USE OF A SPECIALIZED MAGNETORECEPTION SYSTEM FOR HOMING BY THE EASTERN RED-SPOTTED NEWT NOTOPHTHALMUS VIRIDESCENS

1994 ◽  
Vol 188 (1) ◽  
pp. 275-291 ◽  
Author(s):  
J Phillips ◽  
S Borland
Keyword(s):  
Magnetic Field ◽  
Short Wavelength ◽  
Magnetic Compass ◽  
Compass Orientation ◽  
Full Spectrum ◽  
Long Wavelength ◽  
Magnetic Compass Orientation ◽  
Short Wavelength Light ◽  
The Magnetic Field ◽  
Wavelength Light

Laboratory experiments were carried out to investigate the effects of varying the wavelength of light on the use of an earth-strength magnetic field for shoreward orientation and for the compass component of homing. In the earlier shoreward orientation experiments, newts tested under full-spectrum and short-wavelength (i.e. 400 and 450 nm) light exhibited shoreward magnetic compass orientation. Under long-wavelength (i.e. 550 and 600 nm) light, newts exhibited magnetic compass orientation that was rotated 90 ° counterclockwise to the shoreward direction. This wavelength-dependent shift in magnetic compass orientation was shown to be due to a direct effect of light on the underlying magnetoreception mechanism. In homing experiments, newts tested under full-spectrum and short-wavelength light exhibited homeward magnetic compass orientation. Under long-wavelength light, newts were randomly distributed with respect to the magnetic field. The different effects of long-wavelength light on shoreward orientation and homing confirmed earlier evidence that different magnetoreception systems mediate these two forms of orientation behaviour. The properties of the newt's homing response are consistent with the use of a hybrid magnetoreception system receiving inputs from the light-dependent magnetic compass and from a non-light-dependent intensity (or inclination) detector which, unlike the compass, is sensitive to the polarity of the magnetic field.

scholarly journals `Fixed-axis' magnetic orientation by an amphibian: non-shoreward-directed compass orientation, misdirected homing or positioning a magnetite-based map detector in a consistent alignment relative to the magnetic field?

2002 ◽  
Vol 205 (24) ◽  
pp. 3903-3914 ◽  
Author(s):  
John B. Phillips ◽  
S. Chris Borland ◽  
Michael J. Freake ◽  
Jacques Brassart ◽  
Joseph L. Kirschvink
Keyword(s):  
Magnetic Field ◽  
Magnetic Bearing ◽  
Magnetic Compass ◽  
Compass Orientation ◽  
Full Spectrum ◽  
Directional Information ◽  
Long Wavelength ◽  
Fixed Axis ◽  
The Magnetic Field ◽  
Wavelength Light

SUMMARYExperiments were carried out to investigate the earlier prediction that prolonged exposure to long-wavelength (>500 nm) light would eliminate homing orientation by male Eastern red-spotted newts Notophthalmus viridescens. As in previous experiments, controls held in outdoor tanks under natural lighting conditions and tested in a visually uniform indoor arena under full-spectrum light were homeward oriented. As predicted, however,newts held under long-wavelength light and tested under either full-spectrum or long-wavelength light (>500 nm) failed to show consistent homeward orientation. The newts also did not orient with respect to the shore directions in the outdoor tanks in which they were held prior to testing. Unexpectedly, however, the newts exhibited bimodal orientation along a more-or-less `fixed' north-northeast—south-southwest magnetic axis. The orientation exhibited by newts tested under full-spectrum light was indistinguishable from that of newts tested under long-wavelength light,although these two wavelength conditions have previously been shown to differentially affect both shoreward compass orientation and homing orientation. To investigate the possibility that the `fixed-axis' response of the newts was mediated by a magnetoreception mechanism involving single-domain particles of magnetite, natural remanent magnetism (NRM) was measured from a subset of the newts. The distribution of NRM alignments with respect to the head—body axis of the newts was indistinguishable from random. Furthermore, there was no consistent relationship between the NRM of individual newts and their directional response in the overall sample. However, under full-spectrum, but not long-wavelength, light, the alignment of the NRM when the newts reached the 20 cm radius criterion circle in the indoor testing arena (estimated by adding the NRM alignment measured from each newt to its magnetic bearing) was non-randomly distributed. These findings are consistent with the earlier suggestion that homing newts use the light-dependent magnetic compass to align a magnetite-based `map detector'when obtaining the precise measurements necessary to derive map information from the magnetic field. However, aligning the putative map detector does not explain the fixed-axis response of newts tested under long-wavelength light. Preliminary evidence suggests that, in the absence of reliable directional information from the magnetic compass (caused by the 90° rotation of the response of the magnetic compass under long-wavelength light), newts may resort to a systematic sampling strategy to identify alignment(s) of the map detector that yields reliable magnetic field measurements.

