Fig 1.
Photographs of an individual of both the studied species.
Colouration and patterns of adults of (A) Adalia bipunctata (L), “typica” morph and (B) Calvia quatuordecimguttata (L).
Fig 2.
The curves are the reflectance spectra of ten analysed individuals for each species and obtained for (A) the orange zone of A. bipunctata elytra and the creamy (B) and brown (C) zones of C. quatuordecimguttata elytra. A (human) colour scale corresponding to wavelengths axis is placed over each spectrum. The colour patches at the bottom of each figure correspond to the colours that are perceived for each of the reflectance spectra.
Fig 3.
Optical microscope images of a same zone of the elytron surface of an A. bipunctata specimen (A and B) and of a C. quatuordecimguttata specimen (C and D).
Fig 4.
SEM images of the surface of an A. bipunctata (A and B) and of a C. quatuordecimguttata elytra (C and D).
Fig 5.
Transmission electron microscopy.
TEM images of the cross-section microstructure of (top raw) an elytron of A. bipunctata (A) section of an orange zone, (B) section of a black spot zone, (C) zoom on the exocuticle multilayer, and of (bottom raw) an elytron of C. quatuordecimguttata (D) brown zone, (E) transition from brown and creamy spot zone, (F) exocuticle multilayer. Black arrows in panels B and E indicate the location of an electron high absorbing layer. The white arrow in panel E indicates the location of the frontier between the zones with and without the electron high absorbing molecule.
Fig 6.
Simulated structural chromaticity.
Top row: (A) Bragg grating with a fixed periodicity p = 190 nmp = 190 nm; (B) Correspondence between the TEM cross-sectional image of the A. bipunctata elytra structure and its numerical replica; (C) Similar analysis for C. quatuordecimguttata. The grayscale represents variations in the refractive index. Bottom row: Dependence of reflection radiance on the mean refractive index and the corresponding CIE 1931 chromaticity coordinates.
Fig 7.
Raman spectra in different elytral zones.
Raman spectrum of the black dot of an A. bipunctata elytron. (B) superposition of beta carotene reference spectra with the Raman spectra obtained in the orange zone of an A. bipunctata and in the brown zone of a C. quatuordecimguttata elytra.
Fig 8.
Raman spectra of the elytra of ten specimens of (A) A. bipunctata orange zone, and of ten specimens C. quatuordecimguttata (B) creamy and (C) brown zones.
Fig 9.
PCA corresponding to the extracts of A. bipunctata and C. quatuordecimguttata based on the variables (normalized peak area as a function of m/z at an Rt) detected on the LC-MS chromatograms.