A bee-fly (Bombylius major)! Known as the dark-edged or large bee-fly, this fuzzy fly mimics bumble bees (kind of) in appearance. But no sting and only two functional wings - though they are capable of some tricky flying. These flies can yaw, or rotate their bodies around a single point while in the air. I suppose that the dark pattern on the leading edge of the wings is source of the common name, dark-edged bee fly. The photo was taken on a warmish day just last week in Seattle.
As you can see from the image, the dark-edged bee fly has a long proboscis, as long as its body, enabling it to reach deep down when needed in flowers that have a long tubular structure (corolla) leading to their nectar. And, better yet, they can use their proboscis vertically while above flowers that open upwards and horizontally for flowers that open on the sides of a plant. The long proboscis also features a stronger pumping mechanism than that of other related flies. This bee-fly is a pollinator generalist - able to extract nectar and pollen from a variety of different kinds of flowers.
Bee-flies also have a peculiar life cycle in which the young stages (larvae) are parasitic on bee nests. Not honey bees, but mainly ground nesting bees. Female bee-flies drop their eggs near the entrance to a bee’s nest and the larvae emerge to feed on bee larvae and food stores in the nest. So I’m not sure whether bee-flies are a net positive or negative in the overall number of pollinators. Do they contribute more to pollination than the bees they parasitize or does the loss of the bees to parasitism result in fewer pollinators. Also, the bees they parasitize tend to be more specialist pollinators, that focus on a single species or genus of plants. Is the loss of specialist pollinators more of a negative than the increase in the generalist bee-fly pollinator?
I imagine there’s room for both, and it was a pleasure to see this unique pollinator working the flowers in my yard last week.