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Hoppe M, Spratte C, Hanke FD, Sørensen K. Single target acuity for moving targets in the common sunfish (Lepomis gibbosus). Biol Open 2024; 13:bio060455. [PMID: 38738649 PMCID: PMC11179713 DOI: 10.1242/bio.060455] [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: 05/02/2024] [Accepted: 05/07/2024] [Indexed: 05/14/2024] Open
Abstract
The common sunfish (Lepomis gibbosus) likely relies on vision for many vital behaviors that require the perception of small objects such as detection of prey items or body marks of conspecifics. A previous study documented the single target acuity (STA) for stationary targets. Under many, if not most, circumstances, however, objects of interest are moving, which is why the current study tested the effect of the ecologically relevant parameter motion on sunfish STA. The STA was determined in two sunfish for targets moving randomly at a velocity of 3.4 deg/s. The STA for moving targets (0.144±0.002 deg) was equal to the STA for stationary targets obtained from the same fish individuals under the experimental conditions of this/the previous study. Our results contribute to a comprehensive understanding of fish vision, extending the large data set available on grating acuity.
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Affiliation(s)
- Marius Hoppe
- Institute for Biosciences, Neuroethology, University of Rostock, Albert-Einstein-Str. 3, 18059 Rostock, Germany
| | - Caroline Spratte
- Institute for Biosciences, Neuroethology, University of Rostock, Albert-Einstein-Str. 3, 18059 Rostock, Germany
| | - Frederike D Hanke
- Institute for Biosciences, Neuroethology, University of Rostock, Albert-Einstein-Str. 3, 18059 Rostock, Germany
| | - Kenneth Sørensen
- Institute for Biosciences, Neuroethology, University of Rostock, Albert-Einstein-Str. 3, 18059 Rostock, Germany
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2
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Sandow LM, Hanke FD. Aerial single target acuity of harbor seals (Phoca vitulina) for stationary and moving targets of varying contrast. Vision Res 2024; 218:108389. [PMID: 38531191 DOI: 10.1016/j.visres.2024.108389] [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: 09/25/2023] [Revised: 03/11/2024] [Accepted: 03/17/2024] [Indexed: 03/28/2024]
Abstract
Harbor seals (Phoca vitulina) need to detect single objects for example when orienting to landmarks or hunting prey. The detection of single objects, described by the single target acuity (STA), cannot be deduced from formerly determined grating acuity (GA) as different mechanisms underlie STA and GA. Thus, we assessed STA for stationary and moving single targets with varying contrast in two harbor seals in a first approach in air. In a two-alternative-forced-choice discrimination task, the seals had to indicate whether the single target was presented in a left or right stimulus field on a monitor. The STA for full-contrast stationary targets was determined as 0.27 deg of visual angle for both experimental animals. Contrary to our expectations, neither adding motion nor reducing contrast had a strong impact on STA. Additionally, we also determined GA in the two harbor seals (1.2 and 1.1 cycles/deg or 0.42 and 0.45 deg for a single stripe of the grating at threshold) to be slightly inferior to STA. Our results are in good correspondence with contrast sensitivity and allow calculating viewing distances in the context of for example visual orientation.
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Affiliation(s)
- Laura-Marie Sandow
- University of Rostock, Institute for Biosciences, Neuroethology, Albert-Einstein-Str. 3, 18059 Rostock, Germany
| | - Frederike D Hanke
- University of Rostock, Institute for Biosciences, Neuroethology, Albert-Einstein-Str. 3, 18059 Rostock, Germany.
