Skip to main content

Thank you for visiting You are using a browser version with limited support for CSS. To obtain the best experience, we recommend you use a more up to date browser (or turn off compatibility mode in Internet Explorer). In the meantime, to ensure continued support, we are displaying the site without styles and JavaScript.

Cryptochrome mediates light-dependent magnetosensitivity in Drosophila


Although many animals use the Earth’s magnetic field for orientation and navigation1,2, the precise biophysical mechanisms underlying magnetic sensing have been elusive. One theoretical model proposes that geomagnetic fields are perceived by chemical reactions involving specialized photoreceptors3. However, the specific photoreceptor involved in such magnetoreception has not been demonstrated conclusively in any animal. Here we show that the ultraviolet-A/blue-light photoreceptor cryptochrome (Cry) is necessary for light-dependent magnetosensitive responses in Drosophila melanogaster. In a binary-choice behavioural assay for magnetosensitivity, wild-type flies show significant naive and trained responses to a magnetic field under full-spectrum light (300–700 nm) but do not respond to the field when wavelengths in the Cry-sensitive, ultraviolet-A/blue-light part of the spectrum (<420 nm) are blocked. Notably, Cry-deficient cry0 and cryb flies do not show either naive or trained responses to a magnetic field under full-spectrum light. Moreover, Cry-dependent magnetosensitivity does not require a functioning circadian clock. Our work provides, to our knowledge, the first genetic evidence for a Cry-based magnetosensitive system in any animal.

Access options

Rent or Buy article

Get time limited or full article access on ReadCube.


All prices are NET prices.

Figure 1: Behavioural apparatus for magnetosensitivity and behavioural responses in different Drosophila strains.
Figure 2: Short-wavelength light is required for magnetosensitivity in Canton-S flies.
Figure 3: Drosophila Cry mediates magnetosensitivity.
Figure 4: Constant light disrupts circadian function but not Cry-mediated magnetosensitivity in Canton-S flies.


  1. 1

    Lohmann, K. J., Lohmann, C. M. F. & Putman, N. F. Magnetic maps in animals: nature’s GPS. J. Exp. Biol. 210, 3697–3705 (2007)

    Article  Google Scholar 

  2. 2

    Wiltschko, W. & Wiltschko, R. Magnetic orientation and magnetoreception in birds and other animals. J. Comp. Physiol. A Neuroethol. Sens. Neural Behav. Physiol. 191, 675–693 (2005)

    Article  Google Scholar 

  3. 3

    Ritz, T., Adem, S. & Schulten, K. A model for photoreceptor-based magnetoreception in birds. Biophys. J. 78, 707–718 (2000)

    CAS  Article  Google Scholar 

  4. 4

    Luschi, P. et al. Marine turtles use geomagnetic cues during open-sea homing. Curr. Biol. 17, 126–133 (2007)

    CAS  Article  Google Scholar 

  5. 5

    Johnsen, S. & Lohmann, K. J. The physics and neurobiology of magnetoreception. Nature Rev. Neurosci. 6, 703–712 (2005)

    CAS  Article  Google Scholar 

  6. 6

    Kirschvink, J. L. & Gould, J. L. Biogenic magnetite as a basis for magnetic-field detection in animals. Biosystems 13, 181–201 (1981)

    CAS  Article  Google Scholar 

  7. 7

    Walker, M. M. A model for encoding of magnetic field intensity by magnetite-based magnetoreceptor cells. J. Theor. Biol. 250, 85–91 (2008)

    CAS  Article  Google Scholar 

  8. 8

    Kirschvink, J. L., Walker, M. M. & Diebel, C. E. Magnetite-based magnetoreception. Curr. Opin. Neurobiol. 11, 462–467 (2001)

    CAS  Article  Google Scholar 

  9. 9

    Leask, M. J. M. Physicochemical mechanism for magnetic-field detection by migratory birds and homing pigeons. Nature 267, 144–145 (1977)

    ADS  CAS  Article  Google Scholar 

  10. 10

    Schulten, K., Swenberg, C. E. & Weller, A. Biomagnetic sensory mechanism based on magnetic-field modulated coherent electron-spin motion. Z. Phy. Chem. (Frankfurt) 111, 1–5 (1978)

    Article  Google Scholar 

  11. 11

    Cashmore, A. R. Cryptochromes: Enabling plants and animals to determine circadian time. Cell 114, 537–543 (2003)

    CAS  Article  Google Scholar 

  12. 12

    Partch, C. L. & Sancar, A. Photochemistry and photobiology of cryptochrome blue-light photopigments: The search for a photocycle. Photochem. Photobiol. 81, 1291–1304 (2005)

    CAS  Article  Google Scholar 

  13. 13

    Zhu, H. et al. The two CRYs of the butterfly. Curr. Biol. 15, R953–R954 (2005)

    CAS  Article  Google Scholar 

  14. 14

    Yuan, Q., Metterville, D., Briscoe, A. D. & Reppert, S. M. Insect cryptochromes: Gene duplication and loss define diverse ways to construct insect circadian clocks. Mol. Biol. Evol. 24, 948–955 (2007)

