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Karwinkel T, Peter A, Holland RA, Thorup K, Bairlein F, Schmaljohann H. A conceptual framework on the role of magnetic cues in songbird migration ecology. Biol Rev Camb Philos Soc 2024; 99:1576-1593. [PMID: 38629349 DOI: 10.1111/brv.13082] [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: 06/05/2023] [Revised: 03/27/2024] [Accepted: 03/29/2024] [Indexed: 07/06/2024]
Abstract
Migrating animals perform astonishing seasonal movements by orienting and navigating over thousands of kilometres with great precision. Many migratory species use cues from the sun, stars, landmarks, olfaction and the Earth's magnetic field for this task. Among vertebrates, songbirds are the most studied taxon in magnetic-cue-related research. Despite multiple studies, we still lack a clear understanding of when, where and how magnetic cues affect the decision-making process of birds and hence, their realised migratory behaviour in the wild. This understanding is especially important to interpret the results of laboratory experiments in an ecologically appropriate way. In this review, we summarise the current findings about the role of magnetic cues for migratory decisions in songbirds. First, we review the methodological principles for orientation and navigation research, specifically by comparing experiments on caged birds with experiments on free-flying birds. While cage experiments can show the sensory abilities of birds, studies with free-flying birds can characterise the ecological roles of magnetic cues. Second, we review the migratory stages, from stopover to endurance flight, in which songbirds use magnetic cues for their migratory decisions and incorporate this into a novel conceptual framework. While we lack studies examining whether and when magnetic cues affect orientation or navigation decisions during flight, the role of magnetic cues during stopover is relatively well studied, but mostly in the laboratory. Notably, many such studies have produced contradictory results so that understanding the biological importance of magnetic cues for decisions in free-flying songbirds is not straightforward. One potential explanation is that reproducibility of magnetic-cue experiments is low, probably because variability in the behavioural responses of birds among experiments is high. We are convinced that parts of this variability can be explained by species-specific and context-dependent reactions of birds to the study conditions and by the bird's high flexibility in whether they include magnetic cues in a decision or not. Ultimately, this review should help researchers in the challenging field of magnetoreception to design experiments meticulously and interpret results of such studies carefully by considering the migration ecology of their focal species.
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Affiliation(s)
- Thiemo Karwinkel
- Institute of Avian Research 'Vogelwarte Helgoland', An der Vogelwarte 21, 26386, Wilhelmshaven, Germany
- Carl von Ossietzky Universität Oldenburg, School of Mathematics and Science, Institute of Biology and Environmental Sciences, Ammerländer Heerstraße 114-118, 26129, Oldenburg, Germany
| | - Annika Peter
- Carl von Ossietzky Universität Oldenburg, School of Mathematics and Science, Institute of Biology and Environmental Sciences, Ammerländer Heerstraße 114-118, 26129, Oldenburg, Germany
| | - Richard A Holland
- School of Environmental and Natural Sciences, Bangor University, Bangor, LL57 2UW, UK
| | - Kasper Thorup
- Center for Macroecology, Evolution and Climate, Natural History Museum of Denmark, University of Copenhagen, Universitetsparken 15, DK-2100, Copenhagen, Denmark
| | - Franz Bairlein
- Institute of Avian Research 'Vogelwarte Helgoland', An der Vogelwarte 21, 26386, Wilhelmshaven, Germany
- Max Planck Institute of Animal Behavior, Am Obstberg 1, Radolfzell, 78315, Germany
| | - Heiko Schmaljohann
- Institute of Avian Research 'Vogelwarte Helgoland', An der Vogelwarte 21, 26386, Wilhelmshaven, Germany
- Carl von Ossietzky Universität Oldenburg, School of Mathematics and Science, Institute of Biology and Environmental Sciences, Ammerländer Heerstraße 114-118, 26129, Oldenburg, Germany
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Karwinkel T, Winklhofer M, Allenstein D, Brust V, Christoph P, Holland RA, Hüppop O, Steen J, Bairlein F, Schmaljohann H. A refined magnetic pulse treatment method for magnetic navigation experiments with adequate sham control: a case study on free-flying songbirds. J R Soc Interface 2024; 21:20230745. [PMID: 38745460 DOI: 10.1098/rsif.2023.0745] [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: 12/14/2023] [Accepted: 04/18/2024] [Indexed: 05/16/2024] Open
Abstract
Migratory songbirds may navigate by extracting positional information from the geomagnetic field, potentially with a magnetic-particle-based receptor. Previous studies assessed this hypothesis experimentally by exposing birds to a strong but brief magnetic pulse aimed at remagnetizing the particles and evoking an altered behaviour. Critically, such studies were not ideally designed because they lacked an adequate sham treatment controlling for the induced electric field that is fundamentally associated with a magnetic pulse. Consequently, we designed a sham-controlled magnetic-pulse experiment, with sham and treatment pulse producing a similar induced electric field, while limiting the sham magnetic field to a value that is deemed insufficient to remagnetize particles. We tested this novel approach by pulsing more than 250 wild, migrating European robins (Erithacus rubecula) during two autumn seasons. After pulsing them, five traits of free-flight migratory behaviour were observed, but no effect of the pulse could be found. Notably, one of the traits, the migratory motivation of adults, was significantly affected in only one of the two study years. Considering the problem of reproducing experiments with wild animals, we recommend a multi-year approach encompassing large sample size, blinded design and built-in sham control to obtain future insights into the role of magnetic-particle-based magnetoreception in bird navigation.
