1
|
Gutiérrez D, Rigosi E, Nagloo N, O'Carroll D, Warrant EJ. Spatial resolution and optical sensitivity in the compound eyes of two common European wasps, Vespula germanica and Vespula vulgaris. J Exp Biol 2024; 227:jeb246670. [PMID: 39058380 DOI: 10.1242/jeb.246670] [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: 08/23/2023] [Accepted: 07/12/2024] [Indexed: 07/28/2024]
Abstract
Vespula germanica and Vespula vulgaris are two common European wasps that have ecological and economic importance as a result of their artificial introduction into many different countries and environments. Their success has undoubtedly been aided by their capacity for visually guided hunting, foraging, learning and using visual cues in the context of homing and navigation. However, the visual systems of V. germanica and V. vulgaris have not received any deep attention. We used electrophysiology, together with optical and anatomical techniques, to measure the spatial resolution and optical sensitivity of the compound eyes of both species. We found that both wasps have high anatomical spatial resolution with narrow interommatidial angles (Δϕ between 1.0 and 1.5 deg) and a distinct acute zone in the fronto-ventral part of the eye. These narrow interommatidial angles are matched to photoreceptors having narrow angular sensitivities (acute zone acceptance angles Δρ below 1.3 deg), indicating eyes of high spatial resolution that are well suited to their ecological needs. Additionally, we found that both species possess an optical sensitivity that is typical of other day-flying hymenopterans.
Collapse
Affiliation(s)
- Daniel Gutiérrez
- Lund Vision Group, Department of Biology, Lund University, Sölvegatan 35, Lund, S-22362, Sweden
| | - Elisa Rigosi
- Lund Vision Group, Department of Biology, Lund University, Sölvegatan 35, Lund, S-22362, Sweden
| | - Nicolas Nagloo
- Lund Vision Group, Department of Biology, Lund University, Sölvegatan 35, Lund, S-22362, Sweden
| | - David O'Carroll
- Lund Vision Group, Department of Biology, Lund University, Sölvegatan 35, Lund, S-22362, Sweden
| | - Eric J Warrant
- Lund Vision Group, Department of Biology, Lund University, Sölvegatan 35, Lund, S-22362, Sweden
| |
Collapse
|
2
|
Goulard R, Heinze S, Webb B. Emergent spatial goals in an integrative model of the insect central complex. PLoS Comput Biol 2023; 19:e1011480. [PMID: 38109465 PMCID: PMC10760860 DOI: 10.1371/journal.pcbi.1011480] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2023] [Revised: 01/02/2024] [Accepted: 12/01/2023] [Indexed: 12/20/2023] Open
Abstract
The insect central complex appears to encode and process spatial information through vector manipulation. Here, we draw on recent insights into circuit structure to fuse previous models of sensory-guided navigation, path integration and vector memory. Specifically, we propose that the allocentric encoding of location provided by path integration creates a spatially stable anchor for converging sensory signals that is relevant in multiple behavioural contexts. The allocentric reference frame given by path integration transforms a goal direction into a goal location and we demonstrate through modelling that it can enhance approach of a sensory target in noisy, cluttered environments or with temporally sparse stimuli. We further show the same circuit can improve performance in the more complex navigational task of route following. The model suggests specific functional roles for circuit elements of the central complex that helps explain their high preservation across insect species.
Collapse
Affiliation(s)
- Roman Goulard
- Lund Vision Group, Department of Biology, Lund University, Lund, Sweden
| | - Stanley Heinze
- Lund Vision Group, Department of Biology, Lund University, Lund, Sweden
| | - Barbara Webb
- Institute for Perception, Action, and Behaviour, School of Informatics, University of Edinburgh, Edinburgh, Scotland, United Kingdom
| |
Collapse
|
3
|
Ogawa Y, Nicholas S, Thyselius M, Leibbrandt R, Nowotny T, Knight JC, Nordström K. Descending neurons of the hoverfly respond to pursuits of artificial targets. Curr Biol 2023; 33:4392-4404.e5. [PMID: 37776861 DOI: 10.1016/j.cub.2023.08.091] [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: 05/19/2023] [Revised: 07/11/2023] [Accepted: 08/31/2023] [Indexed: 10/02/2023]
Abstract
Many animals use motion vision information to control dynamic behaviors. Predatory animals, for example, show an exquisite ability to detect rapidly moving prey, followed by pursuit and capture. Such target detection is not only used by predators but is also important in conspecific interactions, such as for male hoverflies defending their territories against conspecific intruders. Visual target detection is believed to be subserved by specialized target-tuned neurons found in a range of species, including vertebrates and arthropods. However, how these target-tuned neurons respond to actual pursuit trajectories is currently not well understood. To redress this, we recorded extracellularly from target-selective descending neurons (TSDNs) in male Eristalis tenax hoverflies. We show that they have dorso-frontal receptive fields with a preferred direction up and away from the visual midline. We reconstructed visual flow fields as experienced during pursuits of artificial targets (black beads). We recorded TSDN responses to six reconstructed pursuits and found that each neuron responded consistently at remarkably specific time points but that these time points differed between neurons. We found that the observed spike probability was correlated with the spike probability predicted from each neuron's receptive field and size tuning. Interestingly, however, the overall response rate was low, with individual neurons responding to only a small part of each reconstructed pursuit. In contrast, the TSDN population responded to substantially larger proportions of the pursuits but with lower probability. This large variation between neurons could be useful if different neurons control different parts of the behavioral output.
Collapse
Affiliation(s)
- Yuri Ogawa
- Flinders Health and Medical Research Institute, Flinders University, GPO Box 2100, Adelaide, SA 5001, Australia
| | - Sarah Nicholas
- Flinders Health and Medical Research Institute, Flinders University, GPO Box 2100, Adelaide, SA 5001, Australia
| | - Malin Thyselius
- Department of Medical Cell Biology, Uppsala University, 75123 Uppsala, Sweden; School of Medical Sciences, Faculty of Medicine and Health, Örebro University, Örebro 701 82, Sweden
| | - Richard Leibbrandt
- College of Science and Engineering, Flinders University, GPO Box 2100, Adelaide, SA 5001, Australia
| | - Thomas Nowotny
- School of Engineering and Informatics, University of Sussex, Brighton BN1 9QJ, UK
| | - James C Knight
- School of Engineering and Informatics, University of Sussex, Brighton BN1 9QJ, UK
| | - Karin Nordström
- Flinders Health and Medical Research Institute, Flinders University, GPO Box 2100, Adelaide, SA 5001, Australia; Department of Medical Cell Biology, Uppsala University, 75123 Uppsala, Sweden.
| |
Collapse
|
4
|
Perez M, Bagheri ZM, Brown C, Ogawa Y, Partridge JC, Hemmi JM. Contrast sensitivity, visual acuity and the effect of behavioural state on optokinetic gain in fiddler crabs. J Exp Biol 2023; 226:jeb245799. [PMID: 37732387 DOI: 10.1242/jeb.245799] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2023] [Accepted: 09/14/2023] [Indexed: 09/22/2023]
Abstract
Most animals rely on visual information for a variety of everyday tasks. The information available to a visual system depends in part on its spatial resolving power and contrast sensitivity. Because of their competing demands for physical space within an eye, these traits cannot simultaneously be improved without increasing overall eye size. The contrast sensitivity function is an integrated measure of visual performance that measures both resolution and contrast sensitivity. Its measurement helps us identify how different species have made a trade-off between contrast sensitivity and spatial resolution. It further allows us to identify the evolutionary drivers of sensory processing and visually mediated behaviour. Here, we measured the contrast sensitivity function of the fiddler crab Gelasimus dampieri using its optokinetic responses to wide-field moving sinusoidal intensity gratings of different orientations, spatial frequencies, contrasts and speeds. We further tested whether the behavioural state of the crabs (i.e. whether crabs are actively walking or not) affects their optokinetic gain and contrast sensitivity. Our results from a group of five crabs suggest a minimum perceived contrast of 6% and a horizontal and vertical visual acuity of 0.4 cyc deg-1 and 0.28 cyc deg-1, respectively, in the crabs' region of maximum optomotor sensitivity. Optokinetic gain increased in moving crabs compared with restrained crabs, adding another example of the importance of naturalistic approaches when studying the performance of animals.
Collapse
Affiliation(s)
- Monika Perez
- School of Biological Sciences, the University of Western Australia, Perth, WA 6009, Australia
| | - Zahra M Bagheri
- School of Biological Sciences, the University of Western Australia, Perth, WA 6009, Australia
- The UWA Oceans Institute, the University of Western Australia, Perth, WA 6009, Australia
| | - Courtney Brown
- School of Biological Sciences, the University of Western Australia, Perth, WA 6009, Australia
| | - Yuri Ogawa
- School of Biological Sciences, the University of Western Australia, Perth, WA 6009, Australia
| | - Julian C Partridge
- The UWA Oceans Institute, the University of Western Australia, Perth, WA 6009, Australia
| | - Jan M Hemmi
- School of Biological Sciences, the University of Western Australia, Perth, WA 6009, Australia
- The UWA Oceans Institute, the University of Western Australia, Perth, WA 6009, Australia
| |
Collapse
|
5
|
Nicholas S, Ogawa Y, Nordström K. Dual Receptive Fields Underlying Target and Wide-Field Motion Sensitivity in Looming-Sensitive Descending Neurons. eNeuro 2023; 10:ENEURO.0188-23.2023. [PMID: 37429705 PMCID: PMC10368147 DOI: 10.1523/eneuro.0188-23.2023] [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: 05/31/2023] [Accepted: 06/16/2023] [Indexed: 07/12/2023] Open
Abstract
Responding rapidly to visual stimuli is fundamental for many animals. For example, predatory birds and insects alike have amazing target detection abilities, with incredibly short neural and behavioral delays, enabling efficient prey capture. Similarly, looming objects need to be rapidly avoided to ensure immediate survival, as these could represent approaching predators. Male Eristalis tenax hoverflies are nonpredatory, highly territorial insects that perform high-speed pursuits of conspecifics and other territorial intruders. During the initial stages of the pursuit, the retinal projection of the target is very small, but this grows to a larger object before physical interaction. Supporting such behaviors, E. tenax and other insects have both target-tuned and loom-sensitive neurons in the optic lobes and the descending pathways. We here show that these visual stimuli are not necessarily encoded in parallel. Indeed, we describe a class of descending neurons that respond to small targets, to looming and to wide-field stimuli. We show that these descending neurons have two distinct receptive fields where the dorsal receptive field is sensitive to the motion of small targets and the ventral receptive field responds to larger objects or wide-field stimuli. Our data suggest that the two receptive fields have different presynaptic input, where the inputs are not linearly summed. This novel and unique arrangement could support different behaviors, including obstacle avoidance, flower landing, and target pursuit or capture.
