Connecting the navigational clock to sun compass input in monarch butterfly brain

Neuron. 2005 May 5;46(3):457-67. doi: 10.1016/j.neuron.2005.03.014.


Migratory monarch butterflies (Danaus plexippus) use a time-compensated sun compass to navigate to their overwintering grounds in Mexico. Although polarized light is one of the celestial cues used for orientation, the spectral content (color) of that light has not been fully explored. We cloned the cDNAs of three visual pigment-encoding opsins (ultraviolet [UV], blue, and long wavelength) and found that all three are expressed uniformly in main retina. The photoreceptors of the polarization-specialized dorsal rim area, on the other hand, are monochromatic for the UV opsin. Behavioral studies support the importance of polarized UV light for flight orientation. Next, we used clock protein expression patterns to identify the location of a circadian clock in the dorsolateral protocerebrum of butterfly brain. To provide a link between the clock and the sun compass, we identified a CRYPTOCHROME-staining neural pathway that likely connects the circadian clock to polarized light input entering brain.

Publication types

  • Comparative Study
  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Animal Migration / physiology*
  • Animals
  • Brain / physiology*
  • Butterflies / physiology*
  • CLOCK Proteins
  • Circadian Rhythm / physiology*
  • Gene Expression
  • Immunohistochemistry
  • In Situ Hybridization
  • Neural Pathways / physiology*
  • Photoreceptor Cells, Invertebrate / metabolism
  • Phylogeny
  • Polymerase Chain Reaction
  • Retina / metabolism
  • Rod Opsins / genetics
  • Rod Opsins / metabolism
  • Sunlight
  • Trans-Activators / genetics
  • Trans-Activators / metabolism
  • Ultraviolet Rays


  • Rod Opsins
  • Trans-Activators
  • CLOCK Proteins