensors in the nectary and machine vision to track the motion of hovering moths under two light levels: 0.1 lux (moonlight) and 50 lux (dawn/dusk). We found that moths in higher light conditions took significantly longer to find the nectary, even with repeated visits to the same flower. In addition to taking longer, moths in higher light conditions hovered further from the flower during feeding. Increased light levels adversely affect learning and motor control in these animals.
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Affiliation(s)
- Tanvi Deora
- Department of Biology, University of Washington, Seattle, Washington
| | - Mahad A Ahmed
- Department of Biology, University of Washington, Seattle, Washington
| | - Bingni W Brunton
- Department of Biology, University of Washington, Seattle, Washington
| | - Thomas L Daniel
- Department of Biology, University of Washington, Seattle, Washington
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20
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Abstract
Time is largely a hidden variable in vision. It is the condition for seeing interesting things such as spatial forms and patterns, colours and movements in the external world, and yet is not meant to be noticed in itself. Temporal aspects of visual processing have received comparatively little attention in research. Temporal properties have been made explicit mainly in measurements of resolution and integration in simple tasks such as detection of spatially homogeneous flicker or light pulses of varying duration. Only through a mechanistic understanding of their basis in retinal photoreceptors and circuits can such measures guide modelling of natural vision in different species and illuminate functional and evolutionary trade-offs. Temporal vision research would benefit from bridging traditions that speak different languages. Towards that goal, I here review studies from the fields of human psychophysics, retinal physiology and neuroethology, with a focus on fundamental constraints set by early vision. Summary: Simple measures of temporal vision such as the critical flicker frequency can be useful for modelling natural vision only if their relationship to photoreceptor responses and retinal processing is understood.
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Affiliation(s)
- Kristian Donner
- Molecular and Integrative Biosciences Research Programme, Faculty of Biological and Environmental Sciences, University of Helsinki, 00014 Helsinki, Finland
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21
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Hartbauer M. From Insect Vision to a Novel Bio-Inspired Algorithm for Image Denoising. Biomimetics (Basel) 2021. [DOI: 10.5772/intechopen.91911] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
Night active insects inspired the development of image enhancement methods that uncover the information contained in dim images or movies. Here, I describe a novel bionic night vision (NV) algorithm that operates in the spatial domain to remove noise from static images. The parameters of this NV algorithm can be automatically derived from global image statistics and a primitive type of noise estimate. In a first step, luminance values were ln-transformed, and then adaptive local means’ calculations were executed to remove the remaining noise without degrading fine image details and object contours. Its performance is comparable with several popular denoising methods and can be applied to grey-scale and color images. This novel algorithm can be executed in parallel at the level of pixels on programmable hardware.
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22
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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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23
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Dacke M, Baird E, El Jundi B, Warrant EJ, Byrne M. How Dung Beetles Steer Straight. ANNUAL REVIEW OF ENTOMOLOGY 2021; 66:243-256. [PMID: 32822556 DOI: 10.1146/annurev-ento-042020-102149] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Distant and predictable features in the environment make ideal compass cues to allow movement along a straight path. Ball-rolling dung beetles use a wide range of different signals in the day or night sky to steer themselves along a fixed bearing. These include the sun, the Milky Way, and the polarization pattern generated by the moon. Almost two decades of research into these remarkable creatures have shown that the dung beetle's compass is flexible and readily adapts to the cues available in its current surroundings. In the morning and afternoon, dung beetles use the sun to orient, but at midday, they prefer to use the wind, and at night or in a forest, they rely primarily on polarized skylight to maintain straight paths. We are just starting to understand the neuronal substrate underlying the dung beetle's compass and the mystery of why these beetles start each journey with a dance.
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Affiliation(s)
- Marie Dacke
- Department of Biology, Lund University, 223 62 Lund, Sweden; ,
- School of Animal, Plant and Environmental Sciences, University of the Witwatersrand, Johannesburg, South Africa;
| | - Emily Baird
- Department of Zoology, Stockholm University, 106 91 Stockholm, Sweden;
| | - Basil El Jundi
- Biocenter, University of Wuerzburg, 97074 Wuerzburg, Germany;
| | - Eric J Warrant
- Department of Biology, Lund University, 223 62 Lund, Sweden; ,
| | - Marcus Byrne
- School of Animal, Plant and Environmental Sciences, University of the Witwatersrand, Johannesburg, South Africa;
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24
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Bouchebti S, Arganda S. Insect lifestyle and evolution of brain morphology. CURRENT OPINION IN INSECT SCIENCE 2020; 42:90-96. [PMID: 33038535 DOI: 10.1016/j.cois.2020.09.012] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/15/2020] [Revised: 09/28/2020] [Accepted: 09/29/2020] [Indexed: 06/11/2023]
Abstract
Insect lifestyles are extremely diversified and have important consequences for brain function. Lifestyle determines the resources and information that brains might access and also those that are required to produce adaptive behaviors. Most of the observed adaptations in brain morphology to variation in lifestyle are related to the first stages of sensory information processing (e.g. adaptations to diel habits). However, morphological signatures of lifestyles related to higher order processing of information are more difficult to demonstrate. Co-option of existing neural structures for new behaviors might hinder the detection of morphological changes at a large scale. Current methodological advances will make it possible to investigate finer structural changes (e.g. variation in the connectivity between neurons) and might shed light on whether or not some lifestyles (e.g. eusociality) require morphological adaptations.
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Affiliation(s)
- Sofia Bouchebti
- Departamento de Biología y Geología, Física y Química Inorgánica, Área de Biodiversidad y Conservación, Universidad Rey Juan Carlos, Madrid, Spain
| | - Sara Arganda
- Departamento de Biología y Geología, Física y Química Inorgánica, Área de Biodiversidad y Conservación, Universidad Rey Juan Carlos, Madrid, Spain.
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25
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Stöckl AL, O’Carroll DC, Warrant EJ. Hawkmoth lamina monopolar cells act as dynamic spatial filters to optimize vision at different light levels. SCIENCE ADVANCES 2020; 6:eaaz8645. [PMID: 32494622 PMCID: PMC7164931 DOI: 10.1126/sciadv.aaz8645] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/15/2019] [Accepted: 01/23/2020] [Indexed: 06/11/2023]
Abstract
How neural form and function are connected is a central question of neuroscience. One prominent functional hypothesis, from the beginnings of neuroanatomical study, states that laterally extending dendrites of insect lamina monopolar cells (LMCs) spatially integrate visual information. We provide the first direct functional evidence for this hypothesis using intracellular recordings from type II LMCs in the hawkmoth Macroglossum stellatarum. We show that their spatial receptive fields broaden with decreasing light intensities, thus trading spatial resolution for higher sensitivity. These dynamic changes in LMC spatial properties can be explained by the density and lateral extent of their dendritic arborizations. Our results thus provide the first physiological evidence for a century-old hypothesis, directly correlating physiological response properties with distinctive dendritic morphology.
