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Posts Tagged: Robbin Thorp

A Bee That's a Delight to See

Male green metallic sweat bee. (Photo by Kathy Keatley Garvey)
What's that on the Coreopsis?

Could it be--a bee?

Yes, that's the metallic green sweat bee, also called an ultra green sweat bee, Agapostemon texanus.  This one  (below) is a female. Males and females are easily distinguishable.  The female is all green, from head to thorax to abdomen, while the male (right) is green on the head and thorax but not on the abdomen.

Native pollinator specialist Robbin Thorp, emeritus professor of entomology at UC Davis, talked about them at the recent UC Davis Pollinator Gardening Workshop, sponsored by the California Center for Urban Horticulture.

The Agapostemon are members of the Halictinae family. They are "often called sweat bees because in hot weather they are attracted to human perspiration, which they lap up, probably for the salt it contains," according to the book, Bees of the World, by Christopher O'Toole and Christopher Raw.

Some of the family's many genera, including  Agapostemon, are restricted to the New World. Halictus and Lasioglossum "are common to the Old and New Worlds," the authors write.

Coreopsis, also called tickseed or coreopsis, is a genus of flowering plants in the family Asteraceae.

We spotted the female metallic green sweat bee at the Loch Lomond Marina, San Rafael. We captured the image of the male several years ago on a seaside daisy at the Mostly Natives Nursery, Tomales.

Green sweat bees will be among the bees featured in the book, "California Bees and Blooms: A Guide for Gardeners and Naturalists," to be published in the fall of 2014 by Heyday Press. It's the work of Gordon Frankie of UC Berkeley; Robbin Thorp of UC Davis; photographer Rollin Coville of the Bay Area; and Barbara Ertter of UC Berkeley. It will contain nearly 30 of the most common bee genera in California.

Frankie, Thorp, Coville and Ertter (and others) also published "Native Bees Are a Rich Natural Resource in Urban California Gardens" in California Agriculture.

Female metallic green sweat bee, Agapostemon texanus, on coreopsis. (Photo by Kathy Keatley Garvey)
Female metallic green sweat bee, Agapostemon texanus, on coreopsis. (Photo by Kathy Keatley Garvey)

Female metallic green sweat bee, Agapostemon texanus, on coreopsis. (Photo by Kathy Keatley Garvey

Female metallic green sweat bee peers at the photographer. (Photo by Kathy Keatley Garvey)
Female metallic green sweat bee peers at the photographer. (Photo by Kathy Keatley Garvey)

Female metallic green sweat bee peers at the photographer. (Photo by Kathy Keatley Garvey) Keatley Garvey)

Posted on Tuesday, April 22, 2014 at 8:01 PM

Golden Boy

Robbin Thorp holding a male Valley carpenter bee. (Photo by Kathy Keatley Garvey)
A "golden boy" drew a lot of attention at the Bohart Museum of Entomology last Saturday, April 12 during the campuswide UC Davis Picnic Day.

"Golden boy?" A male Valley carpenter bee (Xylocopa varipuncta) to be exact. This carpenter bee is usually mistaken for a bumble bee but a bumble bee it is not. It's a male Valley carpenter bee. And the females of this species are solid black.

Native pollinator specialist Robbin Thorp, emeritus professor of entomology at UC Davis, provided information to wide-eyed youngsters as he held the golden carpenter bees,  what he calls "the teddy bear bees."  They look and feel soft and cuddly, just like a teddy bear.  

The questions flew.

Visitor: "Does it sting?"

Thorp: ""No, boy bees don't sting. They don't have a stinger."

Visitor: "Why does he act like he's going to sting me?"

Thorp: "He's bluffing. He's trying to make you think he can sting."

Visitor: "Do carpenter bees make honey?"

Thorp: "No, honey bees make honey."

Visitor: "Can I touch it?"

Thorp: "Yes, can you feel it vibrating?"

Visitor: "Does it die after it mates?"

Thorp: "No, it can mate again. A drone (male) honey bee dies after mating, but not carpenter bees."

Visitor: "What are you going to do with it afterwards?"

Thorp: "Release it back into the Häagen-Dazs Honey Bee Haven (a half-acre bee friendly garden on Bee Biology Road that's operated by the UC Davis Department of Entomology and Nematology)."