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Affiliation(s)
- Thiemo Karwinkel
- Institute of Avian Research 'Vogelwarte Helgoland', An der Vogelwarte 21, 26386 Wilhelmshaven, Germany
- School of Mathematics and Science, Institute of Biology and Environmental Sciences, Carl von Ossietzky Universität Oldenburg, Ammerländer Heerstraße 114-118, Oldenburg 26129, Germany
| | - Michael Winklhofer
- School of Mathematics and Science, Institute of Biology and Environmental Sciences, Carl von Ossietzky Universität Oldenburg, Ammerländer Heerstraße 114-118, Oldenburg 26129, Germany
- Research Center for Neurosensory Sciences, Carl von Ossietzky Universität Oldenburg, Ammerländer Heerstraße 114-118, Oldenburg 26129, Germany
| | - Dario Allenstein
- Institute of Avian Research 'Vogelwarte Helgoland', An der Vogelwarte 21, 26386 Wilhelmshaven, Germany
- School of Mathematics and Science, Institute of Biology and Environmental Sciences, Carl von Ossietzky Universität Oldenburg, Ammerländer Heerstraße 114-118, Oldenburg 26129, Germany
| | - Vera Brust
- Institute of Avian Research 'Vogelwarte Helgoland', An der Vogelwarte 21, 26386 Wilhelmshaven, Germany
| | - Paula Christoph
- Institute of Avian Research 'Vogelwarte Helgoland', An der Vogelwarte 21, 26386 Wilhelmshaven, Germany
- School of Mathematics and Science, Institute of Biology and Environmental Sciences, Carl von Ossietzky Universität Oldenburg, Ammerländer Heerstraße 114-118, Oldenburg 26129, Germany
- Institute of Landscape Ecology, Westfälische Wilhelms-Universität Münster, Heisenbergstr. 2, Münster 48149, Germany
| | - Richard A Holland
- School of Environmental and Natural Sciences, University of Bangor, Deiniol Road, Bangor LL57 2UW, UK
| | - Ommo Hüppop
- Institute of Avian Research 'Vogelwarte Helgoland', An der Vogelwarte 21, 26386 Wilhelmshaven, Germany
| | - Jan Steen
- Institute of Avian Research 'Vogelwarte Helgoland', An der Vogelwarte 21, 26386 Wilhelmshaven, Germany
- Institute of Landscape Ecology, Westfälische Wilhelms-Universität Münster, Heisenbergstr. 2, Münster 48149, Germany
| | - Franz Bairlein
- Institute of Avian Research 'Vogelwarte Helgoland', An der Vogelwarte 21, 26386 Wilhelmshaven, Germany
- Max Planck Institute of Animal Behavior, Am Obstberg 1, Radolfzell 78315, Germany
| | - Heiko Schmaljohann
- Institute of Avian Research 'Vogelwarte Helgoland', An der Vogelwarte 21, 26386 Wilhelmshaven, Germany
- School of Mathematics and Science, Institute of Biology and Environmental Sciences, Carl von Ossietzky Universität Oldenburg, Ammerländer Heerstraße 114-118, Oldenburg 26129, Germany
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3
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Zein B, Long JA, Safi K, Kölzsch A, Benitez-Paez F, Wikelski M, Kruckenberg H, Demšar U. Simulating geomagnetic bird navigation using novel high-resolution geomagnetic data. ECOL INFORM 2022. [DOI: 10.1016/j.ecoinf.2022.101689] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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Karwinkel T, Winklhofer M, Christoph P, Allenstein D, Hüppop O, Brust V, Bairlein F, Schmaljohann H. No apparent effect of a magnetic pulse on free-flight behaviour in northern wheatears ( Oenanthe oenanthe) at a stopover site. J R Soc Interface 2022; 19:20210805. [PMID: 35167773 PMCID: PMC8847002 DOI: 10.1098/rsif.2021.0805] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Naïve migrants reach their wintering grounds following a clock-and-compass strategy. During these inaugural migrations, birds internalise, among others, cues from the Earth's magnetic field to create a geomagnetic map, with which they navigate to destinations familiar to them on subsequent migrations. Geomagnetic map cues are thought to be sensed by a magnetic-particle-based receptor, which can be specifically affected by a magnetic pulse. Indeed, the orientation of experienced but not naïve birds was compromised after magnetic pulsing, indicating geomagnetic map use. Little is known about the importance of this putative magnetoreceptor for navigation and decision-making in free-flying migrants. Therefore, we studied in unprecedented detail how a magnetic pulse would affect departure probability, nocturnal departure timing, departure direction and consistency in flight direction over 50–100 km in experienced and naïve long-distant migrant songbirds using a large-scale radio-tracking system. Contrary to our expectations and despite a high sample size (ntotal = 137) for a free-flight study, we found no significant after-effect of the magnetic pulse on the migratory traits, suggesting the geomagnetic map is not essential for the intermediate autumn migration phase. These findings warrant re-thinking about perception and use of geomagnetic maps for migratory decisions within a sensory and ecological context.
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Affiliation(s)
- Thiemo Karwinkel
- Institute of Avian Research 'Vogelwarte Helgoland', An der Vogelwarte 21, 26386 Wilhelmshaven, Germany.,Institute for Biology and Environmental Sciences (IBU), Carl von Ossietzky University of Oldenburg, Carl-von-Ossietzky-Straße 9-11, 26129 Oldenburg, Germany
| | - Michael Winklhofer
- Institute for Biology and Environmental Sciences (IBU), Carl von Ossietzky University of Oldenburg, Carl-von-Ossietzky-Straße 9-11, 26129 Oldenburg, Germany.,Research Center for Neurosensory Sciences, Carl von Ossietzky University Oldenburg, 26111 Oldenburg, Germany
| | - Paula Christoph
- Institute of Avian Research 'Vogelwarte Helgoland', An der Vogelwarte 21, 26386 Wilhelmshaven, Germany.,Institute for Biology and Environmental Sciences (IBU), Carl von Ossietzky University of Oldenburg, Carl-von-Ossietzky-Straße 9-11, 26129 Oldenburg, Germany
| | - Dario Allenstein
- Institute of Avian Research 'Vogelwarte Helgoland', An der Vogelwarte 21, 26386 Wilhelmshaven, Germany.,Institute for Biology and Environmental Sciences (IBU), Carl von Ossietzky University of Oldenburg, Carl-von-Ossietzky-Straße 9-11, 26129 Oldenburg, Germany
| | - Ommo Hüppop
- Institute of Avian Research 'Vogelwarte Helgoland', An der Vogelwarte 21, 26386 Wilhelmshaven, Germany
| | - Vera Brust
- Institute of Avian Research 'Vogelwarte Helgoland', An der Vogelwarte 21, 26386 Wilhelmshaven, Germany
| | - Franz Bairlein
- Institute of Avian Research 'Vogelwarte Helgoland', An der Vogelwarte 21, 26386 Wilhelmshaven, Germany.,Max Planck Institute of Animal Behavior, Am Obstberg 1, 78315 Radolfzell, Germany
| | - Heiko Schmaljohann
- Institute of Avian Research 'Vogelwarte Helgoland', An der Vogelwarte 21, 26386 Wilhelmshaven, Germany.,Institute for Biology and Environmental Sciences (IBU), Carl von Ossietzky University of Oldenburg, Carl-von-Ossietzky-Straße 9-11, 26129 Oldenburg, Germany
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Naisbett-Jones LC, Lohmann KJ. Magnetoreception and magnetic navigation in fishes: a half century of discovery. J Comp Physiol A Neuroethol Sens Neural Behav Physiol 2022; 208:19-40. [PMID: 35031832 DOI: 10.1007/s00359-021-01527-w] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2021] [Revised: 11/22/2021] [Accepted: 11/23/2021] [Indexed: 01/15/2023]
Abstract
As the largest and most diverse vertebrate group on the planet, fishes have evolved an impressive array of sensory abilities to overcome the challenges associated with navigating the aquatic realm. Among these, the ability to detect Earth's magnetic field, or magnetoreception, is phylogenetically widespread and used by fish to guide movements over a wide range of spatial scales ranging from local movements to transoceanic migrations. A proliferation of recent studies, particularly in salmonids, has revealed that fish can exploit Earth's magnetic field not only as a source of directional information for maintaining consistent headings, but also as a kind of map for determining location at sea and for returning to natal areas. Despite significant advances, much about magnetoreception in fishes remains enigmatic. How fish detect magnetic fields remains unknown and our understanding of the evolutionary origins of vertebrate magnetoreception would benefit greatly from studies that include a wider array of fish taxa. The rich diversity of life-history characteristics that fishes exhibit, the wide variety of environments they inhabit, and their suitability for manipulative studies, make fishes promising subjects for magnetoreception studies.
