Leslie Saul-Gershenz (Photo by Kathy Keatley Garvey)

Remember those "long lost" silver digger bees found last week at the San Francisco Presidio? They hadn't been seen in large aggregations for nearly a century.

And yet there they were in the newly restored sand dunes at the Presidio, a former military post now owned and operated by the National Park Service.

UC Davis entomologist Leslie Saul-Gershenz lent her expertise when a volunteer discovered the thriving colonies of bees. An authority on digger bees, she confirmed that they are Habropoda miserabilis and were probably common in the sandy dunes of that area as late as the 1920s. When non-native ivy, eucalyptus and ice plants took over their habitat, the bees disappeared.

“The discovery of a thriving native bee colony on the western side of the Presidio is the latest example of how the removal of invasive plants and the restoration of dunes and grasses at the former military base have helped bring back coastal habitat that thrived in San Francisco for tens of thousands of years before the city was built,” said Saul-Gershenz, who received her doctorate in entomology from UC Davis and is now associate director of research for the Wild Energy Initiative, John Muir Institute of the Environment, on campus.

“I am very happy to see this nest site at the Presidio,” she said. She's worked on the biology, chemical ecology and parasite interactions of this group of bees in the genus Habropoda for many years--on research trips that have taken her to the Oregon coast and the Mojave desert, among others.

“This nest parasite M. franciscanus was originally described from the dunes in San Francisco near Lake Merced by Van Dyke in 1928,” Saul-Gershenz said. “It is presumed to be locally extirpated in San Francisco due to habitat alteration. However its host bee, H. miserabilis  appears to have finally found a suitable nest location in a sand dune area being restored by the Presidio Trust in the Presidio National Park.  The resiliency of nature provides hope for the future.”

In a news story published in the San Francisco Chronicle on March 29, science reporter Peter Fimrite quoted the UC Davis entomologist as saying that the silver digger bees were “all but gone” by the mid-20th century.  However, Saul-Gershenz has kept looking for them. In fact, she collected one near Baker Beach in 1998.

With restoration, comes hope for the return of native plants and insects.

"Biologists have reported a more than tenfold increase in the number of native plants in the Presidio, including at least four that are federally listed endangered or threatened, among them the Presidio clarkia," wrote Fimrite. "The Franciscan manzanita, which was believed to be extinct in the wild, was discovered in the Presidio in 2009. It was the first of its kind seen in its native San Francisco since the old Laurel Hill Cemetery was bulldozed in 1947 and paved over for homes."

Brian Hildebidle, stewardship coordinator for the Presidio Trust, discovered the colonies while surveying a dune restoration project.  Jonathan Young, wildlife ecologist for the Presidio Trust, was also included in the news story.

Gershenz and collaborator Jocelyn Millar of UC Riverside and others deciphered the sex attraction of Habropoda miserabilis and the deceptive mimicking blend used by its nest parasite Meloe franciscanus working with a population on the coast of Oregon (Saul-Gershenz et al. 2018). They documented a new parasite-host location system while conducting research on related species in the same genus Habropoda pallida found in the Mojave and Sonoran Desert (Saul-Gershenz and Millar 2006).

The comeback of silver digger bees is not limited to San Francisco. Fimrite related that several other areas in California are are witnessing comebacks, including Bodega Marine Reserve in Bodega Bay and Lanphere Dunes in the Humboldt Bay National Wildlife Refuge.

We remember seeing volunteers at Dillon's Beach, Bodega Bay, last summer removing ice plants by the bird sanctuary, and in the process, giving native plants, native insects and related wildlife a chance to thrive. We remember beachcombers asking "Why? Why are they doing that? Those ice plants are so PRETTY."

The discovery at the Presidio is why.

As Saul-Gershenz points out, there are 1600 native bee species in California, but scientists know little about many of them.

They are all pollinators. And all life is connected.  As naturalist/environmental philosopher John Muir (1838-1914) wrote in My First Summer in the Sierra: "When we try to pick out anything by itself, we find it hitched to everything else in the Universe."

So it is with the silver digger bees. That's why they're gold.

A male leafcutter bee, Megachile, peers out beneath a rock purslane, Calandrinia grandiflora. (Photo by Kathy Keatley Garvey)

Registration for the seventh annual International Pollinator Conference, billed Wednesday, July 17 through Saturday, July 20 in the UC Davis Conference Center, is now underway.

You can register online on the UC Davis Honey and Pollination Center site.

At the conference, chaired by pollination ecologist/professor Neal M. Williams and Extension apiculturist Elina Lastro Niño, both of the UC Davis Department of Entomology and Nematology, you can learn of recent research advances in the biology and health of pollinators. 

The conference, themed “Multidimensional Solutions to Current and Future Threats to Pollinator Health,” will cover a wide range of topics in pollinator research: from genomics to ecology and their application to land use and management; to breeding of managed bees; and to monitoring of global pollinator populations. Topics discussed will include recent research advances in the biology and health of pollinators, and their policy implications.

Keynote speakers are Christina Grozinger, distinguished professor of entomology and director of the Center for Pollinator Research, Pennsylvania State University, (the research center launched the annual pollinator conferences in 2012) and Lynn Dicks, Natural Environment Research Council (NERC) Research Fellow, School of Biological Sciences, University of East Anglia, England.

Grozinger studies health and social behavior in bees and is developing comprehensive approaches to improving  pollinator health and reduce declines. Lynn Dicks, an internationally respected scientist, studies bee ecology and conservation. She received the 2017 John Spedan Lewis Medal for contributions to insect conservation.

