|Bee Fly Behavior
By Hartmut Wisch and Ron Hemberger
World-wide, there are several thousand species of bee flies. In the U.S. most species live in the arid west, generally in sandy places. Here in Orange County, you can see these often fuzzy creatures flying a foot or two above the ground and hovering around plants or above sandy soil.
The life history has been studied for only a small percentage of species. We do know that adults feed on nectar from flowers, much as butterflies do, through their straw-like proboscis.
Males stake out territories (sometimes called leks), where females go strictly for mating. Like little bombers, females lay eggs (oviposit) while in flight, dropping the eggs into the burrows of bees and other host insects. Most female bee flies have a sand chamber lined with hairs. The sand they take into the chamber is deposited along with the eggs.
After hatching, bee fly larvae feed on insects as external or internal parasites. Which type of host depends on which bee fly species. Insects parasitized by bee flies include: