Multimodal imaging reveals no evidence for magnetite-based magnetoreceptors in the mole-rat eye

ABSTRACT Magnetoreception, the ability to perceive the geomagnetic field, is widespread across animals. The underlying sensory mechanism remains elusive, but a long-standing hypothesis proposes single-domain magnetite linked to mechanosensitive ion channels. The Ansell’s mole-rat ( Fukomys anselli ) is a subterranean rodent with a magnetic sense, and published behavioral and histological data are consistent with magnetite-based magnetoreceptors in the cornea or retina. Here, we systematically screened for magnetite in the mole-rat eye, combining iron detection via enhanced Prussian blue staining and synchrotron X-ray fluorescence microscopy (XFM) with magnetic detection via MRI quantitative susceptibility mapping (MRI-QSM) and quantum-diamond microscopy (QDM). This revealed only a few iron particles in the retina and cornea, which predominantly overlapped with titanium or chromium, indicating a non-biogenic origin. XFM showed iron-enriched lines in the cornea, but these did not show ferrimagnetic signals. Focusing on other ocular tissues, MRI-QSM revealed the highest susceptibility in the ciliary body, where iron-rich pigmented cells were identified. A TEM-screen, however, failed to detect single-domain magnetite particles in these cells. We conclude that our high-sensitivity multimodal screen provides no evidence for magnetite-based magnetoreceptors in the mole-rat eye, suggesting that mole-rat magnetoreceptors either do not reside in the eye or are based on different physical principles.

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Publication Details

Journal
bioRxiv (Cold Spring Harbor Laboratory)
Published
2026-04-06
DOI
https://doi.org/10.64898/2026.04.02.715577
Primary Topic
Geomagnetism and Paleomagnetism Studies
Type
article
Field-Weighted Citation Impact
0.00

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article

Multimodal imaging reveals no evidence for magnetite-based magnetoreceptors in the mole-rat eye

Stephan H. Irsen, Daryl L. Howard, Anna R. Sternberg, Leif Moritz‍ et al.
bioRxiv (Cold Spring Harbor Laboratory)
Geomagnetism and Paleomagnetism Studies
article

Multimodal imaging reveals no evidence for magnetite-based magnetoreceptors in the mole-rat eye

Stephan H. Irsen, Daryl L. Howard, Anna R. Sternberg, Leif Moritz‍, Kamalika Nath, Erich Pascal Malkemper, David Simpson, Sabine Begall, Kristian Bredies, Elisabeth Becher, Malte Brammerloh, Martha M. M. Daniel, Clemens Diwoky, Gerald Falkenberg, Ella P. Walsh, Kadda Medjoubi, Adrian Lange, David J. Paterson, Li Zhang
article en

Abstract

ABSTRACT Magnetoreception, the ability to perceive the geomagnetic field, is widespread across animals. The underlying sensory mechanism remains elusive, but a long-standing hypothesis proposes single-domain magnetite linked to mechanosensitive ion channels. The Ansell’s mole-rat ( Fukomys anselli ) is a subterranean rodent with a magnetic sense, and published behavioral and histological data are consistent with magnetite-based magnetoreceptors in the cornea or retina. Here, we systematically screened for magnetite in the mole-rat eye, combining iron detection via enhanced Prussian blue staining and synchrotron X-ray fluorescence microscopy (XFM) with magnetic detection via MRI quantitative susceptibility mapping (MRI-QSM) and quantum-diamond microscopy (QDM). This revealed only a few iron particles in the retina and cornea, which predominantly overlapped with titanium or chromium, indicating a non-biogenic origin. XFM showed iron-enriched lines in the cornea, but these did not show ferrimagnetic signals. Focusing on other ocular tissues, MRI-QSM revealed the highest susceptibility in the ciliary body, where iron-rich pigmented cells were identified. A TEM-screen, however, failed to detect single-domain magnetite particles in these cells. We conclude that our high-sensitivity multimodal screen provides no evidence for magnetite-based magnetoreceptors in the mole-rat eye, suggesting that mole-rat magnetoreceptors either do not reside in the eye or are based on different physical principles.

bioRxiv (Cold Spring Harbor Laboratory)
Australian Nuclear Science and Technology Organisation (AU), University of Graz (AT), The University of Melbourne (AU), Haldia Institute of Technology (IN), Medical University of Graz (AT), Center of Advanced European Studies and Research (DE), Synchrotron soleil (FR), Deutsches Elektronen-Synchrotron DESY (DE), Centre Hospitalier Universitaire Vaudois (CH), Australian Synchrotron (AU), Graz University of Technology (AT), Graz University Hospital (AT), Max Planck Institute of Neurobiology (DE), University of Duisburg-Essen (DE), University of Lausanne (CH)
Australian Nuclear Science and Technology Organisation, Australian Government, Australian Synchrotron, Max-Planck-Gesellschaft, Australian Research Council, Deutsches Elektronen-Synchrotron
Openalex Percentile: Top 28%
Geomagnetism and Paleomagnetism Studies
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Multimodal imaging reveals no evidence for magnetite-based magnetoreceptors in the mole-rat eye — Stephan H. Irsen, Daryl L. Howard, et al. · bioRxiv (Cold Spring Harbor Laboratory) (2026) | TGRS Research Map | TGRS