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3
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Blary CLM, Duriez O, Bonadonna F, Mitkus M, Caro SP, Besnard A, Potier S. Low achromatic contrast sensitivity in birds: a common attribute shared by many phylogenetic orders. J Exp Biol 2024; 227:jeb246342. [PMID: 38099472 DOI: 10.1242/jeb.246342] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2023] [Accepted: 12/06/2023] [Indexed: 02/10/2024]
Abstract
Vision is an important sensory modality in birds, which can outperform other vertebrates in some visual abilities. However, sensitivity to achromatic contrasts - the ability to discern luminance difference between two objects or an object and its background - has been shown to be lower in birds compared with other vertebrates. We conducted a comparative study to evaluate the achromatic contrast sensitivity of 32 bird species from 12 orders using the optocollic reflex technique. We then performed an analysis to test for potential variability in contrast sensitivity depending on the corneal diameter to the axial length ratio, a proxy of the retinal image brightness. To account for potential influences of evolutionary relatedness, we included phylogeny in our analyses. We found a low achromatic contrast sensitivity for all avian species studied compared with other vertebrates (except small mammals), with high variability between species. This variability is partly related to phylogeny but appears to be independent of image brightness.
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Affiliation(s)
- Constance L M Blary
- CEFE, Univ Montpellier, CNRS, EPHE, IRD, 34293 Montpellier, France
- Agence de l'environnement et de la Maîtrise de l'Energie 20, 49004 Angers Cedex 01, France
| | - Olivier Duriez
- CEFE, Univ Montpellier, CNRS, EPHE, IRD, 34293 Montpellier, France
| | | | - Mindaugas Mitkus
- Institute of Biosciences, Life Sciences Center, Vilnius University, 10257 Vilnius, Lithuania
| | - Samuel P Caro
- CEFE, Univ Montpellier, CNRS, EPHE, IRD, 34293 Montpellier, France
| | - Aurélien Besnard
- CEFE, Univ Montpellier, CNRS, EPHE PSL University, IRD, 34293 Montpellier, France
| | - Simon Potier
- Lund Vision Group, Department of Biology, Lund University, Lund 22362, Sweden
- Les Ailes de l'Urga, 27320 Marcilly la Campagne, France
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4
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Chaib S, Lind O, Kelber A. Fast visual adaptation to dim light in a cavity-nesting bird. Proc Biol Sci 2023; 290:20230596. [PMID: 37161333 PMCID: PMC10170191 DOI: 10.1098/rspb.2023.0596] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/11/2023] Open
Abstract
Many birds move fast into dark nest cavities forcing the visual system to adapt to low light intensities. Their visual system takes between 15 and 60 min for complete dark adaptation, but little is known about the visual performance of birds during the first seconds in low light intensities. In a forced two-choice behavioural experiment we studied how well budgerigars can discriminate stimuli of different luminance directly after entering a darker environment. The birds made their choices within about 1 s and did not wait to adapt their visual system to the low light intensities. When moving from a bright facility into an environment with 0.5 log unit lower illuminance, the budgerigars detected targets with a luminance of 0.825 cd m-2 on a black background. When moving into an environment with 1.7 or 3.5 log units lower illuminance, they detected targets with luminances between 0.106 and 0.136 cd m-2. In tests with two simultaneously displayed targets, the birds discriminated similar luminance differences between the targets (Weber fraction of 0.41-0.54) in all light levels. Our results support the notion that partial adaptation of bird eyes to the lower illumination occurring within 1 s allows them to safely detect and feed their chicks.
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Affiliation(s)
- Sandra Chaib
- Lund Vision Group, Department of Biology, Lund University, 223 62 Lund, Sweden
| | - Olle Lind
- Lund Vision Group, Department of Biology, Lund University, 223 62 Lund, Sweden
| | - Almut Kelber
- Lund Vision Group, Department of Biology, Lund University, 223 62 Lund, Sweden
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5
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Spratte C, Sandow LM, Schnermann JS, Hanke FD. Single target acuity in the common sunfish (Lepomis gibbosus). J Exp Biol 2021; 224:272592. [PMID: 34553768 DOI: 10.1242/jeb.243068] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2021] [Accepted: 09/20/2021] [Indexed: 11/20/2022]
Abstract
Vision contributes to foraging, territorial and reproductive behavior in sunfish. In these contexts, sunfish need to perceive single targets, such as prey items or body markings from either conspecifics or individuals of other sunfish species, from some distance. We determined the single target acuity of six common sunfish in a behavioral experiment to assess whether the visual abilities of sunfish correspond with behavioral observations or reactive distance measures, and thus assessed the limits of vision for the mentioned behaviors. Single target acuity for full-contrast single targets amounted to 0.17 deg (0.13-0.32 deg). When contrast was reduced to Weber contrasts of 0.67 and 0.41, single target acuity dropped to 0.34 deg (0.31-0.37 deg), and finally to 0.42 deg (0.34-0.54 deg). Single target acuity would thus allow common sunfish to perceive biologically relevant stimuli at reasonable distances even when contrast is reduced.
