Extended Data Fig. 5: Loadings plots for principal component axes 1–3.

These loading plots are for the PCA shown in Extended Data Fig. 4. a, Loadings per wavelength and functional group for PC1 (57.118%). Negative loadings are associated with C–N functions, while positive loadings are associated with C–O functions. PC1 separates samples in the chemospace based on pigment type (protoporphyrin IX ratio of C–N to C=O) > biliverdin (ratio of C–N to C=O)), concentration, and PFP contents. b, Loadings per wavelength and functional group for PC2 (23.841%). Negative loadings are associated with prominent PFP bands, whereas positive loadings are associated with eggshell pigments. Thus, PC2 separates samples in the chemo-space on the basis of the presence or absence of eggshell pigments. c, Loadings per wavelength and functional group for PC3 (9.258%).