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Affiliation(s)
- Anna Lisa Stöckl
- Department of Biology, Lund University, Lund, Sweden
- Department of Behavioral Physiology and Sociobiology, Würzburg University, Würzburg, Germany
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26
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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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27
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Ketkar MD, Sporar K, Gür B, Ramos-Traslosheros G, Seifert M, Silies M. Luminance Information Is Required for the Accurate Estimation of Contrast in Rapidly Changing Visual Contexts. Curr Biol 2020; 30:657-669.e4. [PMID: 32008904 DOI: 10.1016/j.cub.2019.12.038] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2019] [Revised: 11/01/2019] [Accepted: 12/11/2019] [Indexed: 11/28/2022]
Abstract
Visual perception scales with changes in the visual stimulus, or contrast, irrespective of background illumination. However, visual perception is challenged when adaptation is not fast enough to deal with sudden declines in overall illumination, for example, when gaze follows a moving object from bright sunlight into a shaded area. Here, we show that the visual system of the fly employs a solution by propagating a corrective luminance-sensitive signal. We use in vivo 2-photon imaging and behavioral analyses to demonstrate that distinct OFF-pathway inputs encode contrast and luminance. Predictions of contrast-sensitive neuronal responses show that contrast information alone cannot explain behavioral responses in sudden dim light. The luminance-sensitive pathway via the L3 neuron is required for visual processing in such rapidly changing light conditions, ensuring contrast constancy when pure contrast sensitivity underestimates a stimulus. Thus, retaining a peripheral feature, luminance, in visual processing is required for robust behavioral responses.
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Affiliation(s)
- Madhura D Ketkar
- Institute of Developmental Biology and Neurobiology, Johannes Gutenberg-Universität Mainz, Hanns-Dieter-Hüsch-Weg 15, Mainz 55128, Germany; European Neuroscience Institute Göttingen, a Joint Initiative of the University Medical Center Göttingen and the Max Planck Society, Grisebachstr. 5, Göttingen 37077, Germany; International Max Planck Research School and Göttingen Graduate School for Neurosciences, Biophysics, and Molecular Biosciences (GGNB) at the University of Göttingen, Justus-von-Liebig-Weg 11, Göttingen 37077, Germany
| | - Katja Sporar
- Institute of Developmental Biology and Neurobiology, Johannes Gutenberg-Universität Mainz, Hanns-Dieter-Hüsch-Weg 15, Mainz 55128, Germany; European Neuroscience Institute Göttingen, a Joint Initiative of the University Medical Center Göttingen and the Max Planck Society, Grisebachstr. 5, Göttingen 37077, Germany; International Max Planck Research School and Göttingen Graduate School for Neurosciences, Biophysics, and Molecular Biosciences (GGNB) at the University of Göttingen, Justus-von-Liebig-Weg 11, Göttingen 37077, Germany
| | - Burak Gür
- Institute of Developmental Biology and Neurobiology, Johannes Gutenberg-Universität Mainz, Hanns-Dieter-Hüsch-Weg 15, Mainz 55128, Germany; European Neuroscience Institute Göttingen, a Joint Initiative of the University Medical Center Göttingen and the Max Planck Society, Grisebachstr. 5, Göttingen 37077, Germany; International Max Planck Research School and Göttingen Graduate School for Neurosciences, Biophysics, and Molecular Biosciences (GGNB) at the University of Göttingen, Justus-von-Liebig-Weg 11, Göttingen 37077, Germany
| | - Giordano Ramos-Traslosheros
- Institute of Developmental Biology and Neurobiology, Johannes Gutenberg-Universität Mainz, Hanns-Dieter-Hüsch-Weg 15, Mainz 55128, Germany; European Neuroscience Institute Göttingen, a Joint Initiative of the University Medical Center Göttingen and the Max Planck Society, Grisebachstr. 5, Göttingen 37077, Germany; International Max Planck Research School and Göttingen Graduate School for Neurosciences, Biophysics, and Molecular Biosciences (GGNB) at the University of Göttingen, Justus-von-Liebig-Weg 11, Göttingen 37077, Germany
| | - Marvin Seifert
- European Neuroscience Institute Göttingen, a Joint Initiative of the University Medical Center Göttingen and the Max Planck Society, Grisebachstr. 5, Göttingen 37077, Germany
| | - Marion Silies
- Institute of Developmental Biology and Neurobiology, Johannes Gutenberg-Universität Mainz, Hanns-Dieter-Hüsch-Weg 15, Mainz 55128, Germany; European Neuroscience Institute Göttingen, a Joint Initiative of the University Medical Center Göttingen and the Max Planck Society, Grisebachstr. 5, Göttingen 37077, Germany.
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28
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Nuutila J, Honkanen AE, Heimonen K, Weckström M. The effect of vertical extent of stimuli on cockroach optomotor response. J Exp Biol 2020:jeb.204768. [PMID: 34005539 DOI: 10.1242/jeb.204768] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2019] [Accepted: 03/09/2020] [Indexed: 11/20/2022]
Abstract
Using tethered American cockroaches walking on a trackball in a spherical virtual reality environment, we tested optomotor responses to horizontally moving black-and-white gratings of different vertical extent under six different light intensities. We found that shortening the vertical extent of the wide-field stimulus grating within a light level weakened response strength, reduced average velocity, and decreased angular walking distance. Optomotor responses with the vertically shortened stimuli persisted down to light intensity levels of 0.05 lx. Response latency seems to be independent of both the height of the stimulus and light intensity. The optomotor response started saturating at the light intensity of 5 lx, where the shortest behaviourally significant stimulus was 1°. This indicates that the number of vertical ommatidial rows needed to elicit an optomotor response at 5 lx and above is in the single digits, maybe even just one. Our behavioural results encourage further inquiry into the interplay of light intensity and stimulus size in insect dim-light vision.
