HMost flies seem kind of ugly to me, or perhaps it’s just their behavior I dislike — buzzing around my head and occasionally biting. But here is a fly to admire, and in fact to cultivate in your garden.
An easily recognized fly, Archytas apicifer, performs a valuable service by pollinating the flowers of many plant species.
Not exactly beautiful, but striking in its features, with its white face, red eyes, and bristly black butt. Archytas apicifer doesn’t seem to have a common name, but I’ll refer to it as White-faced Fly here. It is a member of the Tachinidae family, a very large group (~10,000 species), all of whom are parasites on other organisms. White-faced fly happens to be one of the larger species, about 1 inch in length, and a very fast and agile flyer. The adults are fond of nectar and may be good pollinators. I found them in great numbers on the Black-eyed Susans and Canada Goldenrod in my backyard.
On the Black-eyed Susans, the fly systematically explored every open disc flower by slowly circling the flower head. Its antennae project downward over a scooped out portion of the “face”, which makes me wonder what this curious anatomy is for.
In contrast, when foraging on the Canada Goldenrod, the fly moved randomly, rarely spending more than a few seconds on any one frond. Several species of bees were much more systematic in their search. The difference could have something to do with proboscis or tongue length perhaps.
The larvae also perform a vital ecological service, as they parasitize some of the more noxious pest caterpillars — tent caterpillars, fall webworm, tomato fruitworm, corn earworm, and cutworms. Adults lay their eggs on the underside of the host; when they hatch, the larvae burrow into the host and begin consuming it. One less pest to worry about.
This shot provides a better idea of the fly’s size relative to the central disc of a Black-eyed Susan flower.
Its features don’t inspire immediate affection, but the White-faced Fly is a beneficial insect nevertheless.