scholarly journals Magnetic compass orientation in European robins is dependent on both wavelength and intensity of light

2002 ◽  
Vol 205 (24) ◽  
pp. 3845-3856 ◽  
Author(s):  
Rachel Muheim ◽  
Johan Bäckman ◽  
Susanne Åkesson
Keyword(s):  
Transition Zone ◽  
Wavelength Range ◽  
Short Wavelength ◽  
Monochromatic Light ◽  
Magnetic Compass ◽  
Autumn Migration ◽  
Compass Orientation ◽  
Long Wavelength ◽  
Magnetic Compass Orientation ◽  
And Shifts

SUMMARYMagnetic compass orientation in birds has been shown to be light dependent. Results from behavioural studies indicate that magnetoreception capabilities are disrupted under light of peak wavelengths longer than 565 nm, and shifts in orientation have been observed at higher light intensities(43-44×1015 quanta s-1 m-2). To investigate further the function of the avian magnetic compass with respect to wavelength and intensity of light, we carried out orientation cage experiments with juvenile European robins, caught during their first autumn migration,exposed to light of 560.5 nm (green), 567.5 nm (green-yellow) and 617 nm (red)wavelengths at three different intensities (1 mW m-2, 5 mW m-2 and 10 mW m-2). We used monochromatic light of a narrow wavelength range (half bandwidth of 9-11 nm, compared with half bandwidths ranging between 30 nm and 70 nm used in other studies) and were thereby able to examine the magnetoreception mechanism in the expected transition zone between oriented and disoriented behaviour around 565 nm in more detail. We show (1) that European robins show seasonally appropriate migratory directions under 560.5 nm light, (2) that they are completely disoriented under 567.5 nm light under a broad range of intensities, (3) that they are able to orient under 617 nm light of lower intensities, although into a direction shifted relative to the expected migratory one, and (4) that magnetoreception is intensity dependent, leading to disorientation under higher intensities. Our results support the hypothesis that birds possess a light-dependent magnetoreception system based on magnetically sensitive,antagonistically interacting spectral mechanisms, with at least one high-sensitive short-wavelength mechanism and one low-sensitive long-wavelength mechanism.

The role of extraocular photoreceptors in newt magnetic compass orientation: parallels between light-dependent magnetoreception and polarized light detection in vertebrates

2001 ◽  
Vol 204 (14) ◽  
pp. 2543-2552 ◽  
Author(s):  
John B. Phillips ◽  
Mark E. Deutschlander ◽  
Michael J. Freake ◽  
S. Chris Borland
Keyword(s):  
Short Wavelength ◽  
Pineal Organ ◽  
Spectral Characteristics ◽  
Polarized Light ◽  
Magnetic Compass ◽  
Compass Orientation ◽  
Light Detection ◽  
Long Wavelength ◽  
New Findings ◽  
Magnetic Compass Orientation

