UC Master Gardener Program
UC Master Gardener Program
UC Master Gardener Program
University of California
UC Master Gardener Program

Posts Tagged: Robbin Thorp

A Fly Is a Fly Is a Fly

Honey bee nectaring on Spanish lavender. (Photo by Kathy Keatley Garvey)
A bee is a bee is a bee is a bee.

'Cept when it's a fly.

Lately we've been seeing lots of images on social media (including Facebook and Twitter), news media websites, and stock photo sites of "honey bees." 

But they're actually flies. 

Will the real flies come forth?

Today we saw several drone flies, Eristalis tenax, sipping nectar from our Mexican sunflower (Tithonia). Native pollinator specialist Robbin Thorp, emeritus professor of entomology at the University of California, Davis, jokingly calls this drone fly "the H bee." Why? There's an "H" pattern on its abdomen.

The drone fly and honey bee are similar in size and both are floral visitors in their adult stages. However, the drone fly is quite distinguishable from a honey bee. The fly has large eyes, stubby antennae and one pair of wings.

The larvae of the drone fly is a rat-tailed maggot that lives in drainage ditches, pooled manure piles and other polluted water.

Unlike a honey bee, the drone fly "hovers" over a flower before landing. The  fly belongs to the family Syrphidae (which includes insects commonly known as flower flies, hover flies and syrphids) and the order, Diptera. The honey bee is Apis mellifera, family Apidae, order Hymenoptera.

The case of mistaken identity can cause excruciating pain.  A journalist will spend half a day interviewing bee experts about bee health--investigating colony collapse disorder, malnutrition and Varroa mites--only to have a copy editor illustrate the prized bee story with a fly.  It's more horrific than Halloween.

Likewise, Facebook editors have been known to turn a fly into a bee faster than the beat of a wing. And photographers who know more about "F" stops than "H bees" post misindentified photos on Flickr or sell their mislabeled images to stock photo businesses.

The old saying, "If it looks like a duck, quacks like a duck and walks like a duck, it's probably a duck" doesn't ring true in "the drone bee vs. the honey bee" identity crisis.

If it looks like a bee, acts like a bee and buzzes like a bee, it may be...a drone fly.

Drone fly, Eristalis tenax, sipping nectar from a Mexican sunflower, Tithonia. (Photo by Kathy Keatley Garvey)
Drone fly, Eristalis tenax, sipping nectar from a Mexican sunflower, Tithonia. (Photo by Kathy Keatley Garvey)

Drone fly, Eristalis tenax, sipping nectar from a Mexican sunflower, Tithonia. (Photo by Kathy Keatley Garvey)

The
The "H" is easily seen on the drone fly. (Photo by Kathy Keatley Garvey)

The "H" is easily seen on the drone fly. (Photo by Kathy Keatley Garvey)

Drone fly heads for another blossom. (Photo by Kathy Keatley Garvey)
Drone fly heads for another blossom. (Photo by Kathy Keatley Garvey)

Drone fly heads for another blossom. (Photo by Kathy Keatley Garvey)

Posted on Monday, October 20, 2014 at 9:03 PM

A, B, and C: What They Really Stand for...

Give me an "A" (for excellence).

Give me a "B" (for bee).

Give me a "C" (for Cosmos).

Watching honey bees collect nectar and pollen on the showy Cosmos (Cosmos bipannatus) is not to be missed.

As if performing a ballet, the enchanting bees enter stage left and are such show-stoppers that you want to erupt with applause at every precise move. Bravo!

Cosmos is a spectacular annual with saucer-shaped floral heads, ranging in color from white and pink to lavender and crimson. It's a relatively late bloomer. In our family bee garden, they began blooming in late summer and are continuing into fall.

In their newly published book, California Bees and Blooms: A Guide for Gardeners and Naturalists, entomologists Gordon Frankie of UC Berkeley and Robbin Thorp of UC Davis teamed with photographer Rollin Coville (UC Berkeley-trained entomologist) and botanist Barbara Ertter (UC Berkeley) to offer interesting information on bee species and advice for growing and managing bee friendly plants. It's a "must-have" for every gardener and naturalist or would-be gardeners and naturalists. Did you know there are more than 1600 different species of bees in California alone, and some 4000 throughout the country?

