Flower Visiting and Pollen Transport by the Imported Cabbage Butterfly (Lepidoptera: Pieridae) in a Highly Disturbed Urban Habitat

Abstract

Throughout their flight season from April to November, adult imported cabbage butterflies (ICBS), Pieris rapae , visited one hybrid and 37 flower species in a large, complex urban vegetable and flower garden in Washington, D.C. Of these flower species, 92% were exotic, and the corolla depths of some of them were significantly different. Individual butterflies carried means of from 0.8 to 8.8 pollen grains of each of seven flower species on their tongues and from 0 to 1.7 grains from four flower species on their legs. They transported significantly more pollen grains of radish and Iythrum on their tongues than on their legs. Also, they carried more pollen of radish than three other flowers examined. Their constancy in species of flower visited during foraging bouts and movements of their tongues and legs against stigmas suggest that they may pollinate these flowers, but they seem to function primarily as nectar thieves.