Drone flies appear to be the only active pollinators of yacon here. The yacon flowers are rarely without a visiting drone fly for long. That made me wonder why we don’t see seeds without hand pollination. I spent quite a bit of time watching the flies at work yesterday and almost never saw one contact the ray florets. They tend to land in the middle of the disk and carefully turn in a circle, visiting each disk floret. They rarely even accidentally bump into a ray floret. In combination with the small amount of loose pollen given by yacon flowers, this probably explains the lack of seeds. I wonder if there is a pollinator in the Andes with a longer body to ensure more frequent contact with the ray florets.