Fact is, it's a pollinator. Keep your eyes open for it and other pollinators on May 8. That's when the UC Agriculture and Natural Resources (UC ANR) is conducting "Operation Pollination," one of three events on a Day of Science and Service. Your help is needed. Wherever you are in California--at work or at play--allow three minutes to count the pollinators around you. That could be honey bees, bumble bees, butterflies, sweat bees, syrphid flies, carpenter bees, bats and the like. Take some photos, too. Then register the data and upload your photos on the UC ANR web page.

We suspect that if and when the nearly 5000 visitors who attended the Bohart Museum open house, catch a glimpse of a "golden boy" on May 8, they'll know exactly what it is, whatever they choose to call it.

  • Male Valley carpenter bee
  • Xylocopa varipuncta
  • Boy bee
  • Golden boy
  • "Teddy bear bee"
  • Pollinator

Male Valley carpenter bee draws attention at the Bohart Museum of Entomology's open house on UC Davis Picnic Day. (Photo by Kathy Keatley Garvey)
Male Valley carpenter bee draws attention at the Bohart Museum of Entomology's open house on UC Davis Picnic Day. (Photo by Kathy Keatley Garvey)

Male Valley carpenter bee draws attention at the Bohart Museum of Entomology's open house on UC Davis Picnic Day. (Photo by Kathy Keatley Garvey)

A tentative touch. (Photo by Kathy Keatley Garvey)
A tentative touch. (Photo by Kathy Keatley Garvey)

A tentative touch. (Photo by Kathy Keatley Garvey)

Fingers nestle the male Valley carpenter bee. (Photo by Kathy Keatley Garvey)
Fingers nestle the male Valley carpenter bee. (Photo by Kathy Keatley Garvey)

Fingers nestle the male Valley carpenter bee. (Photo by Kathy Keatley Garvey)

Posted on Monday, April 14, 2014 at 9:01 PM

Mining for Bees!

Genus Andrena, maybe Andrena cerasifolii, foraging on cherry laurels. (Photo by Kathy Keatley Garvey)
Just call it "Mining for Bees."

It was not long after Robbin Thorp's talk on wild bees at the UC Davis Pollinator Gardening Workshop (hosted by the California Center for Urban Horticulture on March 15 at Giedt Hall), that lo and bee-hold: a mining bee appeared in our backyard.

From the family Andrenidae, it was foraging on the cherry laurels (Prunus caroliniana). Thorp, a native pollinator specialist and emeritus professor of entomology at UC Davis, identified the bee from photos as genus Andrena, probably Andrena cerasifolii.  "Note the pollen transport hairs on the hind legs," he said.

In his talk, Thorp mentioned that "there are more than 19,500 named bee species in the world, but more likely 20,000 to maybe 30,000." Of that number, North America has about 4500 bee species; California, 1600; and Yolo County, more than 300.

Indeed, Thorp has detected more than 80 bee species alone in the Häagen-Dazs Honey Bee Haven on Bee Biology Road, UC Davis (Yolo County). Planted in the fall of 2009, it's owned and maintained by the UC Davis Department of Entomology and Nematology.

Here are a few bees you might want to pursue:
Andrenidae (mining bees)
Halictidae (sweat bees)
Colletidae (polyester and masked bees)
Megachilidae (leafcutting, carder and mason bees)
Apidae (digger, carpenter, cuckoo and honey bees)

We're looking forward to "California Bees and Blooms: A Guide for Gardeners and Naturalists," to be published in the fall of 2014 by Heyday Press. It's the work of Gordon Frankie of UC Berkeley; Robbin Thorp of UC Davis; photographer Rollin Coville of the Bay Area; and Barbara Ertter of UC Berkeley. It will contain nearly 30 of the most common bee genera in California.

Frankie, Thorp, Coville and Ertter (and others) also published "Native Bees Are a Rich Natural Resource in Urban California Gardens" in California Agriculture.

Meanwhile, check out  the UC Berkeley Urban Bee Lab website for interesting information on native bees. 

You, too, can attract them to your yard. As Thorp says: "Plant them and they will come. Provide habitat and they will stay and reproduce."