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Affiliation(s)
- Caroline Spratte
- University of Rostock, Institute for Biosciences, Neuroethology, Albert-Einstein-Str.3, 18059 Rostock, Germany
| | - Laura-Marie Sandow
- University of Rostock, Institute for Biosciences, Neuroethology, Albert-Einstein-Str.3, 18059 Rostock, Germany
| | - Julia S Schnermann
- University of Rostock, Institute for Biosciences, Neuroethology, Albert-Einstein-Str.3, 18059 Rostock, Germany
| | - Frederike D Hanke
- University of Rostock, Institute for Biosciences, Neuroethology, Albert-Einstein-Str.3, 18059 Rostock, Germany
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6
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Chaib S, Mussoi JG, Lind O, Kelber A. Visual acuity of budgerigars for moving targets. Biol Open 2021; 10:272046. [PMID: 34382651 PMCID: PMC8473842 DOI: 10.1242/bio.058796] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2021] [Accepted: 07/29/2021] [Indexed: 11/20/2022] Open
Abstract
For a bird, it is often vital to visually detect food items, predators, or individuals from the same flock, i.e. moving stimuli of various shapes. Yet, behavioural tests of visual spatial acuity traditionally use stationary gratings as stimuli. We have behaviourally tested the ability of budgerigars (Melopsittacus undulatus) to detect a black circular target, moving semi-randomly at 1.69 degrees s−1 against a brighter background. We found a detection threshold of 0.107±0.007 degrees of the visual field for a target size corresponding to a resolution of a grating with a spatial frequency of 4.68 cycles degree−1. This detection threshold is lower than the resolution limit for gratings but similar to the threshold for stationary single objects of the same shape. We conclude that the target acuity of budgerigars for moving single targets, just as for stationary single targets, is lower than their acuity for gratings. Summary: Movement does not improve detection: The detection threshold of budgerigars (Melopsittacus undulatus) for moving dark circular targets is similar to the detection threshold for stationary but otherwise similar targets.
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Affiliation(s)
- Sandra Chaib
- Lund Vision Group, Department of Biology, Lund University, 223 62 Lund, Sweden
| | | | - Olle Lind
- Lund Vision Group, Department of Biology, Lund University, 223 62 Lund, Sweden
| | - Almut Kelber
- Lund Vision Group, Department of Biology, Lund University, 223 62 Lund, Sweden
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7
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Nebel C, Sumasgutner P, Pajot A, Amar A. Response time of an avian prey to a simulated hawk attack is slower in darker conditions, but is independent of hawk colour morph. ROYAL SOCIETY OPEN SCIENCE 2019; 6:190677. [PMID: 31598248 PMCID: PMC6731706 DOI: 10.1098/rsos.190677] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/10/2019] [Accepted: 07/08/2019] [Indexed: 06/10/2023]
Abstract
To avoid predation, many species rely on vision to detect predators and initiate an escape response. The ability to detect predators may be lower in darker light conditions or with darker backgrounds. For birds, however, this has never been experimentally tested. We test the hypothesis that the response time of avian prey (feral pigeon Columbia livia f. domestica) to a simulated hawk attack (taxidermy mounted colour-polymorphic black sparrowhawk Accipiter melanoleucus) will differ depending on light levels or background colour. We predict that response will be slower under darker conditions, which would translate into higher predation risk. The speed of response of prey in relation to light level or background colour may also interact with the colour of the predator, and this idea underpins a key hypothesis proposed for the maintenance of different colour morphs in polymorphic raptors. We therefore test whether the speed of reaction is influenced by the morph of the hawk (dark/light) in combination with light conditions (dull/bright), or background colours (black/white). We predict slowest responses to morphs under conditions that less contrast with the plumage of the hawk (e.g. light morph under bright light or white background). In support of our first hypothesis, pigeons reacted slower under duller light and with a black background. However, we found no support for the second hypothesis, with response times observed between the hawk-morphs being irrespective of light levels or background colour. Our findings experimentally confirm that birds detect avian predators less efficiently under darker conditions. These conditions, for example, might occur during early mornings or in dense forests, which could lead to changes in anti-predator behaviours. However, our results provide no support that different morphs may be maintained in a population due to differential selective advantages linked to improved hunting efficiencies in different conditions due to crypsis.
