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Ultraviolet reflecting photonic microstructures in the King Penguin beak
Birgitta Dresp1, Pierre Jouventin, Keith Langley
1CNRS-CEFE, UMR 5175 34293 Montpellier, France.
Biology Letters
|December 7, 2006
Summary
King penguins reflect ultraviolet light from their beaks due to a unique photonic microstructure. This structural coloration likely plays a role in mate selection for these marine birds.
Area of Science:
- Avian biology
- Biophotonics
- Animal coloration
Background:
- King and emperor penguins are unique among marine birds for reflecting ultraviolet (UV) light from their beaks.
- UV perception is common in birds and used in communication, particularly for mate selection, similar to feather coloration in songbirds.
- While king penguins have colorful plumage, only their beaks exhibit UV reflectance, suggesting a role in sexual attraction.
Purpose of the Study:
- To identify the specific structures responsible for UV reflectance in the king penguin beak.
- To investigate the origin of UV reflection, given the absence of known avian UV-reflecting pigments.
Main Methods:
- Combined reflectance spectrophotometry with light and electron microscopy.
- Performed experimental removal of surface layers of the beak horn to analyze underlying structures.
Main Results:
- Characterized a novel multilayer reflector photonic microstructure within the king penguin beak.
- This microstructure is identified as the source of the observed UV reflections.
Conclusions:
- The UV reflectance in king penguin beaks originates from a structural photonic microstructure, not pigments.
- This finding provides the first detailed characterization of the mechanism behind UV beak coloration in birds.