Other speakers include:

• Claudio Gratton, professor, Department of Entomology, University of Wisconsin-Madison
• Quinn McFrederick, assistant professor, Department of Entomology, UC Riverside
• Scott McArt, assistant professor, Department of Entomology, Cornell University
• Maj Rundlöf, International Career Grant Fellow, Department of Biology, Lund University, Sweden
• Juliette Osborne, professor and chair, Applied Ecology, University of Exeter, England
• Maggie Douglas, assistant professor, Environmental Studies, Dickinson College

The UC Davis Honey and Pollination Center, directed by Amina Harris, is playing a major role in the international conference. Events manager Elizabeth Luu is the conference coordinator.

Early-bee registration: $350 (general) and $175 (student discount). After May 15, 2019, registration is $450 (general), $250 (student). For more information, check the website, https://honey.ucdavis.edu/events/2019-international-pollinator-conference.

Robbin Thorp, distinguished emeritus professor of entomology at UC Davis. (Photo by Kathy Keatley Garvey)

Ah, pillow fights, popcorn, and marathon movies on TV, you ask?

No. "Boys' Night Out" is when the longhorned male bees in our pollinator garden in Vacaville engage in sleepovers on our Mexican sunflowers (Tithonia) and other blossoms.

At night, the girls sleep inside their nests, and the boys cluster on flowers.

Lately, we've been admiring a trio of boys--Melissodes (possibly M. robustior, as identified by Robbin Thorp, distinguished emeritus professor of entomology at the University of California, Davis)--bunking down on a Tithonia. Every day, around sunset, they head over to the same flower, arrange themselves in comfortable sleeping positions (hey, quit kicking me), and it's nighty-night! When the sun rises, they vacate the bedroom. Sometimes it's earlier than planned, no thanks to buzzing bumble bees, carpenter bees and honey bees foraging around them and disturbing their beauty sleep. The nerve!

Other species of male longhorned bees--including Melissodes agilis and Svastra obliqua--sleep on flowers at night as well.

"Most frequently, the boy bee overnight clusters are single-species clusters," says Thorp, co-author of California Bees and Blooms, a Guide for Gardeners and Naturalists, with UC-affiliated authors Gordon Frankie, Rollin E. Coville, and Barbara Ertter.

Thorp,  who holds a doctorate in entomology from UC Berkeley and taught entomology at UC Davis from 1964 to 1994,  continues to "bee involved" in research, writings, bee identification and public outreach. He teaches annually at The Bee Course (American Museum of Natural History), at the Southwestern Research Station, Portal, Ariz. The nine-day intensive  course is offered for conservation biologists, pollination ecologists and other biologists who want to gain greater knowledge of the systematics and biology of bees.

In a previous Bug Squad blog, Thorp responded to a reader's inquiry about "stings" from the clustering bees. "Boy bees cannot sting," he pointed out. "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."

 "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," Thorp answered.  "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."

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?"

Said 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."

Longhorned bees are among the more than 1600 species of undomesticated bees that reside in California. In their book, California Bees and Blooms, the authors focus on 22 of the most common genera and the flowers they frequent. Meanwhile, check out Frankie's UC Berkeley Urban Bee Lab website to read more about native bees and the exciting research underway.

This is the European wool carder bee created by Christine Chen. (Photo by Kathy Keatley Garvey)

Christine Chen talks about her European wool carder bee. (Photo by Kathy Keatley Garvey)

The panels feature mostly native bees.

The project dates back to 2011 when 22 UC Davis students enrolled in an Entomology 1 class, "Art, Science and the World of Insects," taught by entomologist-artist Diane Ullman, professor of entomology at UC Davis and self-described "rock artist" Donna Billick of Davis.

The half-acre bee garden, located on Bee Biology Road, next to the Harry H. Laidlaw Jr. Honey Bee Research Facility on Bee Biology Road is open from sunrise to sunset for self-guided tours. No admission is charged. The latest news: The Haven will now be staffed every Friday morning from 10 to noon. You can not only see pollinators foraging on the plants, but view all the art, including Billick's six-foot-long mosaic/ceramic sculpture, "Miss Bee Haven," that anchors the garden. On Fridays, you can also see the bee display case, sign up for a "catch and release" bee vacuum, and buy bee guides and plants, according to the academic management officer Christine Casey.

But back to the bee mural. Then doctoral student Sarah Dalrymple of the Rick Karban lab,  served as the graphics project coordinator and teaching assistant, guiding the students on design, creation and installation of the panels. She went on to be named the 2011 recipient of the UC Davis Outstanding Graduate  Student Teaching Award and praised for fusing the boundaries of biology, art and culture.

The 22 students portrayed 22 bees, including such natives as mason, sweat, squash, leafcutter, blue orchard, carpenter and bumble bees. Notice that the honey bee is not listed? That's because it's not a native. European colonists brought it to America in 1622, and it wasn't introduced to California until 1853.

Another non-native is the European wool carder bee, first detected in the United States (New York) in 1963, and in California (Sunnyvale) in 2007. The carder bee is so named because the female "cards" fuzz from plants for her nest.

The students celebrated their work and talked about their projects at an end-of-the-year gathering in 2011.

And now visitors to the garden can celebrate--and appreciate--all the dedication, ingenuity and creativity that went into this mural.

(Editor's Note: Who are the students and what species did they study and design? They're all listed on this website, as well as the identification of the students in the group photo below. The configuration of this blog does not allow a long caption.)