Figure 2.

The reflectance spectrum of the two flower colors is given as a function of the wavelength (light gray for the yellow morph and black for the purple morph). Two spectra are given for each color representing the range of the spectrum found over 10 individuals. Spectra were recorded by using a portable reflectance spectrophotometer (High Sensitivity Spectrophotometer S2000, New Electro-Optical Concepts, Beaufays, Belgium) that gave a reflectance spectrum across all of the wavelengths (including UV) to which insect pollinators are sensitive (16).