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Affiliation(s)
- Juha Nuutila
- Nano and Molecular Systems Research Unit, University of Oulu, P.O. Box 3000, FIN-90014, Oulu, Finland
| | - Anna E Honkanen
- Lund Vision Group, Department of Biology, Lund University, 22362 Lund, Sweden
| | - Kyösti Heimonen
- Nano and Molecular Systems Research Unit, University of Oulu, P.O. Box 3000, FIN-90014, Oulu, Finland
| | - Matti Weckström
- Nano and Molecular Systems Research Unit, University of Oulu, P.O. Box 3000, FIN-90014, Oulu, Finland
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29
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Hoffmann S, Bley A, Matthes M, Firzlaff U, Luksch H. The Neural Basis of Dim-Light Vision in Echolocating Bats. BRAIN, BEHAVIOR AND EVOLUTION 2019; 94:61-70. [PMID: 31747669 DOI: 10.1159/000504124] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/11/2019] [Accepted: 10/12/2019] [Indexed: 11/19/2022]
Abstract
Echolocating bats evolved a sophisticated biosonar imaging system that allows for a life in dim-light habitats. However, especially for far-range operations such as homing, bats can support biosonar by vision. Large eyes and a retina that mainly consists of rods are assumed to be the optical adjustments that enable bats to use visual information at low light levels. In addition to optical mechanisms, many nocturnal animals evolved neural adaptations such as elongated integration times or enlarged spatial sampling areas to further increase the sensitivity of their visual system by temporal or spatial summation of visual information. The neural mechanisms that underlie the visual capabilities of echolocating bats have, however, so far not been investigated. To shed light on spatial and temporal response characteristics of visual neurons in an echolocating bat, Phyllostomus discolor, we recorded extracellular multiunit activity in the retino-recipient superficial layers of the superior colliculus (SC). We discovered that response latencies of these neurons were generally in the mammalian range, whereas neural spatial sampling areas were unusually large compared to those measured in the SC of other mammals. From this we suggest that echolocating bats likely use spatial but not temporal summation of visual input to improve visual performance under dim-light conditions. Furthermore, we hypothesize that bats compensate for the loss of visual spatial precision, which is a byproduct of spatial summation, by integration of spatial information provided by both the visual and the biosonar systems. Given that knowledge about neural adaptations to dim-light vision is mainly based on studies done in non-mammalian species, our novel data provide a valuable contribution to the field and demonstrate the suitability of echolocating bats as a nocturnal animal model to study the neurophysiological aspects of dim-light vision.
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Affiliation(s)
- Susanne Hoffmann
- Chair of Zoology, Technische Universität München, Freising-Weihenstephan, Germany, .,Max Planck Institute for Ornithology, Department of Behavioural Neurobiology, Seewiesen, Germany,
| | - Alexandra Bley
- Chair of Zoology, Technische Universität München, Freising-Weihenstephan, Germany
| | - Mariana Matthes
- Chair of Zoology, Technische Universität München, Freising-Weihenstephan, Germany
| | - Uwe Firzlaff
- Chair of Zoology, Technische Universität München, Freising-Weihenstephan, Germany
| | - Harald Luksch
- Chair of Zoology, Technische Universität München, Freising-Weihenstephan, Germany
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30
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Differential Tuning to Visual Motion Allows Robust Encoding of Optic Flow in the Dragonfly. J Neurosci 2019; 39:8051-8063. [PMID: 31481434 DOI: 10.1523/jneurosci.0143-19.2019] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2019] [Revised: 07/22/2019] [Accepted: 08/07/2019] [Indexed: 11/21/2022] Open
Abstract
Visual cues provide an important means for aerial creatures to ascertain their self-motion through the environment. In many insects, including flies, moths, and bees, wide-field motion-sensitive neurons in the third optic ganglion are thought to underlie such motion encoding; however, these neurons can only respond robustly over limited speed ranges. The task is more complicated for some species of dragonflies that switch between extended periods of hovering flight and fast-moving pursuit of prey and conspecifics, requiring motion detection over a broad range of velocities. Since little is known about motion processing in these insects, we performed intracellular recordings from hawking, emerald dragonflies (Hemicordulia spp.) and identified a diverse group of motion-sensitive neurons that we named lobula tangential cells (LTCs). Following prolonged visual stimulation with drifting gratings, we observed significant differences in both temporal and spatial tuning of LTCs. Cluster analysis of these changes confirmed several groups of LTCs with distinctive spatiotemporal tuning. These differences were associated with variation in velocity tuning in response to translated, natural scenes. LTCs with differences in velocity tuning ranges and optima may underlie how a broad range of motion velocities are encoded. In the hawking dragonfly, changes in LTC tuning over time are therefore likely to support their extensive range of behaviors, from hovering to fast-speed pursuits.SIGNIFICANCE STATEMENT Understanding how animals navigate the world is an inherently difficult and interesting problem. Insects are useful models for understanding neuronal mechanisms underlying these activities, with neurons that encode wide-field motion previously identified in insects, such as flies, hawkmoths, and butterflies. Like some Dipteran flies, dragonflies exhibit complex aerobatic behaviors, such as hovering, patrolling, and aerial combat. However, dragonflies lack halteres that support such diverse behavior in flies. To understand how dragonflies might address this problem using only visual cues, we recorded from their wide-field motion-sensitive neurons. We found these differ strongly in the ways they respond to sustained motion, allowing them collectively to encode the very broad range of velocities experienced during diverse behavior.
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31
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Kelley JL, Tatarnic NJ, Schröder-Turk GE, Endler JA, Wilts BD. A Dynamic Optical Signal in a Nocturnal Moth. Curr Biol 2019; 29:2919-2925.e2. [PMID: 31402306 DOI: 10.1016/j.cub.2019.07.005] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2019] [Revised: 05/28/2019] [Accepted: 07/01/2019] [Indexed: 11/28/2022]
Abstract
The wings of butterflies and moths generate some of the most spectacular visual displays observed in nature [1-3]. Particularly striking effects are seen when light interferes with nanostructure materials in the wing scales, generating bright, directional colors that often serve as dynamic visual signals [4]. Structural coloration is not known in night-flying Lepidoptera, yet here we show a highly unusual form of wing coloration in a nocturnal, sexually dimorphic moth, Eudocima materna (Noctuidae). Males feature three dark wing patches on the dorsal forewings, and the apparent size of these patches strongly varies depending on the angle of the wing to the viewer. These optical special effects are generated using specialized wing scales that are tilted on the wing and behave like mirrors. At near-normal incidence of light, these "mirror scales" act as thin-film reflectors to produce a sparkly effect, but when light is incident at ∼20°-30° from normal, the reflectance spectrum is dominated by the diffuse scattering of the underlying, black melanin-containing scales, causing a shape-shifting effect. The strong sexual dimorphism in the arrangement and architecture of the scale nanostructures suggests that these patterns might function for sexual signaling. Flickering of the male's wings would yield a flashing, supernormal visual stimulus [5] to a viewer located 20°-30° away from the vertical, while being invisible to a viewer directly above the animal. Our findings reveal a novel use of structural coloration in nature that yields a dynamic, time-dependent achromatic optical signal that may be optimized for visual signaling in dim light.
