Sometimes overlooked as pollinators are the syrphid flies, also known as "hover flies" or "flower flies."
Unfortunately, they are often mistaken for honey bees. Hey, if it's a critter on a flower, it's a bee, right?
Syrphid flies are easily distinguished from honey bees. Among the differences: (1) honey bees don't hover, (2) syrphids have only one pair of wings, while honey bees have two (3) syrphids have short, stubby antennae, while honey bees have long, bent antennae called genticulate antennae and (4) syrphids belong to the order Diptera, while honey bees are in the order Hymenoptera.
We spotted this syprhid fly soaking up some early-morning sun It stayed still for a dorsal photo and then sensing danger, slipped under a leaf.
Scientists estimate that there are more than 6200 species of syrphid flies in the world, and more than 3000 in California alone.
The UC Statewide Integrated Pest Management Program (UC IPM) has this to say about syprhids in its Natural Enemies Gallery post: "Adults are robust to slender flies 1/8 to 1 inch (4–25 mm) long, varying by species. The broad head is about the width of the abdomen or wider and has large eyes with distinct antennae. The body of many adults is black with bands or stripes of orange, yellow, or white, resembling stinging bees or wasps. Some species are mostly brown, metallic blue or green, yellow, or combinations of these or other colors. For example, adults of ant-predaceous Microdon species are blackish to brown or bright to dark greenish."
Many syrphids prey on aphids and mealybugs, so they're good guys and gals to have in your garden.
Says UC IPM: "Most species are predaceous, most commonly on aphids or mealybugs. Some syrphids prey on ants, caterpillars, froghoppers, psyllids, scales, other insects, or mites."
The good guys and gals of the garden...
You've probably seen them hovering over flowers, which is why syprhids are commonly called "hover flies" or "flower flies."
Enter Andrew Young.
He's a UC Davis postdoctoral researcher with the Department of California Food and Agriculture (CDFA) and he researches syrphids.
Young, who specializes in Diptera taxonomy and phylogenetics at CDFA, will present a seminar to the UC Davis Department of Entomology and Nematology on "The Natural History of Syrphidae: from Pollinators to Parasitoids" at 4:10 p.m., Wednesday, Feb. 5 in 122 Briggs Hall, off Kleiber Hall Drive.
"Syrphidae (Dlptera) is a species-rich family of true fly, with over 6200 described species worldwide," he says in his abstract. "Often known as flower flies or hover flies, syrphlds are likely the most significant group of pollinators outside of the bees--especially in Arctic climates. While research into their pollination-related behavior is still nascent, other aspects of flower fly biology have been relatively well-studied."
"Adults of many species are well-known for their impressive mimicry of stinging Hymenoptera, and known larvae display a degree of habitat diversity that is unusually broad for a single family of Diptera. Many larvae are predators on soft-bodied insects such as aphids, and therefore, show potential for crop-pest management, while others are aquatic filter-feeders that may have value in waste-management applications." (See UC Integrated Pest Management Program website on syrphids; in their larval stage, they feed on aphids.)
Young says he will give an overview of the current understanding of flower fly phylogeny, followed by an exploration of the varied many adult and larval natural histories known to the group. He will emphasize "many of the little-known larval life histories that are still actively being discovered by dedicated field researchers. I will conclude by briefly discussing some of my past, present and future flower fly research."
Young studied Syrphidae in the lab of Stephen Marshall, professor of entomology at the University of Guelph, Ontario, Canada. Marshall and Young are among the six co-authors of Field Guide to the Flower Flies of Northeastern North America" (Princeton University Press, 2019), a book described as "a groundbreaking guide to flower flies in North America."
From the Princeton University Press website: "Flower flies are, along with bees, our most important pollinators. Found in a varied range of habitats, from backyard gardens to aquatic ecosystems, these flies are often overlooked because many of their species mimic bees or wasps. Despite this, many species are distinctive and even subtly differentiated species can be accurately identified." The guide includes more than 3,000 color photographs and 400 maps, covering all 416 species of flower flies that occur north of Tennessee and east of the Dakotas, including the high Arctic and Greenland. Each species account provides information on size, identification, abundance, and flight time, along with notes on behavior, classification, hybridization, habitats, larvae, and more."
Lynn Kimsey, director of the Bohart Museum of Entomology and professor of entomology at UC Davis, is the seminar host. Community ecologist Rachel Vannette, assistant professor, coordinates the weekly seminars.
Upcoming seminars for the winter quarter (See speaker list) are at 4:10 p.m. on Wednesday in 122 Briggs Hall.
