Why silver digger bees are like gold...

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.

Imagine having an insect named for you. How awesome is that?

It's especially an honor when a duo--a husband-and-wife nature conservation team--is singled out for that recognition.

Leslie Saul-Gershenz (she holds a doctorate in entomology from UC Davis) and husband, Norm Gershenz, co-founders of the Bay Area-based SaveNature.Org, have namesakes:
Ethmia lesliesaulae and Ethmia normgershenzi are newly discovered species of moths in the rain forests of Costa Rica.

The moths belong to the family Depressariidae and now they're part of the Gershenz family, too!

Both new species and 20 others in the genus are described in the Zookeys paper,  A Synopsis of the Genus Ethmia Hübner in Costa Rica: Biology, Distribution, and Description of 22 New Species (Lepidoptera, Gelechioidea, Depressariidae, Ethmiinae), with Eephasis on the 42 Species known from Área de Conservación Guanacaste by E. Phillips-Rodríguez, J.A. Powell, W. Hallwachs and D. H. Janzen. The larvae feed on plants in the genus Drymonia (Gesneriaceae).

Both of the news species are now listed in Wikipedia:

• Ethmia lesliesaulae has been recorded from both sides of the Cordillera Volcánica de Guanacaste at altitudes ranging from 300 to 645 meters.
• Ethmia normgershenzi has been recorded from the east side of the Cordillera Volcánica de Guanacaste from 400 to 660 meters.

Norm and Leslie co-founded SaveNature.Org, an international conservation program, a 501(c)( 3), to "protect terrestrial and aquatic ecosystems worldwide and to inspire stewardship in the public through hands-on education programs." Norm serves as the chief executive officer and director of the Insect Discovery Lab (IDL). SaveNature.Org conducts nearly 800 hands-on conservation education programs in schools throughout the Greater Bay Area, and reaches more than 38,500 children annually with its IDL.

They make the news. Their work has been highlighted in National Geographic, Time magazine, and ABC's World News Tonight. Robert Pringle's recent article, Upgrading Protected Areas to Conserve Wild Biodiversity, in the journal Nature, details the organization's collaborative work to increase the size of protected areas.

The organization has added 74,000 acres of wildlife habitat to large-scale National Parks around the world and protected marine habitat and watersheds in the Latin America, Asia and the Caribbean. To date, SaveNature.Org has raised more than $4.7 million to help preserve thousands of acres of rain forest, coral reef and desert habitat around the world. Their catchy theme: "Saving Nature Is Habitat Forming."

Norm created and developed the first Adopt-An-Acre program in the United States as well as the award-winning Conservation Parking Meter; both raise funds for international conservation. In 2010 he received the prestigious Elizabeth Terwilliger Prize for Conservation. In 2015 he created Smiles of Hope, a new Nature-Assisted Therapy program for hospitalized children.

Norm was affiliated with the San Francisco Zoo for more than 18 years as an educator, member of the animal care staff, fundraiser, and researcher. Norm has quite the biography: he has tracked black rhinos in Zimbabwe, chased orangutans in Borneo, and stalked the elusive platypus in Australia. He has handled boas and bobcats, pandas and elephants, snow leopards and koalas, hippos and hornbills. He has worked as a field biologist and naturalist in Borneo, Malaysia, India, Nepal, Costa Rica and Namibia.

Leslie received her doctorate in entomology from UC Davis in May 2017. As an evolutionary ecologist, she studies the chemical ecology and parasite-host interactions of solitary native bees and their nest parasites across the western U. S., including the coastal sand dunes of Oregon and the Mojave Desert in south-central California.

Basically, the larvae of the parasitic blister beetle produce a chemical signal or allomone, similar to that of a female bee's  pheromone to lure males to the larval aggregation. The larvae attach to the male bee on contact and then transfer to the female during mating. The end result: the larvae wind up in the nest of a female bee, where they eat the nest provisions and likely the host egg.