SUMMARYTheoretical models implicating specialized photoreceptors in the detection of the geomagnetic field have been the impetus for studying the effects of light on magnetic compass orientation. Magnetic orientation in flies, amphibians and birds has been found to be influenced by light, and in all these groups a shift of approximately 90° in the direction of magnetic compass orientation has been observed under certain wavelengths and/or intensities of light. In the eastern red-spotted newt Notophthalmus viridescens, wavelength-dependent effects of light on magnetic compass orientation appear to result from an antagonistic interaction between short-wavelength (≤450nm) and long-wavelength (≥500nm) photoreception mechanisms. We have demonstrated that at least the short-wavelength input to the newt’s magnetic compass is mediated by extraocular photoreceptors located in or near the pineal organ, and here we present new findings that indicate that the putative long-wavelength mechanism is also associated with pineal photoreceptors. Interestingly, the amphibian pineal organ mediates orientation to both the e-vector of plane-polarized light and the magnetic field. Although the wavelength-dependence of the polarized light orientation in amphibians has not been studied, polarization sensitivity in fishes appears to be mediated by two antagonistic photoreception mechanisms that have similar spectral characteristics to those of the newts’ magnetic compass response. These parallels, along with similarities in the types of receptors that are expected to be involved in light-dependent magnetoreception and polarized light detection, suggest that similar photoreception mechanisms may mediate the light-dependent magnetic and polarized light compasses.

scholarly journals Polarized light modulates light-dependent magnetic compass orientation in birds

2016 ◽  
Vol 113 (6) ◽  
pp. 1654-1659 ◽  
Author(s):  
Rachel Muheim ◽  
Sissel Sjöberg ◽  
Atticus Pinzon-Rodriguez
Keyword(s):  
Magnetic Field ◽  
Radical Pair ◽  
Polarized Light ◽  
Magnetic Compass ◽  
Radical Pair Mechanism ◽  
Magnetic Field Effects ◽  
Compass Orientation ◽  
Magnetic Compass Orientation ◽  
Avian Retina ◽  
The Magnetic Field

Magnetoreception of the light-dependent magnetic compass in birds is suggested to be mediated by a radical-pair mechanism taking place in the avian retina. Biophysical models on magnetic field effects on radical pairs generally assume that the light activating the magnetoreceptor molecules is nondirectional and unpolarized, and that light absorption is isotropic. However, natural skylight enters the avian retina unidirectionally, through the cornea and the lens, and is often partially polarized. In addition, cryptochromes, the putative magnetoreceptor molecules, absorb light anisotropically, i.e., they preferentially absorb light of a specific direction and polarization, implying that the light-dependent magnetic compass is intrinsically polarization sensitive. To test putative interactions between the avian magnetic compass and polarized light, we developed a spatial orientation assay and trained zebra finches to magnetic and/or overhead polarized light cues in a four-arm “plus” maze. The birds did not use overhead polarized light near the zenith for sky compass orientation. Instead, overhead polarized light modulated light-dependent magnetic compass orientation, i.e., how the birds perceive the magnetic field. Birds were well oriented when tested with the polarized light axis aligned parallel to the magnetic field. When the polarized light axis was aligned perpendicular to the magnetic field, the birds became disoriented. These findings are the first behavioral evidence to our knowledge for a direct interaction between polarized light and the light-dependent magnetic compass in an animal. They reveal a fundamentally new property of the radical pair-based magnetoreceptor with key implications for how birds and other animals perceive the Earth’s magnetic field.

Lateralisation of magnetic compass orientation in silvereyes, Zosterops lateralis

2003 ◽  
Vol 51 (6) ◽  
pp. 597 ◽  
Author(s):  
Wolfgang Wiltschko ◽  
Ursula Munro ◽  
Hugh Ford ◽  
Roswitha Wiltschko
Keyword(s):  
Geomagnetic Field ◽  
Magnetic Compass ◽  
Compass Orientation ◽  
Directional Information ◽  
Zosterops Lateralis ◽  
Magnetic Compass Orientation ◽  
Directional Preference ◽  
The Right ◽  
The Brain ◽  
The Magnetic Field

The ability of migratory silvereyes to orient was tested in the geomagnetic field with one eye covered. Silvereyes using only their right eye were able to orient in migratory direction just as well as birds using both eyes. Using only their left eye, however, the birds did not show a significant directional preference. These data indicate that directional information from the magnetic field is mediated almost exclusively by the right eye and processed by the left hemisphere of the brain. Together with corresponding findings from European robins and indications for a similar phenomenon in homing pigeons, they suggest that a strong lateralisation of the magnetic compass is widespread among birds.