Collapse
Affiliation(s)
- Sarah Nicholas
- Flinders Health and Medical Research Institute, Flinders University, Adelaide 5001, Australia
| | - Yuri Ogawa
- Flinders Health and Medical Research Institute, Flinders University, Adelaide 5001, Australia
| | - Karin Nordström
- Flinders Health and Medical Research Institute, Flinders University, Adelaide 5001, Australia
- Department of Medical Cell Biology, Uppsala University, 75123 Uppsala, Sweden
| |
Collapse
|
6
|
Tan C, Cai X, Luo Z, Li Z, Xiu C, Chen Z, Bian L. Visual acuity of Empoasca onukii (Hemiptera, Cicadellidae). INSECTS 2023; 14:370. [PMID: 37103185 PMCID: PMC10145553 DOI: 10.3390/insects14040370] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/10/2023] [Revised: 04/04/2023] [Accepted: 04/05/2023] [Indexed: 06/19/2023]
Abstract
Empoasca onukii is a common tea plant pest with a preference for the color yellow. Past work has shown that host leaf color is a key cue for habitat location for E. onukii. Before studying the effect of foliage shape, size, or texture on habitat localization, it is necessary to determine the visual acuity and effective viewing distance of E. onukii. In this study, a combination of 3D microscopy and X-ray microtomography showed that visual acuity did not significantly differ between females and males, but there were significant differences in the visual acuity and optical sensitivity among five regions of E. onukii's compound eyes. The dorsal ommatidia had the highest visual acuity at 0.28 cycles per degree (cpd) but the lowest optical sensitivity (0.02 μm2sr), which indicated a trade-off between visual resolution and optical sensitivity for E. onukii. The visual acuity determined from the behavioral experiment was 0.14 cpd; E. onukii exhibited low-resolution vision and could only distinguish the units in a yellow/red pattern within 30 cm. Therefore, visual acuity contributes to the limited ability of E. onukii to distinguish the visual details of a distant target, which might be perceived as a lump of blurred color of intermediate brightness.
Collapse
Affiliation(s)
- Chang Tan
- Tea Research Institute, Chinese Academy of Agricultural Science, 9 Meiling South Road, Xihu District, Hangzhou 310008, China
| | - Xiaoming Cai
- Tea Research Institute, Chinese Academy of Agricultural Science, 9 Meiling South Road, Xihu District, Hangzhou 310008, China
- Key Laboratory of Tea Biology and Resource Utilization, Ministry of Agriculture, 9 Meiling South Road, Xihu District, Hangzhou 310008, China
| | - Zongxiu Luo
- Tea Research Institute, Chinese Academy of Agricultural Science, 9 Meiling South Road, Xihu District, Hangzhou 310008, China
- Key Laboratory of Tea Biology and Resource Utilization, Ministry of Agriculture, 9 Meiling South Road, Xihu District, Hangzhou 310008, China
| | - Zhaoqun Li
- Tea Research Institute, Chinese Academy of Agricultural Science, 9 Meiling South Road, Xihu District, Hangzhou 310008, China
- Key Laboratory of Tea Biology and Resource Utilization, Ministry of Agriculture, 9 Meiling South Road, Xihu District, Hangzhou 310008, China
| | - Chunli Xiu
- Tea Research Institute, Chinese Academy of Agricultural Science, 9 Meiling South Road, Xihu District, Hangzhou 310008, China
- Key Laboratory of Tea Biology and Resource Utilization, Ministry of Agriculture, 9 Meiling South Road, Xihu District, Hangzhou 310008, China
| | - Zongmao Chen
- Tea Research Institute, Chinese Academy of Agricultural Science, 9 Meiling South Road, Xihu District, Hangzhou 310008, China
- Key Laboratory of Tea Biology and Resource Utilization, Ministry of Agriculture, 9 Meiling South Road, Xihu District, Hangzhou 310008, China
| | - Lei Bian
- Tea Research Institute, Chinese Academy of Agricultural Science, 9 Meiling South Road, Xihu District, Hangzhou 310008, China
- Key Laboratory of Tea Biology and Resource Utilization, Ministry of Agriculture, 9 Meiling South Road, Xihu District, Hangzhou 310008, China
| |
Collapse
|
7
|
Thyselius M, Ogawa Y, Leibbrandt R, Wardill TJ, Gonzalez-Bellido PT, Nordström K. Hoverfly (Eristalis tenax) pursuit of artificial targets. J Exp Biol 2023; 226:289473. [PMID: 36695720 PMCID: PMC10088529 DOI: 10.1242/jeb.244895] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2022] [Accepted: 01/18/2023] [Indexed: 01/26/2023]
Abstract
The ability to visualize small moving objects is vital for the survival of many animals, as these could represent predators or prey. For example, predatory insects, including dragonflies, robber flies and killer flies, perform elegant, high-speed pursuits of both biological and artificial targets. Many non-predatory insects, including male hoverflies and blowflies, also pursue targets during territorial or courtship interactions. To date, most hoverfly pursuits have been studied outdoors. To investigate hoverfly (Eristalis tenax) pursuits under more controlled settings, we constructed an indoor arena that was large enough to encourage naturalistic behavior. We presented artificial beads of different sizes, moving at different speeds, and filmed pursuits with two cameras, allowing subsequent 3D reconstruction of the hoverfly and bead position as a function of time. We show that male E. tenax hoverflies are unlikely to use strict heuristic rules based on angular size or speed to determine when to start pursuit, at least in our indoor setting. We found that hoverflies pursued faster beads when the trajectory involved flying downwards towards the bead. Furthermore, we show that target pursuit behavior can be broken down into two stages. In the first stage, the hoverfly attempts to rapidly decreases the distance to the target by intercepting it at high speed. During the second stage, the hoverfly's forward speed is correlated with the speed of the bead, so that the hoverfly remains close, but without catching it. This may be similar to dragonfly shadowing behavior, previously coined 'motion camouflage'.
Collapse
Affiliation(s)
- Malin Thyselius
- Department of Medical Cell Biology, Uppsala University, 75123 Uppsala, Sweden
| | - Yuri Ogawa
- Flinders Health and Medical Research Institute, Flinders University, GPO Box 2100, Adelaide, SA 5001, Australia
| | - Richard Leibbrandt
- College of Science and Engineering, Flinders University, GPO Box 2100, Adelaide, SA 5001, Australia
| | - Trevor J Wardill
- Department of Ecology, Evolution and Behavior, University of Minnesota, Saint Paul, MN 55108, USA
| | | | - Karin Nordström
- Department of Medical Cell Biology, Uppsala University, 75123 Uppsala, Sweden.,Flinders Health and Medical Research Institute, Flinders University, GPO Box 2100, Adelaide, SA 5001, Australia
| |
Collapse
|
8
|
Nagloo N, Rigosi E, O'Carroll DC. Acute and chronic toxicity of imidacloprid in the pollinator fly, Eristalis tenax L., assessed using a novel oral bioassay. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2023; 251:114505. [PMID: 36646007 DOI: 10.1016/j.ecoenv.2023.114505] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/25/2022] [Revised: 11/09/2022] [Accepted: 01/02/2023] [Indexed: 06/17/2023]
Abstract
Imidacloprid is a neonicotinoid neurotoxin that remains widely used worldwide and persists in the environment, resulting in chronic exposure to non-target insects. To accurately map dose-dependent effects of such exposure across taxa, toxicological assays need to assess relevant modes of exposure across indicator species. However, due to the difficulty of these experiments, contact bioassays are most frequently used to quantify dose. Here, we developed a novel naturalistic feeding bioassay to precisely measure imidacloprid ingestion and its toxicity for acute and chronic exposure in a dipteran, Eristalis tenax L., an important member of an under-represented pollinator group. Flies which ingested imidacloprid dosages lower than 12.1 ng/mg all showed consistent intake volumes and learned improved feeding efficiency over successive feeding sessions. In contrast, at doses of 12.1 ng/mg and higher flies showed a rapid onset of severe locomotive impairment which prevented them from completing the feeding task. Neither probability of survival nor severe locomotive impairment were significantly higher than the control group until doses of 1.43 ng/mg or higher were reached. We were unable to measure a median lethal dose for acute exposure (72 h) due to flies possessing a relatively high tolerance for imidacloprid. However, with chronic exposure (18 days), mortality went up and an LD50 of 0.41 ng/mg was estimated. Severe locomotive impairment (immobilisation) tended to occur earlier and at lower dosages than lethality, with ED50s of 7.82 ng/mg and 0.17 ng/mg for acute and chronic exposure, respectively. We conclude that adult Eristalis possess a much higher tolerance to this toxin than the honeybees that they mimic. The similarity of the LD50 to other dipterans such as the fruitfly and the housefly suggests that there may be a phylogenetic component to pesticide tolerance that merits further investigation. The absence of obvious adverse effects at sublethal dosages also underscores a need to develop better tools for quantifying animal behaviour to evaluate the impact of insecticides on foraging efficiency in economically important species.
Collapse
Affiliation(s)
| | - Elisa Rigosi
- Department of Biology Lund University, Lund, Sweden
| | | |
Collapse
|
9
|
Skelton PSM, Finn A, Brinkworth RSA. Contrast independent biologically inspired translational optic flow estimation. BIOLOGICAL CYBERNETICS 2022; 116:635-660. [PMID: 36303043 PMCID: PMC9691503 DOI: 10.1007/s00422-022-00948-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/19/2021] [Accepted: 10/11/2022] [Indexed: 06/16/2023]
Abstract
The visual systems of insects are relatively simple compared to humans. However, they enable navigation through complex environments where insects perform exceptional levels of obstacle avoidance. Biology uses two separable modes of optic flow to achieve this: rapid gaze fixation (rotational motion known as saccades); and the inter-saccadic translational motion. While the fundamental process of insect optic flow has been known since the 1950's, so too has its dependence on contrast. The surrounding visual pathways used to overcome environmental dependencies are less well known. Previous work has shown promise for low-speed rotational motion estimation, but a gap remained in the estimation of translational motion, in particular the estimation of the time to impact. To consistently estimate the time to impact during inter-saccadic translatory motion, the fundamental limitation of contrast dependence must be overcome. By adapting an elaborated rotational velocity estimator from literature to work for translational motion, this paper proposes a novel algorithm for overcoming the contrast dependence of time to impact estimation using nonlinear spatio-temporal feedforward filtering. By applying bioinspired processes, approximately 15 points per decade of statistical discrimination were achieved when estimating the time to impact to a target across 360 background, distance, and velocity combinations: a 17-fold increase over the fundamental process. These results show the contrast dependence of time to impact estimation can be overcome in a biologically plausible manner. This, combined with previous results for low-speed rotational motion estimation, allows for contrast invariant computational models designed on the principles found in the biological visual system, paving the way for future visually guided systems.
Collapse
Affiliation(s)
- Phillip S. M. Skelton
- Centre for Defence Engineering Research and Training, College of Science and Engineering, Flinders University, 1284 South Road, Tonsley, South Australia 5042 Australia
| | - Anthony Finn
- Science, Technology, Engineering, and Mathematics, University of South Australia, 1 Mawson Lakes Boulevard, Mawson Lakes, South Australia 5095 Australia
| | - Russell S. A. Brinkworth
- Centre for Defence Engineering Research and Training, College of Science and Engineering, Flinders University, 1284 South Road, Tonsley, South Australia 5042 Australia
| |
Collapse
|
10
|
Stöckl A, Grittner R, Taylor G, Rau C, Bodey AJ, Kelber A, Baird E. Allometric scaling of a superposition eye optimizes sensitivity and acuity in large and small hawkmoths. Proc Biol Sci 2022; 289:20220758. [PMID: 35892218 PMCID: PMC9326294 DOI: 10.1098/rspb.2022.0758] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Animals vary widely in body size within and across species. This has consequences for the function of organs and body parts in both large and small individuals. How these scale, in relation to body size, reveals evolutionary investment strategies, often resulting in trade-offs between functions. Eyes exemplify these trade-offs, as they are limited by their absolute size in two key performance features: sensitivity and spatial acuity. Due to their size polymorphism, insect compound eyes are ideal models for studying the allometric scaling of eye performance. Previous work on apposition compound eyes revealed that allometric scaling led to poorer spatial resolution and visual sensitivity in small individuals, across a range of insect species. Here, we used X-ray microtomography to investigate allometric scaling in superposition compound eyes-the second most common eye type in insects-for the first time. Our results reveal a novel strategy to cope with the trade-off between sensitivity and spatial acuity, as we show that the eyes of the hummingbird hawkmoth retain an optimal balance between these performance measures across all body sizes.