One section goes into depth about plants, including Cosmos. You'll learn its description, origin and natural habitat, range and use in urban California, flowering season, resource for bees (nectar and pollen), most frequent bee visitors, and bee ecology and behavior. It's not surprising that the book, by Heyday, is published in collaboration with the California Native Plant Society.

And what are the most frequent bee visitors? "A wide variety of bee species, especially Melissodes robustior, Melissodes species, and Halictus ligatus. In the Central Valley, it attracts honey bees, Agapostemon texanus, Anthophora urbana, Xeromelecta californica, and Svastra obiqua expurgata."

The authors describe all those species--and more. Some we know generally as longhorned bees, sweat bees, metallic green sweat bees, digger bees, and sunflower bees.

Blooms. Bees. Beautiful.

Honey bee heading for a Cosmos. (Photo by Kathy Keatley Garvey)
Honey bee heading for a Cosmos. (Photo by Kathy Keatley Garvey)

Honey bee heading for a Cosmos. (Photo by Kathy Keatley Garvey)

All the right moves. (Photo by Kathy Keatley Garvey)
All the right moves. (Photo by Kathy Keatley Garvey)

All the right moves. (Photo by Kathy Keatley Garvey)

The grand entrance. (Photo by Kathy Keatley Garvey)
The grand entrance. (Photo by Kathy Keatley Garvey)

The grand entrance. (Photo by Kathy Keatley Garvey)

The reward: nectar and pollen. (Photo by Kathy Keatley Garvey)
The reward: nectar and pollen. (Photo by Kathy Keatley Garvey)

The reward: nectar and pollen. (Photo by Kathy Keatley Garvey)

Posted on Wednesday, October 1, 2014 at 5:34 PM

Hide the Cactus!

Hide the cactus! There's a Mexican cactus fly in our midst.

A large black fly hovers over a Mexican sunflower (Tithonia) in our bee garden and then drops down to sip some nectar. At first glance it looks like a carpenter bee but this one hovers like a syrphid fly, aka flower fly or hover fly.

"Hover fly," I say.

Entomologists Martin Hauser, Lynn Kimsey and Robbin Thorp quickly identified the critter.

Hauser, senior insect biosystematist with the Plant Pest Diagnostics Branch of the California Department of Food and Agriculture, says it's in the genus Copestylum (with over 350 species in the new world) and figured it to be the species,  mexicanum, commonly known as the Mexican cactus fly.

Said Lynn Kimsey, director of the Bohart Museum of Entomology and professor of entomology at UC Davis: "Nice, this is actually a kind of syrphid flower fly, better known as a cactus fly. The larvae breed in rotting cactus tissue."

Native pollinator specialist Robbin Thorp, emeritus professor of entomology, also figured it to be a Mexican cactus fly, Copestylum mexicanum.  "It's commonly known as a cactus fly (Syrphidae, Tribe Volucellini).  "It used to be in the genus Volucella, But now it's in the genus Copestylum."

This fly is not small. It's about 3/4 of an inch long. It lays its eggs in rotting plant material "and they really like rotting cacti," Hauser commented. "As far as I know, they only go into dying cacti and do not attack healthy cacti…. But there is actually not much known about their biology."

The resident cacti expert at our house is worried, showing his best prickly pear expression. He quickly canvasses the yard. Whew! No rotting cacti. All thriving and in good health.

So far, so good...

Black hover fly, aka Mexican cactus fly, sipping nectar from a Mexican sunflower (Tithonia). (Photo by Kathy Keatley Garvey)
Black hover fly, aka Mexican cactus fly, sipping nectar from a Mexican sunflower (Tithonia). (Photo by Kathy Keatley Garvey)

Black hover fly, aka Mexican cactus fly, sipping nectar from a Mexican sunflower (Tithonia). (Photo by Kathy Keatley Garvey)

Side view of the black syrphid fly, a Mexican cactus flower. (Photo by Kathy Keatley Garvey)
Side view of the black syrphid fly, a Mexican cactus flower. (Photo by Kathy Keatley Garvey)

Side view of the black syrphid fly, a Mexican cactus flower. (Photo by Kathy Keatley Garvey

Mexican cactus fly ready to take off. (Photo by Kathy Keatley Garvey)
Mexican cactus fly ready to take off. (Photo by Kathy Keatley Garvey)

Mexican cactus fly ready to take off. (Photo by Kathy Keatley Garvey)

Posted on Tuesday, September 30, 2014 at 5:29 PM

Quit Mimicking Me!

