- Author: Kathy Keatley Garvey
It's Friday Fly Day, and time to post an image of a fly that masquerades as a bee.
That would be "the bee fly," a fly so named because it resembles a bee
Order: Diptera. Family: Bombyliidae.
In its adult stage, it's a pollinator that feeds on nectar and pollen. In its larval stage, it's parasitoid. The adult bee fly lays her eggs in the nests of wasps, beetles or solitary bees and the developing larvae eat their host.
"The Bombyliidae include at least 4,500 described species, and certainly thousands more remain to be described," Wikipedia tells us. "However, most species do not often appear in abundance, and compared to other major groups of pollinators they are much less likely to visit flowering plants in urban parks or suburban gardens. As a result, this is arguably one of the most poorly known families of insects relative to its species richness. The family has a patchy fossil record, with species being known from a handful of localities the oldest known species are known from the Middle Cretaceous Burmese amber, around 99 million years old."
Bee flies have also acquired the nickname of "bomber flies." That because when the adult female is ready to "gift" a host with her eggs, she hovers over the burrow in mid-air and flicks her eggs.
Aren't insects amazing?
- Author: Kathy Keatley Garvey
The late Argentine-born biologist Beatriz Moisset (1934-2022) of Willow Grove, Pa., called the insect "A Pollinator with a Bad Reputation."
Moisset, who received her doctorate from the University of Cordoba, Argentina, and authored the book, Bee Basics, an Introduction to Our Native Bees, was referring to bee flies, from the family Bombyliidae. In their larval stage, these flies parasitize the eggs and larvae of ground-nesting bees, beetles, and wasps.
They superficially resemble bees. If you look closely, however, they have one-pair of wings (bees have two pairs), and their antennae are short and stubby, unlike that of bees.
They neither bite nor sting. Bombyliidae includes some 4500 described species, found throughout North America, Europe and Asia, with many more undescribed.
If you see these long-legged, fuzzy-looking insects, they're usually foraging on flowers or hovering above the ground.
"The reason why it diligently hovers over bare ground early in the spring is that it is looking for bee nests," Moisset wrote in a piece published on the U.S. Forest Service website. "The bees dig tunnels and lay their eggs at their bottoms after collecting enough pollen to feed the larvae. This requires numerous trips, thus the bee fly takes advantage of the mother's absence and lays its eggs in such nests. Making use of its flying prowess, it does not even need to land but it flicks its abdomen while hovering over the open burrow, letting one egg fall in or near it."
"The fly larva finds its way to the chamber where the mother bee has laid the provisions and the egg and proceeds to feed on the stored pollen," Moisset explained. "Afterwards it devours the bee larvae; when it is fully grown, it pupates and stays inside the nest until next spring."
We spotted a bee fly in a Vacaville pollinator on Sept. 19. It zoomed over a yellow zinnia, hovered, and then dropped down to sip some nectar. Meanwhile, looking like a cross between a bee and a fly, it skirted syrphid flies and honey bees also intent on getting their share of nectar.
The bee fly is aptly named.
- Author: Kathy Keatley Garvey
Will all the pollinators please stand up!
Or do a fly-by like the Blue Angels or a crawl-by like babies competing in a diaper derby.
Bees--there are more than 4000 of them in North America--are the main pollinators, but don't overlook butterflies, beetles, birds, bats and moths.
And flies.
Flies?
Yes, flies.
Here's proof positive that flies can pollinate. If you look closely at this little bee fly on a Mexican sunflower (Tithonia), you'll see that it has just grabbed some pollen. It's a member of the genus, Villa, and family, Bombyliidae, according to fly expert Martin Hauser of the California Department of Food and Agriculture.
Many folks mistake flies for bees. Look through any stock photo catalog or macro insect images on Flickr or a Facebook page and you'll often see hover flies, bee flies and other flies identified as bees.
Three of the easiest ways to differentiate a fly from a bee:
- A fly has one set of wings. A bee has two sets.
- A fly has short, stubby antennae. A honey bee doesn't.
- A fly has no corbicula or pollen basket. A honey bee (worker bee) does.
Welcome to the Pollination Nation!
For more information on bee flies, see BugGuide.net. For syrphids, aka flower flies or hover flies, read the UC Statewide Integrated Pest Management's information on managing pests or read entomologist Robert Bugg's free downloadable PDF on the UC ANR website, Flower Flies (Syrphidae) and Other Biological Control Agents for Aphids (Publication No. 8285).
- Author: Kathy Keatley Garvey
There are "bees" and there are "flies."
And then there are "bee flies."
Bee flies? They're so named because they look somewhat like bees. Order: Diptera. Family: Bombyliidae.
We spotted a single bee fly, as identified by UC Davis forensic entomologist Bob Kimsey, foraging on our sedum yesterday. Like a bee, it's a pollinator; the adult bee fly feeds on nectar and pollen. Entomologists estimate there are some 4500 described species of bee flies throughout the world, varying in size from 4 to 40mm.
In the larval stages, they are parasitoids; the adult bee fly lays her eggs in the nests of wasps, beetles or solitary bees. Then the larvae ungraciously thank their hosts by eating them.
This large bee fly (below) apparently found the nectar to its liking. It lumbered from flower to flower sipping nectar.
The honey bees, hover flies and leafcutter bees all scrambled to avoid a collision.