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Affiliation(s)
| | - Kenneth J Lohmann
- Department of Biology, University of North Carolina, Chapel Hill, NC, 27599, USA
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Packmor F, Kishkinev D, Bittermann F, Kofler B, Machowetz C, Zechmeister T, Zawadzki LC, Guilford T, Holland RA. A magnet attached to the forehead disrupts magnetic compass orientation in a migratory songbird. J Exp Biol 2021; 224:jeb243337. [PMID: 34713887 PMCID: PMC8645232 DOI: 10.1242/jeb.243337] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2021] [Accepted: 10/25/2021] [Indexed: 11/20/2022]
Abstract
For studies on magnetic compass orientation and navigation performance in small bird species, controlled experiments with orientation cages inside an electromagnetic coil system are the most prominent methodological paradigm. These are, however, not applicable when studying larger bird species and/or orientation behaviour during free flight. For this, researchers have followed a very different approach, attaching small magnets to birds, with the intention of depriving them of access to meaningful magnetic information. Unfortunately, results from studies using this approach appear rather inconsistent. As these are based on experiments with birds under free-flight conditions, which usually do not allow exclusion of other potential orientation cues, an assessment of the overall efficacy of this approach is difficult to conduct. Here, we directly tested the efficacy of small magnets for temporarily disrupting magnetic compass orientation in small migratory songbirds using orientation cages under controlled experimental conditions. We found that birds which have access to the Earth's magnetic field as their sole orientation cue show a general orientation towards their seasonally appropriate migratory direction. When carrying magnets on their forehead under these conditions, the same birds become disoriented. However, under changed conditions that allow birds access to other (i.e. celestial) orientation cues, any disruptive effect of the magnets they carry appears obscured. Our results provide clear evidence for the efficacy of the magnet approach for temporarily disrupting magnetic compass orientation in birds, but also reveal its limitations for application in experiments under free-flight conditions.
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Affiliation(s)
- Florian Packmor
- School of Natural Sciences, Bangor University, Bangor LL57 2UW, UK
- Institute of Avian Research ‘Vogelwarte Helgoland’, Wilhelmshaven 26386, Germany
| | - Dmitry Kishkinev
- School of Life Sciences, Keele University, Newcastle-under-Lyme ST5 5BG, UK
| | - Flora Bittermann
- Biological Station Lake Neusiedl, Illmitz 7142, Austria
- Nationalpark Neusiedler See – Seewinkel, Apetlon 7143, Austria
- Austrian Ornithological Centre, Konrad-Lorenz Institute of Ethology, University of Veterinary Medicine Vienna, 1160 Wien, Austria
| | | | - Clara Machowetz
- Biological Station Lake Neusiedl, Illmitz 7142, Austria
- Nationalpark Neusiedler See – Seewinkel, Apetlon 7143, Austria
- Austrian Ornithological Centre, Konrad-Lorenz Institute of Ethology, University of Veterinary Medicine Vienna, 1160 Wien, Austria
| | | | | | - Tim Guilford
- Department of Zoology, Oxford University, Oxford OX1 3SZ, UK
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Zein B, Long JA, Safi K, Kölzsch A, Wikelski M, Kruckenberg H, Demšar U. Simulation experiment to test strategies of geomagnetic navigation during long-distance bird migration. MOVEMENT ECOLOGY 2021; 9:46. [PMID: 34526152 PMCID: PMC8442449 DOI: 10.1186/s40462-021-00283-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/01/2021] [Accepted: 08/27/2021] [Indexed: 06/13/2023]
Abstract
BACKGROUND Different theories suggest birds may use compass or map navigational systems associated with Earth's magnetic intensity or inclination, especially during migratory flights. These theories have only been tested by considering properties of the Earth's magnetic field at coarse temporal scales, typically ignoring the temporal dynamics of geomagnetic values that may affect migratory navigational capacity. METHODS We designed a simulation experiment to study if and how birds use the geomagnetic field during migration by using both high resolution GPS tracking data and geomagnetic data at relatively fine spatial and temporal resolutions in comparison to previous studies. Our simulations use correlated random walks (CRW) and correlated random bridge (CRB) models to model different navigational strategies based on underlying dynamic geomagnetic data. We translated navigational strategies associated with geomagnetic cues into probability surfaces that are included in the random walk models. Simulated trajectories from these models were compared to the actual GPS trajectories of migratory birds using 3 different similarity measurements to evaluate which of the strategies was most likely to have occurred. RESULTS AND CONCLUSION We designed a simulation experiment which can be applied to different wildlife species under varying conditions worldwide. In the case of our example species, we found that a compass-type strategy based on taxis, defined as movement towards an extreme value, produced the closest and most similar trajectories when compared to original GPS tracking data in CRW models. Our results indicate less evidence for map navigation (constant heading and bi-gradient taxis navigation). Additionally, our results indicate a multifactorial navigational mechanism necessitating more than one cue for successful navigation to the target. This is apparent from our simulations because the modelled endpoints of the trajectories of the CRW models do not reach close proximity to the target location of the GPS trajectory when simulated with geomagnetic navigational strategies alone. Additionally, the magnitude of the effect of the geomagnetic cues during navigation in our models was low in our CRB models. More research on the scale effects of the geomagnetic field on navigation, along with temporally varying geomagnetic data could be useful for further improving future models.
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Affiliation(s)
- Beate Zein
- School of Geography and Sustainable Development, Irvine Building, University of St Andrews, North Street, KY16 9AL, St Andrews, Scotland, UK.
