Onion growers frequently complain that honey bees are reluctant to visit the male-sterile flowers solely for the nectar. It must be recognized that bees may visit a flower for its pollen, its nectar, or both, and in male-sterile plants only nectar is available. Cooperative work between bee and plant specialists in this area may prove valuable. The primary problem seems to be the relative unattractiveness to bees. Already there are leads in that area.
Some plants show greater attractiveness than others.
The discovery of a strain of beans highly attractive to bees or the development of a way to attract bees to the flowers could almost assure utilization of hybrid vigor in this crop. This is an example of a crop on which cooperative research between bee specialists and plant specialists can no doubt make advances of benefit to both. In this crop, the male-sterile plant produces pollen on the anthers inside the anther tube. The anthers release the pollen only after the style has elongated and pushed the stigma beyond reach of the anthers. Bees visit these flowers freely for nectar, bringing pollen from stigmas that have pushed pollen before them and out of the anther tube.