Spectral variables of typical spectral reflectance curve of adult male C. umbratica. RUV, UV intensity (%); RVIS, VIS intensity (%); λ(RUV), UV hue, the spectral position of UV peak (nm); λ(RVIS), VIS hue, the spectral position of VIS peak (nm); Rtotal, total intensity of reflectance spectra (300–700 nm); λVIS–UV, band separation (nm), wavelength difference between the peaks of UV and VIS bands.