Achromatic Cues Are Important for Flower Visibility to Hawkmoths and Other Insects

Studies on animal colour vision typically focus the chromatic aspect of colour, which is related to spectral distribution, and disregard achromatic aspect, intensity (“brightness”) a stimulus. Although component often most reliable for object recognition because it fairly context independent, may provide signal under specific conditions, example at night when light low. Here we make case importance cues in plant-pollinator signalling, based experimental data naïve Deilephila elpenor Macroglossum stellatarum hawkmoths, optical modelling synthesising published experiments bees, flies, butterflies moths. Our show that ecologically relevant levels hawkmoths express strong preference brighter stimuli. Published suggest flower-visiting butterflies, moths be more important detection than considered. enabled disentangling contribution pigments scattering structures flower’s contrast, illustrates how flower anatomy background are mediating factors. We discuss our findings often-assumed dichotomy between discrimination, versus vision, evolution floral visual signals.