Collapse
Affiliation(s)
- Anna Stöckl
- Behavioral Physiology and Sociobiology (Zoology II), University of Würzburg, Würzburg, Germany
| | - Rebecca Grittner
- Behavioral Physiology and Sociobiology (Zoology II), University of Würzburg, Würzburg, Germany
| | - Gavin Taylor
- Institute for Globally Distributed Open Research and Education (IGDORE), Ribeirão Preto, Brazil
| | - Christoph Rau
- Diamond Light Source, Harwell Science and Innovation Campus, Didcot, UK
| | - Andrew J. Bodey
- Diamond Light Source, Harwell Science and Innovation Campus, Didcot, UK
| | - Almut Kelber
- Department of Biology, Lund University, Lund, Sweden
| | - Emily Baird
- Department of Zoology, Stockholm University, Stockholm, Sweden
| |
Collapse
|
11
|
Evans BJE, O’Carroll DC, Fabian JM, Wiederman SD. Dragonfly Neurons Selectively Attend to Targets Within Natural Scenes. Front Cell Neurosci 2022; 16:857071. [PMID: 35450210 PMCID: PMC9017788 DOI: 10.3389/fncel.2022.857071] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2022] [Accepted: 03/11/2022] [Indexed: 12/05/2022] Open
Abstract
Aerial predators, such as the dragonfly, determine the position and movement of their prey even when both are moving through complex, natural scenes. This task is likely supported by a group of neurons in the optic lobe which respond to moving targets that subtend less than a few degrees. These Small Target Motion Detector (STMD) neurons are tuned to both target size and velocity, whilst also exhibiting facilitated responses to targets traveling along continuous trajectories. When presented with a pair of targets, some STMDs generate spiking activity that represent a competitive selection of one target, as if the alternative does not exist (i.e., selective attention). Here, we describe intracellular responses of CSTMD1 (an identified STMD) to the visual presentation of targets embedded within cluttered, natural scenes. We examine CSTMD1 response changes to target contrast, as well as a range of target and background velocities. We find that background motion affects CSTMD1 responses via the competitive selection between features within the natural scene. Here, robust discrimination of our artificially embedded "target" is limited to scenarios when its velocity is matched to, or greater than, the background velocity. Additionally, the background's direction of motion affects discriminability, though not in the manner observed in STMDs of other flying insects. Our results highlight that CSTMD1's competitive responses are to those features best matched to the neuron's underlying spatiotemporal tuning, whether from the embedded target or other features in the background clutter. In many scenarios, CSTMD1 responds robustly to targets moving through cluttered scenes. However, whether this neuronal system could underlie the task of competitively selecting slow moving prey against fast-moving backgrounds remains an open question.
Collapse
|
12
|
Moradinour Z, Wiklund C, Jie VW, Restrepo CE, Gotthard K, Miettinen A, Perl CD, Baird E. Sensory Organ Investment Varies with Body Size and Sex in the Butterfly Pieris napi. INSECTS 2021; 12:insects12121064. [PMID: 34940152 PMCID: PMC8707955 DOI: 10.3390/insects12121064] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/29/2021] [Revised: 11/23/2021] [Accepted: 11/25/2021] [Indexed: 11/16/2022]
Abstract
In solitary insect pollinators such as butterflies, sensory systems must be adapted for multiple tasks, including nectar foraging, mate-finding, and locating host-plants. As a result, the energetic investments between sensory organs can vary at the intraspecific level and even among sexes. To date, little is known about how these investments are distributed between sensory systems and how it varies among individuals of different sex. We performed a comprehensive allometric study on males and females of the butterfly Pieris napi where we measured the sizes and other parameters of sensory traits including eyes, antennae, proboscis, and wings. Our findings show that among all the sensory traits measured, only antenna and wing size have an allometric relationship with body size and that the energetic investment in different sensory systems varies between males and females. Moreover, males had absolutely larger antennae and eyes, indicating that they invest more energy in these organs than females of the same body size. Overall, the findings of this study reveal that the size of sensory traits in P. napi are not necessarily related to body size and raises questions about other factors that drive sensory trait investment in this species and in other insect pollinators in general.
Collapse
Affiliation(s)
- Zahra Moradinour
- Department of Zoology, Stockholm University, 106 91 Stockholm, Sweden; (C.W.); (V.W.J.); (C.E.R.); (K.G.); (C.D.P.); (E.B.)
- Correspondence:
| | - Christer Wiklund
- Department of Zoology, Stockholm University, 106 91 Stockholm, Sweden; (C.W.); (V.W.J.); (C.E.R.); (K.G.); (C.D.P.); (E.B.)
| | - Vun Wen Jie
- Department of Zoology, Stockholm University, 106 91 Stockholm, Sweden; (C.W.); (V.W.J.); (C.E.R.); (K.G.); (C.D.P.); (E.B.)
| | - Carlos E. Restrepo
- Department of Zoology, Stockholm University, 106 91 Stockholm, Sweden; (C.W.); (V.W.J.); (C.E.R.); (K.G.); (C.D.P.); (E.B.)
| | - Karl Gotthard
- Department of Zoology, Stockholm University, 106 91 Stockholm, Sweden; (C.W.); (V.W.J.); (C.E.R.); (K.G.); (C.D.P.); (E.B.)
| | - Arttu Miettinen
- Swiss Light Source, Paul Scherrer Institute, 5234 Villigen, Switzerland;
- Department of Physics, University of Jyvaskyla, 40014 Jyvaskyla, Finland
| | - Craig D. Perl
- Department of Zoology, Stockholm University, 106 91 Stockholm, Sweden; (C.W.); (V.W.J.); (C.E.R.); (K.G.); (C.D.P.); (E.B.)
- Department of Biology, Lund University, 223 62 Lund, Sweden
- School of Life Sciences, Arizona State University, Tempe, AZ 85281, USA
| | - Emily Baird
- Department of Zoology, Stockholm University, 106 91 Stockholm, Sweden; (C.W.); (V.W.J.); (C.E.R.); (K.G.); (C.D.P.); (E.B.)
| |
Collapse
|
13
|
Abstract
We present a genome assembly from an individual female Eristalis tenax (the drone fly; Arthropoda; Insecta; Diptera; Syriphidae). The genome sequence is 487 megabases in span. The majority of the assembly (96.50%) is scaffolded into six chromosomal pseudomolecules, with the X sex chromosome assembled.
Collapse
|
14
|
Rigosi E, Warrant EJ, O’Carroll DC. A new, fluorescence-based method for visualizing the pseudopupil and assessing optical acuity in the dark compound eyes of honeybees and other insects. Sci Rep 2021; 11:21267. [PMID: 34711871 PMCID: PMC8553845 DOI: 10.1038/s41598-021-00407-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2021] [Accepted: 10/11/2021] [Indexed: 11/24/2022] Open
Abstract
Recent interest in applying novel imaging techniques to infer optical resolution in compound eyes underscores the difficulty of obtaining direct measures of acuity. A widely used technique exploits the principal pseudopupil, a dark spot on the eye surface representing the ommatidial gaze direction and the number of detector units (ommatidia) viewing that gaze direction. However, dark-pigmented eyes, like those of honeybees, lack a visible pseudopupil. Attempts over almost a century to estimate optical acuity in this species are still debated. Here, we developed a method to visualize a stable, reliable pseudopupil by staining the photoreceptors with fluorescent dyes. We validated this method in several species and found it to outperform the dark pseudopupil for this purpose, even in pale eyes, allowing more precise location of the gaze centre. We then applied this method to estimate the sampling resolution in the frontal part of the eye of the honeybee forager. We found a broad frontal acute zone with interommatidial angles below 2° and a minimum interommatidial angle of 1.3°, a broader, sharper frontal acute zone than previously reported. Our study provides a new method to directly measure the sampling resolution in most compound eyes of living animals.
Collapse
Affiliation(s)
- Elisa Rigosi
- grid.4514.40000 0001 0930 2361Department of Biology, Lund University, Sölvegatan 35, 22362 Lund, Sweden
| | - Eric J. Warrant
- grid.4514.40000 0001 0930 2361Department of Biology, Lund University, Sölvegatan 35, 22362 Lund, Sweden
| | - David C. O’Carroll
- grid.4514.40000 0001 0930 2361Department of Biology, Lund University, Sölvegatan 35, 22362 Lund, Sweden
| |
Collapse
|
15
|
Facilitation of neural responses to targets moving against optic flow. Proc Natl Acad Sci U S A 2021; 118:2024966118. [PMID: 34531320 PMCID: PMC8463850 DOI: 10.1073/pnas.2024966118] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/27/2021] [Indexed: 01/08/2023] Open
Abstract
Target detection in visual clutter is a difficult computational task that insects, with their poor spatial resolution compound eyes and small brains, do successfully and with extremely short behavioral delays. We here show that the responses of target selective descending neurons are attenuated by background motion in the same direction as target motion but facilitated by background motion in the opposite direction. This finding is important for understanding how target pursuit can occur in tandem with gaze stabilization. Indeed, the neural facilitation would come into effect if the hoverfly is subjected to background motion in one direction but the target it is pursuing moves in the opposite direction and could therefore be used to override gaze stabilizing corrective turns. For the human observer, it can be difficult to follow the motion of small objects, especially when they move against background clutter. In contrast, insects efficiently do this, as evidenced by their ability to capture prey, pursue conspecifics, or defend territories, even in highly textured surrounds. We here recorded from target selective descending neurons (TSDNs), which likely subserve these impressive behaviors. To simulate the type of optic flow that would be generated by the pursuer’s own movements through the world, we used the motion of a perspective corrected sparse dot field. We show that hoverfly TSDN responses to target motion are suppressed when such optic flow moves syn-directional to the target. Indeed, neural responses are strongly suppressed when targets move over either translational sideslip or rotational yaw. More strikingly, we show that TSDNs are facilitated by optic flow moving counterdirectional to the target, if the target moves horizontally. Furthermore, we show that a small, frontal spatial window of optic flow is enough to fully facilitate or suppress TSDN responses to target motion. We argue that such TSDN response facilitation could be beneficial in modulating corrective turns during target pursuit.
Collapse
|
16
|
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.