    CAS  Article  Google Scholar 

  15. 15

    Öztürk, N., Song, S. H., Selby, C. P. & Sancar, A. Animal type 1 cryptochromes—analysis of the redox state of the flavin cofactor by site-directed mutagenesis. J. Biol. Chem. 283, 3256–3263 (2008)

    Article  Google Scholar 

  16. 16

    Phillips, J. B. & Borland, S. C. Behavioral evidence for use of a light-dependent magnetoreception mechanism by a vertebrate. Nature 359, 142–144 (1992)

    ADS  Article  Google Scholar 

  17. 17

    Ritz, T., Dommer, D. H. & Phillips, J. B. Shedding light on vertebrate magnetoreception. Neuron 34, 503–506 (2002)

    CAS  Article  Google Scholar 

  18. 18

    Wiltschko, R. & Wiltschko, W. Magnetoreception. Bioessays 28, 157–168 (2006)

    CAS  Article  Google Scholar 

  19. 19

    VanVickle-Chavez, S. J. & Van Gelder, R. N. Action spectrum of Drosophila cryptochrome. J. Biol. Chem. 282, 10561–10566 (2007)

    CAS  Article  Google Scholar 

  20. 20

    Helfrich-Forster, C. et al. The extraretinal eyelet of Drosophila: Development, ultrastructure, and putative circadian function. J. Neurosci. 22, 9255–9266 (2002)

    Article  Google Scholar 

  21. 21

    Dolezelova, E., Dolezel, D. & Hall, J. C. Rhythm defects caused by newly engineered null mutations in Drosophila’s cryptochrome gene. Genetics 177, 329–345 (2007)

    CAS  Article  Google Scholar 

  22. 22

    Emery, P. et al. CRY, a Drosophila clock and light-regulated cryptochrome, is a major contributor to circadian rhythm resetting and photosensitivity. Cell 95, 669–679 (1998)

    CAS  Article  Google Scholar 

  23. 23

    Stanewsky, R. et al. The cryb mutation identifies cryptochrome as a circadian photoreceptor in Drosophila . Cell 95, 681–692 (1998)

    CAS  Article  Google Scholar 

  24. 24

    Kirschvink, J. L. Uniform magnetic-fields and double-wrapped coil systems—improved techniques for the design of bioelectromagnetic experiments. Bioelectromagnetics 13, 401–411 (1992)

    CAS  Article  Google Scholar 

  25. 25

    Stanewsky, R. Genetic analysis of the circadian system in Drosophila melanogaster and mammals. J. Neurobiol. 54, 111–147 (2003)

    CAS  Article  Google Scholar 

  26. 26

    Wehner, R. & Labhart, T. Perception of geomagnetic field in fly Drosophila melanogaster . Experientia 26, 967–968 (1970)

    CAS  Article  Google Scholar 

  27. 27

    Phillips, J. B. & Sayeed, O. Wavelength-dependent effects of light on magnetic compass orientation in Drosophila melanogaster . J. Comp. Physiol. A Sens. Neural Behav. Physiol. 172, 303–308 (1993)

    CAS  Article  Google Scholar 

  28. 28

    Maeda, K. et al. Chemical compass model of avian magnetoreception. Nature 453, 387–390 (2008)

    ADS  CAS  Article  Google Scholar 

  29. 29

    Tully, T. & Quinn, W. G. Classical-conditioning and retention in normal and mutant Drosophila melanogaster . J. Comp. Physiol. A Sens. Neural Behav. Physiol. 157, 263–277 (1985)

    CAS  Article  Google Scholar 

  30. 30

    Rush, B. L., Murad, A., Emery, P. & Giebultowicz, J. M. Ectopic CRYPTOCHROME renders TIM light sensitive in the Drosophila ovary. J. Biol. Rhythms 21, 272–278 (2006)

    CAS  Article  Google Scholar 

Download references


We thank H. Zhu for the protein work in Fig. 4b, c; L. Foley for assistance; J. C. Hall for the cry0 flies; P. Emery for the Per and Cry antibodies; and P. Emery, P. Perrat, B. Leung, S. DasGupta, M. Krashes and H. Zhu for discussions. This work was supported by grants from the NIH.

Author Contributions S.M.R. and R.J.G. conceived the idea of using Drosophila to study magnetosensitivity; S.W. and R.J.G. conceived the idea of using appetitive conditioning to study magnetoresponses; R.J.G. designed the experimental apparatus; R.J.G., S.W., A.C. and S.M.R. designed the experiments and analysed the data; R.J.G. performed the experiments with help from A.C.; R.J.G., S.M.R., S.W. and A.C wrote the paper.

Author information



Corresponding author

Correspondence to Steven M. Reppert.

Rights and permissions

Reprints and Permissions

About this article

Cite this article

Gegear, R., Casselman, A., Waddell, S. et al. Cryptochrome mediates light-dependent magnetosensitivity in Drosophila. Nature 454, 1014–1018 (2008).

Download citation

Further reading


By submitting a comment you agree to abide by our Terms and Community Guidelines. If you find something abusive or that does not comply with our terms or guidelines please flag it as inappropriate.


Quick links

Nature Briefing

Sign up for the Nature Briefing newsletter — what matters in science, free to your inbox daily.

Get the most important science stories of the day, free in your inbox. Sign up for Nature Briefing