Female of the genus Andrena (Andrenidae) probably Andrena angustitarsata, as identified by Robbin Thorp.  This is a native, solitary, ground nesting bee. (Photo by Kathy Keatley Garvey)
Female of the genus Andrena (Andrenidae) probably Andrena angustitarsata, as identified by Robbin Thorp. This is a native, solitary, ground nesting bee. (Photo by Kathy Keatley Garvey)

Female of the genus Andrena (Andrenidae) probably Andrena angustitarsata, as identified by Robbin Thorp. This is a native, solitary, ground nesting bee. (Photo by Kathy Keatley Garvey)

Posted on Tuesday, April 1, 2014 at 7:20 PM
Tags: Andrena (2), Andrenidae (1), mining bees (2), Robbin Thorp (124)

Eye on the Buckeye

It won't bloom until summer, but already many eyes are on the California buckeye.

The tree's blossoms are poisonous to honey bees.  Bees are attracted to them and forage on them, but the end result of the food provisions to the colony can be deformed larval development.

We've seen bee hives within a quarter of a mile of California buckeyes (Aesculus californica). And we've seen honey bees, native bees and other pollinators foraging on the blossoms.

At the recent UC Davis Pollinator Gardening Workshop hosted by the California Center for Urban Horticulture, Extension apiculturist Eric Mussen talked about the poisonous plants. (See PowerPoint presentations.) That led to one workshop participant wondering if the flowers of the California buckeye are poisonous to native bees. (Honey bees are not native; the European colonists brought them to the Jamestown colony, Virginia, in 1622).

Responded Mussen: "My guess: either the native bees that have been in the areas around California buckeye for a long, long time are not poisoned by the pollen or they have been selected (by death of the other genetic types) to avoid the pollen, that eons of natural selection have adapted them to coexist with California buckeye while using their resources."  

Native pollinator specialist Robbin Thorp, emeritus professor of entomology at UC Davis, shared: "We know California buckeye nectar and/or pollen is toxic to honey bees from years of experience with managed hives. Toxicity to native bees and other flower visitors is not so easily determined and to my knowledge has not been investigated. The fact that populations of native bees and butterflies visit California buckeye flowers and continue to persist in areas where the tree is a dominant part of the plant community tends to confirm what Extension apiculturist Eric Mussen says about them. Some good research projects here. So we still do not know if it is the nectar, pollen, or both that may be toxic to honey bees, much less to native flower visitors."

According to gardeningguides.com, the seeds in their raw state are poisonous to humans, but native Americans learned  to get around that and use them for food. They pounded the seeds into flour and then cooked the mixture.  "This tree had multiple cultural uses among California Indian tribes," the website says. "Many indigenous groups utilized buckeye seeds for food, often when other plant food sources were scarce. These tribes included the Costanoan, Salinan, Kitanemuk, Serrano, Wappo, Sierra Miwok, Coast Miwok, Chumash, Kawaiisu, Northern Maidu among others. The Pomo ate the seeds even when other important food plants were plentiful. The seeds are poisonous to humans in the raw state. Thus, the nuts were cracked open with a rock, the shells removed, the seeds pounded into flour, and their toxic saponins removed in a lengthy leaching process. The meal was subsequently cooked and eaten. There are many different methods for processing and cooking buckeye seeds for food, depending upon the tribe. The seeds have medicinal properties and were cut into pieces, mixed with water, and made into suppositories for hemorrhoids by the Costanoan and Kawaiisu. The Pomo cut bark from the base of the tree and made a poultice, which was laid on a snakebite. Young buckeye shoots were sometimes used as spindles or twirling sticks in fire-making kits of the Sierra Miwok, Northern Maidu, Wappo, Yahi and other tribes. Many tribes mashed buckeye nuts and poured the contents into quiet pools to stupefy or kill fish."

And, no wildlife will eat buckeye seeds except squirrels, such as the California ground squirrel (Citellus beecheyi).

Meanwhile, the poisonous blossoms continue to beckon the honey bees--and their colonies keep producing deformed bees.

Honey bee foraging last May on a California buckeye, which is poisonous to honey bees. (Photo by Kathy Keatley Garvey)
Honey bee foraging last May on a California buckeye, which is poisonous to honey bees. (Photo by Kathy Keatley Garvey)

Honey bee foraging last May on a California buckeye, which is poisonous to honey bees. (Photo by Kathy Keatley Garvey)

A California buckeye blooming in May of last year on the UC Davis campus. (Photo by Kathy Keatley Garvey)
A California buckeye blooming in May of last year on the UC Davis campus. (Photo by Kathy Keatley Garvey)

A California buckeye blooming in May of last year on the UC Davis campus. (Photo by Kathy Keatley Garvey)

Posted on Wednesday, March 26, 2014 at 10:44 PM

Honey Bee Impostor

A honey bee on ceanothus. (Photo by Kathy Keatley Garvey)
It's often mistaken for a honey bee.