"Our research has added to the understanding of the communication signals of bees in the genus Habropoda," she related. "We now know that they use long-chain hydrocarbons for the female sex attractant and vary the position of the double bounds in different components and vary proportions of these components to avoid cross attraction among closely related species. Parasites co-opt this communication channel to deceive male bees in the Meloe-Habropoda system."

Leslie is also a 2004 graduate of The Bee Course, an intensive 10-day workshop sponsored by the American Museum of Natural History at the Southwestern Research Station, Portal, Ariz.  One of The Bee Course instructors is Robbin Thorp, distinguished emeritus professor of entomology at UC Davis. 

Leslie's  presented her research at the Entomological Society of America meeting in November in Denver, Colo. Her next research presentation will be the California Native Plant Society Conservation conference, scheduled Feb. 1-3, 2018 in Los Angeles.

Overall, moths boast incredible diversity, according to Jerry Powell, emeritus professor at UC Berkeley and co-author Paul Opier, in their masterwork, "Moths of Western North America" (University of California Press). They describe and illustrate some 2500 species in their book. The region is comprised of some 8,000 named species of moths. Most attract attention only when their larvae create economic damage, such as eating holes in woolens, infesting stored foods, boring into apples, damaging crops and garden plants, or defoliating forests. 

Meanwhile, Ethmia lesliesaulae and Ethmia normgershenzi are right at home in the rain forests of Costa Rica, and their namesakes are right at home in their Bay Area-based conservation group.

And meanwhile, if you want an insect named for you or a loved one, here's one way: Contact the Bohart Museum of Entomology's biolegacy program. Insects that need naming include a stiletto fly from Australia and Thailand, said director Lynn Kimsey, professor of entomology at UC Davis.

(Editor's Note: Insect images from Wikipedia, courtesy of E. Phillips-Rodríguez, J. A. Powell, W. Hallwachs and D. H. Janzen)

Evolutionary ecologist Leslie Saul-Gershenz goes places where many have been but few have ever really seen. 

Bees and blister beetles, yes.

We remember writing about her work in April of 2013 when she addressed the Nor Cal Entomology Society (now folded) about her research on how blister beetle nest parasites cooperate to mimic the sex pheromone of a digger bee. She had just returned from the Mojave National Preserve, tracking the solitary bee Habropoda pallida and its nest parasite, a blister beetle, Meloe franciscanus.

Fascinating research! Saul-Gershenz, who grew up in New York, studies the chemical ecology and parasite-host interactions of solitary native bees and their nest parasites across the western U. S., including the coastal sand dunes of Oregon and the Mojave Desert in south-central California.

"The solitary bee is the first native bee to emerge in the spring on the Kelso Dunes in the Mojave National Preserve," she told us.  “The adult beetles emerge on the dunes in the winter months at Kelso Dunes and feed exclusively on the leaves of Astragalus lentiginosus which leafs out in January." 

The bee's emergence is generally synchronized with the onset of blooms of the Borrego milkvetch, which is the sole host plant of adults of the blister beetle at Kelso Dunes.

Basically, the larvae of the parasitic blister beetle produce a chemical signal or allomone, similar to that of a female bee's  pheromone to lure males to the larval aggregation. The larvae attach to the male bee on contact and then transfer to the female during mating. The end result: the larvae wind up in the nest of a female bee, where they eat the nest provisions and likely the host egg.

Leslie is now Dr. Saul-Gershenz. She received her doctorate in entomology in May 2017. And on Wednesday, Oct. 18, she will share her research at her exit seminar, "Host Range Evolution of the Bee Parasite Meloe franciscanus," set from 4:10 to 5 p.m. in 122 Briggs Hall, Kleiber Hall Drive.

