While I’ve been walking outside our little town in Italy, missing my vegetable garden, I have paid attention to the local plants. On good days, I see a lot of flowers and pollinator-insects. At first, I thought the pollinators were all bees. Then, I looked closer. Many of them are actually flower flies, a different group of beneficial garden insects.
What are flower flies?
Flower flies really are flies, but a lot of them look like bees. It is possible that looking like a bee prevents some predators from eating them. I don’t know if that mimicry really works, though. We used to have a dog that ate carpenter bees when she could catch them. The stinging inside her mouth didn’t seem to stop her from catching and eating more.
Flower flies do not sting or bite, but they do eat nectar and/or pollen as adults. As they visit flowers to gather food, they pollinate the flowers. Flower fly babies (larvae) eat aphids and other small insects. These are definitely beneficial garden insects!
Organic gardens, in particular, rely on pollinators and predators in the garden to increase harvests and reduce pest problems. We can wait for our helpful predators (like flower flies, wasps and ladybugs) to eat the aphids, no spraying required!
Flower flies are also known as syrphid flies and as hover flies.
How can I tell which is a flower fly and which is a bee?
With only a brief glance, it is not easy to tell bees and flower flies apart. If you have the fortitude (and lack of bee-allergies) that allows you to look a little longer, you might see the difference.
Check the antennae
Flower flies have short, straight, stubby antennae. The antennae may be so short that they are hard to see. Bees have longer antennae, and their antennae are more likely to bend.
Check the wings
All flies have only two wings (one pair), and you can easily see them. One wing is on each side of the body.
Bees have fours wings (two pairs). The larger front pair of wings is easy to see, but the hind-wings can be hidden below the front pair. You might not be able to see that there are four wings.
Check the eyes
Eyes of flower flies are larger, and more on the front of their heads. Bee eyes are shifted a little to the sides of their heads.
Check the back legs
Flies do not collect pollen in clumps on their back legs. Some kinds of bees, especially our native, solitary bees, also do not collect and carry pollen on their back legs.
However, bumble bees and honeybees often store clumps of pollen on their back legs, to carry back to their colonies. If you see a bee-like insect that has pads of orange, or red, or yellow on its back legs, that is a good sign that the insect is some kind of bumble bee or a honeybee.
How can I attract flower flies to my garden?
University of California has published an easy-to-use table of plants that attract flower flies (see page 16). The table is deep within a document that is not super-easy to read, and not all the plants will grow well in the Southeastern US, but many will.
Here is a short list of plants that are known to attract and/or support flower flies to your organic garden, that I know will grow in the Southeastern US:
buckwheat, coriander/cilantro, thyme, Italian oregano, sweet alyssum, fennel, tansy, white-flowered yarrow