scholarly journals Orientation to polarized light in tethered flying honeybees

2020 ◽  
Vol 223 (23) ◽  
pp. jeb228254
Author(s):  
Norihiro Kobayashi ◽  
Ryuichi Okada ◽  
Midori Sakura
Keyword(s):  
Light Stimulus ◽  
Polarized Light ◽  
Rotation Frequency ◽  
Compass Orientation ◽  
Black Paint ◽  
Flight Direction ◽  
Periodic Movement ◽  
Vector Information ◽  
Vector Orientation ◽  
Partial Plane

ABSTRACTMany insects exploit the partial plane polarization of skylight for visual compass orientation and/or navigation. In the present study, using a tethering system, we investigated how flying bees respond to polarized light stimuli. The behavioral responses of honeybees (Apis mellifera) to a zenithal polarized light stimulus were observed using a tethered animal in a flight simulator. Flight direction of the bee was recorded by monitoring the horizontal movement of its abdomen, which was strongly anti-correlated with its torque. When the e-vector orientation of the polarized light was rotated clockwise or counterclockwise, the bee responded with periodic right-and-left abdominal movements; however, the bee did not show any clear periodic movement under the static e-vector or depolarized stimulus. The steering frequency of the bee was well coordinated with the e-vector rotation frequency of the stimulus, indicating that the flying bee oriented itself to a certain e-vector orientation, i.e. exhibited polarotaxis. The percentage of bees exhibiting clear polarotaxis was much smaller under the fast stimulus (3.6 deg s−1) compared with that under a slow stimulus (0.9 or 1.8 deg s−1). Bees did not demonstrate any polarotactic behavior after the dorsal rim area of the eyes, which mediates insect polarization vision in general, was bilaterally covered with black paint. Preferred e-vector orientations under the clockwise stimulus varied among individuals and distributed throughout −90 to 90 deg. Some bees showed similar preferred e-vector orientations for clockwise and counterclockwise stimuli whereas others did not. Our results strongly suggest that flying honeybees utilize the e-vector information from the skylight to deduce their heading orientation for navigation.

scholarly journals Orientation to polarized light in tethered flying honeybees

2019 ◽  
Author(s):  
Norihiro Kobayashi ◽  
Ryuichi Okada ◽  
Midori Sakura
Keyword(s):  
Light Stimulus ◽  
Polarized Light ◽  
Rotation Frequency ◽  
Black Paint ◽  
Flight Direction ◽  
Periodic Movement ◽  
High Preference ◽  
Foraging Experience ◽  
Vector Information ◽  
Vector Orientation

ABSTRACTBehavioral responses of honeybees to a zenithal polarized light stimulus were observed using a tethered animal in a flight simulator. Flight direction of the bee was recorded by monitoring the horizontal movement of its abdomen, which was strongly anti-correlated with its torque. When the e-vector orientation of the polarized light was rotated clockwise or counterclockwise, the bee responded with periodic right-and-left abdominal movements; however, the bee did not show any clear periodic movement under the static e-vector or depolarized stimulus. The steering frequency of the bee was well coordinated with the e-vector rotation frequency of the stimulus, indicating that the flying bee oriented itself to a certain e-vector orientation, i.e., exhibited polarotaxis. The percentage of bees exhibiting clear polarotaxis was much smaller under the fast stimulus (3.6 ° s-1) compared with that of the slow stimulus (0.9 or 1.8 ° s-1). The bee did not demonstrate any polarotactic behavior after the dorsal rim region of its eyes, which mediates insect polarization vision in general, was bilaterally covered with black paint. The bees demonstrated a high preference for e-vector orientations between 120 to 180°. Each bee exhibited similar e-vector preferences under clockwise and counterclockwise stimuli, indicating that each bee has its own e-vector preference, which probably depends on the bee’s previous foraging experience. Our results strongly suggest that the flying honeybees utilize the e-vector information from the skylight to deduce their heading orientation for navigation.Summary statementTethered flying bees exhibited polarotaxis under a zenithal rotating e-vector stimulus, in which their right-and-left abdominal movements were coincident with the rotation of the stimulus.

scholarly journals Evidence for instantaneous e-vector detection in the honeybee using an associative learning paradigm

