Spectral purity, intensity and dominant wavelength: Disparate colour preferences of two Brazilian stingless bee species.

Bees use floral colour as a major long distance orientation cue. While it is known for bumblebees and honeybees that dominant wavelength (≙ colour hue), colour contrast and spectral purity (≙ saturation) are crucial for flower detection and discrimination, only little is known about colour preferences in stingless bees (Meliponini). In this experiment freely flying workers of two Brazilian species of stingless bees-Partamona helleri and Melipona bicolor-were tested for colour preferences concerning the colour parameters dominant wavelength, spectral purity and intensity (≙ brightness). Each individual bee had to perform 57 tests, in which a definite series of dual choices between colour stimuli varying in intensity, spectral purity or dominant wavelength were presented. The results show that P. helleri chose colours of higher spectral purity and preferred bluish colours, while M. bicolor made generalized colour choices. Intensity did not influence the colour choice of any bee species. The results of P. helleri are consistent with findings for honeybees and bumblebees, while colour preferences in M. bicolor seem to be absent.