scholarly journals Why do horseflies need polarization vision for host detection? Polarization helps tabanid flies to select sunlit dark host animals from the dark patches of the visual environment

2017 ◽  
Vol 4 (11) ◽  
pp. 170735 ◽  
Author(s):  
Gábor Horváth ◽  
Tamás Szörényi ◽  
Ádám Pereszlényi ◽  
Balázs Gerics ◽  
Ramón Hegedüs ◽  
...  
Keyword(s):  
Polarized Light ◽  
Degree Of Polarization ◽  
Polarization Sensitivity ◽  
Host Animal ◽  
Linearly Polarized ◽  
Imaging Polarimetry ◽  
Host Detection ◽  
Vegetation Region ◽  
Two Parameters ◽  
Polarization Of Light

Horseflies (Tabanidae) are polarotactic, being attracted to linearly polarized light when searching for water or host animals. Although it is well known that horseflies prefer sunlit dark and strongly polarizing hosts, the reason for this preference is unknown. According to our hypothesis, horseflies use their polarization sensitivity to look for targets with higher degrees of polarization in their optical environment, which as a result facilitates detection of sunlit dark host animals. In this work, we tested this hypothesis. Using imaging polarimetry, we measured the reflection–polarization patterns of a dark host model and a living black cow under various illumination conditions and with different vegetation backgrounds. We focused on the intensity and degree of polarization of light originating from dark patches of vegetation and the dark model/cow. We compared the chances of successful host selection based on either intensity or degree of polarization of the target and the combination of these two parameters. We show that the use of polarization information considerably increases the effectiveness of visual detection of dark host animals even in front of sunny–shady–patchy vegetation. Differentiation between a weakly polarizing, shady (dark) vegetation region and a sunlit, highly polarizing dark host animal increases the efficiency of host search by horseflies.

scholarly journals The linearly polarized light field in clear, tropical marine waters: spatial and temporal variation of light intensity, degree of polarization and e-vector angle

2001 ◽  
Vol 204 (14) ◽  
pp. 2461-2467 ◽  
Author(s):  
Thomas W. Cronin ◽  
Nadav Shashar
Keyword(s):  
Light Field ◽  
Marine Invertebrates ◽  
Polarized Light ◽  
Florida Keys ◽  
Degree Of Polarization ◽  
Spatial And Temporal Variation ◽  
Polarization Sensitivity ◽  
Marine Animals ◽  
Linearly Polarized ◽  
Vector Angle

SUMMARYSensitivity to polarized light is widespread among marine animals, including crustaceans, cephalopods and some fishes. They use this ability to orient and find prey, and possibly for a number of other visual tasks. Unlike the ultraviolet-sensitive polarization receptors of most insects, the polarization receptors of marine invertebrates tend to be maximally sensitive near 500nm, suggesting that polarized light in water differs from that in air. The underwater field of partially linearly polarized light has been studied for nearly 50 years, but data are still limited and sparse. We measured the submarine polarized light field from 350 to 600nm throughout the day on a coral reef in the Florida Keys at a depth of 15m using the underwater laboratory Aquarius as a research platform. Our results show that the angle of polarization as viewed along any given line of sight at this depth is a relatively simple function of solar position and that the degree of polarization is greatest 60–90° from the sun. Both e-vector angle and degree of polarization vary only slightly with wavelength, although light is sometimes less polarized in the ultraviolet. Since light is most intense at medium wavelengths and polarization is nearly maximal at these wavelengths, invertebrate polarization photoreceptors are spectrally well placed. Also, the relative spectral constancy of the angle and degree of polarization supports fish polarization sensitivity, which relies on spectrally diverse photoreceptor sets.

scholarly journals Attractiveness of thermally different, uniformly black targets to horseflies: Tabanus tergestinus prefers sunlit warm shiny dark targets

2019 ◽  
Vol 6 (10) ◽  
pp. 191119 ◽  
Author(s):  
Gábor Horváth ◽  
Ádám Pereszlényi ◽  
Tímea Tóth ◽  
Szabolcs Polgár ◽  
Imre M. Jánosi
Keyword(s):  
Field Experiments ◽  
Elevated Temperatures ◽  
Thermal Characteristics ◽  
Optical Characteristics ◽  
Degree Of Polarization ◽  
Small Scale ◽  
Host Animal ◽  
Reflected Light ◽  
Scale Models ◽  
Imaging Polarimetry

