Driveway Hoverfly

hover fly

Here’s a “driveway moment,” but not the National Public Radio kind:*

After hovering around our faces for a comically long time, this little hoverfly decided the most attractive thing in the driveway was the eraser of a new Ticonderoga pencil. It hugged the pink tip while we examined it (such big eyes you have!), while we took photos, while we passed it between us, and even after we had to set the pencil on a rock because our hands had gotten tired.

We assumed it was a hoverfly because it hovered, and we were right. After staring at entries at BugGuide, my guess is Allograpta obliqua. And a male, because those big, red eyes are so close together. But the important thing is that it is hoverfly.

Syrphid fly is the proper name. BugGuide says there are 813 different species of syrphid flies in our area. I am happy I’ve met at least one.

Another common name for these creatures is flower fly, which is a better clue to how they function in driveways and gardens. They are famous pollinators. Our black-eyed Susans are full of them.

But before flies are flies, they are maggots. You could say larvae and be correct, but to say maggot is more fun, don’t you think?

Izzy and I raised a maggot a few weeks ago. We had been looking for caterpillars on hackberry leaves when we found a tiny, green blob. No eyes, no mouth, no legs. It undulated where it wished to go. And to decide where it wished to go, it stretched itself and tap, tap, tapped all around. This was how we figured out which end was front and which was rear. When not stretched, the body was only about 3mm long.

It was a hoverfly maggot.

We kept watching, and in a moment we saw why gardeners consider hoverfly larvae to be “beneficial insects.”  We also saw why aphids might consider hoverfly larvae to be terrifying, insatiable monsters.

I should mention the underside of the hackberry leaf was covered in white, woolly aphids. (Every hackberry leaf this year is covered in white, woolly aphids.) Well, the green blob felt its way toward the nearest aphid, plunged some kind of unseen mouth part into it, and sucked the poor creature dry. From the moment of contact, the aphid jerked and writhed, and its little legs waved like mad. And at the same moment, all the other aphids panicked. Some dithered in circles. Some danced in place. Some began to flee. It was as if the victim aphid was screaming a warning.

Later, I read that what we saw was indeed aphid communication, but not by scream: by pheromone.

We kept baby Fly Guy in a cage on my butterfly rearing table, and we gave it fresh, loaded hackberry leaves every day. We felt sorry for the aphids as individuals, but not sorry to see our wooly aphid community diminished by a few dozen. They make a terrible mess under the hackberry trees. Aphid honeydew rains down to coat everything below, and then black, sooty mold moves in. The honeydew / mold combo is one of the main reasons hackberry trees have such a bad reputation. And it isn’t even the trees’ fault: the aphids were accidentally imported from China.

During this adventure, I dreamed one night—all night—that our captive maggot had escaped its little plastic snap-lid container. It oozed its tiny, translucent, slug-like self through the minute gap offered by a box designed to keep jewelry, not insects, and it groped and nodded along the table to smell or feel or bumble its way to every one of my caterpillars and to suck each dry in turn.

In real life, baby Fly Guy did disappear from the cage, but was just hidden as a pupa. A few days later, an adorable, big-eyed hoverfly had taken its place. I released it, and can only hope it is among my Black-eyed Susans now, sucking nectar (not aphids).

Fresh Hoverfly.jpg
new hoverfly

I wish I could show you photos of our larva, but I can’t find them. If you’d like to see what one looks like, try this page at the University of Florida’s Entomology department, and scroll to just below the eggs.



*”A ‘driveway moment’ is when you’re so captivated by a story on NPR that you stay in your car to hear it to the end—even if you’re sitting in your own driveway.” (Definition from the NPR Shop.)