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Affiliation(s)
- Jennifer L Kelley
- School of Biological Sciences, The University of Western Australia, Perth, WA 6009, Australia.
| | - Nikolai J Tatarnic
- School of Biological Sciences, The University of Western Australia, Perth, WA 6009, Australia; Western Australian Museum, Locked bag 49, Welshpool DC, Perth, WA 6986, Australia
| | - Gerd E Schröder-Turk
- Mathematics and Statistics, Murdoch University, Perth, WA 6150, Australia; Department of Food Science, Copenhagen University, Rolighedsvej 26, 1958 Frederiksberg C, Denmark; Physical Chemistry, Lund University, Naturvetarvägen 14, 221 00 Lund, Sweden
| | - John A Endler
- School of Life & Environmental Sciences, Deakin University, Waurn Ponds, 3216 VIC, Australia
| | - Bodo D Wilts
- Adolphe Merkle Institute, University of Fribourg, Chemin des Verdiers 4, Fribourg 1700, Switzerland.
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32
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Renoult JP, Mendelson TC. Processing bias: extending sensory drive to include efficacy and efficiency in information processing. Proc Biol Sci 2019; 286:20190165. [PMID: 30940061 DOI: 10.1098/rspb.2019.0165] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Communication signals often comprise an array of colours, lines, spots, notes or odours that are arranged in complex patterns, melodies or blends. Receiver perception is assumed to influence preference and thus the evolution of signal design, but evolutionary biologists still struggle to understand how perception, preference and signal design are mechanistically linked. In parallel, the field of empirical aesthetics aims to understand why people like some designs more than others. The model of processing bias discussed here is rooted in empirical aesthetics, which posits that preferences are influenced by the emotional system as it monitors the dynamics of information processing and that attractive signals have effective designs that maximize information transmission, efficient designs that allow information processing at low metabolic cost, or both. We refer to the causal link between preference and the emotionally rewarding experience of effective and efficient information processing as the processing bias, and we apply it to the evolutionary model of sensory drive. A sensory drive model that incorporates processing bias hypothesizes a causal chain of relationships between the environment, perception, pleasure, preference and ultimately the evolution of signal design, both simple and complex.
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Affiliation(s)
- Julien P Renoult
- 1 Centre of Evolutionary and Functional Ecology (CEFE UMR5175), CNRS-University of Montpellier-University Paul-Valery Montpellier-EPHE) , 1919 route de Mende, 34293 Montpellier , France
| | - Tamra C Mendelson
- 2 Department of Biological Sciences, University of Maryland Baltimore County , 1000 Hilltop Circle, Baltimore, MD 21250 , USA
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33
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Seymoure BM, Linares C, White J. Connecting spectral radiometry of anthropogenic light sources to the visual ecology of organisms. J Zool (1987) 2019. [DOI: 10.1111/jzo.12656] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Affiliation(s)
- B. M. Seymoure
- Department of Biology Colorado State University Fort Collins CO USA
- Department of Fish, Wildlife, and Conservation Biology Colorado State University Fort Collins CO USA
| | - C. Linares
- Department of Biology Colorado State University Fort Collins CO USA
- Department of Fish, Wildlife, and Conservation Biology Colorado State University Fort Collins CO USA
| | - J. White
- Department of Biology Colorado State University Fort Collins CO USA
- Department of Fish, Wildlife, and Conservation Biology Colorado State University Fort Collins CO USA
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34
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Ogawa Y, Ryan LA, Palavalli-Nettimi R, Seeger O, Hart NS, Narendra A. Spatial Resolving Power and Contrast Sensitivity Are Adapted for Ambient Light Conditions in Australian Myrmecia Ants. Front Ecol Evol 2019. [DOI: 10.3389/fevo.2019.00018] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
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35
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Sheehan ZBV, Kamhi JF, Seid MA, Narendra A. Differential investment in brain regions for a diurnal and nocturnal lifestyle in Australian Myrmecia ants. J Comp Neurol 2019; 527:1261-1277. [PMID: 30592041 DOI: 10.1002/cne.24617] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2018] [Revised: 12/07/2018] [Accepted: 12/22/2018] [Indexed: 12/29/2022]
Abstract
Animals are active at different times of the day. Each temporal niche offers a unique light environment, which affects the quality of the available visual information. To access reliable visual signals in dim-light environments, insects have evolved several visual adaptations to enhance their optical sensitivity. The extent to which these adaptations reflect on the sensory processing and integration capabilities within the brain of a nocturnal insect is unknown. To address this, we analyzed brain organization in congeneric species of the Australian bull ant, Myrmecia, that rely predominantly on visual information and range from being strictly diurnal to strictly nocturnal. Weighing brains and optic lobes of seven Myrmecia species, showed that after controlling for body mass, the brain mass was not significantly different between diurnal and nocturnal ants. However, the optic lobe mass, after controlling for central brain mass, differed between day- and night-active ants. Detailed volumetric analyses showed that the nocturnal ants invested relatively less in the primary visual processing regions but relatively more in both the primary olfactory processing regions and in the integration centers of visual and olfactory sensory information. We discuss how the temporal niche occupied by each species may affect cognitive demands, thus shaping brain organization among insects active in dim-light conditions.
