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.

Rayleigh Scattering of Linearly Polarized Light from Optically Active Quartz

1968 ◽  
Vol 7 (10) ◽  
pp. 1913 ◽  
Author(s):  
C. A. Arguello ◽  
D. L. Rousseau ◽  
S. P. S. Porto ◽  
L. E. Cheesman ◽  
J. F. Scott
Keyword(s):  
Rayleigh Scattering ◽  
Polarized Light ◽  
Optically Active ◽  
Linearly Polarized

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.

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 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.

scholarly journals 1. On the compensations of polarized light, with the descrip­tion of a polarimeter for Measuring Degrees of Polarization

1843 ◽  
Vol 4 ◽  
pp. 306-307
Keyword(s):  
Polarized Light ◽  
Physical Property ◽  
The Other ◽  
Degree Of Polarization ◽  
Angle Of Incidence ◽  
Direct System ◽  
Equal Degree ◽  
In Virtue Of ◽  
Different Parts ◽  
Partial Polarization

In four papers published in the Philosophical Transactions for 1830, the author maintained, in opposition to the prevailing theory, that light either reflected or refracted at angles different from that at which it is completely polarized, does not consist of two portions, one completely polarized, and the other completely unpolarized, but that every portion of it has the same physical property, having approximated in an equal degree to the state of complete polarization. This conclusion, which had been derived from reasoning on the hy­pothesis that a pencil of light, composed of two pencils polarized respectively at angles of + and - 45° with the plane of reflexion, was equivalent to a pencil of common light, is confirmed in this paper by experiment, made with common light itself, reflected from different parts of the atmosphere, and from which the uniaxal or biaxal systems of rings were obtained. On placing such a system between light partially polarized in an opposite plane, the author found that the rings disappeared, the direct system being seen on one side of the plane of disappearance, and the complementary system on the other side. In this experiment the polarization of the light in one plane was compensated by the polarization of the same light in the opposite plane; and, consequently, both the pencils, which had undergone the two successive polarizing actions, had received the same degree of polarization in opposite planes; and in virtue of these two equal and opposite polarizations, the light at the point of compensation, where the system of rings disappeared, had been re­stored from partially polarized to common light; and the light on each side of this point of compensation was in opposite states of partial polarization. In order to give a distinct view of the nature of this experiment, the author details the phenomena observed at particular angles of incidence on glass. From the results at an angle of incidence of 24°, the ray suffering one refraction at 80°, and a second reflexion at 83½°, lie concludes that the compensation which takes place is produced neither by an equality of oppositely polarized rays, nor by a proportional admixture of common light, but by equal and oppo­site physical states of the whole pencil, whether reflected or refracted.

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.

Stories and the Self

2020 ◽  
Vol 32 (2) ◽  
pp. 47-58 ◽  
Author(s):  
Stefan Krause ◽  
Markus Appel
Keyword(s):  
Meta Analysis ◽  
The Self ◽  
The Other ◽  
Lower Degree ◽  
Contrast Effects ◽  
Self Perception ◽  
Self Perceptions ◽  
Other Hand ◽  
The One ◽  
Implicit And Explicit

Abstract. Two experiments examined the influence of stories on recipients’ self-perceptions. Extending prior theory and research, our focus was on assimilation effects (i.e., changes in self-perception in line with a protagonist’s traits) as well as on contrast effects (i.e., changes in self-perception in contrast to a protagonist’s traits). In Experiment 1 ( N = 113), implicit and explicit conscientiousness were assessed after participants read a story about either a diligent or a negligent student. Moderation analyses showed that highly transported participants and participants with lower counterarguing scores assimilate the depicted traits of a story protagonist, as indicated by explicit, self-reported conscientiousness ratings. Participants, who were more critical toward a story (i.e., higher counterarguing) and with a lower degree of transportation, showed contrast effects. In Experiment 2 ( N = 103), we manipulated transportation and counterarguing, but we could not identify an effect on participants’ self-ascribed level of conscientiousness. A mini meta-analysis across both experiments revealed significant positive overall associations between transportation and counterarguing on the one hand and story-consistent self-reported conscientiousness on the other hand.

Visual asymmetries during face encoding Increased dwell time and fixations in the upper and left hemifields

2018 ◽  
Author(s):  
Fatima Maria Felisberti
Keyword(s):  
Face Recognition ◽  
Eye Movements ◽  
Visual Field ◽  
Face Processing ◽  
Dwell Time ◽  
The Other ◽  
Environmental Cues ◽  
Reading Habits ◽  
The Right

Visual field asymmetries (VFA) in the encoding of groups rather than individual faces has been rarely investigated. Here, eye movements (dwell time (DT) and fixations (Fix)) were recorded during the encoding of three groups of four faces tagged with cheating, cooperative, or neutral behaviours. Faces in each of the three groups were placed in the upper left (UL), upper right (UR), lower left (LL), or lower right (LR) quadrants. Face recognition was equally high in the three groups. In contrast, the proportion of DT and Fix were higher for faces in the left than the right hemifield and in the upper rather than the lower hemifield. The overall time spent looking at the UL was higher than in the other quadrants. The findings are relevant to the understanding of VFA in face processing, especially groups of faces, and might be linked to environmental cues and/or reading habits.

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