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Affiliation(s)
- Carina Nebel
- FitzPatrick Institute of African Ornithology, DST-NRF Centre of Excellence, University of Cape Town, Private Bag X3, Rondebosch, 7701 Cape Town, South Africa
| | - Petra Sumasgutner
- FitzPatrick Institute of African Ornithology, DST-NRF Centre of Excellence, University of Cape Town, Private Bag X3, Rondebosch, 7701 Cape Town, South Africa
| | - Adrien Pajot
- FitzPatrick Institute of African Ornithology, DST-NRF Centre of Excellence, University of Cape Town, Private Bag X3, Rondebosch, 7701 Cape Town, South Africa
- Bordeaux Sciences Agro, 1 Cours du Général de Gaulle, 33170 Gradignan, France
| | - Arjun Amar
- FitzPatrick Institute of African Ornithology, DST-NRF Centre of Excellence, University of Cape Town, Private Bag X3, Rondebosch, 7701 Cape Town, South Africa
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8
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How lovebirds maneuver through lateral gusts with minimal visual information. Proc Natl Acad Sci U S A 2019; 116:15033-15041. [PMID: 31289235 DOI: 10.1073/pnas.1903422116] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Flying birds maneuver effectively through lateral gusts, even when gust speeds are as high as flight speeds. What information birds use to sense gusts and how they compensate is largely unknown. We found that lovebirds can maneuver through 45° lateral gusts similarly well in forest-, lake-, and cave-like visual environments. Despite being diurnal and raised in captivity, the birds fly to their goal perch with only a dim point light source as a beacon, showing that they do not need optic flow or a visual horizon to maneuver. To accomplish this feat, lovebirds primarily yaw their bodies into the gust while fixating their head on the goal using neck angles of up to 30°. Our corroborated model for proportional yaw reorientation and speed control shows how lovebirds can compensate for lateral gusts informed by muscle proprioceptive cues from neck twist. The neck muscles not only stabilize the lovebirds' visual and inertial head orientations by compensating low-frequency body maneuvers, but also attenuate faster 3D wingbeat-induced perturbations. This head stabilization enables the vestibular system to sense the direction of gravity. Apparently, the visual horizon can be replaced by a gravitational horizon to inform the observed horizontal gust compensation maneuvers in the dark. Our scaling analysis shows how this minimal sensorimotor solution scales favorably for bigger birds, offering local wind angle feedback within a wingbeat. The way lovebirds glean wind orientation may thus inform minimal control algorithms that enable aerial robots to maneuver in similar windy and dark environments.