Wednesday, Feb. 12
Kevin Rice, University of Missouri, Columbia
Topic: "Lasers, Drones, and Growth Promoting Fungus: New Technologies for IPM"
Host: Ian Grettenberger, assistant professor
Wednesday, Feb. 19
Mercedes Burns, University of Maryland,>Baltimore County
Topic: (pending) She studies evolutionary ecology of reproductive traits and behaviors, sexual conflict, reproductive polymorphism, arthropod biology
Host: Jason Bond, professor and Schlinger Chair in Insect Systematics
Wednesday, Feb. 26:
Faculty Flash Talks (featuring faculty members Rachel Vannette, Ian Grettenberger, Shahid Siddique, Geoffrey Attardo, Jason Bond)
Wednesday, March 4
Brendon Boudinot, doctoral candidate, Phil Ward lab, exit seminar
Topic: "Morphology and Evolution of the Insects, and the Ancestors of the Ants"
Host: Phil Ward, professor
Remember that line in Gertrude Stein's 1913 poem, Sacred Emily: "A rose is a rose is a rose"?
Well, to paraphrase Stein: "A bee is a bee is a bee...except when it's not a bee."
In a recent interactive feature in the New York Times, writer Joanna Klein wondered how we can save the bees if we don't recognize them. She asked "Can You Pick the Bees Out of This Insect Lineup?" and posted an image of bees and wanna-be bees.
All entomologists, we're sure, passed. Many others--those who think every floral visitor is a honey bee--probably not.
Bee expert Robbin Thorp, distinguished emeritus professor of entomology at the University of California, Davis, passed it with flying colors--colors that included that gorgeous photo of a metallic green sweat bee. "Photo editors for news articles need to take this test judging by all the images of faux bees that accompany a variety of articles on bees, especially articles designed to educate the public about bees," commented Thorp, who, by the way, is the co-author of Bumble Bees of North America: an Identification Guide (Princeton University Press) and California's Bees and Blooms: a Guide for Gardeners and Naturalists (Heyday). "I suspect that this is what Joe Wilson had in mind when he created the plate of bees and faux bees."
Joseph S. Wilson, as you may recall, co-authored The Bees in Your Backyard: A Guide to North America's Bees (Princeton University Press) with Olivia J. Messenger Carrill. Wilson is also featured in a fantastic TED talk on "Save the Bees! Wait, Was That a Bee?"
Lynn Kimsey, director of the Bohart Museum of Entomology and professor of entomology at UC Davis, gets that a lot--"Is this a bee? Is that a bee?" She recently wrote a piece in the Bohart Museum newsletter about flies masquerading 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.
A bee is a bee is a bee...except when it's not a bee. Take the New York Times' quiz.
At the end, you'll be asked the number of bee species in the United States. Get ready...
The bush germander (Teucrium fruticans) is definitely a great fall-winter plant that's a magnet for bees. Just look at the bees that frequent the germander in the Häagen-Dazs Honey Bee Haven on Bee Biology Road at UC Davis.
As soon as the temperature rises to a sunny 50 or 55 (good bee-flying weather), the honey bees head over to the haven from the nearby Harry H. Laidlaw Jr. Honey Bee Research Facility.
Last Saturday's visit to the haven yielded an "out-to-lunch" bunch that included a dozen honey bees in the germander and one syrphid fly (aka flower fly or hover fly). Bumble bee aficionado Gary Zamzow, one of the volunteers in the haven, found something better: A bumble bee, a queen Bombus melanopygus or black-tailed bumble bee, foraging in the germander.
The germander bush is one of several plants blooming in the haven in the dead of winter, according to Missy Borel, haven volunteer and program manager of the California Center for Urban Horticulture at UC Davis. Among the others blooming or just finishing a bloom:
- Autumn sage (Salvia greggii)
- Blanket flower (Gallardia)
- Bulbine (Bulbine frutescens)
- Butterfly rose (Rosa mutabilis)
- Catmint (Nepeta)
- Cleveland sage (Salvia clevelandii)
- Coreopsis (Coreopsis)
- Red hot poker (Kniphofia)
- Dwarf plumbago (Ceratostigma plumbaginoides)
- Oregano (Origanum vulgare ‘Betty Rollins’ )
- Lavender (Lavandula)
- Rosemary (Rosmarinus)
- Sage (salvia)
- Seaside daisies (Erigeron glaucus 'Wayne Roderick')
"Honey bees in California will seek forage on warm sunny days in California," Thorp noted. "Some Asteraceae and mint family flowers will continue blooming and provide some food for honey bees, but they primarily rely on their stored honey to get them through the winter."
Every insect looks prettier when it lands on a tower of jewels (Echiium wildpretti).
When in full bloom, the 9-to-10-foot-high plant, native to the Canary Islands, blazes with firecracker-red flowers. It's a showstopper.
Syrphid flies, aka flower flies or hover flies, battle with honey bees to sip the sweet nectar.
The flower flies flit in and out of the blossoms, barely visible.
However, these insects suffer from an identity crisis. Their wasp-like coloring wards off predators. That same coloring confuses people, too. The average person on the street--or in a flower bed--thinks they're bees.
They're not. They're flies.
UC Davis-trained entomologist Robert Bugg wrote an excellent pamphlet on flower flies that's downloadable free from the UC Division of Agriculture and Natural Resources. Titled Flower Flies (Syrphidae) and Other Biological Control Agents (Publication 8285, May 2008), it will help you identity flower flies.
Not bees. Not wasps. Flies.