The "Fly-whal"

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Photo: John Howard

Perhaps you've seen what appear to be tiny, excessively fuzzy hummingbirds tapping flower nectar this spring. These hummer wannabes hover in front of dandelions, spring-beautys and other flowers, extracting the goods via a disproportionately long proboscis. These are the bee flies, in the genus Bombylius. I believe John Howard's fine photo above, and mine that follow, depict Bombylius major, a common species in these parts. Don't stick a fork in me if I'm wrong, though - it's a huge family, and I'm no Bombyliidophile.

Photo: Wiki Commons

This is the nearly mythical whale of northern seas known as the Narwhal. One of its teeth is modified into a greatly elongated tusk, making it a unicorn of the sea. Skip back to the first photo, then revisit this Narwhal photo. The bee fly might be called a "fly-whal", and indeed it has been.

Photo: Wiki Commons

The Narwhals (females rarely have tusks) apparently have these protuberances as an outward sexual characteristic. The bigger the tusk, the bigger the stud, and the higher its status in Narwhalian social hierarchy.

The bee fly, on the other hand, uses its "tusk" to suck nectar from flowers.

On a recent excursion, I attempted to make nice photos of bee flies in action, but was thwarted by unusually uncooperative bee flies. I did manage this image, which shows one of the flies hovering before a gill-over-the-ground, Glechoma hederacea, and slurping up its sugary wares. That's what their tusk is for.

After much effort, I caught this bee fly in mid-hover last year. Territorial bee flies often hover for extended periods in sunny spots, chasing off other bee flies and other small winged critters. Most people who see one of these insects would consider them rather attractive, if not downright cute.

Bee flies, at least the aforementioned Bombylius major, are often found in the proximity of solitary bees.The animal above is a solitary bee in the genus Andrena, and they swarm about dry sandy areas in spring. Solitary bees dig tunnel-like burrows in the soil, which they provision with masses of pollen. Once an adequate stash has been stocked, the bee lays an egg or eggs in the burrow, and seals it off. When the bee larva emerges from the egg, it is as if it has been born into a giant ball of cotton candy. The grub eats its way through the pollen, and grows to maturity fueled by by tasty plant dust. This is about as Disneyesque as it gets in nature. Cute little bees that don't sting, digging charming little earthen bungalows, and feeding their offspring pollen.

A solitary bee digging a burrow. This bee had best hope a bee fly doesn't come along to shatter its dreams, and hopes of leaving a legacy. You see, the fuzzy little bee flies are parasitoids of solitary bees.

A female bee fly on the hunt lurks around the proximity of nesting solitary bees, awaiting the perfect moment. As the bee finishes its work in the burrow, and backs out to prepare to seal the entrance, the bee fly springs to action. She moves near, and flicks her eggs down into the chamber. If successful, the bee fly eggs get sealed in as well. You can guess the rest. The bee fly egg spawns a grub which eventually eats the host solitary bee's grub. And, apparently, the pollen, too.

Bee fly = 1. Solitary bee = 0.

Bee flies

If you've spent much time afield, investigating spring wildflowers, you've doubtless noticed the strange beast shown here. These odd insects suggest animals far removed from their lineage, such as little hummingbird moths, or bees. Neither, nor.

This is a bee fly. Yes, a fly. I photographed the one above a few years back, as it drew nectar from the staminate (male) flowers of Pussy-toes, Antennaria plantaginifolia. Bee flies are rather hard to photograph when on the roll, as they are awesome fliers and quick to dart and dash about.

On my recent trip into the depths of the I'on Swamp in South Carolina, I happened along a sandy, sunny woodland gap that had several bee flies on the wing. So, I devoted some ten minutes of my life trying to get decently clear images of the insects in flight. A few of them came out; most were deposited in the recycle bin.

This species, I believe, is the same as in the prior photo and it is the big boy of the crowd: the aptly named Large Bee Fly, Bombylius major. Keep in mind, "large" is a relative term. These things look like a miniature jelly bean covered with fur, and I suppose an aeronautics engineer would take a glance at one and proclaim that it should not be able to rise aloft.

But fly they do - these things are the Blue Angels of the fly world. This particular bee fly was diligently guarding a patch of turf, and whenever another bee fly would foolishly impinge on its territory, this fly would dart after it with an impressive burst of speed, astonishingly fast jags and jigs, and a clearly audible chainsaw buzzing of the wings. Note its long proboscis, the better to suck nectar from plants.

This is some sort of solitary bee, or digger bee, in the act of creating her burrow. Into said burrow she will deposit a sweet ball of plant pollen, and lay an egg along with the pollen. Then the chamber is sealed. Life for the digger bee grub seems unusually Disneyesque for an insect. The bee larvae hatches to what amounts to a giant sugar ball; it is as if the grub is born into cotton candy and must eat its way out. What could possibly go wrong?

Enter the "cute" Bombylius major, that adorable little fuzzy hummingbirdlike fly. Like the digger bees, this fly too collects much pollen and as with the bees, is undoubtedly an important pollinator. But the Large Bee Fly is a digger bee's worst nightmare.

When the time for reproduction rolls around, the female bee fly sneaks over to a digger bee's burrow before it's sealed, and hurls her eggs at the entrance. I'm not sure exactly how she "hurls" them, but whatever the means of locomotion, if her aim is good the eggs either tumble into the burrow or land near its entrance.

Upon hatching, the predatory fly larva - which probably lacks any sort of the cuteness of the adults - begin feeding on the pollen provisioned by the hard-working digger bee. When that's exhausted if not before, the fly larva digs into the digger bee grub and feasts on that. Life in the bee burrow becomes quite the horror show, thanks to the bizarre reproductive strategy of one of our most charming flies - indeed, a fly that anyone would like! - the Large Bee Fly.