From a large distance tabanid flies may find their host animal by means of its shape, size, motion, odour, radiance and degree of polarization of host-reflected light. After alighting on the host, tabanids may use their mechano-, thermo-, hygro- and chemoreceptors to sense the substrate characteristics. Female tabanids prefer to attack sunlit against shady dark host animals, or dark against bright hosts for a blood meal, the exact reasons for which are unknown. Since sunlit darker surfaces are warmer than shady ones or sunlit/shady brighter surfaces, the differences in surface temperatures of dark and bright as well as sunlit and shady hosts may partly explain their different attractiveness to tabanids. We tested this observed warmth preference in field experiments, where we compared the attractiveness to tabanids ( Tabanus tergestinus ) of a warm and a cold shiny black barrel imitating dark hosts with the same optical characteristics. Using imaging polarimetry, thermography and Schlieren imaging, we measured the optical and thermal characteristics of both barrels and their small-scale models. We recorded the number of landings on these targets and measured the time periods spent on them. Our study revealed that T. tergestinus tabanid flies prefer sunlit warm shiny black targets against sunlit or shady cold ones with the same optical characteristics. These results support our new hypothesis that a blood-seeking female tabanid prefers elevated temperatures, partly because her wing muscles are more rapid and her nervous system functions better (due to faster conduction velocities and synaptic transmission of signals) in a warmer microclimate, and thus, she can avoid the parasite-repelling reactions of host animals by a prompt take-off.

scholarly journals Patterns and properties of polarized light in air and water

2011 ◽  
Vol 366 (1565) ◽  
pp. 619-626 ◽  
Author(s):  
Thomas W. Cronin ◽  
Justin Marshall
Keyword(s):  
Polarized Light ◽  
Natural Scenes ◽  
Circularly Polarized Light ◽  
Circularly Polarized ◽  
Current State ◽  
Visual Systems ◽  
The Earth ◽  
Predictable Pattern ◽  
Linearly Polarized ◽  
Polarization Of Light

Natural sources of light are at best weakly polarized, but polarization of light is common in natural scenes in the atmosphere, on the surface of the Earth, and underwater. We review the current state of knowledge concerning how polarization and polarization patterns are formed in nature, emphasizing linearly polarized light. Scattering of sunlight or moonlight in the sky often forms a strongly polarized, stable and predictable pattern used by many animals for orientation and navigation throughout the day, at twilight, and on moonlit nights. By contrast, polarization of light in water, while visible in most directions of view, is generally much weaker. In air, the surfaces of natural objects often reflect partially polarized light, but such reflections are rarer underwater, and multiple-path scattering degrades such polarization within metres. Because polarization in both air and water is produced by scattering, visibility through such media can be enhanced using straightforward polarization-based methods of image recovery, and some living visual systems may use similar methods to improve vision in haze or underwater. Although circularly polarized light is rare in nature, it is produced by the surfaces of some animals, where it may be used in specialized systems of communication.

scholarly journals Behavioural relevance of polarization sensitivity as a target detection mechanism in cephalopods and fishes

2011 ◽  
Vol 366 (1565) ◽  
pp. 734-741 ◽  
Author(s):  
Vincenzo Pignatelli ◽  
Shelby E. Temple ◽  
Tsyr-Huei Chiou ◽  
Nicholas W. Roberts ◽  
Shaun P. Collin ◽  
...  
Keyword(s):  
Target Detection ◽  
Polarized Light ◽  
Luminance Contrast ◽  
Polarization Sensitivity ◽  
Prey Detection ◽  
Free Swimming ◽  
Detection Mechanism ◽  
Set Up ◽  
Polarization Of Light

Aquatic habitats are rich in polarized patterns that could provide valuable information about the environment to an animal with a visual system sensitive to polarization of light. Both cephalopods and fishes have been shown to behaviourally respond to polarized light cues, suggesting that polarization sensitivity (PS) may play a role in improving target detection and/or navigation/orientation. However, while there is general agreement concerning the presence of PS in cephalopods and some fish species, its functional significance remains uncertain. Testing the role of PS in predator or prey detection seems an excellent paradigm with which to study the contribution of PS to the sensory assets of both groups, because such behaviours are critical to survival. We developed a novel experimental set-up to deliver computer-generated, controllable, polarized stimuli to free-swimming cephalopods and fishes with which we tested the behavioural relevance of PS using stimuli that evoke innate responses (such as an escape response from a looming stimulus and a pursuing behaviour of a small prey-like stimulus). We report consistent responses of cephalopods to looming stimuli presented in polarization and luminance contrast; however, none of the fishes tested responded to either the looming or the prey-like stimuli when presented in polarization contrast.

