Native bee chart from UC scientists published in California Agriculture.

Back in the 2009, a team of University of California scientists, led by Gordon Frankie of UC Berkeley and Robbin Thorp (1933-2019) of UC Davis, wrote this incredible article, "Native Bees are a Rich Natural Resource in Urban California Gardens," published in California Agriculture (UC Agriculture and Natural Resources).

It's an excellent resource.

The abstract:

"Evidence is mounting that pollinators of crop and wildland plants are declining worldwide. Our research group at UC Berkeley and UC Davis conducted a 3-year survey of bee pollinators in seven cities from Northern California to Southern California. Results indicate that many types of urban residential gardens provide floral and nesting resources for the reproduction and survival of bees, especially a diversity of native bees. Habitat gardening for bees, using targeted ornamental plants, can predictably increase bee diversity and abundance, and provide clear pollination benefits."

Frankie and Thorp co-authored the paper with eight colleagues: Mark Rizzardi of Humboldt State University, and UC Berkeley-affiliated Jennifer Hernandez, Barbara Ertter, Jaime Pawelek, Sara Witt, Mary Schindler, Rollin Coville, and Victoria Wojcik. Coville provided the images.

"Outdoor urban areas worldwide are known to support a rich diversity of insect life (Frankie and Ehler 1978)," they wrote. "Some insects are undesirable and characterized as pests, such as aphids, snails, earwigs and borers; urban residents are most aware of these. Other urban insects are considered beneficial or aesthetically pleasing, such as ladybird beetles and butterflies; this category includes a rich variety of insects whose roles in gardens go largely unnoticed and are thus underappreciated (Grissell 2001; Tallamy 2009). They regularly visit flowers and pollinate them, an important ecological service."

"We report the results of a 2005-to-2007 survey of bees and their associations with a wide variety of ornamental plant species in seven urban areas, from Northern California to Southern California. While non-native honey bees (Apis mellifera) are common in many gardens, numerous California native bee species also visit urban ornamental flowers. Of about 4,000 bee species known in the entire United States, about 1,600 have been recorded in California."

That deserves to be repeated. Of the 4000 bee species known in the United States, about 1600 reside in California.  See some of them listed on the chart above.  

Notice it includes the non-native bee, the honey bee, Apis mellfera. It is an "introduced bee," although numerous  non-scientists think it's a native. European colonists introduced it to America (in what is now Virginia) in 1622. 

The phrase, "Save the (Honey) Bees," became prominent during the colony collapse disorder. But the bees that need saving now are the natives. 

If you want to know more about the native bees in California, this book should be in your library: California Bees and Blooms: A Guide for Gardeners and Naturalists by UC-affiliated scientists Gordon Frankie, Robbin Thorp, Barbara Ertter and Rollin Coville.

"Sweat bees have earned their common name from the tendency, especially of the smaller species,to alight on one's skin and lap up perspiration for both its moisture and salt content."

So write University of California scientists in their award-winning book, California Bees and Blooms, a Guide for Gardeners and Naturalists.

California has some 1600 species of undomesticated or wild bees, point out the authors (Gordon Frankie, Robbin Thorp, Rollin Coville and Barbara Ertter).

And one of them is the sweat bee, Halictus ligatus, a  member of the family Halictidae. It's a medium-sized, ground-nesting bee with a striped abdomen.

This week one of these species (as identified by research scientist John Ascher) looked especially striking on a Black-Eyed Susan, Rudbeckia hirta, a member of the Aster (Asteraceae) family.  Both the plant and the bee are natives.

Several years ago we managed to photograph a flameskimmer dragonfly, Libellula saturata, munching on one of these sweat bees. Not a good day for that little gal!

No dragonflies were around, however, when we watched this one foraging on a Black-Eyed Susan. 

Did you know that the Black-Eyed Susan is the designated state flower of Maryland? And that it was the inspiration for the University of Southern Mississippi's school colors (black and gold)? And that it's a larval host to butterflies such as the bordered batch, gorgone checkerspot and silvery checkerspot?

Who knew? If you plant it, though, be aware that it is toxic (when ingested) to cats.

A male metallic green sweat bee in flight. (Photo by Kathy Keatley Garvey)

What was that foraging on a pink iceplant blossom near a path to the ocean? A metallic green sweat bee, Agapostemon texanus, also called an ultra green sweat bee.

We usually don't see A. texanus unless it's spring or summer, but there it was, out of season. Or rather, there "he" was. Males and females are easily distinguishable.  The female is solid green, from head to thorax to abdomen, while the green coloration on the male appears on the head and thorax. 