Collapse
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
| |
Collapse
|
17
|
Paterson JR, Edgecombe GD, García-Bellido DC. Disparate compound eyes of Cambrian radiodonts reveal their developmental growth mode and diverse visual ecology. SCIENCE ADVANCES 2020; 6:6/49/eabc6721. [PMID: 33268353 PMCID: PMC7821881 DOI: 10.1126/sciadv.abc6721] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/07/2020] [Accepted: 10/20/2020] [Indexed: 05/28/2023]
Abstract
Radiodonts are nektonic stem-group euarthropods that played various trophic roles in Paleozoic marine ecosystems, but information on their vision is limited. Optical details exist only in one species from the Cambrian Emu Bay Shale of Australia, here assigned to Anomalocaris aff. canadensis We identify another type of radiodont compound eye from this deposit, belonging to 'Anomalocaris' briggsi This ≤4-cm sessile eye has >13,000 lenses and a dorsally oriented acute zone. In both taxa, lenses were added marginally and increased in size and number throughout development, as in many crown-group euarthropods. Both species' eyes conform to their inferred lifestyles: The macrophagous predator A. aff. canadensis has acute stalked eyes (>24,000 lenses each) adapted for hunting in well-lit waters, whereas the suspension-feeding 'A.' briggsi could detect plankton in dim down-welling light. Radiodont eyes further demonstrate the group's anatomical and ecological diversity and reinforce the crucial role of vision in early animal ecosystems.
Collapse
Affiliation(s)
- John R Paterson
- Palaeoscience Research Centre, School of Environmental and Rural Science, University of New England, Armidale, NSW 2351, Australia.
| | - Gregory D Edgecombe
- Department of Earth Sciences, The Natural History Museum, Cromwell Road, London SW7 5BD, UK
| | - Diego C García-Bellido
- School of Biological Sciences, University of Adelaide, Adelaide, SA 5005, Australia
- South Australian Museum, North Terrace, Adelaide, SA 5000, Australia
| |
Collapse
|
18
|
Persistent Firing and Adaptation in Optic-Flow-Sensitive Descending Neurons. Curr Biol 2020; 30:2739-2748.e2. [PMID: 32470368 DOI: 10.1016/j.cub.2020.05.019] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2020] [Revised: 04/22/2020] [Accepted: 05/06/2020] [Indexed: 02/07/2023]
Abstract
A general principle of sensory systems is that they adapt to prolonged stimulation by reducing their response over time. Indeed, in many visual systems, including higher-order motion sensitive neurons in the fly optic lobes and the mammalian visual cortex, a reduction in neural activity following prolonged stimulation occurs. In contrast to this phenomenon, the response of the motor system controlling flight maneuvers persists following the offset of visual motion. It has been suggested that this gap is caused by a lingering calcium signal in the output synapses of fly optic lobe neurons. However, whether this directly affects the responses of the post-synaptic descending neurons, leading to the observed behavioral output, is not known. We use extracellular electrophysiology to record from optic-flow-sensitive descending neurons in response to prolonged wide-field stimulation. We find that, as opposed to most sensory and visual neurons, and in particular to the motion vision sensitive neurons in the brains of both flies and mammals, the descending neurons show little adaption during stimulus motion. In addition, we find that the optic-flow-sensitive descending neurons display persistent firing, or an after-effect, following the cessation of visual stimulation, consistent with the lingering calcium signal hypothesis. However, if the difference in after-effect is compensated for, subsequent presentation of stimuli in a test-adapt-test paradigm reveals adaptation to visual motion. Our results thus show a combination of adaptation and persistent firing in the neurons that project to the thoracic ganglia and thereby control behavioral output.
Collapse
|
19
|
Taylor GJ, Hall SA, Gren JA, Baird E. Exploring the visual world of fossilized and modern fungus gnat eyes (Diptera: Keroplatidae) with X-ray microtomography. J R Soc Interface 2020; 17:20190750. [PMID: 32019468 PMCID: PMC7061697 DOI: 10.1098/rsif.2019.0750] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
Animal eyes typically possess specialized regions for guiding different behavioural tasks within their specific visual habitat. These specializations, and evolutionary changes to them, can be crucial for understanding an animal's ecology. Here, we explore how the visual systems of some of the smallest flying insects, fungus gnats, have adapted to different types of forest habitat over time (approx. 30 Myr to today). Unravelling how behavioural, environmental and phylogenetic factors influence the evolution of visual specializations is difficult, however, because standard quantitative techniques often require fresh tissue and/or provide data in eye-centric coordinates that prevent reliable comparisons between species with different eye morphologies. Here, we quantify the visual world of three gnats from different time periods and habitats using X-ray microtomography to create high-resolution three-dimensional models of the compound eyes of specimens in different preservation states—fossilized in amber, dried or stored in ethanol. We present a method for analysing the geometric details of individual corneal facets and for estimating and comparing the sensitivity, spatial resolution and field of view of species across geographical space and evolutionary time. Our results indicate that, despite their miniature size, fungus gnats do have variations in visual properties across their eyes. We also find some indication that these visual specializations vary across species and may represent adaptations to their different forest habitats. Overall, the findings demonstrate how such investigations can be used to study the evolution of visual specializations—and sensory ecology in general—across a range of insect taxa from different geographical locations and across time.
Collapse
Affiliation(s)
| | - Stephen A Hall
- Division of Solid Mechanics, Lund University, Lund, Sweden
| | - Johan A Gren
- Department of Geology, Lund University, Lund, Sweden
| | - Emily Baird
- Department of Biology, Lund University, Lund, Sweden.,Department of Zoology, Stockholm University, Stockholm, Sweden
| |
Collapse
|
20
|
Nicholas S, Leibbrandt R, Nordström K. Visual motion sensitivity in descending neurons in the hoverfly. J Comp Physiol A Neuroethol Sens Neural Behav Physiol 2020; 206:149-163. [PMID: 31989217 PMCID: PMC7069906 DOI: 10.1007/s00359-020-01402-0] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2019] [Accepted: 12/06/2019] [Indexed: 01/11/2023]
Abstract
Many animals use motion vision information to control dynamic behaviors. For example, flying insects must decide whether to pursue a prey or not, to avoid a predator, to maintain their current flight trajectory, or to land. The neural mechanisms underlying the computation of visual motion have been particularly well investigated in the fly optic lobes. However, the descending neurons, which connect the optic lobes with the motor command centers of the ventral nerve cord, remain less studied. To address this deficiency, we describe motion vision sensitive descending neurons in the hoverfly Eristalis tenax. We describe how the neurons can be identified based on their receptive field properties, and how they respond to moving targets, looming stimuli and to widefield optic flow. We discuss their similarities with previously published visual neurons, in the optic lobes and ventral nerve cord, and suggest that they can be classified as target-selective, looming sensitive and optic flow sensitive, based on these similarities. Our results highlight the importance of using several visual stimuli as the neurons can rarely be identified based on only one response characteristic. In addition, they provide an understanding of the neurophysiology of visual neurons that are likely to affect behavior.
Collapse
Affiliation(s)
- Sarah Nicholas
- Centre for Neuroscience, Flinders University, GPO Box 2100, Adelaide, SA, 5001, Australia
| | - Richard Leibbrandt
- Centre for Neuroscience, Flinders University, GPO Box 2100, Adelaide, SA, 5001, Australia
| | - Karin Nordström
- Centre for Neuroscience, Flinders University, GPO Box 2100, Adelaide, SA, 5001, Australia. .,Department of Neuroscience, Uppsala University, Box 593, 751 24 , Uppsala, Sweden.
| |
Collapse
|
21
|
Liang Y, Zhu T, Xi M, Song Y, Fu J, Zhao D, Wang Y, Wang J, Wang K, Wang H. Fabrication of biomimetic compound eye on single crystal diamond. OPTICS EXPRESS 2019; 27:20508-20515. [PMID: 31510143 DOI: 10.1364/oe.27.020508] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/17/2019] [Accepted: 06/15/2019] [Indexed: 06/10/2023]
Abstract
In this study, a biomimetic compound eye (BCE) was realized on diamond by combining thermal reflow with dry etching techniques. Firstly, photoresist pillars were developed on diamond surface by standard photolithography. Then, these pillars were reflowed on a hotplate to form spherical segment patterns. Furthermore, dry etching technique was used to transfer these patterns into diamond surface to form the convex curve surface with diameter of 300 μm, on which, ommatidia with diameter of 18 μm and space of 35 μm were fabricated with the same processes to obtain BCE. Finally, the as-fabricated diamond BCE was characterized, indicating a well-uniformity according to the point spread function and exhibiting clear images of the testing pattern in projection experiment, which is expected to work under harsh conditions such as high intensity irradiation and strong acid.
Collapse
|
22
|
Image statistics of the environment surrounding freely behaving hoverflies. J Comp Physiol A Neuroethol Sens Neural Behav Physiol 2019; 205:373-385. [PMID: 30937518 PMCID: PMC6579776 DOI: 10.1007/s00359-019-01329-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2018] [Revised: 02/12/2019] [Accepted: 03/14/2019] [Indexed: 12/04/2022]
Abstract
Natural scenes are not as random as they might appear, but are constrained in both space and time. The 2-dimensional spatial constraints can be described by quantifying the image statistics of photographs. Human observers perceive images with naturalistic image statistics as more pleasant to view, and both fly and vertebrate peripheral and higher order visual neurons are tuned to naturalistic image statistics. However, for a given animal, what is natural differs depending on the behavior, and even if we have a broad understanding of image statistics, we know less about the scenes relevant for particular behaviors. To mitigate this, we here investigate the image statistics surrounding Episyrphus balteatus hoverflies, where the males hover in sun shafts created by surrounding trees, producing a rich and dense background texture and also intricate shadow patterns on the ground. We quantified the image statistics of photographs of the ground and the surrounding panorama, as the ventral and lateral visual field is particularly important for visual flight control, and found differences in spatial statistics in photos where the hoverflies were hovering compared to where they were flying. Our results can, in the future, be used to create more naturalistic stimuli for experimenter-controlled experiments in the laboratory.
Collapse
|
23
|
Taylor GJ, Tichit P, Schmidt MD, Bodey AJ, Rau C, Baird E. Bumblebee visual allometry results in locally improved resolution and globally improved sensitivity. eLife 2019; 8:40613. [PMID: 30803484 PMCID: PMC6391067 DOI: 10.7554/elife.40613] [Citation(s) in RCA: 47] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2018] [Accepted: 12/23/2018] [Indexed: 12/19/2022] Open
Abstract
The quality of visual information that is available to an animal is limited by the size of its eyes. Differences in eye size can be observed even between closely related individuals, yet we understand little about how this affects vision. Insects are good models for exploring the effects of size on visual systems because many insect species exhibit size polymorphism. Previous work has been limited by difficulties in determining the 3D structure of eyes. We have developed a novel method based on x-ray microtomography to measure the 3D structure of insect eyes and to calculate predictions of their visual capabilities. We used our method to investigate visual allometry in the bumblebee Bombus terrestris and found that size affects specific aspects of vision, including binocular overlap, optical sensitivity, and dorsofrontal visual resolution. This reveals that differential scaling between eye areas provides flexibility that improves the visual capabilities of larger bumblebees. Bees fly through complex environments in search of nectar from flowers. They are aided in this quest by excellent eyesight. Scientists have extensively studied the eyesight of honeybees to learn more about how such tiny eyes work and how they process and learn visual information. Less is known about the honeybee’s larger cousins, the bumblebees, which are also important pollinators. Bumblebees come in different sizes and one question scientists have is how eye size affects vision. Bigger bumblebees are known to have bigger eyes, and bigger eyes are usually better. But which aspects of vision are improved in larger eyes is not clear. For example, does the size of a bee’s eyes affect how large their field of view is, or how sensitive they are to light? Or does it impact their visual acuity, a measurement of the smallest objects the eye can see? Scaling up an eye would likely improve all these aspects of sight slightly, but changes in a small area of the eye might more drastically improve some parts of vision. Now, Taylor et al. show that larger bumblebees with bigger eyes have better vision than their smaller counterparts. In the experiments, a technique called microtomography was used to measure the 3D structure of bumblebee eyes. The measurements were then applied to build 3D models of the bumblebee eyes, and computational geometry was used to calculate the sensitivity, acuity, and viewing direction across the entire surface of each model eye. Taylor et al. found that larger bees had improved ability to see small objects in front or slightly above them. They had a bigger area of overlap between the sight in both eyes when they looked forward and up. They were also more sensitive to light across the eye. The experiments show that improvements in eyesight with larger size are very specific and likely help larger bees to adapt to their environment. Behavioral studies could help scientists better understand how these changes help bigger bees and how the traits evolved. These findings might also help engineers trying to design miniature cameras to help small, flying autonomous vehicles navigate. Bees fly through complex environments and face challenges similar to those small flying vehicles would face. Emulating the design of bee eyes and how they change with size might lead to the development of better cameras for these vehicles.