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Affiliation(s)
- Zachary B V Sheehan
- Department of Biological Sciences, Macquarie University, Sydney, New South Wales, Australia
| | - J Frances Kamhi
- Department of Biological Sciences, Macquarie University, Sydney, New South Wales, Australia
| | - Marc A Seid
- Department of Biological Sciences, Macquarie University, Sydney, New South Wales, Australia.,Biology Department, Neuroscience Program, The University of Scranton, Scranton, Pennsylvania
| | - Ajay Narendra
- Department of Biological Sciences, Macquarie University, Sydney, New South Wales, Australia
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36
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Birk MH, Blicher ME, Garm A. Deep-sea starfish from the Arctic have well-developed eyes in the dark. Proc Biol Sci 2019; 285:rspb.2017.2743. [PMID: 29436504 DOI: 10.1098/rspb.2017.2743] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2017] [Accepted: 01/11/2018] [Indexed: 11/12/2022] Open
Abstract
Asteroids, starfish, are important members of the macro-benthos in almost all marine environments including the deep sea. Starfish are in general assumed to be largely olfactory guided, but recent studies have shown that two tropical shallow water species rely on vision alone to find their habitat at short distances. Their compound eyes are found at the tip of each arm and they vary little between examined species. Still, nothing is known about vision in the species found in the aphotic zone of the deep sea or whether they even have eyes. Here, 13 species of starfish from Greenland waters, covering a depth range from shallow waters to the deep sea below 1000 m, were examined for the presence of eyes and optical and morphological examinations were used to estimate the quality of vision. Further, species found in the aphotic zone below 320 m were checked for bioluminescence. All species, except the infaunal Ctenodiscus crispatus, had eyes, and two were found to be bioluminescent. Interestingly, one of the species found in the aphotic zone, Novodinia americana, had close to the highest spatial resolution known for starfish eyes along with being bioluminescent. Accordingly, we hypothesize that this species communicates visually using bioluminescent flashes putatively for reproductive purposes. Other species have greatly enhanced sensitivity with few large ommatidia but at the sacrifice of spatial resolution. The discovery of eyes in deep-sea starfish with a huge variation in optical quality and sensitivity indicates that their visual ecology also differs greatly.
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Affiliation(s)
- Marie Helene Birk
- Marine Biological Section, University of Copenhagen, Universitetsparken 4, 2100 Copenhagen Ø, Denmark.,Greenland Climate Research Centre, Greenland Institute of Natural Resources, Kivioq 2, 3900 Nuuk, Greenland
| | - Martin E Blicher
- Greenland Climate Research Centre, Greenland Institute of Natural Resources, Kivioq 2, 3900 Nuuk, Greenland
| | - Anders Garm
- Marine Biological Section, University of Copenhagen, Universitetsparken 4, 2100 Copenhagen Ø, Denmark
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37
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Dahake A, Stöckl AL, Foster JJ, Sane SP, Kelber A. The roles of vision and antennal mechanoreception in hawkmoth flight control. eLife 2018; 7:37606. [PMID: 30526849 PMCID: PMC6303104 DOI: 10.7554/elife.37606] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2018] [Accepted: 12/08/2018] [Indexed: 01/28/2023] Open
Abstract
Flying animals need continual sensory feedback about their body position and orientation for flight control. The visual system provides essential but slow feedback. In contrast, mechanosensory channels can provide feedback at much shorter timescales. How the contributions from these two senses are integrated remains an open question in most insect groups. In Diptera, fast mechanosensory feedback is provided by organs called halteres and is crucial for the control of rapid flight manoeuvres, while vision controls manoeuvres in lower temporal frequency bands. Here, we have investigated the visual-mechanosensory integration in the hawkmoth Macroglossum stellatarum. They represent a large group of insects that use Johnston’s organs in their antennae to provide mechanosensory feedback on perturbations in body position. Our experiments show that antennal mechanosensory feedback specifically mediates fast flight manoeuvres, but not slow ones. Moreover, we did not observe compensatory interactions between antennal and visual feedback.
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Affiliation(s)
- Ajinkya Dahake
- Vision Group, Lund University, Lund, Sweden.,National Centre for Biological Sciences, Tata Institute of Fundamental Research, Bangalore, India
| | | | | | - Sanjay P Sane
- National Centre for Biological Sciences, Tata Institute of Fundamental Research, Bangalore, India
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38
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Rosencrans RF, Leslie CE, Perkins KA, Walkowski W, Gordon WC, Richards-Zawacki CL, Bazan NG, Farris HE. Quantifying the relationship between optical anatomy and retinal physiological sensitivity: A comparative approach. J Comp Neurol 2018; 526:3045-3057. [PMID: 30198557 PMCID: PMC10075234 DOI: 10.1002/cne.24531] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2018] [Revised: 07/27/2018] [Accepted: 08/27/2018] [Indexed: 02/03/2023]
Abstract
Light intensity varies 1 million-fold between night and day, driving the evolution of eye morphology and retinal physiology. Despite extensive research across taxa showing anatomical adaptations to light niches, surprisingly few empirical studies have quantified the relationship between such traits and the physiological sensitivity to light. In this study, we employ a comparative approach in frogs to determine the physiological sensitivity of eyes in two nocturnal (Rana pipiens, Hyla cinerea) and two diurnal species (Oophaga pumilio, Mantella viridis), examining whether differences in retinal thresholds can be explained by ocular and cellular anatomy. Scotopic electroretinogram (ERG) analysis of relative b-wave amplitude reveals 10- to 100-fold greater light sensitivity in nocturnal compared to diurnal frogs. Ocular and cellular optics (aperture, focal length, and rod outer segment dimensions) were assessed via the Land equation to quantify differences in optical sensitivity. Variance in retinal thresholds was overwhelmingly explained by Land equation solutions, which describe the optical sensitivity of single rods. Thus, at the b-wave, stimulus-response thresholds may be unaffected by photoreceptor convergence (which create larger, combined collecting areas). Follow-up experiments were conducted using photopic ERGs, which reflect cone vision. Under these conditions, the relative difference in thresholds was reversed, such that diurnal species were more sensitive than nocturnal species. Thus, photopic data suggest that rod-specific adaptations, not ocular anatomy (e.g., aperture and focal distance), drive scotopic thresholds differences. To the best of our knowledge, these data provide the first quantified relationship between optical and physiological sensitivity in vertebrates active in different light regimes.
