Just got back to our farm today in upstate NY, and noticed a LOT of these gangly, slow black flies on many of the fruit trees. Research says it’s the St. Mark’s Fly (because they appear around the feast of St. Mark), but no info on whether they do any damage after pollination has taken place. Any thoughts?
St. Mark’s Fly as a common name can refer to many species in the Bibionidae (March flies) family. I think your ID is correct.
Adults may be significant pollinators.
The link below has good info in the Food and the Life Cycle paragraphs.
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