Collapse
Affiliation(s)
| | - Pierre Tichit
- Department of Biology, Lund University, Lund, Sweden
| | - Marie D Schmidt
- Department of Biology, Lund University, Lund, Sweden.,Westphalian University of Applied Sciences, Bocholt, Germany
| | | | | | - Emily Baird
- Department of Biology, Lund University, Lund, Sweden.,Department of Zoology, Stockholm University, Stockholm, Sweden
| |
Collapse
|
24
|
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
|
25
|
Bagheri ZM, Jessop AL, Kato S, Partridge JC, Shaw J, Ogawa Y, Hemmi JM. A new method for mapping spatial resolution in compound eyes suggests two visual streaks in fiddler crabs. J Exp Biol 2019; 223:jeb.210195. [DOI: 10.1242/jeb.210195] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2019] [Accepted: 12/01/2019] [Indexed: 11/20/2022]
Abstract
Visual systems play a vital role in guiding the behaviour of animals. Understanding the visual information animals are able to acquire is therefore key to understanding their visually-mediated decision making. Compound eyes, the dominant eye type in arthropods, are inherently low-resolution structures. Their ability to resolve spatial detail depends on sampling resolution (interommatidial angle) and the quality of ommatidial optics. Current techniques for estimating interommatidial angles are difficult, and generally require in vivo measurements. Here, we present a new method for estimating interommatidial angles based on the detailed analysis of 3D Micro-CT images of fixed samples. Using custom-made MATLAB software we determine the optical axes of individual ommatidia and project these axes into the three-dimensional space around the animal. The combined viewing directions of all ommatidia, estimated from geometrical optics, allow us to estimate interommatidial angles and map the animal's sampling resolution across its entire visual field. The resulting topographic representations of visual acuity match very closely the previously published data obtained from both fiddler and grapsid crabs. However, the new method provides additional detail that was not previously detectable and reveals that fiddler crabs, rather than having a single horizontal visual streak as is common in flat world inhabitants, likely have two parallel streaks located just above and below the visual horizon. A key advantage of our approach is that it can be used on appropriately preserved specimens allowing the technique to be applied to animals such as deep-sea crustaceans that are inaccessible or unsuitable for in vivo approaches.
Collapse
Affiliation(s)
- Zahra M. Bagheri
- School of Biological Sciences, the University of Western Australia, Perth, Australia
| | - Anna-Lee Jessop
- School of Biological Sciences, the University of Western Australia, Perth, Australia
| | - Susumu Kato
- School of Biological Sciences, the University of Western Australia, Perth, Australia
| | - Julian C. Partridge
- The UWA Oceans Institute, the University of Western Australia, Perth, Australia
| | - Jeremy Shaw
- Centre for Microscopy, Characterisation and Analysis, the University of Western Australia, Perth, Australia
| | - Yuri Ogawa
- School of Biological Sciences, the University of Western Australia, Perth, Australia
| | - Jan M. Hemmi
- School of Biological Sciences, the University of Western Australia, Perth, Australia
- The UWA Oceans Institute, the University of Western Australia, Perth, Australia
| |
Collapse
|
26
|
Agrawal S, Dickinson MH. The effects of target contrast on Drosophila courtship. J Exp Biol 2019; 222:jeb.203414. [DOI: 10.1242/jeb.203414] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2019] [Accepted: 07/11/2019] [Indexed: 12/27/2022]
Abstract
Many animals use visual cues like object shape, color, and motion to detect and pursue conspecific mates. Contrast is another possibly informative visual cue, but has not been studied in great detail. In this study, we presented male Drosophila melanogaster with small, fly-sized, moving objects painted either black, white, or grey to test if they use contrast cues to identify mates. We found that males frequently chased grey objects and rarely chased white or black objects. Although males started chasing black objects as often as grey objects, the resulting chases were much shorter. To test whether the attraction to grey objects was mediated via contrast, we fabricated black and grey behavioral chambers. However, wildtype males almost never chased any objects in these darkly colored chambers. To circumvent this limitation, we increased baseline levels of chasing by thermogenetically activating P1 neurons to promote courtship. Males with thermogenetically activated P1 neurons maintained a similar preference for grey objects despite elevated levels of courtship behavior. When placed in a black chamber, males with activated P1 neurons switched their preference and chased black objects more than grey objects. We also tested whether males use contrast cues to orient to particular parts of the female's body during courtship. When presented with moving objects painted two colors, males positioned themselves next to the grey half regardless of whether the other half was painted black or white. These results suggest that males can use contrast to recognize potential mates and to position themselves during courtship.
Collapse
Affiliation(s)
- Sweta Agrawal
- Department of Biophysics and Physiology, University of Washington, Seattle, WA, USA
| | | |
Collapse
|
27
|
Palavalli-Nettimi R, Ogawa Y, Ryan LA, Hart NS, Narendra A. Miniaturisation reduces contrast sensitivity and spatial resolving power in ants. J Exp Biol 2019; 222:jeb.203018. [DOI: 10.1242/jeb.203018] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2019] [Accepted: 05/17/2019] [Indexed: 12/30/2022]
Abstract
Vision is crucial for animals to find prey, locate conspecifics, and to navigate within cluttered landscapes. Animals need to discriminate objects against a visually noisy background. However, the ability to detect spatial information is limited by eye size. In insects, as individuals become smaller, the space available for the eyes reduces, which affects the number of ommatidia, the size of the lens and the downstream information processing capabilities. The evolution of small body size in a lineage, known as miniaturisation, is common in insects. Here, using pattern electroretinography with vertical sinusoidal gratings as stimuli, we studied how miniaturisation affects spatial resolving power and contrast sensitivity in four diurnal ants that live in a similar environment but varied in their body and eye size. We found that ants with fewer and smaller ommatidial facets had lower spatial resolving power and contrast sensitivity. The spatial resolving power was maximum in the largest ant Myrmecia tarsata at 0.60 cycles per degree (cpd) compared to the ant with smallest eyes Rhytidoponera inornata that had 0.48 cpd. Maximum contrast sensitivity (minimum contrast threshold) in M. tarsata (2627 facets) was 15.51 (6.4% contrast detection threshold) at 0.1 cpd, while the smallest ant R. inornata (227 facets) had a maximum contrast sensitivity of 1.34 (74.1% contrast detection threshold) at 0.05 cpd. This is the first study to physiologically investigate contrast sensitivity in the context of insect allometry. Miniaturisation thus dramatically decreases maximum contrast sensitivity and also reduces spatial resolution, which could have implications for visually guided behaviours.
Collapse
Affiliation(s)
| | - Yuri Ogawa
- Department of Biological Sciences, Macquarie University, Sydney, NSW 2109, Australia
| | - Laura A. Ryan
- Department of Biological Sciences, Macquarie University, Sydney, NSW 2109, Australia
| | - Nathan S. Hart
- Department of Biological Sciences, Macquarie University, Sydney, NSW 2109, Australia
| | - Ajay Narendra
- Department of Biological Sciences, Macquarie University, Sydney, NSW 2109, Australia
| |
Collapse
|
28
|
Copley S, Parthasarathy K, Willis MA. Optomotor steering and flight control requires a specific sub-section of the compound eye in the hawkmoth, Manduca sexta. ACTA ACUST UNITED AC 2018; 221:jeb.178210. [PMID: 29967220 DOI: 10.1242/jeb.178210] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2018] [Accepted: 06/26/2018] [Indexed: 11/20/2022]
Abstract
While tracking odor plumes, male hawkmoths use optic flow cues to stabilize their flight movements with respect to their environment. We studied the responses of freely flying moths tracking odor plumes in a laboratory wind tunnel and tethered moths in an optomotor flight simulator to determine the locations on the compound eye on which critical optic flow cues are detected. In these behavioral experiments, we occluded specific regions of the compound eye and systematically examined the moths' behavior for specific deficits in optic flow processing. Freely flying moths with the dorsal half of the compound eye painted were unable to maintain stable flight and track the wind-borne odor plume. However, the plume tracking performance of moths with the ventral half of their compound eyes painted was the same as unpainted controls. In a matched set of experiments, we presented tethered moths with moving vertically oriented sinusoidal gratings and found that individuals with their eyes unpainted, ventrally painted and medially painted all responded by attempting optomotor-driven turns in the same proportion. In contrast, individuals with their compound eyes dorsally painted, laterally painted and completely painted showed no optomotor turning response. We decreased the contrast of the visual stimulus and found that this relationship was consistent down to a contrast level of 2.5%. We conclude that visual input from the dorso-lateral region of the moth's visual world is critical for successful maintenance of flight stability and that this species' visual environment must meet or exceed a contrast ratio of 2.5% to support visual flight control.
Collapse
Affiliation(s)
- Sean Copley
- Department of Biology, Case Western Reserve University, Cleveland, OH 44106, USA
| | | | - Mark A Willis
- Department of Biology, Case Western Reserve University, Cleveland, OH 44106, USA
| |
Collapse
|
29
|
Thyselius M, Gonzalez-Bellido PT, Wardill TJ, Nordström K. Visual approach computation in feeding hoverflies. ACTA ACUST UNITED AC 2018; 221:jeb.177162. [PMID: 29720383 PMCID: PMC5992577 DOI: 10.1242/jeb.177162] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2018] [Accepted: 04/02/2018] [Indexed: 12/05/2022]
Abstract
On warm sunny days, female hoverflies are often observed feeding from a wide range of wild and cultivated flowers. In doing so, hoverflies serve a vital role as alternative pollinators, and are suggested to be the most important pollinators after bees and bumblebees. Unless the flower hoverflies are feeding from is large, they do not readily share the space with other insects, but instead opt to leave if another insect approaches. We used high-speed videography followed by 3D reconstruction of flight trajectories to quantify how female Eristalis hoverflies respond to approaching bees, wasps and two different hoverfly species. We found that, in 94% of the interactions, the occupant female left the flower when approached by another insect. We found that compared with spontaneous take-offs, the occupant hoverfly's escape response was performed at ∼3 times higher speed (spontaneous take-off at 0.2±0.05 m s−1 compared with 0.55±0.08 m s−1 when approached by another Eristalis). The hoverflies tended to take off upward and forward, while taking the incomer's approach angle into account. Intriguingly, we found that, when approached by wasps, the occupant Eristalis took off at a higher speed and when the wasp was further away. This suggests that feeding hoverflies may be able to distinguish these predators, demanding impressive visual capabilities. Our results, including quantification of the visual information available before occupant take-off, provide important insight into how freely behaving hoverflies perform escape responses from competitors and predators (e.g. wasps) in the wild. Highlighted Article: Reconstruction of the take-off and flight of feeding female hoverflies when approached by other insects, and quantification of visual parameters, reveals how freely behaving hoverflies perform escape responses from competitors and predators in the wild.
