"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.
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.
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."
It's a party.
It's a pollinator party.
It's the Bay Area Bee Fair in Berkeley.
And it's the place to be on Sunday, Oct. 13 at the Berkeley Flea Market, located at Ashby BART.
The second annual event, free and family friendly, is set from 10 a.m. to 3 p.m. It will feature a presentation on "How to Save the Bees" by UC Berkeley professor Gordon Frankie; educational and entertainment opportunities, kids' art activities, pollinator-themed art, and plant, book and bee condo sales, as well as honey and bee products, according to organizers Jackie Dragon and Mary Lynn Morales, who describe themselves as "Bee Fair dreamers."
The Bay Area Bee Fair is a time to "celebrate, educate and motivate the community about bees and other pollinators," they said. "Their health is vital to our health."
- 10 a.m.: Opening and welcome
- 11 a.m.: "How to Make a Pollinator-Friendly Garden Presentation" by Andrea Hurd, of Mariposa Gardening
- Noon: "How to Save the Bees" by bee scientist Gordon Frankie, UC Berkeley professor and co-author of California Bees and Blooms: A Guide for Gardeners and Naturalists.
- 2:30 p.m.: Giant Puppets Pollinator Parade
- 3 p.m.: Closing
For more information, access:
What was that!
If you grow Mexican sunflowers (Tithonia) in your pollinator garden, you've probably noticed the fast-flying longhorned male bees being totally territorial.
Their job is to target whatever's on the Tithonia. It doesn't matter if it's a bumble bee, a honey bee, or a butterfly--it's fair game.
As the late Robbin Thorp (1933-2019), a global expert on bees and a distinguished emeritus professor of entomology at the University of California, Davis, used to say about the male longhorned bees, Melissodes agilis: "They're trying to save the flowers for their own species, per chance to mate with them."
Watching the territorial behavior is jaw-dropping, but imagine if you're a butterfly trying to sip a little nectar.
"Oh no! What was that heading straight at me?"
"Horrors! Here he comes again! Can't a pollinator get a little peace around here?"
The longhorned bee, Melissodes agilis, is just one of the more than 1600 species of bees found in California. If you want to learn more about them, be sure to read California Bees and Blooms: A Guide for Gardeners and Naturalists (Heyday, 2014), co-authored by scientists from UC Berkeley and UC Davis.
"California Bees and Blooms (co-authored by Gordon Frankie, Robbin Thorp, Barbara Ertter and Rollin Coville) holds a magnifying glass up to the twenty-two most common genera (and six species of cuckoo bees), describing each one's distinctive behaviors, social structures, flight season, preferred flowers, and enemies," according to Heyday.
That it does. And if you try to stop the action with your camera, it helps to set the shutter speed at 1/3000 to 1/4000 of a second. (The two images of the bee and painted lady butterfly captured with a Nikon D500 camera, mounted with a 70-180 mm macro zoom lens, with the aperture set at 5.6 and ISO at 800. Image of the bee and monarch taken with a Nikon D800 mounted with a 105mm lens, and with similar settings.)