| | - Jed A Long
- School of Geography and Sustainable Development, Irvine Building, University of St Andrews, North Street, KY16 9AL, St Andrews, Scotland, UK
- Department of Geography & Environment, Western University, London, ON, Canada
| | - Kamran Safi
- Department of Migration, MPI of Animal Behavior, Radolfzell, Germany
- Department of Biology, University of Konstanz, Konstanz, Germany
| | - Andrea Kölzsch
- Department of Migration, MPI of Animal Behavior, Radolfzell, Germany
- Department of Biology, University of Konstanz, Konstanz, Germany
- Institute for Wetlands and Waterbird Research E.V, Verden (Aller), Germany
| | - Martin Wikelski
- Department of Migration, MPI of Animal Behavior, Radolfzell, Germany
- Department of Biology, University of Konstanz, Konstanz, Germany
- Centre for the Advanced Study of Collective Behaviour, University of Konstanz, 78457, Konstanz, Germany
| | - Helmut Kruckenberg
- Institute for Wetlands and Waterbird Research E.V, Verden (Aller), Germany
| | - Urška Demšar
- School of Geography and Sustainable Development, Irvine Building, University of St Andrews, North Street, KY16 9AL, St Andrews, Scotland, UK
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Ernst DA, Fitak RR, Schmidt M, Derby CD, Johnsen S, Lohmann KJ. Pulse magnetization elicits differential gene expression in the central nervous system of the Caribbean spiny lobster, Panulirus argus. J Comp Physiol A Neuroethol Sens Neural Behav Physiol 2020; 206:725-742. [PMID: 32607762 DOI: 10.1007/s00359-020-01433-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2019] [Revised: 05/18/2020] [Accepted: 06/15/2020] [Indexed: 12/12/2022]
Abstract
Diverse animals use Earth's magnetic field to guide their movements, but the neural and molecular mechanisms underlying the magnetic sense remain enigmatic. One hypothesis is that particles of the mineral magnetite (Fe3O4) provide the basis of magnetoreception. Here we examined gene expression in the central nervous system of a magnetically sensitive invertebrate, the Caribbean spiny lobster (Panulirus argus), after applying a magnetic pulse known to alter magnetic orientation behavior. Numerous genes were differentially expressed in response to the pulse, including 647 in the brain, 1256 in the subesophageal ganglion, and 712 in the thoracic ganglia. Many such genes encode proteins linked to iron regulation, oxidative stress, and immune response, consistent with possible impacts of a magnetic pulse on magnetite-based magnetoreceptors. Additionally, however, altered expression also occurred for numerous genes with no apparent link to magnetoreception, including genes encoding proteins linked to photoreception, carbohydrate and hormone metabolism, and other physiological processes. Overall, the results are consistent with the magnetite hypothesis of magnetoreception, yet also reveal that in spiny lobsters, a strong pulse altered expression of > 10% of all expressed genes, including many seemingly unrelated to sensory processes. Thus, caution is required when interpreting the effects of magnetic pulses on animal behavior.
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Affiliation(s)
- David A Ernst
- Department of Biology, University of North Carolina, Chapel Hill, NC, 27599, USA. .,Department of Biological Sciences, University of Arkansas, Fayetteville, AR, 72701, USA.
| | - Robert R Fitak
- Genomics and Bioinformatics Cluster, Department of Biology, University of Central Florida, Orlando, FL, 32816, USA
| | - Manfred Schmidt
- Neuroscience Institute and Department of Biology, Georgia State University, Atlanta, GA, 30303, USA
| | - Charles D Derby
- Neuroscience Institute and Department of Biology, Georgia State University, Atlanta, GA, 30303, USA
| | - Sönke Johnsen
- Department of Biology, Duke University, Durham, NC, 27708, USA
| | - Kenneth J Lohmann
- Department of Biology, University of North Carolina, Chapel Hill, NC, 27599, USA
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Bell AM, Robinson JT. The rotating magnetocaloric effect as a potential mechanism for natural magnetic senses. PLoS One 2019; 14:e0222401. [PMID: 31574085 PMCID: PMC6773214 DOI: 10.1371/journal.pone.0222401] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2019] [Accepted: 08/28/2019] [Indexed: 12/01/2022] Open
Abstract
Many animals are able to sense the earth’s magnetic field, including varieties of arthropods and members of all major vertebrate groups. While the existence of this magnetic sense is widely accepted, the mechanism of action remains unknown. Building from recent work on synthetic magnetoreceptors, we propose a new model for natural magnetosensation based on the rotating magnetocaloric effect (RME), which predicts that heat generated by magnetic nanoparticles may allow animals to detect features of the earth’s magnetic field. Using this model, we identify the conditions for the RME to produce physiological signals in response to the earth’s magnetic field and suggest experiments to distinguish between candidate mechanisms of magnetoreception.
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Affiliation(s)
- A. Martin Bell
- Applied Physics Program, Rice University, Houston, Texas, United States of America
- Department of Electrical and Computer Engineering, Rice University, Houston, Texas, United States of America
| | - Jacob T. Robinson
- Department of Electrical and Computer Engineering, Rice University, Houston, Texas, United States of America
- Department of Bioengineering, Rice University, Houston, Texas, United States of America
- Department of Neuroscience, Baylor College of Medicine, Houston, Texas, United States of America
- * E-mail:
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Abstract
Birds can use two kinds of information from the geomagnetic field for navigation: the direction of the field lines as a compass and probably magnetic intensity as a component of the navigational ‘map’. The direction of the magnetic field appears to be sensed via radical pair processes in the eyes, with the crucial radical pairs formed by cryptochrome. It is transmitted by the optic nerve to the brain, where parts of the visual system seem to process the respective information. Magnetic intensity appears to be perceived by magnetite-based receptors in the beak region; the information is transmitted by the ophthalmic branch of the trigeminal nerve to the trigeminal ganglion and the trigeminal brainstem nuclei. Yet in spite of considerable progress in recent years, many details are still unclear, among them details of the radical pair processes and their transformation into a nervous signal, the precise location of the magnetite-based receptors and the centres in the brain where magnetic information is combined with other navigational information for the navigational processes.
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Affiliation(s)
- Roswitha Wiltschko
- FB Biowissenschaften, Goethe-Universität Frankfurt, Frankfurt am Main, Germany
| | - Wolfgang Wiltschko
- FB Biowissenschaften, Goethe-Universität Frankfurt, Frankfurt am Main, Germany
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11
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Transduction of the Geomagnetic Field as Evidenced from alpha-Band Activity in the Human Brain. eNeuro 2019; 6:ENEURO.0483-18.2019. [PMID: 31028046 PMCID: PMC6494972 DOI: 10.1523/eneuro.0483-18.2019] [Citation(s) in RCA: 55] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2018] [Revised: 02/15/2019] [Accepted: 02/26/2019] [Indexed: 11/21/2022] Open
Abstract
Magnetoreception, the perception of the geomagnetic field, is a sensory modality well-established across all major groups of vertebrates and some invertebrates, but its presence in humans has been tested rarely, yielding inconclusive results. We report here a strong, specific human brain response to ecologically-relevant rotations of Earth-strength magnetic fields. Following geomagnetic stimulation, a drop in amplitude of electroencephalography (EEG) alpha-oscillations (8–13 Hz) occurred in a repeatable manner. Termed alpha-event-related desynchronization (alpha-ERD), such a response has been associated previously with sensory and cognitive processing of external stimuli including vision, auditory and somatosensory cues. Alpha-ERD in response to the geomagnetic field was triggered only by horizontal rotations when the static vertical magnetic field was directed downwards, as it is in the Northern Hemisphere; no brain responses were elicited by the same horizontal rotations when the static vertical component was directed upwards. This implicates a biological response tuned to the ecology of the local human population, rather than a generic physical effect. Biophysical tests showed that the neural response was sensitive to static components of the magnetic field. This rules out all forms of electrical induction (including artifacts from the electrodes) which are determined solely on dynamic components of the field. The neural response was also sensitive to the polarity of the magnetic field. This rules out free-radical “quantum compass” mechanisms like the cryptochrome hypothesis, which can detect only axial alignment. Ferromagnetism remains a viable biophysical mechanism for sensory transduction and provides a basis to start the behavioral exploration of human magnetoreception.