2011 ◽  
Vol 279 (1728) ◽  
pp. 535-542 ◽  
Author(s):  
Midori Sakura ◽  
Ryuichi Okada ◽  
Hitoshi Aonuma
Keyword(s):  
Compound Eye ◽  
Polarized Light ◽  
Green Light ◽  
Sequential Method ◽  
Sugar Water ◽  
Conditioning Paradigm ◽  
Flight Direction ◽  
Vector Information ◽  
Proboscis Extension ◽  
Vector Orientation

Many insects use the polarization pattern of the sky for obtaining compass information during orientation or navigation. E-vector information is collected by a specialized area in the dorsal-most part of the compound eye, the dorsal rim area (DRA). We tested honeybees' capability of learning certain e-vector orientations by using a classical conditioning paradigm with the proboscis extension reflex. When one e-vector orientation (CS+) was associated with sugar water, while another orientation (CS−) was not rewarded, the honeybees could discriminate CS+ from CS−. Bees whose DRA was inactivated by painting did not learn CS+. When ultraviolet (UV) polarized light (350 nm) was used for CS, the bees discriminated CS+ from CS−, but no discrimination was observed in blue (442 nm) or green light (546 nm). Our data indicate that honeybees can learn and discriminate between different e-vector orientations, sensed by the UV receptors of the DRA, suggesting that bees can determine their flight direction from polarized UV skylight during foraging. Fixing the bees' heads during the experiments did not prevent learning, indicating that they use an ‘instantaneous’ algorithm of e-vector detection; that is, the bees do not need to actively scan the sky with their DRAs (‘sequential’ method) to determine e-vector orientation.

scholarly journals How polarization-sensitive interneurones of crickets perform at low degrees of polarization

1996 ◽  
Vol 199 (7) ◽  
pp. 1467-1475 ◽  
Author(s):  
T Labhart
Keyword(s):  
Compound Eye ◽  
Polarized Light ◽  
Degree Of Polarization ◽  
Modulation Amplitude ◽  
Optimal Conditions ◽  
Vector Information ◽  
Vector Orientation ◽  
D Values ◽  
Low Degrees ◽  
Sinusoidal Function

In crickets, polarized-light information from the blue sky is processed by polarization-opponent interneurones (POL-neurones). These neurones receive input from the polarization-sensitive blue receptors found in the specialized dorsal rim area of the compound eye. Even under optimal conditions, the degree of polarization d does not exceed 0.75 in the blue region of the spectrum and it is normally much lower. The aim of this study is to assess how POL-neurones perform at low, physiologically relevant degrees of polarization. The spiking activity of POL-neurones is a sinusoidal function of e-vector orientation with a 180 ° period. The modulation amplitude of this function decreases strongly as the degree of polarization decreases. However, our data indicate that POL-neurones can signal e-vector information at d-values as low as 0.05, which would allow the polarization-sensitive system of crickets to exploit polarized light from the sky for orientation even under unfavourable meteorological conditions.

scholarly journals Polarized Skylight Navigation in Insects: Model and Electrophysiology of e-Vector Coding by Neurons in the Central Complex

2008 ◽  
Vol 99 (2) ◽  
pp. 667-682 ◽  
Author(s):  
Midori Sakura ◽  
Dimitrios Lambrinos ◽  
Thomas Labhart
Keyword(s):  
Vision System ◽  
Gain Control ◽  
Central Complex ◽  
Degree Of Polarization ◽  
Insect Brain ◽  
Atmospheric Conditions ◽  
Compass Orientation ◽  
Vector Coding ◽  
Skylight Polarization ◽  
Vector Orientation

Many insects exploit skylight polarization for visual compass orientation or course control. As found in crickets, the peripheral visual system (optic lobe) contains three types of polarization-sensitive neurons (POL neurons), which are tuned to different (∼60° diverging) e-vector orientations. Thus each e-vector orientation elicits a specific combination of activities among the POL neurons coding any e-vector orientation by just three neural signals. In this study, we hypothesize that in the presumed orientation center of the brain (central complex) e-vector orientation is population-coded by a set of “compass neurons.” Using computer modeling, we present a neural network model transforming the signal triplet provided by the POL neurons to compass neuron activities coding e-vector orientation by a population code. Using intracellular electrophysiology and cell marking, we present evidence that neurons with the response profile of the presumed compass neurons do indeed exist in the insect brain: each of these compass neuron-like (CNL) cells is activated by a specific e-vector orientation only and otherwise remains silent. Morphologically, CNL cells are tangential neurons extending from the lateral accessory lobe to the lower division of the central body. Surpassing the modeled compass neurons in performance, CNL cells are insensitive to the degree of polarization of the stimulus between 99% and at least down to 18% polarization and thus largely disregard variations of skylight polarization due to changing solar elevations or atmospheric conditions. This suggests that the polarization vision system includes a gain control circuit keeping the output activity at a constant level.