Polarization vision in cuttlefish in a concealed communication channel?

1996 ◽  
Vol 199 (9) ◽  
pp. 2077-2084
Author(s):  
N Shashar ◽  
P Rutledge ◽  
T Cronin
Keyword(s):  
Polarized Light ◽  
Egg Laying ◽  
Polarization Sensitivity ◽  
Polarization Vision ◽  
Microscopical Examination ◽  
Polarization Pattern ◽  
Behavioral Experiments ◽  
Marine Animals ◽  
Linearly Polarized ◽  
Electron Microscopical

Polarization sensitivity is well documented in marine animals, but its function is not yet well understood. Of the cephalopods, squid and octopus are known to be sensitive to the orientation of polarization of incoming light. This sensitivity arises from the orthogonal orientation of neighboring photoreceptors. Electron microscopical examination of the retina of the cuttlefish Sepia officinalis L. revealed the same orthogonal structure, suggesting that cuttlefish are also sensitive to linearly polarized light. Viewing cuttlefish through an imaging polarized light analyzer revealed a prominent polarization pattern on the arms, around the eyes and on the forehead of the animals. The polarization pattern disappeared when individuals lay camouflaged on the bottom and also during extreme aggression display, attacks on prey, copulation and egg-laying behavior in females. In behavioral experiments, the responses of cuttlefish to their images reflected from a mirror changed when the polarization patterns of the reflected images were distorted. These results suggest that cuttlefish use polarization vision and display for intraspecific recognition and communication.

scholarly journals No evidence for polarization sensitivity in the pigeon electroretinogram

1995 ◽  
Vol 198 (2) ◽  
pp. 325-335 ◽  
Author(s):  
J J Vos Hzn ◽  
M A J M Coemans ◽  
J F W Nuboer
Keyword(s):  
White Light ◽  
Monochromatic Light ◽  
Polarized Light ◽  
Polarization Sensitivity ◽  
Slow Rotation ◽  
Unpolarized Light ◽  
Linearly Polarized

The electroretinographical response to flashes of linearly polarized light directed at the pigeon's yellow field was compared with that to flashes of unpolarized light. This was carried out for white light and for monochromatic light of various wavelengths, including ultraviolet. In addition, responses to slow rotation of the E-vector of polarized light were measured. Neither the presence or absence of polarization, nor the orientation of the E-vector, influenced any of the electrophysiological variables that were monitored in these experiments.

Does reflection polarization by plants influence colour perception in insects? Polarimetric measurements applied to a polarization-sensitive model retina ofPapiliobutterflies

2002 ◽  
Vol 205 (21) ◽  
pp. 3281-3298 ◽  
Author(s):  
Gábor Horváth ◽  
József Gál ◽  
Thomas Labhart ◽  
Rüdiger Wehner
Keyword(s):  
Quantitative Model ◽  
Polarization Sensitivity ◽  
Natural Conditions ◽  
Colour Perception ◽  
Linearly Polarized ◽  
Imaging Polarimetry ◽  
Reflecting Surfaces ◽  
Plant Surfaces

SUMMARYUsing imaging polarimetry, we have measured some typical reflection-polarization patterns of plant surfaces (leaves and flowers) under different illuminations. Using a quantitative model to determine photon absorptions in the weakly polarization-sensitive (PS≈2)photoreceptors of Papilio butterflies, we have calculated the influence of reflection polarization on the colours of leaves and flowers perceived by Papilio. Compared with a retina containing polarization-blind colour receptors, the colour loci of specularly reflecting and, thus, strongly polarizing areas on a plant are slightly shifted, which could cause the perception of false colours. However, the colour of specularly reflecting surfaces is strongly masked by white glare, which may prevent the perception of polarization-induced hue shifts. Although the perception of polarizational false colours by Papilio butterflies was previously demonstrated with artificial, strongly colour-saturated and totally linearly polarized stimuli, we expect that the weak polarization sensitivity of Papilio photoreceptors hardly influences colour perception under natural conditions.