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Affiliation(s)
- Robert F Rosencrans
- Neuroscience Center, Louisiana State University School of Medicine, New Orleans, Louisiana
| | - Caitlin E Leslie
- Department of Integrative Biology, University of Texas, Austin, Texas
| | - Keith A Perkins
- Neuroscience Center, Louisiana State University School of Medicine, New Orleans, Louisiana
| | - Whitney Walkowski
- Neuroscience Center, Louisiana State University School of Medicine, New Orleans, Louisiana
| | - William C Gordon
- Neuroscience Center, Louisiana State University School of Medicine, New Orleans, Louisiana.,Department of Ophthalmology, Louisiana State University School of Medicine, New Orleans, Louisiana
| | | | - Nicolas G Bazan
- Neuroscience Center, Louisiana State University School of Medicine, New Orleans, Louisiana.,Department of Ophthalmology, Louisiana State University School of Medicine, New Orleans, Louisiana
| | - Hamilton E Farris
- Neuroscience Center, Louisiana State University School of Medicine, New Orleans, Louisiana.,Department of Otorhinolaryngology, Louisiana State University School of Medicine, New Orleans, Louisiana.,Department of Cell Biology and Anatomy, Louisiana State University School of Medicine, New Orleans, Louisiana
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39
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Narendra A, Ribi WA. Ocellar structure is driven by the mode of locomotion and activity time in Myrmecia ants. ACTA ACUST UNITED AC 2018; 220:4383-4390. [PMID: 29187620 DOI: 10.1242/jeb.159392] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2017] [Accepted: 09/25/2017] [Indexed: 01/09/2023]
Abstract
Insects have exquisitely adapted their compound eyes to suit the ambient light intensity in the different temporal niches they occupy. In addition to the compound eye, most flying insects have simple eyes known as ocelli, which assist in flight stabilisation, horizon detection and orientation. Among ants, typically the flying alates have ocelli while the pedestrian workers lack this structure. The Australian ant genus Myrmecia is one of the few ant genera in which both workers and alates have three ocellar lenses. Here, we studied the variation in the ocellar structure in four sympatric species of Myrmecia that are active at different times of the day. In addition, we took advantage of the walking and flying modes of locomotion in workers and males, respectively, to ask whether the type of movement influences the ocellar structure. We found that ants active in dim light had larger ocellar lenses and wider rhabdoms compared with those in bright-light conditions. In the ocellar rhabdoms of workers active in dim-light habitats, typically each retinula cell contributed microvilli in more than one direction, probably destroying polarisation sensitivity. The organisation of the ocellar retina in the day-active workers and the males suggests that in these animals some cells are sensitive to the pattern of polarised skylight. We found that the night-flying males had a tapetum that reflects light back to the rhabdom, increasing their optical sensitivity. We discuss the possible functions of ocelli to suit the different modes of locomotion and the discrete temporal niches that animals occupy.
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Affiliation(s)
- Ajay Narendra
- Department of Biological Sciences, Macquarie University, Sydney, NSW 2109, Australia
| | - Willi A Ribi
- Research School of Biology, The Australian National University, Canberra, ACT 2601, Australia
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40
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O'Carroll DC, Warrant EJ. Vision in dim light: highlights and challenges. Philos Trans R Soc Lond B Biol Sci 2018; 372:rstb.2016.0062. [PMID: 28193807 DOI: 10.1098/rstb.2016.0062] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/22/2016] [Indexed: 11/12/2022] Open
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41
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Lessios N, Rutowski RL, Cohen JH, Sayre ME, Strausfeld NJ. Multiple spectral channels in branchiopods. I. Vision in dim light and neural correlates. ACTA ACUST UNITED AC 2018; 221:jeb.165860. [PMID: 29622664 DOI: 10.1242/jeb.165860] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2017] [Accepted: 03/31/2018] [Indexed: 11/20/2022]
Abstract
Animals that have true color vision possess several spectral classes of photoreceptors. Pancrustaceans (Hexapoda+Crustacea) that integrate spectral information about their reconstructed visual world do so from photoreceptor terminals supplying their second optic neuropils, with subsequent participation of the third (lobula) and deeper centers (optic foci). Here, we describe experiments and correlative neural arrangements underlying convergent visual pathways in two species of branchiopod crustaceans that have to cope with a broad range of spectral ambience and illuminance in ephemeral pools, yet possess just two optic neuropils, the lamina and the optic tectum. Electroretinographic recordings and multimodel inference based on modeled spectral absorptance were used to identify the most likely number of spectral photoreceptor classes in their compound eyes. Recordings from the retina provide support for four color channels. Neuroanatomical observations resolve arrangements in their laminas that suggest signal summation at low light intensities, incorporating chromatic channels. Neuroanatomical observations demonstrate that spatial summation in the lamina of the two species are mediated by quite different mechanisms, both of which allow signals from several ommatidia to be pooled at single lamina monopolar cells. We propose that such summation provides sufficient signal for vision at intensities equivalent to those experienced by insects in terrestrial habitats under dim starlight. Our findings suggest that despite the absence of optic lobe neuropils necessary for spectral discrimination utilized by true color vision, four spectral photoreceptor classes have been maintained in Branchiopoda for vision at very low light intensities at variable ambient wavelengths that typify conditions in ephemeral freshwater habitats.
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Affiliation(s)
- Nicolas Lessios
- School of Life Sciences, Arizona State University, Tempe, AZ 85287, USA .,Department of Neuroscience, University of Arizona, 611 Gould-Simpson, Tucson, AZ 85721, USA
| | - Ronald L Rutowski
- School of Life Sciences, Arizona State University, Tempe, AZ 85287, USA
| | - Jonathan H Cohen
- School of Marine Science and Policy, College of Earth, Ocean and Environment, University of Delaware, 700 Pilottown Road, Lewes, DE 19958, USA
| | - Marcel E Sayre
- Department of Neuroscience, University of Arizona, 611 Gould-Simpson, Tucson, AZ 85721, USA
| | - Nicholas J Strausfeld
- Department of Neuroscience, University of Arizona, 611 Gould-Simpson, Tucson, AZ 85721, USA
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Kohn JR, Heath SL, Behnia R. Eyes Matched to the Prize: The State of Matched Filters in Insect Visual Circuits. Front Neural Circuits 2018; 12:26. [PMID: 29670512 PMCID: PMC5893817 DOI: 10.3389/fncir.2018.00026] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2017] [Accepted: 03/13/2018] [Indexed: 12/16/2022] Open
Abstract
Confronted with an ever-changing visual landscape, animals must be able to detect relevant stimuli and translate this information into behavioral output. A visual scene contains an abundance of information: to interpret the entirety of it would be uneconomical. To optimally perform this task, neural mechanisms exist to enhance the detection of important features of the sensory environment while simultaneously filtering out irrelevant information. This can be accomplished by using a circuit design that implements specific "matched filters" that are tuned to relevant stimuli. Following this rule, the well-characterized visual systems of insects have evolved to streamline feature extraction on both a structural and functional level. Here, we review examples of specialized visual microcircuits for vital behaviors across insect species, including feature detection, escape, and estimation of self-motion. Additionally, we discuss how these microcircuits are modulated to weigh relevant input with respect to different internal and behavioral states.
