SPONTANEOUS AND LEARNED PREFERENCES FOR VISUAL FLOWER FEATURES IN A DIURNAL HAWKMOTH

Abstract

Macroglossum stellatarum is a diurnal member of the otherwise crepuscular sphin- gid family. The moths of this species are known to visit flowers of almost all colors, sizes, and patterns, but at a time, they are flower-constant. They are mainly attracted by the visual cues of flowers, odors being less important. The choices for flower-like objects differing in color, size, and pattern were analyzed in flight cages with free-flying animals of the laboratory livestock. Newly eclosed moths spontaneously choose 440 nm and 540 nm more frequently than other colors, radial patterns rather than ring patterns, and paper disks with a central spot more often than those without it. They are attracted to disks of about 32 mm diameter with a large distance to the background. These spontaneous choices enable them to find a first nectar reward. The moths can be trained to colors and sizes. They learn spectral colors much faster than paper colors, and their choices after color learning are compatible with true color vision phenomena. Most probably they also have a time-place memory.