"We report that different populations of M. franciscanus exhibit local adaptations that mimic both the behaviors and the chemical composition of the sex pheromones of locally available bee host species," she writes in her abstract. "We compared a population of M. franciscanus larvae, known as triungulins, parasitizing nests of Habropoda miserabilis (Hymenoptera: Apidae) from the coastal sand dunes of Oregon with a population parasitizing the congener H. pallida in the Mojave Desert in south-central California. We determined that M. franciscanus populations are the same species using molecular analyses.

Working in collaboration with the Neal Williams bee lab and the Steve Nadler molecular lab in the UC Davis Department of Entomology and Nematology, she and chemical ecologist Jocelyn Millar at UC Riverside found that multiple populations of the blister beetle Meloe franciscanus are locally adapted to different bee hosts in different allopatric populations. (Professor Williams is a pollination ecologist, and Nadler is a nematologist and chair of the department.)

The UC Davis evolutionary ecologist also explored which functional traits of hosts are useful for predicting parasite host range. In another study, she brought together a dream team of bee biologists and received funding from the Bureau of Land Management to study the impact of utility-scale solar development on desert bees. This study documented that these landscapes are biologically rich, even in drought years, and contain a minimum of 114 species of bees including six undescribed species of bee.

The significance of her work?

"Our research has added to the understanding of the communication signals of bees in the genus Habropoda," she related. "We now know that they use long-chain hydrocarbons for the female sex attractant and vary the position of the double bounds in different components and vary proportions of these components to avoid cross attraction among closely related species. Parasites co-opt this communication channel to deceive male bees in the Meloe-Habropoda system.

"In our host functional trait research we show that annual host abundance and host abundance from year to year, as well as local temporal overlap are highly predictive of host range."

Results on the impact of utility-scale solar development on desert bees showed high bee species diversity in the Mojave and western Sonoran region. "This suggests the importance of careful regional planning and additional research to protect this area of significant floral and fauna biodiversity," she said.

Future plans? To continue her research.

Leslie Saul-Gershenz, recipient of numerous grants and author of a number of publications ranging from peer-reviewed papers to books, is the co-founder of the Bay Area-based SaveNature.Org and director of Research and Conservation (1988 to present). The international conservation consortium works with partners to protect ecosystems around the world.

She is also a 2004 graduate of The Bee Course, an intensive 10-day workshop sponsored by the American Museum of Natural History at the Southwestern Research Station, Portal, Ariz. One of the instructors is Robbin Thorp, distinguished emeritus professor of entomology at UC Davis, also one of her many collaborators.

Among her other current collaborators: scientists Lynn Kimsey, Neal Williams,  Tom Zavortink,  Rebecca Hernandez, all of UC Davis; Terry Griswold, USDA-ARS, Bee Biology Lab; Monica Geber, Cornell University; and John Ascher, National University of Singapore.

Her next presentations of her research will be at the Entomological Society of America's annual conference, "Ignite, Inspire, Innovate," scheduled Nov. 5-8 in Denver,Colo., and the California Native Plant Society Conservation Conference, scheduled Feb. 1-3, 2018 in Los Angeles.

Let's hear it for Rei!

Margaret “Rei” Scampavia, a doctoral candidate who studies with major professors Neal Williams and Edwin Lewis of the Department of Entomology and Nematology, won first place for her research poster at the recent UC Davis Bee Symposium, held in the Robert Mondavi Center for Wine and Food Science. 

Scampavia's poster,  “Farming Practices Affect Nest Site Selection of Native Ground Nesting Bees,” won her the $1500 grand prize. The Henry J. Kaiser Family Foundation generously provided the funding.

Two other graduate students in the Neal Williams' lab won second and third place. Jennifer Van Wyk placed second for her poster on “Wet Meadow Restoration Buffers the Impact of Climate Change: Pollinator Resilience During the California Drought” and Leslie Saul-Gershenz, who also studies with professor Steve Nadler, placed third for her poster on “Native Bee Parasite Shows Multitrait, Host Specific Variation and Local Adaptation.” Van Wyk received a $1000 prize and Saul Gershenz, $500.