Collapse
Affiliation(s)
- Malin Thyselius
- Department of Neuroscience, Uppsala University, 75124 Uppsala, Sweden
| | - Paloma T Gonzalez-Bellido
- Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge CB3 2EG, UK
| | - Trevor J Wardill
- Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge CB3 2EG, UK
| | - Karin Nordström
- Department of Neuroscience, Uppsala University, 75124 Uppsala, Sweden .,Centre for Neuroscience, Flinders University, GPO Box 2100, Adelaide, SA 5001, Australia
| |
Collapse
|
30
|
Rigosi E, Wiederman SD, O'Carroll DC. Photoreceptor signalling is sufficient to explain the detectability threshold of insect aerial pursuers. ACTA ACUST UNITED AC 2017; 220:4364-4369. [PMID: 29187619 DOI: 10.1242/jeb.166207] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2017] [Accepted: 09/25/2017] [Indexed: 11/20/2022]
Abstract
An essential biological task for many flying insects is the detection of small, moving targets, such as when pursuing prey or conspecifics. Neural pathways underlying such 'target-detecting' behaviours have been investigated for their sensitivity and tuning properties (size, velocity). However, which stage of neuronal processing limits target detection is not yet known. Here, we investigated several skilled, aerial pursuers (males of four insect species), measuring the target-detection limit (signal-to-noise ratio) of light-adapted photoreceptors. We recorded intracellular responses to moving targets of varying size, extended well below the nominal resolution of single ommatidia. We found that the signal detection limit (2× photoreceptor noise) matches physiological or behavioural target-detection thresholds observed in each species. Thus, across a diverse range of flying insects, individual photoreceptor responses to changes in light intensity establish the sensitivity of the feature detection pathway, indicating later stages of processing are dedicated to feature tuning, tracking and selection.
Collapse
Affiliation(s)
- Elisa Rigosi
- Department of Biology, Lund University, Sölvegatan 35, S-22362 Lund, Sweden
| | - Steven D Wiederman
- Adelaide Medical School, The University of Adelaide, Adelaide, SA 5005, Australia
| | - David C O'Carroll
- Department of Biology, Lund University, Sölvegatan 35, S-22362 Lund, Sweden
| |
Collapse
|
31
|
Dyakova O, Nordström K. Image statistics and their processing in insect vision. CURRENT OPINION IN INSECT SCIENCE 2017; 24:7-14. [PMID: 29208226 DOI: 10.1016/j.cois.2017.08.002] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/16/2017] [Revised: 08/17/2017] [Accepted: 08/24/2017] [Indexed: 06/07/2023]
Abstract
Natural scenes may appear random, but are not only constrained in space and time, but also show strong spatial and temporal correlations. Spatial constraints and correlations can be described by quantifying image statistics, which include intuitive measures such as contrast, color and luminance, but also parameters that need some type of transformation of the image. In this review we will discuss some common tools used to quantify spatial and temporal parameters of naturalistic visual input, and how these tools have been used to inform us about visual processing in insects. In particular, we will review findings that would not have been possible using conventional, experimenter defined stimuli.
Collapse
Affiliation(s)
- Olga Dyakova
- Department of Neuroscience, Uppsala University, Box 593, 751 24 Uppsala, Sweden
| | - Karin Nordström
- Department of Neuroscience, Uppsala University, Box 593, 751 24 Uppsala, Sweden; Centre for Neuroscience, Flinders University, GPO Box 2100, Adelaide, SA 5001, Australia.
| |
Collapse
|
32
|
Bagheri ZM, Cazzolato BS, Grainger S, O’Carroll DC, Wiederman SD. An autonomous robot inspired by insect neurophysiology pursues moving features in natural environments. J Neural Eng 2017; 14:046030. [DOI: 10.1088/1741-2552/aa776c] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
|
33
|
Bagheri ZM, Wiederman SD, Cazzolato BS, Grainger S, O'Carroll DC. Performance of an insect-inspired target tracker in natural conditions. BIOINSPIRATION & BIOMIMETICS 2017; 12:025006. [PMID: 28112099 DOI: 10.1088/1748-3190/aa5b48] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Robust and efficient target-tracking algorithms embedded on moving platforms, are a requirement for many computer vision and robotic applications. However, deployment of a real-time system is challenging, even with the computational power of modern hardware. As inspiration, we look to biological lightweight solutions-lightweight and low-powered flying insects. For example, dragonflies pursue prey and mates within cluttered, natural environments, deftly selecting their target amidst swarms. In our laboratory, we study the physiology and morphology of dragonfly 'small target motion detector' neurons likely to underlie this pursuit behaviour. Here we describe our insect-inspired tracking model derived from these data and compare its efficacy and efficiency with state-of-the-art engineering models. For model inputs, we use both publicly available video sequences, as well as our own task-specific dataset (small targets embedded within natural scenes). In the context of the tracking problem, we describe differences in object statistics within the video sequences. For the general dataset, our model often locks on to small components of larger objects, tracking these moving features. When input imagery includes small moving targets, for which our highly nonlinear filtering is matched, the robustness outperforms state-of-the-art trackers. In all scenarios, our insect-inspired tracker runs at least twice the speed of the comparison algorithms.
Collapse
Affiliation(s)
- Zahra M Bagheri
- Adelaide Medical School, The University of Adelaide, Adelaide, SA, 5005, Australia. School of Mechanical Engineering, The University of Adelaide, Adelaide, SA, 5005, Australia
| | | | | | | | | |
Collapse
|
34
|
Eichorn C, Hrabar M, Van Ryn EC, Brodie BS, Blake AJ, Gries G. How flies are flirting on the fly. BMC Biol 2017; 15:2. [PMID: 28193269 PMCID: PMC5307768 DOI: 10.1186/s12915-016-0342-6] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2016] [Accepted: 12/09/2016] [Indexed: 11/22/2022] Open
Abstract
Background Flies have some of the most elaborate visual systems in the Insecta, often featuring large, sexually dimorphic eyes with specialized “bright zones” that may have a functional role during mate-seeking behavior. The fast visual system of flies is considered to be an adaptation in support of their advanced flight abilities. Here, we show that the immense processing speed of the flies’ photoreceptors plays a crucial role in mate recognition. Results Video-recording wing movements of abdomen-mounted common green bottle flies, Lucilia sericata, under direct light at 15,000 frames per second revealed that wing movements produce a single, reflected light flash per wing beat. Such light flashes were not evident when we video-recorded wing movements under diffuse light. Males of L. sericata are strongly attracted to wing flash frequencies of 178 Hz, which are characteristic of free-flying young females (prospective mates), significantly more than to 212, 235, or 266 Hz, characteristic of young males, old females, and old males, respectively. In the absence of phenotypic traits of female flies, and when given a choice between light emitting diodes that emitted either constant light or light pulsed at a frequency of 110, 178, 250, or 290 Hz, males show a strong preference for the 178-Hz pulsed light, which most closely approximates the wing beat frequency of prospective mates. Conclusions We describe a previously unrecognized visual mate recognition system in L. sericata. The system depends upon the sex- and age-specific frequencies of light flashes reflecting off moving wings, and the ability of male flies to distinguish between the frequency of light flashes produced by rival males and prospective mates. Our findings imply that insect photoreceptors with fast processing speed may not only support agile flight with advanced maneuverability but may also play a supreme role in mate recognition. The low mating propensity of L. sericata males on cloudy days, when light flashes from the wings of flying females are absent, seems to indicate that these flies synchronize sexual communication with environmental conditions that optimize the conspicuousness of their communication signals, as predicted by sensory drive theory. Electronic supplementary material The online version of this article (doi:10.1186/s12915-016-0342-6) contains supplementary material, which is available to authorized users.
Collapse
Affiliation(s)
- Courtney Eichorn
- Department of Biological Sciences, Simon Fraser University, 8888 University Drive, Burnaby, British Columbia, V5A 1S6, Canada
| | - Michael Hrabar
- Department of Biological Sciences, Simon Fraser University, 8888 University Drive, Burnaby, British Columbia, V5A 1S6, Canada
| | - Emma C Van Ryn
- Department of Biological Sciences, Simon Fraser University, 8888 University Drive, Burnaby, British Columbia, V5A 1S6, Canada
| | - Bekka S Brodie
- Department of Biological Sciences, Simon Fraser University, 8888 University Drive, Burnaby, British Columbia, V5A 1S6, Canada
| | - Adam J Blake
- Department of Biological Sciences, Simon Fraser University, 8888 University Drive, Burnaby, British Columbia, V5A 1S6, Canada
| | - Gerhard Gries
- Department of Biological Sciences, Simon Fraser University, 8888 University Drive, Burnaby, British Columbia, V5A 1S6, Canada.
| |
Collapse
|
35
|
Somanathan H, Borges RM, Warrant EJ, Kelber A. Visual Adaptations for Mate Detection in the Male Carpenter Bee Xylocopa tenuiscapa. PLoS One 2017; 12:e0168452. [PMID: 28107354 PMCID: PMC5249068 DOI: 10.1371/journal.pone.0168452] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2016] [Accepted: 12/01/2016] [Indexed: 11/18/2022] Open
Abstract
Sexual dimorphism in eye structure is attributed to sexual selection in animals that employ vision for locating mates. In many male insects, large eyes and eye regions of higher acuity are believed to facilitate the location of females. Here, we compare various features of male and female eyes in three sympatric carpenter bee species, which include two diurnal species (Xylocopa tenuiscapa and X. leucothorax) as well as a nocturnal species (X. tranquebarica). In X. tenuiscapa, males have larger eyes than females, while in the nocturnal X. tranquebarica, males have slightly smaller eyes and in X. leucothorax, the eyes are of similar size in both sexes. X. tenuiscapa males detect females by perching near nest sites (resource defence) or along fly-ways and other open areas with good visibility. Males of the other two species search for females by patrolling. We postulate that the larger eyes of male X. tenuiscapa are beneficial to their mode of mate detection since perching males may benefit from a larger visual area of high resolution detecting moving stimuli across the sky, and which may be germane to the more social and gregarious nesting behaviour of this species, compared to the other solitary bees. We tested the performance of the eyes of male X. tenuiscapa behaviourally and find that a perching male can detect a flying female at a distance of 20 m, which darkens the visual field of a single ommatidium by just 2%. This, together with the bee's high spatial resolution permits detection of moving stimuli at least as well or even better than achieved by honey bee drones.
