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.
You could call it a slacker, a deadbeat, a moocher, a sponger, or a loafer.
Or you could call it a cuckoo bee.
Take the cuckoo bee, Xeromelecta californica, a parasite of the digger bee, Anthophora.
When the female Anthophora leaves its nest to collect more pollen, the female cuckoo bee sneaks in and lays an egg.
"When the host female seals her nest, it seals the doom of her own offspring," distinguished emeritus professor Robbin Thorp of the UC Davis Department of Entomology and Nematology told the crowd at last week's 40th annual Western Apicultural Society meeting, held at UC Davis. They eat the provisions, a pollen ball meant for the host offspring, and kill and eat the host larvae.
The cuckoo bee offspring emerge.
Thorp, co-author of California Bees and Blooms: A Guide for Gardeners and Naturalists, also called attention to their "pointy abdomen" and "wasp-looking appearance."
But they are bees--cuckoo bees. They're also called parasitic bees or "kleptoparasites" or "cleptoparasitises."
They have no pollen-carrying/collecting apparatus, like a scopa, because they don't need any, Thorp said, just as they do not construct their own nests.
If you look around a pollinator garden, you just might sight some cuckoo bees. Last week we saw a Xeromelecta californica (as identified by Thorp and Lynn Kimsey, director of the Bohart Museum of Entomology and UC Davis professor of entomology). It was sipping nectar from a tropical milkweed, Asclepias curassavica.
We've also spotted Anthophora urbana nectaring on our lavender.
One thing's for certain: a cuckoo bee didn't lay its eggs in the Anthophora nest that time or the urbana wouldn't have been there.
It's not often you see a monarch butterfly and a digger bee in the same photo.
Such was the case on a recent visit to a lantana patch at a west Vacaville home.
The monarch butterfly touched down on a blossom and was beginning to nectar when along comes a digger bee, a male Anthophora urbana (as identified by native pollinator specialist Robbin Thorp, emeritus professor of entomology at the Universit of California, Davis.)
"Maybe it was planing on dive bombing the big intruder from his territory," Thorp said. "However, these males are not known to be especially territorial. Maybe he's just checking out the competition for nectar."
This is the solitary, ground-nesting bee that Leslie Saul-Gershenz, graduate student in the Neal Williams lab at UC Davis, is researching. She's published research on a species of digger bee, Habropoda pallida, a solitary ground-nesting bee, and its nest parasite, a blister beetle, Meloe franciscanus, found in the Mojave Desert ecosystem.
Now she's also including Anthophora.
“Our preliminary data show that the blister beetle exploits four other native California bees including important pollinators in the genus Habropoda and Anthophora," she recently told us.
Historically, the blister beetle, Meloe franciscanus, was known to be a nest parasite of Anthophora edwardsii, distributed throughout California.
See her amazing photo of the parasitic larvae of the blister beetle on the digger bee, Habropoda pallida, on the UC Davis Entomology website.
Diggin' the digger bee...
We spotted this female digger bee, Anthophora urbana, zooming in on some zinnias at UC Davis. She buzzed loudly, virtually owning the zinnia patch. Smaller sweat bees scattered.
The bee, identified by native pollinator specialist Robbin Thorp, emeritus professor of entomology, is a solitary, ground nesting bee. "She has been around for a while judging by the worn (hairless) patch in the middle of the thorax," Thorp points out. "She has a dense brush of white hairs on her hind legs (scopa) for pollen transport."
Anthophoridae, described by Christopher O'Toole and Anthony Raw in their book, Bees of the World, is a "very large family...found in all parts of the world. Many are robust and resemble bumble bees."
"Most species nest in the ground while a few excavate in dead wood," they write.
The genus, Anthophora, includes more than 450 species worldwide. It's one of the largest in the Apidae family, which includes honey bees, carpenter bees, bumble bees, cuckoo bees and the like.
Anthophora urbana differs sharply from our honey bee, Apis mellifera.
The honey bee is social, living in a hive with some 60,000 other bees and sharing the workload. The digger bee is solitary.
The honey bee gathers nectar and pollen (and also propolis, from plant resin) and makes honey. The digger bee forages for nectar and pollen but does not make honey.
Occasionally, as floral visitors, they bump into each other. The social and the solitary...
If that word is not in your everyday vocabulary, just think of a symbiotic relationship where one organism transports another organism of a different species for the benefit of both.
And there you have it--at least part of it--of what evolutionary ecologist Leslie Saul-Gershenz of the University of California, Davis, is doing.
Saul-Gershenz researches a species of digger bee, Habropoda pallida, a solitary ground-nesting bee, and its nest parasite, a blister beetle, Meloe franciscanus, found in the Mojave Desert ecosystem.
She and Neal Williams (her major professor) of UC Davis and Jocelyn Millar of UC Riverside just received a grant to study digger bee ecology and conservation. They're working with SaveNature.Org, which Saul-Gershenz co-founded.
The relationship between the bee and the blister beetle is part of it.
What's this symbiotic relationship about? The larvae of the parasitic blister beetle produce a chemical cue or a pheromone similar to that of a female solitary bee to lure males to the larval aggregation. The larvae attach to the male bee 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, Saul-Gershenz says.
Like to read more about this exciting research? Saul-Gershenz and Millar published their blister beetle/digger bee work, "Phoretic Nest Parasites Use Sexual Deception to Obtain Transport to their Host's Nest," in the Proceedings of the National Academy of Sciences (PNAS, 2006).
That led Pulitzer Prize-winning author Natalie Angier to feature their work in "The Art of Deception," published in the August 2009 edition of the National Geographic magazine. Most recently, U. S. Department of Agriculture (USDA) Forest Service entomologist Michael Ulyshen, writing for the Journal of Natural History, mentioned their work in "Bugback Riding: Transportation for the Masses" (September 2011).
Saul-Gershenz said she became interested in the subject while she was a graduate student at San Francisco State University. She wrote "Beetle Larvae Cooperate to Mimic Bees" in the journal Nature (2000).
Of her newest grant, she says: “Our preliminary data show that the blister beetle exploits four other native California bees including important pollinators in the genus Habropoda and Anthophora." Historically, M. franciscanus was known to be a nest parasite of Anthophora edwardsii distributed throughout California.
You may know Saul-Gershenz as a past president of the Pacific Coast Entomological Society. In 1991, she became the first female president in its 91-year history.