Yellow Blue-bead Lily and Dagger Flies

I did a quick non-scientific survey, for interest sake, of the Yellow Blue-bead Lilies, Clintonia borealis, in several areas next to Hix Small Road, leading to the Hix Small Cemetery.

I read that Clintonia generally spread by underground rhizomes, so I figured that there wouldn't be many individuals that would be flowering.

I surveyed 4 groups of plants with the number of flower stalks with flowers present: 1/58, 2/47, 2/23, 1/22. Out of 150 plants, only 6 were flowering. But, it leaves me to question what biological factors stimulate a few plants to flower when the rhizome method of reproduction is so successful. BY THE WAY, I also looked at groupings of Yellow Blue-bead Lilies in the Center Point Preserve and found many more in bloom. In fact, in one area I saw 7 out of 24 plants that were blooming.

On another note, I saw several Yellow Blue-bead Lilies that had Dagger Flies, Empidid flies (Empididae) crawling all around them. I couldn't find any information about pollinators as these plants, like the Lady's Slippers, are very successful at asexual reproduction with rhizomes.

Thanks to Edwin Barkdoll for the ID. He also told me that these flies are generally carnivorous, but that he mostly sees them supping on nectar and pollen.