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Abstract
Magnetic fields pass through tissue undiminished and without producing harmful effects, motivating their use as a wireless, minimally invasive means to control neural activity. Here, we review mechanisms and techniques coupling magnetic fields to changes in electrochemical potentials across neuronal membranes. Biological magnetoreception, although incompletely understood, is discussed as a potential source of inspiration. The emergence of magnetic properties in materials is reviewed to clarify the distinction between biomolecules containing transition metals and ferrite nanoparticles that exhibit significant net moments. We describe recent developments in the use of magnetic nanomaterials as transducers converting magnetic stimuli to forms readily perceived by neurons and discuss opportunities for multiplexed and bidirectional control as well as the challenges posed by delivery to the brain. The variety of magnetic field conditions and mechanisms by which they can be coupled to neuronal signaling cascades highlights the desirability of continued interchange between magnetism physics and neurobiology.
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Affiliation(s)
- Michael G Christiansen
- Department of Health Sciences and Technology, Swiss Federal Institute of Technology, 8093 Zürich, Switzerland
| | - Alexander W Senko
- Department of Materials Science and Engineering, Research Laboratory of Electronics, and McGovern Institute for Brain Research, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA;
| | - Polina Anikeeva
- Department of Materials Science and Engineering, Research Laboratory of Electronics, and McGovern Institute for Brain Research, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA;
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13
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Abstract
Diverse animals ranging from worms and insects to birds and turtles perform impressive journeys using the magnetic field of the earth as a cue. Although major cellular and molecular mechanisms for sensing mechanical and chemical cues have been elucidated over the past three decades, the mechanisms that animals use to sense magnetic fields remain largely mysterious. Here we survey progress on the search for magnetosensory neurons and magnetosensitive molecules important for animal behaviors. Emphasis is placed on magnetosensation in insects and birds, as well as on the magnetosensitive neuron pair AFD in the nematode Caenorhabditis elegans. We also review conventional criteria used to define animal magnetoreceptors and suggest how approaches used to identify receptors for other sensory modalities may be adapted for magnetoreceptors. Finally, we discuss prospects for underutilized and novel approaches to identify the elusive magnetoreceptors in animals.
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Affiliation(s)
- Benjamin L Clites
- Institute for Cell and Molecular Biology, Center for Brain, Behavior and Evolution, Center for Learning and Memory, Waggoner Center for Alcohol and Addiction Research, and Department of Neuroscience, University of Texas, Austin, Texas 78712; ,
| | - Jonathan T Pierce
- Institute for Cell and Molecular Biology, Center for Brain, Behavior and Evolution, Center for Learning and Memory, Waggoner Center for Alcohol and Addiction Research, and Department of Neuroscience, University of Texas, Austin, Texas 78712; ,
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Heyers D, Elbers D, Bulte M, Bairlein F, Mouritsen H. The magnetic map sense and its use in fine-tuning the migration programme of birds. J Comp Physiol A Neuroethol Sens Neural Behav Physiol 2017; 203:491-497. [PMID: 28365788 DOI: 10.1007/s00359-017-1164-x] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2016] [Revised: 03/06/2017] [Accepted: 03/07/2017] [Indexed: 10/19/2022]
Abstract
The Earth's magnetic field is one of several natural cues, which migratory birds can use to derive directional ("compass") information for orientation on their biannual migratory journeys. Moreover, magnetic field effects on prominent aspects of the migratory programme of birds, such as migratory restlessness behaviour, fuel deposition and directional orientation, implicate that geomagnetic information can also be used to derive positional ("map") information. While the magnetic "compass" in migratory birds is likely to be based on radical pair-forming molecules embedded in their visual system, the sensory correlates underlying a magnetic "map" sense currently remain elusive. Behavioural, physiological and neurobiological findings indicate that the sensor is most likely innervated by the ophthalmic branch of the trigeminal nerve and based on magnetic iron particles. Information from this unknown sensor is neither necessary nor sufficient for a functional magnetic compass, but instead could contribute important components of a multifactorial "map" for global positioning. Positional information could allow migratory birds to make vitally important dynamic adaptations of their migratory programme at any relevant point during their journeys.
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Affiliation(s)
- D Heyers
- AG Animal Navigation, Faculty of Biology/Environmental Sciences, University of Oldenburg, 26111, Oldenburg, Germany. .,Research Centre for Neurosensory Sciences, University of Oldenburg, 26111, Oldenburg, Germany.
| | - D Elbers
- AG Animal Navigation, Faculty of Biology/Environmental Sciences, University of Oldenburg, 26111, Oldenburg, Germany.,Research Centre for Neurosensory Sciences, University of Oldenburg, 26111, Oldenburg, Germany.,AG Biochemistry, Faculty of Medicine/Health Sciences, University of Oldenburg, 26111, Oldenburg, Germany
| | - M Bulte
- , Schmidtkunzstraße 13, 86199, Augsburg, Germany.,Institute for Avian Research "Vogelwarte Helgoland", 26386, Wilhelmshaven, Germany
| | - F Bairlein
- Institute for Avian Research "Vogelwarte Helgoland", 26386, Wilhelmshaven, Germany
| | - H Mouritsen
- AG Animal Navigation, Faculty of Biology/Environmental Sciences, University of Oldenburg, 26111, Oldenburg, Germany.,Research Centre for Neurosensory Sciences, University of Oldenburg, 26111, Oldenburg, Germany
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15
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Navigation. J Comp Physiol A Neuroethol Sens Neural Behav Physiol 2017; 203:455-463. [DOI: 10.1007/s00359-017-1160-1] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2016] [Revised: 02/17/2017] [Accepted: 02/20/2017] [Indexed: 10/20/2022]
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Affiliation(s)
- P. J. Hore
- Department of Chemistry, University of Oxford, Oxford OX1 3QZ, United Kingdom;
| | - Henrik Mouritsen
- Institut für Biologie und Umweltwissenschaften, Carl von Ossietzky Universität Oldenburg, DE-26111 Oldenburg, Germany;
- Research Centre for Neurosensory Sciences, University of Oldenburg, DE-26111 Oldenburg, Germany
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17
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Ernst DA, Lohmann KJ. Effect of magnetic pulses on Caribbean spiny lobsters: implications for magnetoreception. ACTA ACUST UNITED AC 2016; 219:1827-32. [PMID: 27045095 DOI: 10.1242/jeb.136036] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2015] [Accepted: 03/18/2016] [Indexed: 11/20/2022]
Abstract
The Caribbean spiny lobster, Panulirus argus, is a migratory crustacean that uses Earth's magnetic field as a navigational cue, but how these lobsters detect magnetic fields is not known. Magnetic material thought to be magnetite has previously been detected in spiny lobsters, but its role in magnetoreception, if any, remains unclear. As a first step toward investigating whether lobsters might have magnetite-based magnetoreceptors, we subjected lobsters to strong, pulsed magnetic fields capable of reversing the magnetic dipole moment of biogenic magnetite crystals. Lobsters were subjected to a single pulse directed from posterior to anterior and either: (1) parallel to the horizontal component of the geomagnetic field (i.e. toward magnetic north); or (2) antiparallel to the horizontal field (i.e. toward magnetic south). An additional control group was handled but not subjected to a magnetic pulse. After treatment, each lobster was tethered in a water-filled arena located within 200 m of the capture location and allowed to walk in any direction. Control lobsters walked in seemingly random directions and were not significantly oriented as a group. In contrast, the two groups exposed to pulsed fields were significantly oriented in approximately opposite directions. Lobsters subjected to a magnetic pulse applied parallel to the geomagnetic horizontal component walked westward; those subjected to a pulse directed antiparallel to the geomagnetic horizontal component oriented approximately northeast. The finding that a magnetic pulse alters subsequent orientation behavior is consistent with the hypothesis that magnetoreception in spiny lobsters is based at least partly on magnetite-based magnetoreceptors.