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9
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Single target acuity is not higher than grating acuity in a bird, the budgerigar. Vision Res 2019; 160:37-42. [DOI: 10.1016/j.visres.2019.04.005] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2018] [Revised: 04/09/2019] [Accepted: 04/18/2019] [Indexed: 12/27/2022]
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10
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Potier S, Mitkus M, Kelber A. High resolution of colour vision, but low contrast sensitivity in a diurnal raptor. Proc Biol Sci 2018; 285:20181036. [PMID: 30158305 PMCID: PMC6125913 DOI: 10.1098/rspb.2018.1036] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2018] [Accepted: 08/01/2018] [Indexed: 02/04/2023] Open
Abstract
Animals are thought to use achromatic signals to detect small (or distant) objects and chromatic signals for large (or nearby) objects. While the spatial resolution of the achromatic channel has been widely studied, the spatial resolution of the chromatic channel has rarely been estimated. Using an operant conditioning method, we determined (i) the achromatic contrast sensitivity function and (ii) the spatial resolution of the chromatic channel of a diurnal raptor, the Harris's hawk Parabuteo unicinctus The maximal spatial resolution for achromatic gratings was 62.3 c deg-1, but the contrast sensitivity was relatively low (10.8-12.7). The spatial resolution for isoluminant red-green gratings was 21.6 c deg-1-lower than that of the achromatic channel, but the highest found in the animal kingdom to date. Our study reveals that Harris's hawks have high spatial resolving power for both achromatic and chromatic vision, suggesting the importance of colour vision for foraging. By contrast, similar to other bird species, Harris's hawks have low contrast sensitivity possibly suggesting a trade-off with chromatic sensitivity. The result is interesting in the light of the recent finding that double cones-thought to mediate high-resolution vision in birds-are absent in the central fovea of raptors.
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Affiliation(s)
- Simon Potier
- Department of Biology, Lund University, Sölvegatan 35, Lund 22362, Sweden
| | - Mindaugas Mitkus
- Department of Biology, Lund University, Sölvegatan 35, Lund 22362, Sweden
| | - Almut Kelber
- Department of Biology, Lund University, Sölvegatan 35, Lund 22362, Sweden
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11
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Dai J, Wang Y. Contrast coding in the primary visual cortex depends on temporal contexts. Eur J Neurosci 2018; 47:947-958. [DOI: 10.1111/ejn.13893] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2017] [Revised: 02/06/2018] [Accepted: 02/20/2018] [Indexed: 11/30/2022]
Affiliation(s)
- Ji Dai
- State Key Laboratory of Brain and Cognitive Sciences; Institute of Biophysics; Chinese Academy of Sciences; Beijing 100101 China
- Shenzhen Key Lab of Neuropsychiatric Modulation and Collaborative Innovation Center for Brain Science; CAS Center for Excellence in Brain Science and Intelligence Technology; the Brain Cognition and Brain Disease Institute; Shenzhen Institutes of Advanced Technology; Chinese Academy of Sciences; Shenzhen 518055 China
| | - Yi Wang
- State Key Laboratory of Brain and Cognitive Sciences; Institute of Biophysics; Chinese Academy of Sciences; Beijing 100101 China
- University of Chinese Academy of Sciences; Beijing 100101 China
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12
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Chakravarthi A, Rajus S, Kelber A, Dacke M, Baird E. Differences in spatial resolution and contrast sensitivity of flight control in the honeybees Apis cerana and Apis mellifera. J Exp Biol 2018; 221:jeb.184267. [DOI: 10.1242/jeb.184267] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2018] [Accepted: 08/14/2018] [Indexed: 11/20/2022]
Abstract
Visually-guided behaviour is constrained by the capacity of the visual system to resolve detail. This is, in turn, limited by the spatial resolution and contrast sensitivity of the underlying visual system. Because these properties are interdependent and vary non-uniformly, it is only possible to fully understand the limits of a specific visually guided behaviour when they are investigated in combination. To understand the visual limits of flight control in bees, which rely heavily on vision to control flight, and to explore whether they vary between species, we tested how changes in spatial resolution and contrast sensitivity affect the speed and position control of the Asian and European honeybees (Apis cerana and A. mellifera). Despite their apparent similarity, we found some interesting and surprising differences between the visual limits of these species. While the effect of spatial frequency and contrast on position control is similar between the species, ground speed is differently affected by these variables. A comparison with published data from the bumblebee Bombus terrestris reveals further differences. The visual resolution that limits the detection and use of optic flow for flight control in both species of honeybees is lower than previously anatomically determined resolution and differs from object detection limits of A. mellifera, providing evidence that the limits of spatial resolution and contrast sensitivity are highly tuned to the particular behavioural task of a species.