Last weekend a little critter made its first-ever appearance in our family bee garden. It was neither a grand entrance nor a grand insect.   

"A fly!" I thought, as I looked at its knoblike bristle or arista on the end of each antenna.

But its body--what little I could see of it before it winged out of there--definitely resembled a wasp. A Western yellowjacket (Vespula pensylvanica) or European paper wasp (Polistes dominula).

Native pollinator specialist Robbin Thorp, emeritus professor of entomology at the UC Davis Department of Entomology and Nematology, identified it as a syrphid fly, genus Ceriana, family Syrphidae. 

Talented Davis photographer Allan Jones captured an excellent photo of Ceriana in 2012. A full body shot: head, thorax and abdomen! His excellent image (second one, below) shows the distinguishing characteristics: two wings (fly), not four wings  (bees, wasps), as well as the arista (fly) and the spongelike mouthparts (fly).

BugGuide.Net posted some excellent images of Ceriana on its site. Class: Insecta. Order, Diptera. Family: Syrphidae: Genus: Ceriana.

Ceriana is a genus of wasp mimics. Basically, it's a syrphid fly, a pollinator. It's also known as a hover fly or flower fly as it hovers, helicopterlike, over flowers before drops down to forage.

Would-be predators, no doubt, avoid Ceriana because of its coloration. "Oops, don't mess with that! That's a wasp!"

Picnickers who don't know a faux wasp from a real one would probably run from it, or swat at it.

"It's definitely a good mimic and probably gets a lot of protection from that coloration," said Lynn Kimsey, director of the Bohart Museum of Entomology and professor of entomology at UC Davis.

So true!

This wasp mimic is actually a fly, genus Ceriana. (Photo by Kathy Keatley Garvey)
This wasp mimic is actually a fly, genus Ceriana. (Photo by Kathy Keatley Garvey)

This wasp mimic is actually a fly, genus Ceriana. (Photo by Kathy Keatley Garvey)

Davis photographer Allan Jones captured this fantastic  image of the wasp mimic, Ceriana. (Photo by Kathy Keatley Garvey)
Davis photographer Allan Jones captured this fantastic image of the wasp mimic, Ceriana. (Photo by Kathy Keatley Garvey)

Davis photographer Allan Jones captured this fantastic image of the wasp mimic, Ceriana. (Photo by Kathy Keatley Garvey)

This is a Western yellowjacket, Vespula pensylvanic, which looks a lot like the wasp mimic, genus Ceriana. (Photo by Kathy Keatley Garvey)
This is a Western yellowjacket, Vespula pensylvanic, which looks a lot like the wasp mimic, genus Ceriana. (Photo by Kathy Keatley Garvey)

This is a Western yellowjacket, Vespula pensylvanic, which looks a lot like the wasp mimic, genus Ceriana. (Photo by Kathy Keatley Garvey)

This is a European paper wasp, Polistes dominula. A syrphid fly mimics this. (Photo by Kathy Keatley Garvey)
This is a European paper wasp, Polistes dominula. A syrphid fly mimics this. (Photo by Kathy Keatley Garvey)

This is a European paper wasp, Polistes dominula. A syrphid fly mimics this. (Photo by Kathy Keatley Garvey)

Posted on Monday, September 8, 2014 at 6:07 PM

About Those Sleepovers...

We're receiving lots of inquiries about sleepovers ever since we began posting images of male longhorned bees, Melissodes agilis, sleeping on our lavender.

Boys' Night Out!

While the females sleep in their underground nests, the males cluster on stems. No, they don't have pillow fights or nightcaps but they do wiggle around a lot until they get comfortable.

Now the boys have moved from their favorite spot on the lavender (vertical sleepover) to the guara (horizontal sleepover). We suspect this may be due to several reasons: (1) The presence of three praying mantids in the lavender (2)  the lavender is fading while the guara is flourishing and (3) the guara offers a definite height advantage, which may deter a few predators (but not birds).

Nevertheless, the boys start arriving for their nightly sleepover around 5 p.m. and don't budge until around 7 p.m., sometimes as late as 9 or 10.