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Affiliation(s)
- David A Ernst
- Department of Biology, University of North Carolina, Chapel Hill, NC 27599, USA
| | - Kenneth J Lohmann
- Department of Biology, University of North Carolina, Chapel Hill, NC 27599, USA
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Affiliation(s)
- Henrik Mouritsen
- Institut für Biologie und Umweltwissenschaften, Carl-von-Ossietzky-Universität Oldenburg, D-26111 Oldenburg, Germany; ,
- Research Center Neurosensory Sciences, University of Oldenburg, D-26111 Oldenburg, Germany
| | - Dominik Heyers
- Institut für Biologie und Umweltwissenschaften, Carl-von-Ossietzky-Universität Oldenburg, D-26111 Oldenburg, Germany; ,
- Research Center Neurosensory Sciences, University of Oldenburg, D-26111 Oldenburg, Germany
| | - Onur Güntürkün
- Department of Biopsychology, Institute of Cognitive Neuroscience, Faculty of Psychology, Ruhr-University Bochum, D-44780 Bochum, Germany;
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Shaw J, Boyd A, House M, Woodward R, Mathes F, Cowin G, Saunders M, Baer B. Magnetic particle-mediated magnetoreception. J R Soc Interface 2015; 12:0499. [PMID: 26333810 PMCID: PMC4614459 DOI: 10.1098/rsif.2015.0499] [Citation(s) in RCA: 56] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2015] [Accepted: 08/12/2015] [Indexed: 11/12/2022] Open
Abstract
Behavioural studies underpin the weight of experimental evidence for the existence of a magnetic sense in animals. In contrast, studies aimed at understanding the mechanistic basis of magnetoreception by determining the anatomical location, structure and function of sensory cells have been inconclusive. In this review, studies attempting to demonstrate the existence of a magnetoreceptor based on the principles of the magnetite hypothesis are examined. Specific attention is given to the range of techniques, and main animal model systems that have been used in the search for magnetite particulates. Anatomical location/cell rarity and composition are identified as two key obstacles that must be addressed in order to make progress in locating and characterizing a magnetite-based magnetoreceptor cell. Avenues for further study are suggested, including the need for novel experimental, correlative, multimodal and multidisciplinary approaches. The aim of this review is to inspire new efforts towards understanding the cellular basis of magnetoreception in animals, which will in turn inform a new era of behavioural research based on first principles.
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Affiliation(s)
- Jeremy Shaw
- Centre for Microscopy, Characterisation and Analysis, The University of Western Australia, Perth, Western Australia 6009, Australia
| | - Alastair Boyd
- Centre for Microscopy, Characterisation and Analysis, The University of Western Australia, Perth, Western Australia 6009, Australia
| | - Michael House
- School of Physics, The University of Western Australia, Perth, Western Australia 6009, Australia
| | - Robert Woodward
- School of Physics, The University of Western Australia, Perth, Western Australia 6009, Australia
| | - Falko Mathes
- School of Earth and Environment, The University of Western Australia, Perth, Western Australia 6009, Australia
| | - Gary Cowin
- Centre for Advanced Imaging, The University of Queensland, Brisbane, Queensland 4072, Australia
| | - Martin Saunders
- Centre for Microscopy, Characterisation and Analysis, The University of Western Australia, Perth, Western Australia 6009, Australia
| | - Boris Baer
- Centre for Integrative Bee Research (CIBER), The University of Western Australia, Perth, Western Australia 6009, Australia
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The BAARA (Biological AutomAted RAdiotracking) system: a new approach in ecological field studies. PLoS One 2015; 10:e0116785. [PMID: 25714910 PMCID: PMC4340905 DOI: 10.1371/journal.pone.0116785] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2014] [Accepted: 11/28/2014] [Indexed: 11/19/2022] Open
Abstract
Radiotracking is an important and often the only possible method to explore specific habits and the behaviour of animals, but it has proven to be very demanding and time-consuming, especially when frequent positioning of a large group is required. Our aim was to address this issue by making the process partially automated, to mitigate the demands and related costs. This paper presents a novel automated tracking system that consists of a network of automated tracking stations deployed within the target area. Each station reads the signals from telemetry transmitters, estimates the bearing and distance of the tagged animals and records their position. The station is capable of tracking a theoretically unlimited number of transmitters on different frequency channels with the period of 5-15 seconds per single channel. An ordinary transmitter that fits within the supported frequency band might be used with BAARA (Biological AutomAted RAdiotracking); an extra option is the use of a custom-programmable transmitter with configurable operational parameters, such as the precise frequency channel or the transmission parameters. This new approach to a tracking system was tested for its applicability in a series of field and laboratory tests. BAARA has been tested within fieldwork explorations of Rousettus aegyptiacus during field trips to Dakhla oasis in Egypt. The results illustrate the novel perspective which automated radiotracking opens for the study of spatial behaviour, particularly in addressing topics in the domain of population ecology.
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Kishkinev DA, Chernetsov NS. Magnetoreception systems in birds: A review of current research. ACTA ACUST UNITED AC 2015. [DOI: 10.1134/s2079086415010041] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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22
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Affiliation(s)
- R. A. Holland
- School of Biological Sciences; Queen's University of Belfast; Belfast UK
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23
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Kishkinev D, Chernetsov N, Heyers D, Mouritsen H. Migratory Reed Warblers Need Intact Trigeminal Nerves to Correct for a 1,000 km Eastward Displacement. PLoS One 2013; 8:e65847. [PMID: 23840374 PMCID: PMC3694148 DOI: 10.1371/journal.pone.0065847] [Citation(s) in RCA: 61] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2012] [Accepted: 05/04/2013] [Indexed: 11/19/2022] Open
Abstract
Several studies have shown that experienced night-migratory songbirds can determine their position, but it has remained a mystery which cues and sensory mechanisms they use, in particular, those used to determine longitude (east–west position). One potential solution would be to use a magnetic map or signpost mechanism like the one documented in sea turtles. Night-migratory songbirds have a magnetic compass in their eyes and a second magnetic sense with unknown biological function involving the ophthalmic branch of the trigeminal nerve (V1). Could V1 be involved in determining east–west position? We displaced 57 Eurasian reed warblers (Acrocephalus scirpaceus) with or without sectioned V1. Sham operated birds corrected their orientation towards the breeding area after displacement like the untreated controls did. In contrast, V1-sectioned birds did not correct for the displacement. They oriented in the same direction after the displacement as they had done at the capture site. Thus, an intact ophthalmic branch of the trigeminal nerve is necessary for detecting the 1,000 km eastward displacement in this night-migratory songbird. Our results suggest that V1 carries map-related information used in a large-scale map or signpost sense that the reed warblers needed to determine their approximate geographical position and/or an east–west coordinate.
