If you've noticed what looks like a hairless bee hovering in midair over the flowers in your garden, you were probably spotting a hover, or syrphid, fly. These insects resemble bees, though they are flies. They are helpful to garden plants.
You can distinguish between hover flies and true bees by counting the wings. The former have two wings while bees have four. Hover flies also hold true to their name with their ability to hover in midair. Bees cannot hover. Hover flies often have a flat abdomen while bees have round abdomens.
Hover flies are good pollinators. They feed on nectar and while doing so they collect pollen and transfer it from flower to flower. Some hover fly larvae prey on aphids and other garden pests. Female hover flies will lay their eggs within an aphid colony, ensuring their young are well fed (and your aphid problems are controlled).
Hover flies' bee-like appearance tricks potential predators into thinking they can sting and leaving them alone. In truth they can't sting, and there's no reason to fear them. Welcome hover flies to your garden by planting nectar-rich flowers. Be sure to include kinds that will bloom in different seasons, as well as long-blooming annuals, to provide a consistent food source. Avoid using insecticides.
Image: "Syrphid Fly on a Grape Hyacinth" by KirinX at en.wikipedia - Own work. Licensed under Creative Commons Attribution-Share Alike 2.5 via Wikimedia Commons.
Learn all about helpful garden insects, what they can do for your garden and how to welcome them in Jessica Walliser's Attracting Beneficial Bugs to Your Garden.
Choose and care for the best blooming plants for your garden with The Flower Gardener's Bible.