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Affiliation(s)
| | - Santosh Rajus
- National Centre for Biological Sciences, Bangalore, India
| | - Almut Kelber
- Department of Biology, Lund University, Lund, Sweden
| | - Marie Dacke
- Department of Biology, Lund University, Lund, Sweden
| | - Emily Baird
- Department of Biology, Lund University, Lund, Sweden
- Current address: Department of Zoology, Stockholm University, Stockholm, Sweden
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13
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Chakravarthi A, Kelber A, Baird E, Dacke M. High contrast sensitivity for visually guided flight control in bumblebees. J Comp Physiol A Neuroethol Sens Neural Behav Physiol 2017; 203:999-1006. [PMID: 28879513 PMCID: PMC5696488 DOI: 10.1007/s00359-017-1212-6] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2017] [Revised: 08/23/2017] [Accepted: 08/26/2017] [Indexed: 11/25/2022]
Abstract
Many insects rely on vision to find food, to return to their nest and to carefully control their flight between these two locations. The amount of information available to support these tasks is, in part, dictated by the spatial resolution and contrast sensitivity of their visual systems. Here, we investigate the absolute limits of these visual properties for visually guided position and speed control in Bombus terrestris. Our results indicate that the limit of spatial vision in the translational motion detection system of B. terrestris lies at 0.21 cycles deg−1 with a peak contrast sensitivity of at least 33. In the perspective of earlier findings, these results indicate that bumblebees have higher contrast sensitivity in the motion detection system underlying position control than in their object discrimination system. This suggests that bumblebees, and most likely also other insects, have different visual thresholds depending on the behavioral context.
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Affiliation(s)
| | - Almut Kelber
- Department of Biology, Lund University, Sölvegatan 35, Lund, Sweden
| | - Emily Baird
- Department of Biology, Lund University, Sölvegatan 35, Lund, Sweden
| | - Marie Dacke
- Department of Biology, Lund University, Sölvegatan 35, Lund, Sweden
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14
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Dakin R, McCrossan O, Hare JF, Montgomerie R, Amador Kane S. Biomechanics of the Peacock's Display: How Feather Structure and Resonance Influence Multimodal Signaling. PLoS One 2016; 11:e0152759. [PMID: 27119380 PMCID: PMC4847759 DOI: 10.1371/journal.pone.0152759] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2016] [Accepted: 03/19/2016] [Indexed: 11/19/2022] Open
Abstract
Courtship displays may serve as signals of the quality of motor performance, but little is known about the underlying biomechanics that determines both their signal content and costs. Peacocks (Pavo cristatus) perform a complex, multimodal "train-rattling" display in which they court females by vibrating the iridescent feathers in their elaborate train ornament. Here we study how feather biomechanics influences the performance of this display using a combination of field recordings and laboratory experiments. Using high-speed video, we find that train-rattling peacocks stridulate their tail feathers against the train at 25.6 Hz, on average, generating a broadband, pulsating mechanical sound at that frequency. Laboratory measurements demonstrate that arrays of peacock tail and train feathers have a broad resonant peak in their vibrational spectra at the range of frequencies used for train-rattling during the display, and the motion of feathers is just as expected for feathers shaking near resonance. This indicates that peacocks are able to drive feather vibrations energetically efficiently over a relatively broad range of frequencies, enabling them to modulate the feather vibration frequency of their displays. Using our field data, we show that peacocks with longer trains use slightly higher vibration frequencies on average, even though longer train feathers are heavier and have lower resonant frequencies. Based on these results, we propose hypotheses for future studies of the function and energetics of this display that ask why its dynamic elements might attract and maintain female attention. Finally, we demonstrate how the mechanical structure of the train feathers affects the peacock's visual display by allowing the colorful iridescent eyespots-which strongly influence female mate choice-to remain nearly stationary against a dynamic iridescent background.