Daphnia pulex swims towards the most strongly polarized light - a response that leads to ‘shore flight’

1999 ◽  
Vol 202 (24) ◽  
pp. 3631-3635 ◽  
Author(s):  
R. Schwind
Keyword(s):  
Visual Field ◽  
Rayleigh Scattering ◽  
Daphnia Pulex ◽  
Polarized Light ◽  
Open Water ◽  
The Other ◽  
Lower Degree ◽  
Degree Of Polarization ◽  
Large Area ◽  
Linearly Polarized

When Daphnia pulex are presented on one side of their visual field with diffuse, large-area linearly polarized light with a horizontal e-vector and on the other side of their visual field with large-area polarized light with a lower degree of polarization, they swim towards the place with the higher degree of polarization. The response is intensity-invariant: Daphnia pulex swim towards the place of maximal polarization regardless of which side of their visual field has the higher intensity of light. As a result of Rayleigh scattering in a pond, the light surrounding the Daphnia is polarized and has a horizontal e-vector. Near the shore, polarization is not homogeneous. The light seen in the direction of the open water has a higher degree of polarization than that seen in the direction towards the shore. Therefore, in a pond, swimming towards the place with the highest degree of polarization leads the Daphnia away from the shore. For Daphnia, this response explains a mechanism that underlies the well-known phenomenon of ‘shore flight’, the active departure of small pelagic crustaceans from shore zones.

scholarly journals Polarization-Sensitive Light Sensors Based on a Bulk Perovskite MAPbBr3 Single Crystal

Materials ◽  
2021 ◽  
Vol 14 (5) ◽  
pp. 1238
Author(s):  
Yuan Wang ◽  
Laipan Zhu ◽  
Cuifeng Du
Keyword(s):  
Single Crystal ◽  
Polarized Light ◽  
Light Polarization ◽  
Polarization Sensitivity ◽  
Anisotropy Ratio ◽  
Spin Orbit Coupling ◽  
Band Tail ◽  
Linearly Polarized ◽  
Halide Perovskites ◽  
Shed Light

Organic-inorganic halide perovskites have attracted much attention thanks to their excellent optoelectronic performances. Here, a bulk CH3NH3PbBr3 (MAPbBr3) single crystal (SC) was fabricated, whose temperature and light polarization dependence was investigated by measuring photoluminescence. The presence of obvious band tail states was unveiled when the applied temperature was reduced from room temperature to 78 K. Temperature dependence of the bandgap of the MAPbBr3 SC was found to be abnormal compared with those of traditional semiconductors due to the presence of instabilization of out-of-phase tail states. The MAPbBr3 SC revealed an anisotropy light absorption for linearly polarized light with an anisotropy ratio of 1.45, and a circular dichroism ratio of up to 9% was discovered due to the spin-orbit coupling in the band tail states, exhibiting great polarization sensitivity of the MAPbBr3 SC for the application of light sensors. These key findings shed light on the development of potential optoelectronic and spintronic applications based on large-scaled organic-inorganic perovskite SCs.

scholarly journals Orienting to Polarized Light at Night—Matching Lunar Skylight to Performance in a Nocturnal Beetle

2018 ◽  
Author(s):  
James J. Foster ◽  
John D. Kirwan ◽  
Basil el Jundi ◽  
Jochen Smolka ◽  
Lana Khaldy ◽  
...  
Keyword(s):  
South African ◽  
Polarized Light ◽  
Dung Beetle ◽  
Degree Of Polarization ◽  
Specific Reference ◽  
Lunar Phase ◽  
Orientation Behaviour ◽  
Linearly Polarized ◽  
Summary Statement ◽  
Night Sky

AbstractFor polarized light to inform behaviour, the typical range of degrees of polarization observable in the animal’s natural environment must be above the threshold for detection and interpretation. Here we present the first investigation of the degree of linear polarization threshold for orientation behaviour in a nocturnal species, with specific reference to the range of degrees of polarization measured in the night sky. An effect of lunar phase on the degree of polarization of skylight was found, with smaller illuminated fractions of the moon’s surface corresponding to lower degrees of polarization in the night sky. We found that South African dung beetleEscarabaeus satyrus(Boheman, 1860) can orient to polarized light for a range of degrees of polarization similar to that observed in diurnal insects, reaching a lower threshold between 0.04 and 0.32, possibly as low as 0.11. For degrees of polarization lower than 0.23, as measured on a crescent moon night, orientation performance was considerably weaker than that observed for completely linearly-polarized stimuli, but was nonetheless stronger than in the absence of polarized light.Summary StatementA degree-of-polarization threshold for orientation behaviour is reported for nocturnal dung beetleEscarabaeus satyrusin the context of measurements showing changes in the degree of polarization of skylight with lunar phase.

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