“…To explore the importance of blue flower color and considering bee pollinator color vision, it is interesting to compare reflectance spectra of plants from different latitudes and geographic regions. Datasets from Australia (Dyer et al, 2012;Shrestha et al, 2019a,b), Nepal (Shrestha et al, 2014), Norway (Arnold et al, 2009(Arnold et al, , 2010, and Brazil (Camargo et al, 2019) provide an accessible comparison, because similar data collection methods were employed in the various studies, although some abiotic factors including background and/or light can vary with increasing altitude (Niu et al, 2020). The floral spectra from these studies were expressed in a bee color space, a geometrical interpretation allowing for modeling colors as perceived by an animal observer (Figure 8) (Kelber et al, 2003;Renoult et al, 2017); this model is implemented using a visual namogram (Stavenga et al, 1993) to model spectral sensitivity functions (Figure 7) for typical bee photoreceptors (350, 440, and 540 nm), using standard foliage background and open midday illumination (Judd et al, 1964), enabling the calculation of a spectral locus for the main flower color for each plant species (Figure 8).…”