Two-Channel Polarization Analyzer in the Sustaining Fiber-Dimming Fiber Ensemble of Crayfish Visual System

1998 ◽  
Vol 80 (5) ◽  
pp. 2571-2583 ◽  
Author(s):  
Raymon M. Glantz ◽  
Andy McIsaac
Keyword(s):  
Visual System ◽  
Polarized Light ◽  
Polarization Sensitivity ◽  
Visual Responses ◽  
Polarization Analyzer ◽  
Peripheral Neurons ◽  
Steady State Responses ◽  
Vector Orientation ◽  
Channel Polarization ◽  
State Responses

Glantz, Raymon M. and Andy McIsaac. Two-channel polarization analyzer in the sustaining fiber-dimming fiber ensemble of crayfish visual system. J. Neurophysiol. 80: 2571–2583, 1998. Polarization sensitivity (PS) was examined in two classes of neurons, sustaining fibers and dimming fibers, in the medulla externa (second optic neuropile) of the crayfish, Pacifasticus leniusculus. Visual responses were recorded intracellularly and extracellularly. The influence of e-vector orientation (θ) was probed in steady-state responses, with brief flashes and with a rotating polarizer. The results indicate that the entire sustaining fiber population appears to be maximally sensitive to vertically polarized light. Although the evidence is less complete for dimming fibers, they appear to be maximally inhibited by vertically polarized light and excited by horizontally polarized light. Thus the sustaining fibers and dimming fibers form a two-channel polarization analyzer that captures the main features of the polarization system established in photoreceptors and lamina monopolar cells. The available evidence suggests that this two-channel system has the same characteristics across most or all of the retinula. Lateral inhibition in sustaining fibers is differentially sensitive to θ. Inhibition is substantial at θ = 90° (horizontal) and essentially absent at θ = 0°. The details of the sustaining fiber polarization response closely follow features established in more peripheral neurons, including the magnitude of PS, enhanced responsiveness to a changing e-vector, and modest directionality to a changing e-vector in∼40% of the cells.

scholarly journals Behavioural and physiological mechanisms of polarized light sensitivity in birds

2011 ◽  
Vol 366 (1565) ◽  
pp. 763-771 ◽  
Author(s):  
Rachel Muheim
Keyword(s):  
Physiological Mechanism ◽  
Polarized Light ◽  
Light Sensitivity ◽  
Convincing Evidence ◽  
Polarization Pattern ◽  
Compass Orientation ◽  
Receptor System ◽  
Sun Compass ◽  
Skylight Polarization ◽  
Compass Calibration

Polarized light (PL) sensitivity is relatively well studied in a large number of invertebrates and some fish species, but in most other vertebrate classes, including birds, the behavioural and physiological mechanism of PL sensitivity remains one of the big mysteries in sensory biology. Many organisms use the skylight polarization pattern as part of a sun compass for orientation, navigation and in spatial orientation tasks. In birds, the available evidence for an involvement of the skylight polarization pattern in sun-compass orientation is very weak. Instead, cue-conflict and cue-calibration experiments have shown that the skylight polarization pattern near the horizon at sunrise and sunset provides birds with a seasonally and latitudinally independent compass calibration reference. Despite convincing evidence that birds use PL cues for orientation, direct experimental evidence for PL sensitivity is still lacking. Avian double cones have been proposed as putative PL receptors, but detailed anatomical and physiological evidence will be needed to conclusively describe the avian PL receptor. Intriguing parallels between the functional and physiological properties of PL reception and light-dependent magnetoreception could point to a common receptor system.

scholarly journals Skylight Polarization patterns and Animal Orientation

1982 ◽  
Vol 96 (1) ◽  
pp. 69-91 ◽  
Author(s):  
MICHAEL L. BRINES ◽  
JAMES L. GOULD
Keyword(s):  
Rayleigh Scattering ◽  
Polarized Light ◽  
Processing System ◽  
Light Polarization ◽  
Degree Of Polarization ◽  
Atmospheric Conditions ◽  
Apparent Paradox ◽  
Skylight Polarization ◽  
Visible Wavelengths ◽  
Vector Orientation