One reader asked some interesting questions.

"There is a nightly cluster of boys on an aster stem in my front yard and I wanted to find out more about them. In particular, do they/can they/will they sting?"

No, boys don't sting--just the girls. As native pollinator specialist Robbin Thorp, emeritus professor of entomology at UC Davis, explains: "Boy bees cannot sting.  They lack a stinger which is a modified ovipositor in their wasp ancestors.  Occasionally a girl bee may spend the night out if she is caught by sudden drop in temperature.  Usually she will not be part of a group sleep over.  So don't attempt to handle unless you are confident you can tell boy bees from girl bees or they are too sleepy to defend themselves."

The reader also asked: "Typically how close to the girls' nest(s) do the boys' slumber? I want to try and make sure I don't touch it when planting at end of summer."

Says Thorp: "Boy sleeping aggregations are based on a suitable perch and not related to where females are nesting, but probably no more than 100 yards from the nearest female nest.  Females nest in the ground and have rather distinctive round holes about the diameter of a pencil or slightly smaller, sometimes with small piles of dirt around them looking like mini-volcanos.  The holes may be widely separated or clustered together depending on the species, but each female digs her own burrow."

Of course, not all slumbering bees in this area are Melissodes agilis,  as Thorp points out. Some may be other species of the genus Melissodes and some may belong to the closely related Svastra obliqua.

The reader also wondered: "When watching the boys tonight, about ten of them started waking up and kicking each other. They finally settled down and started to nestle back in for the 'night'--it was only 6 p.m.--but I wasn't sure if my presence was getting them riled or they tend to act like kids sharing a bed?"

Says Thorp: "The boys usually settle in as the light dims in the evening.  Cool, and drizzly conditions may modify bed time.  Each establishes his own spot, so there may be some jostling for position initially."

We've noticed that, too. We've also noticed that the early morning risers--the carpenter bees, bumble bees, honey bees and syrphid flies--work around the slumbering Melissodes agilis. All that buzzing must sound like the human version of a chainsaw. "Will ya shaddup, already? Can't you see we're trying to sleep?"

Once the boys awaken, though, watch out! They'll dive-bomb the pollinators or any critter working or resting on "their" flowers.  They're very territorial and determined to save the food source for the females of their species. The butterflies, including the Western tiger swallowtail, anise swallowtail, Gulf Fritillary and cabbage whites, don't linger when the boys target them.

And speaking of California bees, we're eagerly awaiting the arrival of the book, California Blooms and Bees: an Identification Guide for Gardeners and Naturalists. It's co-authored by research entomologist/professor Gordon Frankie of UC Berkeley; Thorp (who received his doctorate from UC Berkeley); and their UC Berkeley affiliates, photographer/entomologist Rollin Coville and floral/herbarium curator Barbara Ertter.

More than 1600 species of undomesticated bees call California their home. The authors focus on 22 of the most common genera and the flowers they frequent.

Meanwhile, you'll want to check out Frankie's UC Berkeley Urban Bee Lab website to read more about native bees and his exciting research.

Male longhorned bees jockeying for position on a guara stem. (Photo by Kathy Keatley Garvey)
Male longhorned bees jockeying for position on a guara stem. (Photo by Kathy Keatley Garvey)

Male longhorned bees jockeying for position on a guara stem. (Photo by Kathy Keatley Garvey)

Not every stem is taken and not all the males cluster six or seven to a stem. These two appear to want space. (Photo by Kathy Keatley Garvey)
Not every stem is taken and not all the males cluster six or seven to a stem. These two appear to want space. (Photo by Kathy Keatley Garvey)

Not every stem is taken and not all the males cluster six or seven to a stem. These two appear to want space. (Photo by Kathy Keatley Garvey)

This male Melissodes agilis, is sleeping solo on a guara blossom. (Photo by Kathy Keatley Garvey)
This male Melissodes agilis, is sleeping solo on a guara blossom. (Photo by Kathy Keatley Garvey)

This male Melissodes agilis, is sleeping solo on a guara blossom. (Photo by Kathy Keatley Garvey)

Posted on Monday, July 28, 2014 at 10:01 PM

Next 5 stories | Last story

Webmaster Email: mgwomack@ucanr.edu