A Fly Went By

Photo from 11-21-07

We've had some pretty chilly weather here in the last week and there's more to come (for the next four months), but the Calendula officinalis is still hanging in there. This syrphid fly or hover fly (Eristalis sp.) is taking advantage of them, too. I see these insects all the time in the garden and I always thought they were bees. They look very much like them, but they're flies.

How to tell the difference?

• Bees have two sets of wings; flies have just one set
• Bees have long antennae; flies' antennae are stubby
• Bees have simple eyes; flies have large compound eyes

These flies are very beneficial to the garden, not only as pollinators, but for their voracious appetite aiding in garden pest control. In their larval form, they consume thrips, mites, and copious amounts of aphids. After about four weeks of eating aphids until the leaf they're on can't support them anymore, they drop to the ground and pupate. About two weeks later, they emerge as adults, where they fly around the garden in search of pollen and nectar-rich plants such as lovage, dill and yarrow. We had all three of these in our garden, and they clearly love the Calendula. In fact, herbs are their favorite source of nourishment.

Our friend in the picture is a female syrphid. We know, because her eyes don't meet in the middle as the male's do.

Another great thing about hover flies - they don't bite or sting!