An observational study found that out of more than 2,400 pollinator visits to flowers at urban and rural farms in in Western Washington about 35% of were made by flies — most of which were the black-and-yellow-striped syrphid flies. For a few plants, including peas, kale and lilies, flies were the only pollinators observed. Bees still made the majority, about 61%, of floral visits, but the rest were made by other insects and spiders.