Magnetic compass orientation in the blind mole rat Spalax ehrenbergi

2001 ◽  
Vol 204 (4) ◽  
pp. 751-758 ◽  
Author(s):  
T. Kimchi ◽  
J. Terkel
Keyword(s):  
Magnetic Field ◽  
Magnetic Compass ◽  
Food Store ◽  
Earth’S Magnetic Field ◽  
Compass Orientation ◽  
Spalax Ehrenbergi ◽  
Mole Rat ◽  
Earth's Magnetic Field ◽  
Magnetic Compass Orientation ◽  
Directional Preference

The blind mole rat Spalax ehrenbergi is a solitary, subterranean rodent that digs and inhabits a system of branching tunnels, with no above-ground exits, which it never leaves unless forced to. To survive, the mole rat must be able to orient efficiently in its tunnel system. The sensory channels available for spatial orientation in the subterranean environment are restricted in comparison with those existing above ground. This study examined the possibility that the mole rat is able to perceive and use the earth's magnetic field to orient in space. Experiments were performed using a device constructed from a pair of electromagnetic ‘Helmholtz coils’, which create a magnetic field whose direction and strength can be altered. In the first experiment, we tested a group of mole rats (N=33) in an eight-armed maze under the earth's natural magnetic field to determine whether they have directional preferences for the location of their sleeping nest, food chamber and toilet site. A second group of mole rats (N=30) was tested for their directional preference after the earth's magnetic field had been experimentally shifted by 180 degrees. We found that the first group exhibited a significant preference (P<0.001) to build both their sleeping nest and their food store in the southern sector of the maze, whereas the second group shifted the location of their nests (P<0.01) and food store (P<0.05), to the northern sector of the maze, corresponding to the shift in the magnetic field. In the second experiment, we tested whether the magnetic compass orientation found in the first experiment depends on a light stimulus by testing a group of mole rats in the eight-armed maze under total darkness. No significant difference in directional preference between light and dark test conditions was observed. It can be concluded, therefore, that, in contrast to some amphibians and birds, magnetic compass orientation in the mole rat is independent of light stimulation. In the third experiment, we examined whether mole rats (N=24) use the earth's magnetic field as a compass cue to orient in a labyrinth. In the first stage (trials 1–13), the animals were trained to reach a goal box at the end of a complex labyrinth until all individuals had learned the task. In the second stage (trial 14), half the trained mole rats underwent another labyrinth trial under the earth's natural magnetic field, while the other half were tested under a magnetic field shifted by 180 degrees. We found a significant decrease (P<0.001) in performance of the mole rats tested under the shifted magnetic field compared with the group tested under the natural magnetic field. The findings from these experiments prove that the mole rat is able to perceive and use the earth's magnetic field to orient in space.

The case for light-dependent magnetic orientation in animals

1999 ◽  
Vol 202 (8) ◽  
pp. 891-908 ◽  
Author(s):  
M.E. Deutschlander ◽  
J.B. Phillips ◽  
S.C. Borland
Keyword(s):  
Magnetic Field ◽  
Physiological Model ◽  
Magnetic Compass ◽  
Magnetic Orientation ◽  
Orientation Behavior ◽  
Long Wavelength ◽  
Alternative Hypotheses ◽  
Magnetite Particles ◽  
The Magnetic Field ◽  
Effect Of Light

Light-dependent models of magnetoreception have been proposed which involve an interaction between the magnetic field and either magnetite particles located within a photoreceptor or excited states of photopigment molecules. Consistent with a photoreceptor-based magnetic compass mechanism, magnetic orientation responses in salamanders, flies and birds have been shown to be affected by the wavelength of light. In birds and flies, it is unclear whether the effects of light on magnetic orientation are due to a direct effect on a magnetoreception system or to a nonspecific (e.g. motivational) effect of light on orientation behavior. Evidence from shoreward-orienting salamanders, however, demonstrates that salamanders perceive a 90 degrees counterclockwise shift in the direction of the magnetic field under long-wavelength (>=500 nm) light. A simple physiological model based on the antagonistic interaction between two magnetically sensitive spectral mechanisms suggests one possible way in which the wavelength-dependent effects of light on the salamander's magnetic compass response might arise. Assuming that the wavelength-dependent characteristics of the avian magnetic response can be attributed to an underlying magnetoreception system, we discuss several hypotheses attempting to resolve the differences observed in the wavelength-dependent effects of light on magnetic orientation in birds and salamanders. By considering the evidence in the context of photoreceptor- and non-photoreceptor-based mechanisms for magnetoreception, we hope to encourage future studies designed to distinguish between alternative hypotheses concerning the influence of light on magnetoreception.