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Affiliation(s)
- Roslyn Dakin
- Department of Zoology, University of British Columbia, Vancouver, Canada
- * E-mail: (SAK); (RD)
| | - Owen McCrossan
- Drexel University, Philadelphia, PA, United States of America
| | - James F. Hare
- Department of Biological Sciences, University of Manitoba, Winnipeg, Canada
| | | | - Suzanne Amador Kane
- Physics Department, Haverford College, Haverford, PA, United States of America
- * E-mail: (SAK); (RD)
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15
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Chakravarthi A, Baird E, Dacke M, Kelber A. Spatial Vision in Bombus terrestris. Front Behav Neurosci 2016; 10:17. [PMID: 26912998 PMCID: PMC4753314 DOI: 10.3389/fnbeh.2016.00017] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2015] [Accepted: 01/29/2016] [Indexed: 11/13/2022] Open
Abstract
Bombus terrestris is one of the most commonly used insect models to investigate visually guided behavior and spatial vision in particular. Two fundamental measures of spatial vision are spatial resolution and contrast sensitivity. In this study, we report the threshold of spatial resolution in B. terrestris and characterize the contrast sensitivity function of the bumblebee visual system for a dual choice discrimination task. We trained bumblebees in a Y-maze experimental set-up to associate a vertical sinusoidal grating with a sucrose reward, and a horizontal grating with absence of a reward. Using a logistic psychometric function, we estimated a resolution threshold of 0.21 cycles deg−1 of visual angle. This resolution is in the same range but slightly lower than that found in honeybees (Apis mellifera and A. cerana) and another bumblebee species (B. impatiens). We also found that the contrast sensitivity of B. terrestris was 1.57 for the spatial frequency 0.090 cycles deg−1 and 1.26 for 0.18 cycles deg−1.
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Affiliation(s)
| | - Emily Baird
- Department of Biology, Lund University Lund, Sweden
| | - Marie Dacke
- Department of Biology, Lund University Lund, Sweden
| | - Almut Kelber
- Department of Biology, Lund University Lund, Sweden
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16
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WATANABE S, HASE Y, NAKAMURA N. DO BUDGERIGARS (<i>MELOPSITTACUS UNDULATUS</i>) PERCEIVE THE DELBOEUF ILLUSION?: A PRELIMINARY STUDY WITH A SIMULTANEOUS DISCRIMINATION TASK. PSYCHOLOGIA 2016. [DOI: 10.2117/psysoc.2016.121] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Affiliation(s)
| | - Yuriko HASE
- Course for School Teachers, Osaka Kyoiku University
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17
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Eye surface temperature detects stress response in budgerigars (Melopsittacus undulatus). Neuroreport 2015; 26:642-6. [DOI: 10.1097/wnr.0000000000000403] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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18
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Abstract
As a research tool, virtual environments (VEs) hold immense promise for brain scientists. Yet to fully realize this potential in non-human systems, theoretical and conceptual perspectives must be developed. When selectively coupled to nervous systems, virtual environments can help us better understand the functional architecture of animals’ brains during naturalistic behaviors. While this will no doubt allow us to further our understanding of the neural basis of behavior, there is also an opportunity to uncover the diversity inherent in brain activity and behavior. This is due to two properties of virtual environments: the ability to create sensory illusions, and the ability to dilate space and/or time. These and other potential manipulations will be characterized as the effects of virtuality. In addition, the systems-level outcomes of virtual environment enhanced perception will be discussed in the context of the uncanny valley and other expected relationships between emotional valence, cognition, and training. These effects and their usefulness for brain science will be understood in the context of three types of neurobehavioral phenomena: sensorimotor integration, spatial navigation, and interactivity. For each of these behaviors, a combination of illusory and space/time dilation examples will be reviewed. Once these examples are presented, the implications for improving upon virtual models for more directly inducing the mental phenomena of illusion and space/time dilation will be considered. To conclude, future directions for integrating the use of VEs into a strategy of broader biological inquiry will be presented.
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