With the bounty of flowers blooming this time of year, you’re likely to spot one of the most helpful little critters in the garden, though you may not recognize it as such. What appears to be a small bee hovering like a tiny helicopter over a blossom but looks and may even sound like a buzzing bee, is most likely a syrphid fly. Commonly known as flower flies or hover flies, these are really good guys for the garden.
The brightly colored adults range in size from a quarter to three-quarter inches long, most adorned with black or brown coloring, yellow banded abdomens and body markings. They may look like a honeybee or bumblebee, a wasp or even a yellow jacket; it’s thought that this bee or wasp-like appearance mimics bee species to ward off their main predators, birds. While the resemblance to bees may be striking, if you look closely, you can tell the difference. The syrphid fly has a single pair of wings, while bees are equipped with two pair. Flies have big compound eyes while bees have simple eyes. Bees have long antennae; those of the syrphid fly are stubby. And these flies don’t bite or sting!
Adults feast on pollen and nectar; some flowers that are especially attractive to them include wild carrot and mustard, coriander, dill, fennel, sweet alyssum, and yarrow. Their movement from flower to flower makes them an important pollinator. They are usually most visible in the later half of the growing season, after aphid infestations have been well established. They don’t seem to get credit for helping to reduce the aphid population that their larger, more readily recognized fellow predator, the ladybug does, but they ought to.
It’s the little guys, the fly larvae, that are the predators, going after aphids, small caterpillars, thrips, and other small insects. One syrphid fly larva can consume as many as 400 aphids in their very short lifetime. They vary in color and patterning, but most have a yellow longitudinal stripe down their back. You can distinguish them from caterpillar larvae by their tapered head, lack of legs, and opaque skin.
With their big appetites for destructive bugs, their active pollination activities, and their delightful appearance, do welcome these little good guys to your own garden.