scholarly journals Alerting and Circadian Effects of Short-Wavelength vs. Long-Wavelength Narrow-Bandwidth Light during a Simulated Night Shift

2020 ◽  
Vol 2 (4) ◽  
pp. 502-522
Author(s):  
Erlend Sunde ◽  
Torhild Pedersen ◽  
Jelena Mrdalj ◽  
Eirunn Thun ◽  
Janne Grønli ◽  
...  
Keyword(s):  
Task Performance ◽  
Short Wavelength ◽  
Night Shift ◽  
Spectral Composition ◽  
Photon Density ◽  
Light Conditions ◽  
Long Wavelength ◽  
Narrow Bandwidth ◽  
Short Wavelength Light ◽  
Wavelength Light

Light can be used to facilitate alertness, task performance and circadian adaptation during night work. Novel strategies for illumination of workplaces, using ceiling mounted LED-luminaires, allow the use of a range of different light conditions, altering intensity and spectral composition. This study (ClinicalTrials.gov Identifier NCT03203538) investigated the effects of short-wavelength narrow-bandwidth light (λmax = 455 nm) compared to long-wavelength narrow-bandwidth light (λmax = 625 nm), with similar photon density (~2.8 × 1014 photons/cm2/s) across light conditions, during a simulated night shift (23:00–06:45 h) when conducting cognitive performance tasks. Light conditions were administered by ceiling mounted LED-luminaires. Using a within-subjects repeated measurements study design, a total of 34 healthy young adults (27 females and 7 males; mean age = 21.6 years, SD = 2.0 years) participated. The results revealed significantly reduced sleepiness and improved task performance during the night shift with short-wavelength light compared to long-wavelength light. There was also a larger shift of the melatonin rhythm (phase delay) after working a night shift in short-wavelength light compared to long-wavelength light. Participants’ visual comfort was rated as better in the short-wavelength light than the long-wavelength light. Ceiling mounted LED-luminaires may be feasible to use in real workplaces, as these have the potential to provide light conditions that are favorable for alertness and performance among night workers.

Turtle C-type horizontal cells act as push–pull devices

2001 ◽  
Vol 18 (6) ◽  
pp. 893-900 ◽  
Author(s):  
G. TWIG ◽  
H. LEVY ◽  
I. PERLMAN
Keyword(s):  
Short Wavelength ◽  
Horizontal Cells ◽  
Background Illumination ◽  
Voltage Range ◽  
Long Wavelength ◽  
Relative Contribution ◽  
Color Opponency ◽  
Light Stimuli ◽  
Short Wavelength Light ◽  
Wavelength Light

Chromaticity (C-type) horizontal cells in the retina of cold-blooded vertebrates receive antagonistic inputs from cone photoreceptors of different spectral types leading to color opponency. The relative contribution of each spectral type of cones can be selectively altered by chromatic background illumination. Therefore, the spectral properties of C-type horizontal cells are expected to change when the intensity and color of ambient illumination are altered. In this study, we investigated the effects of chromatic background lights upon color opponency in Red/Green (RGH) and Yellow/Blue (YBH) C-type horizontal cells in the everted eyecup preparation of the turtle Mauremys caspica. Photoresponses were elicited by long-wavelength and short-wavelength light stimuli in the dark-adapted state and under conditions of chromatic background illumination. We found that the total voltage range, within which graded depolarizing and the hyperpolarizing photoresponses could be elicited, either increased or decreased depending upon the color of the background light. However, the maximal and minimal potential levels determined respectively by long-wavelength and short-wavelength light stimuli of supersaturating intensity remained unchanged, regardless of the wavelength and intensity of the background. These findings indicate that turtle C-type horizontal cells operate as push–pull devices. A sufficiently bright short-wavelength stimulus can push them all the way to the maximal hyperpolarizing level while a very bright long-wavelength stimulus can pull them towards the most depolarizing potential.

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