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Affiliation(s)
- Dmitry Kishkinev
- Arbeitsgruppe “Neurosensorik/Animal Navigation”, Institut für Biologie und Umweltwissenschaften & Research Centre for Neurosensory Sciences, University of Oldenburg, Oldenburg, Germany
- * E-mail:
| | - Nikita Chernetsov
- Biological Station Rybachy, Zoological Institute of Russian Academy of Sciences, Rybachy, Kaliningrad Region, Russia
| | - Dominik Heyers
- Arbeitsgruppe “Neurosensorik/Animal Navigation”, Institut für Biologie und Umweltwissenschaften & Research Centre for Neurosensory Sciences, University of Oldenburg, Oldenburg, Germany
| | - Henrik Mouritsen
- Arbeitsgruppe “Neurosensorik/Animal Navigation”, Institut für Biologie und Umweltwissenschaften & Research Centre for Neurosensory Sciences, University of Oldenburg, Oldenburg, Germany
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Holland RA, Helm B. A strong magnetic pulse affects the precision of departure direction of naturally migrating adult but not juvenile birds. J R Soc Interface 2013; 10:20121047. [PMID: 23389901 DOI: 10.1098/rsif.2012.1047] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
The mechanisms by which migratory birds achieve their often spectacular navigational performance are still largely unclear, but perception of cues from the Earth's magnetic field is thought to play a role. Birds that possess migratory experience can use map-based navigation, which may involve a receptor that uses ferrimagnetic material for detecting gradients in the magnetic field. Such a mechanism can be experimentally disrupted by applying a strong magnetic pulse that re-magnetizes ferrimagnetic materials. In captivity, this treatment indeed affected bearings of adult but not of naive juvenile birds. However, field studies, which expose birds to various navigational cues, yielded mixed results. Supportive studies were difficult to interpret because they were conducted in spring when all age groups navigate back to breeding areas. The present study, therefore, applied a magnetic pulse treatment in autumn to naturally migrating, radio-tagged European robins. We found that, although overall bearings were seasonally correct, orientation of adult but not juvenile robins was compromised by a pulse. Pulsed adults that departed within 10 days of treatment failed to show significant orientation and deviated more from mean migration direction than adult controls and juveniles. Thus, our data give field-based support for a possible ferrimagnetic map-sense during bird migration.
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Affiliation(s)
- Richard A Holland
- Department for Migration and Immune-ecology, Max Planck Institute for Ornithology, Schlossallee 2, Radolfzell 78315, Germany.
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25
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Holland R, Filannino C, Gagliardo A. A magnetic pulse does not affect homing pigeon navigation: a GPS tracking experiment. J Exp Biol 2013; 216:2192-200. [DOI: 10.1242/jeb.083543] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Summary
The cues by which homing pigeons are able to return to a home loft after displacement to unfamiliar release sites remain debated. A number of experiments in which migratory birds have been treated with a magnetic pulse have produced a disruption in their orientation, which argues that a ferrimagnetic sense is used for navigation in birds. One previous experiment has also indicated an effect of magnetic pulses on homing pigeon navigation, although with inconsistent results. Previous studies have shown that some magnetic-related information is transmitted by the trigeminal nerve to the brain in some bird species including the homing pigeon. The function of this information is still unclear. It has been suggested that this information is important for navigation. Previous studies with trigeminal nerve lesioned pigeons have clearly shown that the lack of trigeminally mediated information, even if magnetic, is not crucial for homing performance in homing pigeons. However, this result does not completely exclude the possibility that other ferrimagnetic receptors in the homing pigeon play role in navigation. Additionally, recent studies on homing pigeons suggested the existence of a ferrimagnetic sense in a novel location presumably located in the inner ear (lagena). In the current study, we tested whether any ferrimagnetic magnetoreceptors, irrespective of their location in the bird's head, are involved in pigeons' homing. To do this, we treated homing pigeons with a strong magnetic pulse before release, tracked birds with GPS-loggers and analyzed whether this treatment affected homing performance. In the single previous magnetic pulse experiment on homing pigeons only initial orientation at a release site was considered and the results were inconsistent.We observed no effect of the magnetic pulse at any of the sites used, either in initial orientation, homing performance, tortuosity or track efficiency, which does not support a role for the ferrimagnetic sense in homing pigeon navigation, at least not in this geographic area, where magnetic field variations are in the region of 200 nT intensity and 0.8° inclination.
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26
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Wiltschko R, Wiltschko W. The magnetite-based receptors in the beak of birds and their role in avian navigation. J Comp Physiol A Neuroethol Sens Neural Behav Physiol 2012; 199:89-98. [PMID: 23111859 PMCID: PMC3552369 DOI: 10.1007/s00359-012-0769-3] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2012] [Revised: 10/11/2012] [Accepted: 10/12/2012] [Indexed: 11/01/2022]
Abstract
Iron-rich structures have been described in the beak of homing pigeons, chickens and several species of migratory birds and interpreted as magnetoreceptors. Here, we will briefly review findings associated with these receptors that throw light on their nature, their function and their role in avian navigation. Electrophysiological recordings from the ophthalmic nerve, behavioral studies and a ZENK-study indicate that the trigeminal system, the nerves innervating the beak, mediate information on magnetic changes, with the electrophysiological study suggesting that these are changes in intensity. Behavioral studies support the involvement of magnetite and the trigeminal system in magnetoreception, but clearly show that the inclination compass normally used by birds represents a separate system. However, if this compass is disrupted by certain light conditions, migrating birds show 'fixed direction' responses to the magnetic field, which originate in the receptors in the beak. Together, these findings point out that there are magnetite-based magnetoreceptors located in the upper beak close to the skin. Their natural function appears to be recording magnetic intensity and thus providing one component of the multi-factorial 'navigational map' of birds.