“Availability of foraging and nesting habitat potentially limits native bee range, which affects where pollinator services occur,” Scampavia wrote in her introduction. “Prior studies focus on how foraging habitat influences bee distribution, but few consider nesting limitations. Understanding how different soil properties affect native bee nest site preference can help predict where these nests will be found in agricultural landscapes, as well as whether particular farming practices could affect the health of nesting bees.”

Her objective: “to determine whether tillage, irrigation and application of pesticides impact nest site selection using a controlled choice assay.”

Scampavia examined nesting in experimental plots in Davis in 2013 and 2014. She measured the nest initiation in each of the four soil treatment groups with soil emergence traps. The treatment groups were (1) tilled, irrigated, esfenvalerate applied (2) tilled, irrigated (3) tilled only (4) irrigated only and (5) negative control. Esfenvalerate, a synthetic pyrethroid, is commonly used for pest management in California.

She examined the nests of bees in four genus categories: Lasioglossum, Halictus, Svastra and Melissodes.

Scampavia concluded “The two soil treatments that positively influenced nest initiation (tillage and irrigation) would be found in actively farmed areas, rather than fallow fields or field margins. If the presence of insecticide residues or tillage affects offspring survival, these results suggest that bees nesting in agricultural areas are faced with an ecological trap that could negatively affect development and overwintering survival. Providing strips of bare, tilled and irrigated soil in early spring in field margins or hedgerows could be one way to create attractive pesticide and late-season tillage-free shelters in which native bees could nest.”

Prior to coming to UC Davis, Scampavia worked for the U.S. Forest service as a biological technician, studying pollinator visitation to rare plants of the Mojave Desert. She also volunteered at Scripps College (Jupiter, Fla.) as a planner and coordinator for large education outreach events.

Her current research deals with isolating and identifying specific soil attributes that affect nest site selection in bee species, and how these attributes impact offspring success. “I mostly focus on native ground nesting bees, but also study the impact of chlorpyrifos leaf residues on nesting alfalfa leafcutter bees,” she said. “I am also interested in how nesting habitat availability shapes bee community composition and distribution across the landscape. My current focus is on sunflower fields, alfalfa seed production, and mosaic landscapes in serpentine chaparral.”

In addition to her PhD research, she participates in a variety of education outreach and conservation projects. She has presented lectures for the U.S. Fish and Wildlife Service as part of the Schoolyard Habitat Project; worked for the California Native Plant Society, documenting bee diversity in a threatened portion of Knowland Park in Oakland; and co-taught an undergraduate course focusing on current threats to pollinator populations and how to educate the general public to effect positive change.

Scampavia writes a bee blog, “Diadasia, The Lives of Other Bees,” at https://diadasia.wordpress.com/ that she launched in February 2012.

The Bee Symposium, sponsored by the Honey and Pollination Center and the UC Davis Department of Entomology and Nematology, featured keynote speaker Marla Spivak, Distinguished McKnight Professor, University of Minnesota and a 2010 MacArthur Fellow, who discussed "Helping Bees Stand on Their Own Six Feet." The symposium drew 360 people.

Entomology doctoral candidate Matthew Prebus of the Phil Ward lab, UC Davis Department of Entomology and Nematology, video-recorded the presentations and uploaded them today.

They are all on YouTube.

Marla Spivak: Protecting Pollinators

Amy Toth: Combined Effects of Viruses and Nutritional Stress on Honey Bee Health

Elina Niño: Best Management Practices to Support Honey Bee Health

Neal Williams: Enhancing Forage for Bees

Sarah Laird: The Bee Girl

Jake Reisdorf: Getting into Beekeeping- Thoughts from a 12-year-old Beekeeper

Katharina Ullmann: Project Integrated Crop Pollination

John Miller: Keeping Bees Healthy with Forage

Benjamin Sallman: Bee Informed Partnership

Gretchen LeBuhn: The Giant Sunflower Project

Christine Casey: Introduction to the Häagen Dazs Honey Bee Haven