Collapse
Affiliation(s)
- Hema Somanathan
- IISER TVM Centre for Research and Education in Ecology and Evolution (ICREEE), School of Biology, Indian Institute of Science Education and Research Thiruvananthapuram, Kerala, India
- * E-mail:
| | - Renee Maria Borges
- Centre for Ecological Sciences, Indian Institute of Science, Bangalore, India
| | - Eric J. Warrant
- Lund Vision Group, Department for Biology, Lund University, Lund, Sweden
| | - Almut Kelber
- Lund Vision Group, Department for Biology, Lund University, Lund, Sweden
| |
Collapse
|
36
|
Douglass JK, Wehling MF. Rapid mapping of compound eye visual sampling parameters with FACETS, a highly automated wide-field goniometer. J Comp Physiol A Neuroethol Sens Neural Behav Physiol 2016; 202:839-851. [PMID: 27655343 DOI: 10.1007/s00359-016-1119-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2016] [Revised: 07/27/2016] [Accepted: 07/29/2016] [Indexed: 11/29/2022]
Abstract
A highly automated goniometer instrument (called FACETS) has been developed to facilitate rapid mapping of compound eye parameters for investigating regional visual field specializations. The instrument demonstrates the feasibility of analyzing the complete field of view of an insect eye in a fraction of the time required if using non-motorized, non-computerized methods. Faster eye mapping makes it practical for the first time to employ sample sizes appropriate for testing hypotheses about the visual significance of interspecific differences in regional specializations. Example maps of facet sizes are presented from four dipteran insects representing the Asilidae, Calliphoridae, and Stratiomyidae. These maps provide the first quantitative documentation of the frontal enlarged-facet zones (EFZs) that typify asilid eyes, which, together with the EFZs in male Calliphoridae, are likely to be correlated with high-spatial-resolution acute zones. The presence of EFZs contrasts sharply with the almost homogeneous distribution of facet sizes in the stratiomyid. Moreover, the shapes of EFZs differ among species, suggesting functional specializations that may reflect differences in visual ecology. Surveys of this nature can help identify species that should be targeted for additional studies, which will elucidate fundamental principles and constraints that govern visual field specializations and their evolution.
Collapse
Affiliation(s)
- John K Douglass
- Eglin Air Force Base, 101 W. Eglin Blvd., Eglin AFB, FL, 32542, USA.
| | - Martin F Wehling
- Eglin Air Force Base, 101 W. Eglin Blvd., Eglin AFB, FL, 32542, USA
| |
Collapse
|
37
|
McCulloch KJ, Osorio D, Briscoe AD. Sexual dimorphism in the compound eye of Heliconius erato: a nymphalid butterfly with at least five spectral classes of photoreceptor. J Exp Biol 2016; 219:2377-87. [DOI: 10.1242/jeb.136523] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2015] [Accepted: 05/23/2016] [Indexed: 11/20/2022]
Abstract
Most butterfly families expand the number of spectrally-distinct photoreceptors in their compound eye by opsin gene duplications together with lateral filter pigments, however most nymphalid genera have limited diversity, with only three or four spectral types of photoreceptor. Here we examine the spatial pattern of opsin expression and photoreceptor spectral sensitivities in Heliconius erato, a nymphalid with duplicate ultraviolet opsin genes, UVRh1 and UVRh2. We find that the H. erato compound eye is sexually dimorphic. Females express the two UV opsin proteins in separate photoreceptors, but males do not express UVRh1. Intracellular recordings confirmed that females have three short wavelength-sensitive photoreceptors (λmax=356 nm, ∼390 nm and 470 nm), while males have two (λmax=390 nm and ∼470 nm). We also found two long wavelength-sensitive photoreceptors (green, λmax ∼555 nm, and red, λmax ∼600 nm), which express the same LW opsin. The red cell's shifted sensitivity is probably due to perirhabdomal filtering pigments. Sexual dimorphism of the UV-absorbing rhodopsins may reflect the females' need to discriminate conspecifics from co-mimics. Red-green color vision may be used to detect differences in red coloration on Heliconius wings, or for host-plant identification. Among nymphalids so far investigated, only H. erato is known to possess five spectral classes of photoreceptor; sexual dimorphism of the eye via suppression of one class of opsin (here UVRh1 in males) has not—to our knowledge—been reported in any animal.
Collapse
Affiliation(s)
- Kyle J. McCulloch
- Department of Ecology and Evolutionary Biology, University of California, Irvine, 321 Steinhaus Hall, Irvine, CA 92697, USA
| | - Daniel Osorio
- School of Life Sciences, University of Sussex, Brighton, BN1 9QG, United Kingdom
| | - Adriana D. Briscoe
- Department of Ecology and Evolutionary Biology, University of California, Irvine, 321 Steinhaus Hall, Irvine, CA 92697, USA
| |
Collapse
|
38
|
Dyakova O, Lee YJ, Longden KD, Kiselev VG, Nordström K. A higher order visual neuron tuned to the spatial amplitude spectra of natural scenes. Nat Commun 2015; 6:8522. [PMID: 26439748 PMCID: PMC4600736 DOI: 10.1038/ncomms9522] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2015] [Accepted: 09/02/2015] [Indexed: 12/26/2022] Open
Abstract
Animal sensory systems are optimally adapted to those features typically encountered in natural surrounds, thus allowing neurons with limited bandwidth to encode challengingly large input ranges. Natural scenes are not random, and peripheral visual systems in vertebrates and insects have evolved to respond efficiently to their typical spatial statistics. The mammalian visual cortex is also tuned to natural spatial statistics, but less is known about coding in higher order neurons in insects. To redress this we here record intracellularly from a higher order visual neuron in the hoverfly. We show that the cSIFE neuron, which is inhibited by stationary images, is maximally inhibited when the slope constant of the amplitude spectrum is close to the mean in natural scenes. The behavioural optomotor response is also strongest to images with naturalistic image statistics. Our results thus reveal a close coupling between the inherent statistics of natural scenes and higher order visual processing in insects.
Collapse
Affiliation(s)
- Olga Dyakova
- Department of Neuroscience, Uppsala University, Box 593, 75124 Uppsala, Sweden
| | - Yu-Jen Lee
- Department of Neuroscience, Uppsala University, Box 593, 75124 Uppsala, Sweden
| | - Kit D. Longden
- HHMI Janelia Research Campus, 19700 Helix Drive, Ashburn, Virginia 20176, USA
| | - Valerij G. Kiselev
- Medical Physics, Department of Radiology, University Medical Center Freiburg, Breisacher Strasse 60a, 79106 Freiburg, Germany
| | - Karin Nordström
- Department of Neuroscience, Uppsala University, Box 593, 75124 Uppsala, Sweden
- Anatomy and Histology, Centre for Neuroscience, Flinders University, GPO Box 2100, Adelaide, South Australia 5001, Australia
| |
Collapse
|
39
|
Spatio-temporal dynamics of impulse responses to figure motion in optic flow neurons. PLoS One 2015; 10:e0126265. [PMID: 25955416 PMCID: PMC4425674 DOI: 10.1371/journal.pone.0126265] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2014] [Accepted: 03/31/2015] [Indexed: 11/24/2022] Open
Abstract
White noise techniques have been used widely to investigate sensory systems in both vertebrates and invertebrates. White noise stimuli are powerful in their ability to rapidly generate data that help the experimenter decipher the spatio-temporal dynamics of neural and behavioral responses. One type of white noise stimuli, maximal length shift register sequences (m-sequences), have recently become particularly popular for extracting response kernels in insect motion vision. We here use such m-sequences to extract the impulse responses to figure motion in hoverfly lobula plate tangential cells (LPTCs). Figure motion is behaviorally important and many visually guided animals orient towards salient features in the surround. We show that LPTCs respond robustly to figure motion in the receptive field. The impulse response is scaled down in amplitude when the figure size is reduced, but its time course remains unaltered. However, a low contrast stimulus generates a slower response with a significantly longer time-to-peak and half-width. Impulse responses in females have a slower time-to-peak than males, but are otherwise similar. Finally we show that the shapes of the impulse response to a figure and a widefield stimulus are very similar, suggesting that the figure response could be coded by the same input as the widefield response.
Collapse
|
40
|
Fenk LM, Poehlmann A, Straw AD. Asymmetric processing of visual motion for simultaneous object and background responses. Curr Biol 2014; 24:2913-9. [PMID: 25454785 DOI: 10.1016/j.cub.2014.10.042] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2014] [Revised: 09/19/2014] [Accepted: 10/14/2014] [Indexed: 10/24/2022]
Abstract
Visual object fixation and figure-ground discrimination in Drosophila are robust behaviors requiring sophisticated computation by the visual system, yet the neural substrates remain unknown. Recent experiments in walking flies revealed object fixation behavior mediated by circuitry independent from the motion-sensitive T4-T5 cells required for wide-field motion responses. In tethered flight experiments under closed-loop conditions, we found similar results for one feedback gain, whereas intact T4-T5 cells were necessary for robust object fixation at a higher feedback gain and in figure-ground discrimination tasks. We implemented dynamical models (available at http://strawlab.org/asymmetric-motion/) based on neurons downstream of T4-T5 cells—one a simple phenomenological model and another, physiologically more realistic model—and found that both predict key features of stripe fixation and figure-ground discrimination and are consistent with a classical formulation. Fundamental to both models is motion asymmetry in the responses of model neurons, whereby front-to-back motion elicits stronger responses than back-to-front motion. When a bilateral pair of such model neurons, based on well-understood horizontal system cells, downstream of T4-T5, is coupled to turning behavior, asymmetry leads to object fixation and figure-ground discrimination in the presence of noise. Furthermore, the models also predict fixation in front of a moving background, a behavior previously suggested to require an additional pathway. Thus, the models predict several aspects of object responses on the basis of neurons that are also thought to serve a key role in background stabilization.
Collapse
Affiliation(s)
- Lisa M Fenk
- Research Institute of Molecular Pathology, Vienna Biocenter, Dr. Bohr-Gasse 7, 1030 Vienna, Austria
| | - Andreas Poehlmann
- Research Institute of Molecular Pathology, Vienna Biocenter, Dr. Bohr-Gasse 7, 1030 Vienna, Austria
| | - Andrew D Straw
- Research Institute of Molecular Pathology, Vienna Biocenter, Dr. Bohr-Gasse 7, 1030 Vienna, Austria.
| |
Collapse
|
41
|
Temporal statistics of natural image sequences generated by movements with insect flight characteristics. PLoS One 2014; 9:e110386. [PMID: 25340761 PMCID: PMC4207754 DOI: 10.1371/journal.pone.0110386] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2014] [Accepted: 09/09/2014] [Indexed: 11/19/2022] Open
Abstract
Many flying insects, such as flies, wasps and bees, pursue a saccadic flight and gaze strategy. This behavioral strategy is thought to separate the translational and rotational components of self-motion and, thereby, to reduce the computational efforts to extract information about the environment from the retinal image flow. Because of the distinguishing dynamic features of this active flight and gaze strategy of insects, the present study analyzes systematically the spatiotemporal statistics of image sequences generated during saccades and intersaccadic intervals in cluttered natural environments. We show that, in general, rotational movements with saccade-like dynamics elicit fluctuations and overall changes in brightness, contrast and spatial frequency of up to two orders of magnitude larger than translational movements at velocities that are characteristic of insects. Distinct changes in image parameters during translations are only caused by nearby objects. Image analysis based on larger patches in the visual field reveals smaller fluctuations in brightness and spatial frequency composition compared to small patches. The temporal structure and extent of these changes in image parameters define the temporal constraints imposed on signal processing performed by the insect visual system under behavioral conditions in natural environments.
Collapse
|
42
|
Abstract
In view of the traditional image difference method for camera movement under the condition of low accuracy on moving target detection, the image difference method based on bionic compound eye moving target detection algorithm was proposed and optimized. It used the image difference method based on bionic compound eye to detect the moving targets, and optimize the result by pixel interpolation and the ratio. The experimental conclusions show that the accuracy about new motion detection method is 25% higher than the traditional method.