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Affiliation(s)
- R Wiltschko
- FB Biowissenschaften, J.W.Goethe-Universität Frankfurt, Siesmayerstraße 70, 60054, Frankfurt a.M, Germany
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27
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Válková T, Vácha M. How do honeybees use their magnetic compass? Can they see the North? BULLETIN OF ENTOMOLOGICAL RESEARCH 2012; 102:461-467. [PMID: 22313997 DOI: 10.1017/s0007485311000824] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
While seeking food sources and routes back to their hive, bees make use of their advanced nervous and sensory capacities, which underlie a diverse behavioral repertoire. One of several honeybee senses that is both exceptional and intriguing is magnetoreception - the ability to perceive the omnipresent magnetic field (MF) of the Earth. The mechanism by which animals sense MFs has remained fascinating as well as elusive because of the intricacies involved, which makes it one of the grand challenges for neural and sensory biology. However, investigations in recent years have brought substantial progress to our understanding of how such magneto-receptor(s) may work. Some terrestrial animals (birds) are reported to be equipped even with a dual perception system: one based on diminutive magnetic particles - in line with the original model which has also always been hypothesized for bees - and the other one, as the more recent model describes, based on a sensitivity of some photochemical reactions to MF (radical-pair or chemical mechanism). The latter model postulates a close link to vision and supposes that the animals can see the position of the geomagnetic North as a visible pattern superimposed on the picture of the environment. In recent years, a growing body of evidence has shown that radical-pair magnetoreception might also be used by insects. It is realistic to expect that such evidence will inspire a re-examination and extension or confirmation of established views on the honeybee magnetic-compass mechanism. However, the problem of bee magnetoreception will not be solved at the moment that a receptor is discovered. On the contrary, the meaning of magnetoreception in insect life and its involvement in the orchestration of other senses is yet to be fully understood. The crucial question to be addressed in the near future is whether the compass abilities of the honeybee could suffer from radio frequency (RF) smog accompanying modern civilization and whether the fitness of this dominant pollinator might be affected by RF fields. The goal of this review is to provide an overview of the path that the behavioral research on honeybee magnetoreception has taken and to discuss it in the context of contemporary data obtained on other insects.
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Affiliation(s)
- T Válková
- Department of Animal Physiology and Immunology, Faculty of Science, Masaryk University, Kotlarska 2, 611 37, Brno, Czech Republic
| | - M Vácha
- Department of Animal Physiology and Immunology, Faculty of Science, Masaryk University, Kotlarska 2, 611 37, Brno, Czech Republic
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28
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Wiltschko W, Wiltschko R. Global navigation in migratory birds: tracks, strategies, and interactions between mechanisms. Curr Opin Neurobiol 2012; 22:328-35. [DOI: 10.1016/j.conb.2011.12.012] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2011] [Revised: 12/22/2011] [Accepted: 12/22/2011] [Indexed: 10/14/2022]
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Wiltschko R, Denzau S, Gehring D, Thalau P, Wiltschko W. Magnetic orientation of migratory robins, Erithacus rubecula, under long-wavelength light. J Exp Biol 2011; 214:3096-101. [DOI: 10.1242/jeb.059212] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
SUMMARY
The avian magnetic compass is an inclination compass that appears to be based on radical pair processes. It requires light from the short-wavelength range of the spectrum up to 565 nm green light; under longer wavelengths, birds are disoriented. When pre-exposed to longer wavelengths for 1 h, however, they show oriented behavior. This orientation is analyzed under 582 nm yellow light and 645 nm red light in the present study: while the birds in spring prefer northerly directions, they do not show southerly tendencies in autumn. Inversion of the vertical component does not have an effect whereas reversal of the horizontal component leads to a corresponding shift, indicating that a polar response to the magnetic field is involved. Oscillating magnetic fields in the MHz range do not affect the behavior but anesthesia of the upper beak causes disorientation. This indicates that the magnetic information is no longer provided by the radical pair mechanism in the eye but by the magnetite-based receptors in the skin of the beak. Exposure to long-wavelength light thus does not expand the spectral range in which the magnetic compass operates but instead causes a different mechanism to take over and control orientation.
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Affiliation(s)
- Roswitha Wiltschko
- Fachbereich Biowissenschaften, J. W. Goethe-Universität Frankfurt, Siesmayerstraße 70, D-60054 Frankfurt am Main, Germany
| | - Susanne Denzau
- Fachbereich Biowissenschaften, J. W. Goethe-Universität Frankfurt, Siesmayerstraße 70, D-60054 Frankfurt am Main, Germany
| | - Dennis Gehring
- Fachbereich Biowissenschaften, J. W. Goethe-Universität Frankfurt, Siesmayerstraße 70, D-60054 Frankfurt am Main, Germany
| | - Peter Thalau
- Fachbereich Biowissenschaften, J. W. Goethe-Universität Frankfurt, Siesmayerstraße 70, D-60054 Frankfurt am Main, Germany
| | - Wolfgang Wiltschko
- Fachbereich Biowissenschaften, J. W. Goethe-Universität Frankfurt, Siesmayerstraße 70, D-60054 Frankfurt am Main, Germany
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Thorup K, Ortvad TE, Rabøl J, Holland RA, Tøttrup AP, Wikelski M. Juvenile songbirds compensate for displacement to oceanic islands during autumn migration. PLoS One 2011; 6:e17903. [PMID: 21464975 PMCID: PMC3064565 DOI: 10.1371/journal.pone.0017903] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2010] [Accepted: 02/15/2011] [Indexed: 11/30/2022] Open
Abstract
To what degree juvenile migrant birds are able to correct for orientation errors
or wind drift is still largely unknown. We studied the orientation of passerines
on the Faroe Islands far off the normal migration routes of European migrants.
The ability to compensate for displacement was tested in naturally occurring
vagrants presumably displaced by wind and in birds experimentally displaced 1100
km from Denmark to the Faroes. The orientation was studied in orientation cages
as well as in the free-flying birds after release by tracking departures using
small radio transmitters. Both the naturally displaced and the experimentally
displaced birds oriented in more easterly directions on the Faroes than was
observed in Denmark prior to displacement. This pattern was even more pronounced
in departure directions, perhaps because of wind influence. The clear
directional compensation found even in experimentally displaced birds indicates
that first-year birds can also possess the ability to correct for displacement
in some circumstances, possibly involving either some primitive form of true
navigation, or ‘sign posts’, but the cues used for this are highly
speculative. We also found some indications of differences between species in
the reaction to displacement. Such differences might be involved in the
diversity of results reported in displacement studies so far.
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Affiliation(s)
- Kasper Thorup
- Center for Macroecology, Evolution and
Climate, Zoological Museum, University of Copenhagen, Copenhagen,
Denmark
- * E-mail:
| | - Troels Eske Ortvad
- Center for Macroecology, Evolution and
Climate, Zoological Museum, University of Copenhagen, Copenhagen,
Denmark
| | - Jørgen Rabøl
- Center for Macroecology, Evolution and
Climate, Zoological Museum, University of Copenhagen, Copenhagen,
Denmark
| | - Richard A. Holland
- Department of Migration and Immuno-ecology,
Max Planck Institute for Ornithology, Radolfzell, Germany
| | - Anders P. Tøttrup
- Department of Biology, Center for
Macroecology, Evolution and Climate, University of Copenhagen, Copenhagen,
Denmark
| | - Martin Wikelski
- Department of Migration and Immuno-ecology,
Max Planck Institute for Ornithology, Radolfzell, Germany
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