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Affiliation(s)
- Jessica R Kohn
- Department of Neuroscience, Columbia University, New York, NY, United States
| | - Sarah L Heath
- Department of Neuroscience, Columbia University, New York, NY, United States
| | - Rudy Behnia
- Department of Neuroscience, Columbia University, New York, NY, United States
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Stöckl AL, O'Carroll D, Warrant EJ. Higher-order neural processing tunes motion neurons to visual ecology in three species of hawkmoths. Proc Biol Sci 2018. [PMID: 28637860 DOI: 10.1098/rspb.2017.0880] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
To sample information optimally, sensory systems must adapt to the ecological demands of each animal species. These adaptations can occur peripherally, in the anatomical structures of sensory organs and their receptors; and centrally, as higher-order neural processing in the brain. While a rich body of investigations has focused on peripheral adaptations, our understanding is sparse when it comes to central mechanisms. We quantified how peripheral adaptations in the eyes, and central adaptations in the wide-field motion vision system, set the trade-off between resolution and sensitivity in three species of hawkmoths active at very different light levels: nocturnal Deilephila elpenor, crepuscular Manduca sexta, and diurnal Macroglossum stellatarum. Using optical measurements and physiological recordings from the photoreceptors and wide-field motion neurons in the lobula complex, we demonstrate that all three species use spatial and temporal summation to improve visual performance in dim light. The diurnal Macroglossum relies least on summation, but can only see at brighter intensities. Manduca, with large sensitive eyes, relies less on neural summation than the smaller eyed Deilephila, but both species attain similar visual performance at nocturnal light levels. Our results reveal how the visual systems of these three hawkmoth species are intimately matched to their visual ecologies.
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Affiliation(s)
- A L Stöckl
- Department of Biology, University of Lund, Sölvegatan 35, 22362 Lund, Sweden
| | - D O'Carroll
- Department of Biology, University of Lund, Sölvegatan 35, 22362 Lund, Sweden
| | - E J Warrant
- Department of Biology, University of Lund, Sölvegatan 35, 22362 Lund, Sweden
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44
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Kalyanasundaram P, Willis MA. Parameters of motion vision in low-light in the hawkmoth, Manduca sexta. J Exp Biol 2018; 221:jeb.173344. [DOI: 10.1242/jeb.173344] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2017] [Accepted: 06/28/2018] [Indexed: 11/20/2022]
Abstract
The hawkmoth Manduca sexta, is nocturnally active, beginning its flight activity at sunset, and executing rapid controlled maneuvers to search for food and mates in dim light conditions. This moth's visual system has been shown to trade off spatial and temporal resolution for increased sensitivity in these conditions. The study presented here uses tethered flying moths to characterize the flight performance envelope of M. sexta's wide-field-motion-triggered steering response in low light conditions by measuring attempted turning in response to wide-field visual motion. Moths were challenged with a horizontally oscillating sinusoidal grating at a range of luminance, from daylight to starlight conditions. The impact of luminance on response to a range of temporal frequencies and spatial wavelengths was assessed across a range of pattern contrasts. The optomotor response decreased as a function of decreasing luminance, and the lower limit of the moth's contrast sensitivity was found to be between 1% to 5%. The preferred spatial frequency for M. sexta increased from 0.06 to 0.3 cycles/degree as the luminance decreased, but the preferred temporal frequency remained stable at 4.5 Hz across all conditions. The relationship between the optomotor response time to the temporal frequency of the pattern movement did not vary significantly with luminance levels. Taken together, these results suggest that the behavioral response to wide-field visual input in M. sexta is adapted to operate during crepuscular to nocturnal luminance levels, and the decreasing light levels experienced during that period changes visual acuity and does not affect their response time significantly.
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Affiliation(s)
- P. Kalyanasundaram
- Department of Biology, Case Western Reserve University, Cleveland, OH 44106-7080, USA
| | - M. A. Willis
- Department of Biology, Case Western Reserve University, Cleveland, OH 44106-7080, USA
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45
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Chakravarthi A, Rajus S, Kelber A, Dacke M, Baird E. Differences in spatial resolution and contrast sensitivity of flight control in the honeybees Apis cerana and Apis mellifera. J Exp Biol 2018; 221:jeb.184267. [DOI: 10.1242/jeb.184267] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2018] [Accepted: 08/14/2018] [Indexed: 11/20/2022]
Abstract
Visually-guided behaviour is constrained by the capacity of the visual system to resolve detail. This is, in turn, limited by the spatial resolution and contrast sensitivity of the underlying visual system. Because these properties are interdependent and vary non-uniformly, it is only possible to fully understand the limits of a specific visually guided behaviour when they are investigated in combination. To understand the visual limits of flight control in bees, which rely heavily on vision to control flight, and to explore whether they vary between species, we tested how changes in spatial resolution and contrast sensitivity affect the speed and position control of the Asian and European honeybees (Apis cerana and A. mellifera). Despite their apparent similarity, we found some interesting and surprising differences between the visual limits of these species. While the effect of spatial frequency and contrast on position control is similar between the species, ground speed is differently affected by these variables. A comparison with published data from the bumblebee Bombus terrestris reveals further differences. The visual resolution that limits the detection and use of optic flow for flight control in both species of honeybees is lower than previously anatomically determined resolution and differs from object detection limits of A. mellifera, providing evidence that the limits of spatial resolution and contrast sensitivity are highly tuned to the particular behavioural task of a species.
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Affiliation(s)
| | - Santosh Rajus
- National Centre for Biological Sciences, Bangalore, India
| | - Almut Kelber
- Department of Biology, Lund University, Lund, Sweden
| | - Marie Dacke
- Department of Biology, Lund University, Lund, Sweden
| | - Emily Baird
- Department of Biology, Lund University, Lund, Sweden
- Current address: Department of Zoology, Stockholm University, Stockholm, Sweden
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Honkanen A, Immonen EV, Salmela I, Heimonen K, Weckström M. Insect photoreceptor adaptations to night vision. Philos Trans R Soc Lond B Biol Sci 2017; 372:rstb.2016.0077. [PMID: 28193821 DOI: 10.1098/rstb.2016.0077] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/10/2016] [Indexed: 01/25/2023] Open
Abstract
Night vision is ultimately about extracting information from a noisy visual input. Several species of nocturnal insects exhibit complex visually guided behaviour in conditions where most animals are practically blind. The compound eyes of nocturnal insects produce strong responses to single photons and process them into meaningful neural signals, which are amplified by specialized neuroanatomical structures. While a lot is known about the light responses and the anatomical structures that promote pooling of responses to increase sensitivity, there is still a dearth of knowledge on the physiology of night vision. Retinal photoreceptors form the first bottleneck for the transfer of visual information. In this review, we cover the basics of what is known about physiological adaptations of insect photoreceptors for low-light vision. We will also discuss major enigmas of some of the functional properties of nocturnal photoreceptors, and describe recent advances in methodologies that may help to solve them and broaden the field of insect vision research to new model animals.This article is part of the themed issue 'Vision in dim light'.
