Related Experiment Video
Updated: May 14, 2026

Laboratory Maintenance of the Lower Dipteran Fly Bradysia (Sciara) coprophila: A New/Old Emerging Model Organism
Published on: April 19, 2024
Subtle design changes control the difference in colour reflection from the dorsal and ventral wing-membrane surfaces
M R Nixon1, A G Orr, P Vukusic
1School of Physics, University of Exeter, EX4 4QL, UK. M.R.Nixon@exeter.ac.uk
Abstract:
The hind wings of males of the damselfly Matronoides cyaneipennis exhibit iridescence that is blue dorsally and green ventrally. These structures are used semiotically in agonistic and courtship display. Transmission electron microscopy reveals these colours are due to two near-identical 5-layer distributed Bragg reflectors, one placed either side of the wing membrane. Interestingly the thicknesses of corresponding layers in each distributed Bragg reflector are very similar for all but the second layer from each outer surface. This one key difference creates the significant disparity between the reflected spectra from the distributed Bragg reflectors and the observed colours of either side of the wing. Modelling indicates that modifications to the thickness of this layer alone create a greater change in the peak reflected wavelength than is observed for similar modifications to the thickness of any other layer. This results in an optimised and highly effective pair of semiotic reflector systems, based on extremely comparable design parameters, with relatively low material and biomechanical costs.
Related Concept Videos
Mate Choice
Position-effect Variegation
Background and Environment Affect Phenotype
An example of how genetic background affects phenotype can be seen in horses. The Extension gene in horses is responsible for their coat color. A wild-type gene (EE) produces black pigment in the coat, while a mutant gene (ee) produces red pigment. A...

