Table 1.

Threshold E-values for the “blue” and “green” spectral regions for the 5 plant species showing no modulation in the UV region when considering green adaptation background and a color discrimination threshold value of 0.04 hexagon units (second column)

Species\spectral parameters	Threshold E-value		Mean maximum E-value		Is iridescence perceivable?
	“Green”	“Blue”	“Green”	“Blue”	“Green”	“Blue”
Alyogyne huegelii	0.417	0.764	0.412±0.09	0.472±0.05	Yes	No
Solanum laciniatum	0.406	0.786	0.477±0.04	0.497±0.02	Yes	No
Lycianthes rantonnetii a	NI	NI	NI	NI	NI	NI
Tropaeolum majus	0.328	0.050	0.018±0.002	0.196±0.05	No	Yesb
Hibiscus heterophyllum	0.804	0.709	0.493±0.01	0.378±0.08	No	No
Pelargonium rodneyanum	0.572	0.847	0.350±0.11	0.474±0.05	No	No

Mean E-values and standard deviations corresponding to the maximum E-value obtained on each of the n = 37 linearized images representing various viewing points recorded for each species

^a Solanum rantonnetii potentially modulates the UV-sensitive photoreceptor in the honeybee; however, as this spectral region is beyond our current system capability, this species was not included in the reported results. NI, not included.

^bPerceivable iridescence mainly corresponds to flower regions not involved in sexual reproduction (Figure 5).