Theory 06/Biophotonics
Colour Is a Period Ratio
The claim
Structural colour in butterfly wings is set by the ratio of nanostructure period to wavelength, so a 5% change in development produces a different hue without any pigment change.
01Mechanism
Interference depends on the optical path difference; the period relative to wavelength determines which colours reinforce.
02Predictions
- P1Hue should track the period ratio.
- P2Pigment content alone should mispredict.
03Refutation
Hue tracking pigment would remove the structural term.
04Why it resists the grid
A photonic crystal is built by a developing organism, so the claim spans physics, development and sexual selection at once.