We remember pollinator specialist Robbin Thorp (1933-2019) emeritus professor of entomology at UC Davis, talking about them. He delighted in seeing them at his monitoring site, the Department of Entomology and Nematology's Häagen-Dazs Honey Bee Haven on Bee Biology Road,  UC Davis campus. The Agapostemon are members of the Halictinae family. They are often called "sweat bees" because they are attracted to human sweat, probably for the salt.

Green sweat bees are among the bees featured in the book, "California Bees and Blooms: A Guide for Gardeners and Naturalists," co-authored by the University of California team of Gordon Frankie, UC Berkeley; Robbin Thorp,  UC Davis; and UC Berkeley affiliates Rollin Coville (photographer and entomologist) and Barbara Ertter (plant specialist). Frankie, Thorp, Coville and Ertter (and others) also published "Native Bees Are a Rich Natural Resource in Urban California Gardens" in California Agriculture.

Have you ever pulled up a chair in your garden and watched honey bees foraging?

They are so intent on their "bees-ness" that they don't know you're there.  It's a great opportunity to photograph them.

Sometimes, if you're lucky, they'll buzz over your head on their way back to their colony, and you'll see:

• The three main body parts: head, thorax and abdomen
• The two pairs of wings
• The three pairs of legs
• The pair of antennae

Such was the case in Vacaville this week when we were watching honey bees forage in our African blue basil,  a  bee magnet that we plant annually.  We first learned of African blue basil, (Ocimum kilimandscharicum × basilicum 'Dark Opal'),  through Gordon Frankie, UC Berkeley professor and the late Robbin Thorp, distinguished emeritus professor of entomology at UC Davis. They co-authored the book, California Bees and Blooms: a Guide for Gardeners and Naturalists (Heyday Books) with Rollin Coville and Barbara Ertter, also affiliated with UC Berkeley.

Want to know more about honey bees?  Be sure to read the newly published The Art of the Honey Bee; Shaping the Environment from Landscapes to Societies (Oxford University Press) by noted bee geneticist and biologist Robert E. Page Jr., who maintains strong ties to UC Davis and Arizona State University (ASU). Also learn about honey bee anatomy on ASU's web page, "Ask a Biologist."

Page, who holds a doctorate in entomology from UC Davis, is a former chair of the UC Davis Department of Entomology.   In 2004, Arizona State University (ASU) recruited him for what would become a series of top-level administrative roles. He advanced from director of the School of Life Sciences to dean of Life Sciences; vice provost and dean of the College of Liberal Arts and Sciences; and university provost. Today he holds the titles of provost emeritus of ASU and Regents professor emeritus, as well as UC Davis department chair emeritus, professor emeritus, and UC Davis distinguished emeritus professor.

Tool Kit
Did you know a bee has a tool kit? Page lists the tool kit in his book, The Art of the Bee: a compass, an odometer and a path integrator.

'As 'central place foragers,' bees fly out from the nest site and explore the surrounding environment in search of food resources,"  writes Page, renowned for his research on honey bee behavior and population genetics, particularly the evolution of complex social behavior. "They return to the nest with the resources they collect. To do this, they need to be able to navigate out and find their way back. To aid them, they have a toolkit of navigation mechanisms."

One tool in their tool kit is their internal compass that depends on the location of the sun.

"As light from the sun passes through the atmosphere, it becomes polarized," Page writes. "The pattern of polarized light in the sky depends on the angle of the sun relative to where you are looking. Bees have special sensors in their eyes for detecting the polarized light patterns. On cloudy days, they can't see the sky; but they can still locate the sun using ultraviolet light detectors. Ultraviolet light penetrates cloud cover, allowing bees to use the location of the sun as a navigational marker. With heavy clouds, bees can get to and from a resource by relying solely on landmarks that they learn; otherwise, they stay home until the weather changes. However, as the earth turns, the sun is always changing location relative to the horizon, making it an unreliable marker unless you know the time of day, and bees do. They learn the movement of the sun across the sky and reference it to an internal clock. We know they have the clock because we can train them to forage at specific times of day. If you anesthetize a bee, you can stop her clock. When she awakens and takes a foraging trip to a learned foraging station, her flight path will be offset by the amount of time lost. In other words, she will misinterpret the direction based on the current location of the sun by the amount of time she was anesthetized."

"The odometer plus the ability to determine a flight vector (direction and distance) from a given landmark along a resource flight path, using their sun compass and internal clock, give bees the basic tools for navigation,"  Page writes. "The last tool in the toolkit is a path integrator that combines the compass and odometer information."

It's a fascinating book by Page, whose most salient contributions to science include constructing the first genomic map of the honey bee, which sparked a variety of pioneering contributions not only to insect biology but to genetics at large.

Meanwhile, take the challenge. Pull up a chair in your garden and watch and photograph the bees going about their "bees-ness."