Indeed, to the untrained eye, the drone fly (Eristalis tenax) appears to be a bee. It's not; it's a fly.

Native pollinator specialist Robbin Thorp, emeritus professor of entomology at UC Davis, calls the drone fly "The H Bee." That's because there's an "H" on its abdomen (see photo). Like all flies, however, it can be distinguished by one pair of wings and stubby antennae. The larva of the fly is a rat-tailed maggot that lives in drainage ditches, pooled manure piles and other polluted water. The adults are floral visitors. Pollinators.

The "H Bee" was among the pollinators that Thorp discussed at the UC Davis Pollinator Gardening Workshop, hosted March 6 by the California Center for Urban Horticulture.

Extension apiculturist Eric Mussen of the UC Davis Department of Entomology and Nematology, switched from bee mimics (drone flies, syrphid flies and other insects) to talk about the "real" honey bees, Apis mellifera, which European colonists introduced to what is now the United States in 1622 "The honey bees' biggest problem today is malnourishment," he said.  "A single honey bee colony requires an acre of bloom to meet its nutritional needs each day," he said. 

The queen can lay 2000 eggs a day in peak season. "One cell of honey and one cell of pollen make one bee."

He urged the participants to "try to plant for late summer and fall bloom, when honey bees in California are having a hard time finding nectar and pollen resources."

A drone fly on ceanothus. (Photo by Kathy Keatley Garvey)
Particularly attractive to bees are manzanita species, Eucalyptus trees, catalpa, basswood, tulip tree, wild mustard and radish, ceanothus  (wild lilac) and ornamental shrubs such as lavender, rosemary and thyme. Also, borage, sunflower, asters, catmint and other mints, chives, filaree, vetch, tarweed, goldenrod, blue curls (Trichostema lanceolatum), phacelia and penstemon.

Mussen cautioned that bees are subjected to toxic pollens and unnatural toxins (pesticides). Plants poisonous to bees include the California buckeye (Aesculus californica) death camas (Toxicoscordion venenosum), corn lily (Veratrum californicum) and some locoweeeds (Astragalus spp.)  

Pesticides inside the hive (used to control varroa mites) and outside the hives can be fatal. However, he said, "any kind of pesticide a bee encounters--there's always a physiological change."

Following the morning-long speaker presentations, the participants visited the UC Davis Arboretum Teaching Nursery on Garrod Drive to check out and/or purchase Arboretum All-Stars and other plants, and they toured the Häagen-Dazs Honey Bee Haven, a half-acre bee friendly garden on Bee Biology Road that is under the wing of the UC Davis Department of Entomology and Nematology. The garden is located next to the Harry H. Laidlaw Jr. Honey Bee Research Facility.

Among those traveling the longest distance were Lake Tahoe UC Master Gardeners Lynne Broche and Bonnie Turnbull and  Turnbull's 14-year-old daughter, Jessie Brown, a junior Master Gardener and an avid insect photographer.

The ceanothus blooming in the haven especially drew the attention of the workshop participants. Insects foraging in the ceanothus included two so-called "H bees"--the honey bee and its impostor, the H-marked drone fly. 

The drone fly, Eristalis tenax, is often mistaken for a bee. The fly has the letter
The drone fly, Eristalis tenax, is often mistaken for a bee. The fly has the letter "H" on its thorax. (Photo by Kathy Keatley Garvey)

The drone fly, Eristalis tenax, is often mistaken for a bee. The fly has the letter "H" on its abdomen. (Photo by Kathy Keatley Garvey)

essie Brown, 14, a junior UC Master Gardener with the Lake Tahoe Master Gardeners, photographs insects in the ceanothus at the Häagen-Dazs Honey Bee Haven.  (Photo by Kathy Keatley Garvey)
essie Brown, 14, a junior UC Master Gardener with the Lake Tahoe Master Gardeners, photographs insects in the ceanothus at the Häagen-Dazs Honey Bee Haven. (Photo by Kathy Keatley Garvey)

Jessie Brown, 14, a junior UC Master Gardener with the Lake Tahoe Master Gardeners, photographs insects in the ceanothus at the Häagen-Dazs Honey Bee Haven. (Photo by Kathy Keatley Garvey)

Posted on Friday, March 21, 2014 at 11:22 PM

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