1. Although many invertebrate animals orient by means of ultraviolet sky-light polarization patterns, existing measurements of these patterns are inadequate for full analysis of the biologically relevant information available from the sky. To fill this gap we have used a precision scanning polarimeter to measure simultaneously the intensity, degree, and direction of vibration (E-vector orientation) of polarized light at 5° intervals over the sky. The resulting sky maps were constructed for u.v. (350 nm) and visible wavelengths (500 and 650 nm) under a variety of atmospheric conditions. 2. Our measurements confirmed that the patterns of radiance and degree of polarization of skylight are highly variable and hence unreliable as orientation cues; but patterns of E-vector orientation are relatively stable and predictable over most of the sky under all but very hazy or overcast conditions. 3. The observed E-vector patterns correspond more closely to predictions based on first order (Rayleigh) scattering at 650 and 500 nm than at 350 nm. This is true both in terms of absolute accuracy and the proportion of the sky with relatively ‘correct’ information. Yet most insects respond to polarization patterns only at u.v. wavelengths. This apparent paradox can perhaps be resolved by assuming that there is no great selective advantage for any particular wavelength when large areas of blue sky are visible, but that under special and difficult conditions ultraviolet has advantages over longer wavelengths. Measurements under partially cloud-covered sky, for instance, or under extensive vegetation, show that both spuriously polarized and unpolarized light resulting from reflexions present more troublesome interference at longer wavelengths than in the u.v. 4. The accuracy of orientation achieved by dancing honey bees appears to be greater than can readily be accounted for by assuming that they use a strictly geometrical or analytical processing system for their orientation to polarized light.

Navigation and Compass Orientation by Insects According to the Polarization Pattern of the Sky

1988 ◽  
Vol 43 (5-6) ◽  
pp. 467-469 ◽  
Author(s):  
K. Kirschfeld
Keyword(s):  
Polarized Light ◽  
Recent Theory ◽  
Polarization Pattern ◽  
Natural Conditions ◽  
Compass Orientation ◽  
Small Patch ◽  
Foraging Site

A recent theory attempts to explain how bees take their compass orientation from the pattern of polarized light in the sky (S. Rossel and R . Wehner, Nature 323, 128-131 (1986)). According to this theory, orientation can be erroneous and lead to the wrong course of a recruited bee in search of the foraging site whenever only a small patch of the blue sky is visible to the bee. It is shown that orientation under natural conditions is not erroneous, if the compass reference is variable in time but equally defined for both, scout bees and recruits.

scholarly journals Polarization reversal of scattered thermal dust emission in protoplanetary disks at submillimetre wavelengths

2019 ◽  
Vol 627 ◽  
pp. L10 ◽  
Author(s):  
R. Brunngräber ◽  
S. Wolf
Keyword(s):  
Dust Emission ◽  
Polarized Light ◽  
Protoplanetary Disks ◽  
Polarization Vector ◽  
Polarization Reversal ◽  
Polarization Pattern ◽  
Polarization Mechanism ◽  
Net Flux ◽  
Vector Orientation ◽  
Dust Grain

Investigation of the polarized light of protoplanetary disks is key for constraining dust properties, disk morphology, and embedded magnetic fields. However, different polarization mechanisms and the diversity of dust grain shapes and compositions lead to ambiguities in the polarization pattern. The so-called “self-scattering” of thermal, re-emitted radiation in the infrared and millimetre and submillimetre wavelengths is discussed as a major polarization mechanism. If the net flux of the radiation field is in the radial direction, it is commonly assumed that the polarization pattern produced by scattering in a protoplanetary disk shows concentric rings for disks seen in face-on orientation. We show that a change of 90° of the polarization vector orientation may occur and mimic the typical pattern of dichroic emission of dust grains aligned by a toroidal magnetic field in disks seen close to face-on. Furthermore, this effect of polarization reversal is a fast-changing function of wavelength and grain size, and is thus a powerful tool to constrain grain composition and size distribution present in protoplanetary disks. In addition, the effect may also provide unique constraints for the disk inclination, especially if the disk is seen close to face-on.

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