Collapse
|
43
|
Visual ecology of flies with particular reference to colour vision and colour preferences. J Comp Physiol A Neuroethol Sens Neural Behav Physiol 2014; 200:497-512. [PMID: 24664124 DOI: 10.1007/s00359-014-0895-1] [Citation(s) in RCA: 90] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2013] [Revised: 02/19/2014] [Accepted: 02/25/2014] [Indexed: 10/25/2022]
Abstract
The visual ecology of flies is outstanding among insects due to a combination of specific attributes. Flies' compound eyes possess an open rhabdom and thus separate rhabdomeres in each ommatidium assigned to two visual pathways. The highly sensitive, monovariant neural superposition system is based on the excitation of the peripheral rhabdomeres of the retinula cells R1-6 and controls optomotor reactions. The two forms of central rhabdomeres of R7/8 retinula cells in each ommatidium build up a system with four photoreceptors sensitive in different wavelength ranges and thought to account for colour vision. Evidence from wavelength discrimination tests suggests that all colour stimuli are assigned to one of just four colour categories, but cooperation of the two pathways is also evident. Flies use colour cues for various behavioural reactions such as flower visitation, proboscis extension, host finding, and egg deposition. Direct evidence for colour vision, the ability to discriminate colours according to spectral shape but independent of intensity, has been demonstrated for few fly species only. Indirect evidence for colour vision provided from electrophysiological recordings of the spectral sensitivity of photoreceptors and opsin genes indicates similar requisites in various flies; the flies' responses to coloured targets, however, are much more diverse.
Collapse
|
44
|
Streinzer M, Spaethe J. Functional morphology of the visual system and mating strategies in bumblebees (Hymenoptera, Apidae,Bombus). Zool J Linn Soc 2014. [DOI: 10.1111/zoj.12117] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Affiliation(s)
- Martin Streinzer
- Department of Behavioral Physiology and Sociobiology; Biozentrum; University of Würzburg; D-97074 Würzburg Germany
- Department of Evolutionary Biology; Faculty of Life Sciences; University of Vienna; A-1090 Vienna Austria
| | - Johannes Spaethe
- Department of Behavioral Physiology and Sociobiology; Biozentrum; University of Würzburg; D-97074 Würzburg Germany
| |
Collapse
|
45
|
O'Carroll DC, Wiederman SD. Contrast sensitivity and the detection of moving patterns and features. Philos Trans R Soc Lond B Biol Sci 2014; 369:20130043. [PMID: 24395970 DOI: 10.1098/rstb.2013.0043] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Theories based on optimal sampling by the retina have been widely applied to visual ecology at the level of the optics of the eye, supported by visual behaviour. This leads to speculation about the additional processing that must lie in between-in the brain itself. But fewer studies have adopted a quantitative approach to evaluating the detectability of specific features in these neural pathways. We briefly review this approach with a focus on contrast sensitivity of two parallel pathways for motion processing in insects, one used for analysis of wide-field optic flow, the other for detection of small features. We further use a combination of optical modelling of image blur and physiological recording from both photoreceptors and higher-order small target motion detector neurons sensitive to small targets to show that such neurons operate right at the limits imposed by the optics of the eye and the noise level of single photoreceptors. Despite this, and the limitation of only being able to use information from adjacent receptors to detect target motion, they achieve a contrast sensitivity that rivals that of wide-field motion sensitive pathways in either insects or vertebrates-among the highest in absolute terms seen in any animal.
Collapse
Affiliation(s)
- David C O'Carroll
- Adelaide Centre for Neuroscience Research, School of Medical Sciences, The University of Adelaide, , Adelaide, South Australia 5000, Australia
| | | |
Collapse
|
46
|
Fox JL, Aptekar JW, Zolotova NM, Shoemaker PA, Frye MA. Figure-ground discrimination behavior in Drosophila. I. Spatial organization of wing-steering responses. ACTA ACUST UNITED AC 2013; 217:558-69. [PMID: 24198267 PMCID: PMC3922833 DOI: 10.1242/jeb.097220] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
The behavioral algorithms and neural subsystems for visual figure–ground discrimination are not sufficiently described in any model system. The fly visual system shares structural and functional similarity with that of vertebrates and, like vertebrates, flies robustly track visual figures in the face of ground motion. This computation is crucial for animals that pursue salient objects under the high performance requirements imposed by flight behavior. Flies smoothly track small objects and use wide-field optic flow to maintain flight-stabilizing optomotor reflexes. The spatial and temporal properties of visual figure tracking and wide-field stabilization have been characterized in flies, but how the two systems interact spatially to allow flies to actively track figures against a moving ground has not. We took a systems identification approach in flying Drosophila and measured wing-steering responses to velocity impulses of figure and ground motion independently. We constructed a spatiotemporal action field (STAF) – the behavioral analog of a spatiotemporal receptive field – revealing how the behavioral impulse responses to figure tracking and concurrent ground stabilization vary for figure motion centered at each location across the visual azimuth. The figure tracking and ground stabilization STAFs show distinct spatial tuning and temporal dynamics, confirming the independence of the two systems. When the figure tracking system is activated by a narrow vertical bar moving within the frontal field of view, ground motion is essentially ignored despite comprising over 90% of the total visual input.
Collapse
Affiliation(s)
- Jessica L Fox
- Howard Hughes Medical Institute and Department of Integrative Biology and Physiology, University of California Los Angeles, Los Angeles, CA 90095-7239, USA
| | | | | | | | | |
Collapse
|
47
|
Zhao F, Bottjer DJ, Hu S, Yin Z, Zhu M. Complexity and diversity of eyes in early Cambrian ecosystems. Sci Rep 2013; 3:2751. [PMID: 24067397 PMCID: PMC3783037 DOI: 10.1038/srep02751] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2013] [Accepted: 09/06/2013] [Indexed: 12/05/2022] Open
Abstract
Here we report exceptionally preserved non-biomineralized compound eyes of a non-trilobite arthropod Cindarella eucalla from the lower Cambrian Chengjiang Lagerstätte, China. The specimen represents the oldest microanatomical evidence confirming the occurrence of highly developed vision in the early Cambrian, over 2,000 ommatidia in each eye. Moreover, a quantitative analysis of the distribution of eyes related to life habit, feeding types, and phyla respectively, from the Chengjiang biota indicates that specimens with eyes mostly belong to the arthropods, and they usually were actively mobile epifaunal and nektonic forms as hunters or scavengers. Arthropods took the lead in evolution of ‘good vision' and domination in Cambrian communities, which supports the hypothesis that the origin and evolution of ‘good vision' was a key trait that promoted preferential diversification and formed the foundation of modern benthic ecosystems in the early Cambrian ocean.
Collapse
Affiliation(s)
- Fangchen Zhao
- 1] State Key Laboratory of Palaeobiology and Stratigraphy, Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences, Nanjing 210008, China [2] Department of Earth Sciences, University of Southern California, Los Angeles, California 90089, USA
| | | | | | | | | |
Collapse
|
48
|
Abstract
Many animals use visual motion cues for navigating within their surroundings. Both flies and vertebrates compute local motion by temporal correlation of neighboring photoreceptors, via so-called elementary motion detectors (EMDs). In the fly lobula plate and the vertebrate visual cortex the output from many EMDs is pooled in neurons sensitive to wide-field optic flow. Although the EMD has been the preferred model for more than 50 years, recent work has highlighted its limitations in describing some visual behaviors, such as responses to higher-order motion stimuli. Non-EMD motion processing may therefore serve an important function in vision. Here, we describe a novel neuron class in the fly lobula plate that clearly does not derive its input from classic EMDs. The centrifugal stationary inhibited flicker excited (cSIFE) neuron is strongly excited by flicker, up to very high temporal frequencies. The non-EMD driven flicker sensitivity leads to strong, nondirectional responses to high-speed, wide-field motion. Furthermore, cSIFE is strongly inhibited by stationary patterns, within a narrow wavelength band. cSIFE's outputs overlap with the inputs of well described optic flow-sensitive lobula plate tangential cells (LPTCs). Driving cSIFE affects the active dendrites of LPTCs, and cSIFE may therefore play a large role in motion vision.
Collapse
|
49
|
Yang X, Guo A. Distinct acute zones for visual stimuli in different visual tasks in Drosophila. PLoS One 2013; 8:e61313. [PMID: 23585891 PMCID: PMC3621824 DOI: 10.1371/journal.pone.0061313] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2012] [Accepted: 03/07/2013] [Indexed: 11/18/2022] Open
Abstract
The fruit fly Drosophila melanogaster has a sophisticated visual system and exhibits complex visual behaviors. Visual responses, vision processing and higher cognitive processes in Drosophila have been studied extensively. However, little is known about whether the retinal location of visual stimuli can affect fruit fly performance in various visual tasks. We tested the response of wild-type Berlin flies to visual stimuli at several vertical locations. Three paradigms were used in our study: visual operant conditioning, visual object fixation and optomotor response. We observed an acute zone for visual feature memorization in the upper visual field when visual patterns were presented with a black background. However, when a white background was used, the acute zone was in the lower visual field. Similar to visual feature memorization, the best locations for visual object fixation and optomotor response to a single moving stripe were in the lower visual field with a white background and the upper visual field with a black background. The preferred location for the optomotor response to moving gratings was around the equator of the visual field. Our results suggest that different visual processing pathways are involved in different visual tasks and that there is a certain degree of overlap between the pathways for visual feature memorization, visual object fixation and optomotor response.
Collapse
Affiliation(s)
- Xing Yang
- Institute of Neuroscience and State Key Laboratory of Neuroscience, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, China
| | | |
Collapse
|
50
|
Dunbier JR, Wiederman SD, Shoemaker PA, O'Carroll DC. Facilitation of dragonfly target-detecting neurons by slow moving features on continuous paths. Front Neural Circuits 2012; 6:79. [PMID: 23112764 PMCID: PMC3483020 DOI: 10.3389/fncir.2012.00079] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2012] [Accepted: 10/11/2012] [Indexed: 11/14/2022] Open
Abstract
Dragonflies detect and pursue targets such as other insects for feeding and conspecific interaction. They have a class of neurons highly specialized for this task in their lobula, the “small target motion detecting” (STMD) neurons. One such neuron, CSTMD1, reaches maximum response slowly over hundreds of milliseconds of target motion. Recording the intracellular response from CSTMD1 and a second neuron in this system, BSTMD1, we determined that for the neurons to reach maximum response levels, target motion must produce sequential local activation of elementary motion detecting elements. This facilitation effect is most pronounced when targets move at velocities slower than what was previously thought to be optimal. It is completely disrupted if targets are instantaneously displaced a few degrees from their current location. Additionally, we utilize a simple computational model to discount the parsimonious hypothesis that CSTMD1's slow build-up to maximum response is due to it incorporating a sluggish neural delay filter. Whilst the observed facilitation may be too slow to play a role in prey pursuit flights, which are typically rapidly resolved, we hypothesize that it helps maintain elevated sensitivity during prolonged, aerobatically intricate conspecific pursuits. Since the effect seems to be localized, it most likely enhances the relative salience of the most recently “seen” locations during such pursuit flights.
Collapse
Affiliation(s)
- James R Dunbier
- Adelaide Centre for Neuroscience Research, School of Medical Sciences, The University of Adelaide Adelaide, SA, Australia
| | | | | | | |
Collapse
|