The uncommonly common drone fly: A shrewd drone lookalike

I’m convinced that the common drone fly, Eristalis tenax, is the most photographed “bee” in the world. You need not search long to find hundreds of drone flies labeled as honey bees in books, magazines, websites, and advertisements.

One of the most famous drone fly portraits, with its stubby little antennae in full view, appeared on the glossy cover of the 2004 book, “Bees of the World” published by Facts on File. Needless to say, the author was mortified.

All the misidentification tells you that drone flies are very good at what they do, namely impersonating honey bee drones. From a distance, their size, coloring, eye shape, and even their sound can confuse those who are unsure. However, why the common drone fly elected to impersonate a bee that doesn’t sting and never visits flowers is confusing and something I cannot explain.

The flower fly family

Drone flies belong to the Syrphidae family, known as hover flies or, more accurately, flower flies because the ability to hover varies with species. Some can remain stationary in mid-air for minutes, while others are less adept. Flies, in general, are responsible for about one-third of all pollination services but, among the flies, the Syrphidae do most of the pollinating, visiting a wide selection of blooms in a variety of habitats.

Although adult flower flies do the pollinating, the larvae of many species—including the drone flies—have another important environmental role. Unlike the bees they mimic, these flies prefer damp or aqueous environments, even dung piles, for laying eggs. The resulting larvae, called rat-tailed maggots, thrive on moist, decaying organic material, resulting in surprising amounts of fecal recycling.

The very common drone fly

Drone flies belong to the most diverse of the four subfamilies of flower flies, the Eristalinae. Introduced into North America from Europe, the common drone fly, Eristalis tenax, easily spread throughout the continent. They are not skittish compared with many insects and will readily pose for photographs, which probably accounts for the plethora of portraits we see in print.

Although drone flies are active from March through November, they are most often seen in the spring and fall when flowers are plentiful. Many flower flies, including the common drone fly, practice hill-topping, a reliable method of finding a mate. Since scattered individuals have little hope of finding each other, they need a preordained meeting place, much like a honey bee drone congregation area. Individuals gather at the top of the highest hill in their local area to meet and greet. It doesn’t have to be especially high, just the highest. There they mingle in the early morning, usually dispersing by noon.

How to hunt for drone flies

If you want to find drone flies, those hills are an excellent starting point. Although drone flies are most active from early morning to mid-afternoon, they are strictly sun-lovers, disappearing when the sun slides behind a cloud. You can often find them resting on leaves or sitting on petals, sunning themselves between bouts of activity.

The drone fly’s abdomen is variable in appearance, but the dark brown and orange stripes clearly mimic the honey bee. Unlike bees, flies have only one set of wings, no wasp waist, and their antennae are short and closely spaced at the base. Female flies have some space between their compound eyes, while males have eyes that nearly touch just above the antennae. “Hand washing” behavior is a fly trait that can also help you distinguish them from bees, and their ability to hover is first-rate.

Rusty Burlew
Honey Bee Suite