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Affiliation(s)
- Anna Honkanen
- Nano and Molecular Systems Research Unit, Faculty of Science, University of Oulu, Oulu, Finland
| | - Esa-Ville Immonen
- Nano and Molecular Systems Research Unit, Faculty of Science, University of Oulu, Oulu, Finland
| | - Iikka Salmela
- Nano and Molecular Systems Research Unit, Faculty of Science, University of Oulu, Oulu, Finland
| | - Kyösti Heimonen
- Nano and Molecular Systems Research Unit, Faculty of Science, University of Oulu, Oulu, Finland
| | - Matti Weckström
- Nano and Molecular Systems Research Unit, Faculty of Science, University of Oulu, Oulu, Finland
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Warrant EJ. The remarkable visual capacities of nocturnal insects: vision at the limits with small eyes and tiny brains. Philos Trans R Soc Lond B Biol Sci 2017; 372:rstb.2016.0063. [PMID: 28193808 DOI: 10.1098/rstb.2016.0063] [Citation(s) in RCA: 50] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/25/2016] [Indexed: 11/12/2022] Open
Abstract
Nocturnal insects have evolved remarkable visual capacities, despite small eyes and tiny brains. They can see colour, control flight and land, react to faint movements in their environment, navigate using dim celestial cues and find their way home after a long and tortuous foraging trip using learned visual landmarks. These impressive visual abilities occur at light levels when only a trickle of photons are being absorbed by each photoreceptor, begging the question of how the visual system nonetheless generates the reliable signals needed to steer behaviour. In this review, I attempt to provide an answer to this question. Part of the answer lies in their compound eyes, which maximize light capture. Part lies in the slow responses and high gains of their photoreceptors, which improve the reliability of visual signals. And a very large part lies in the spatial and temporal summation of these signals in the optic lobe, a strategy that substantially enhances contrast sensitivity in dim light and allows nocturnal insects to see a brighter world, albeit a slower and coarser one. What is abundantly clear, however, is that during their evolution insects have overcome several serious potential visual limitations, endowing them with truly extraordinary night vision.This article is part of the themed issue 'Vision in dim light'.
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Affiliation(s)
- Eric J Warrant
- Lund Vision Group, Department of Biology, University of Lund, Sölvegatan 35, 22362 Lund, Sweden
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48
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Stöckl AL, Kihlström K, Chandler S, Sponberg S. Comparative system identification of flower tracking performance in three hawkmoth species reveals adaptations for dim light vision. Philos Trans R Soc Lond B Biol Sci 2017; 372:rstb.2016.0078. [PMID: 28193822 DOI: 10.1098/rstb.2016.0078] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/23/2016] [Indexed: 11/12/2022] Open
Abstract
Flight control in insects is heavily dependent on vision. Thus, in dim light, the decreased reliability of visual signal detection also prompts consequences for insect flight. We have an emerging understanding of the neural mechanisms that different species employ to adapt the visual system to low light. However, much less explored are comparative analyses of how low light affects the flight behaviour of insect species, and the corresponding links between physiological adaptations and behaviour. We investigated whether the flower tracking behaviour of three hawkmoth species with different diel activity patterns revealed luminance-dependent adaptations, using a system identification approach. We found clear luminance-dependent differences in flower tracking in all three species, which were explained by a simple luminance-dependent delay model, which generalized across species. We discuss physiological and anatomical explanations for the variance in tracking responses, which could not be explained by such simple models. Differences between species could not be explained by the simple delay model. However, in several cases, they could be explained through the addition on a second model parameter, a simple scaling term, that captures the responsiveness of each species to flower movements. Thus, we demonstrate here that much of the variance in the luminance-dependent flower tracking responses of hawkmoths with different diel activity patterns can be captured by simple models of neural processing.This article is part of the themed issue 'Vision in dim light'.
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Affiliation(s)
- Anna L Stöckl
- Department of Biology, Lund University, Sölvegatan 35, Lund, Sweden
| | - Klara Kihlström
- Department of Biology, Lund University, Sölvegatan 35, Lund, Sweden
| | - Steven Chandler
- School of Physics, Georgia Institute of Technology, Atlanta, GA, USA.,School of Biological Sciences, Georgia Institute of Technology, Atlanta, GA, USA
| | - Simon Sponberg
- School of Physics, Georgia Institute of Technology, Atlanta, GA, USA.,School of Biological Sciences, Georgia Institute of Technology, Atlanta, GA, USA
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Stöckl A, Smolka J, O'Carroll D, Warrant E. Resolving the Trade-off Between Visual Sensitivity and Spatial Acuity-Lessons from Hawkmoths. Integr Comp Biol 2017; 57:1093-1103. [PMID: 28992251 DOI: 10.1093/icb/icx058] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
The visual systems of many animals, particularly those active during the day, are optimized for high spatial acuity. However, at night, when photons are sparse and the visual signal competes with increased noise levels, fine spatial resolution cannot be sustained and is traded-off for the greater sensitivity required to see in dim light. High spatial acuity demands detectors and successive visual processing units whose receptive fields each cover only a small area of visual space, in order to reassemble a finely sampled and well resolved image. However, the smaller the sampled area, the fewer the photons that can be collected, and thus the worse the visual sensitivity becomes-leading to the classical trade-off between sensitivity and resolution. Nocturnal animals usually resolve this trade-off in favour of sensitivity, and thus have lower spatial acuity than their diurnal counterparts. Here we review results highlighting how hawkmoths, a highly visual group of insects with species active at different light intensities, resolve the trade-off between sensitivity and spatial resolution. We compare adaptations both in the optics and retina, as well as at higher levels of neural processing in a nocturnal and a diurnal hawkmoth species, and also give a perspective on the behavioral consequences. We broaden the scope of our review by drawing comparisons with the adaptive strategies used by other nocturnal and diurnal insects.
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Affiliation(s)
- Anna Stöckl
- Department of Biology, Lund University, Lund 22362, Sweden
| | - Jochen Smolka
- Department of Biology, Lund University, Lund 22362, Sweden
| | | | - Eric Warrant
- Department of Biology, Lund University, Lund 22362, Sweden
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50
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Olsson P, Lind O, Kelber A. Chromatic and achromatic vision: parameter choice and limitations for reliable model predictions. Behav Ecol 2017. [DOI: 10.1093/beheco/arx133] [Citation(s) in RCA: 107] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Affiliation(s)
- Peter Olsson
- Department of Biology, Lund University, Lund, Sweden
| | - Olle Lind
- Department of Philosophy, Lund University, Lund, Sweden
| | - Almut Kelber
- Department of Biology, Lund University, Lund, Sweden
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