- Author: Kathy Keatley Garvey
A female Melissodes agilis, the so-called "agile longhorned bee," is foraging on a Mexican sunflower, Tithonia rotundifola.
Longhorned? So named because they have unusually long antennae. Think of this species as the insect version of Texas longhorns!
Melissodes are ground-nesting solitary bees. While the males congregate on a flower to sleep overnight, each female is returns to her ground nest.
This female (below) rose early on July 3 to sip a little nectar while the males were fast asleep.
We find this species every year on our Mexican sunflowers, Tithonia rotundifola, in our family's Vacaville pollinator garden. It's native to North America and Central America.
They're a delight to see. The males are quite territorial as they target assorted critters on "their" flowers. As the late pollinator specialist Robbin Thorp, UC Davis distinguished emeritus professor of entomology, used to say: "They're saving the flowers for the females of their species, so they can mate with them."
But if you're a "gal bee" and awaken early, you have the flowers all to yourself.
Thorp used to tell us there are some 20,000 undomesticated bee species are there in the world. Some 4000 species llve in the United States. And some 1600 species, including Melissodes agilis, live in California.
Internationally recognized for his expertise, Thorp co-authored two books in 2014: the UC California book, California Bees and Blooms: A Guide for Gardeners and Naturalists (Heyday) and Bumble Bees of North America: An Identification Guide (Princeton University Press).
- Author: Kathy Keatley Garvey
Hey, the sun's up! It's time to rise and shine! Maybe I'll shine before I rise...or maybe I'll...
Anyway, I just woke up, and I'm starting to stir. I'm ready to conquer the day. I shall
- Sip nectar
- Seek girlfriend
- Guard the flower patch by dive-bombing and chasing off all critters.
- Repeat.
The scenario: a male longhorned bee, Melissodes agilis, has just spent the night sleeping--and quite cozily at that--on a Mexican sunflower, Tithonia rotundifola.
He is Boy Bee With the Green Mesmerizing Eyes.
Boy Bee With the Green Mesmerizing Eyes does not know--nor would he care if he could--that today is the beginning of National Pollinator Week, an international annual event celebrating pollinator health.
According to the Pollinator Partnership, "pollination is a vital stage in the life cycle of all flowering plants. When pollen is moved within a flower or carried from one flower to another of the same species it leads to fertilization. This transfer of pollen is necessary for healthy and productive native and agricultural ecosystems." It's crucial to our ecosystem.
As the Pollinator Partnership says on its website:
- "About 75 percent of all flowering plant species need the help of animals to move their heavy pollen grains from plant to plant for fertilization."
- "About 1,000 of all pollinators are vertebrates such as birds, bats, and small mammals."
- "Most pollinators (about 200,000 species) are beneficial insects such as flies, beetles, wasps, ants, butterflies, moths, and bees."
But back to Boy Bee With the Mesmerizing Green Eyes.
Noted bee expert, the late Robbin Thorp, a UC Davis distinguished emeritus professor of entomology and co-author of California Bees and Blooms: A Guide for Gardeners and Naturalists (Heyday), used to talk about these little guys bullying all the floral tenants--from honey bees to syrphid flies to butterflies to lady beetles--and more.
Boy, do they move fast. A good time to photograph them is when they're sleeping or just waking up. Otherwise, try to capture images of them at a shutter speed of about 1/5000 of a second.
Happy Beginning of National Pollinator Week!
- Author: Kathy Keatley Garvey
There's a way for a bear to outsmart a fox.
A teddy bear bee, that is.
We just witnessed a male Valley carpenter bee, Xylocopa sonorina, aka "the teddy bear bee," buzz up to a patch of foxgloves, Digitalis purpurea.
Then he engaged in the foraging behavior known as nectar-robbing. That's when a carpenter bee or bumble bee drills a hole at the base of the corolla--or finds a hole already drilled--and "robs" the nectar, bypassing the flower's reproductive parts that lead to pollination.
Hey, I'm not going through the front door! I'm not! I'm taking the back door.
We usually see female Valley carpenter bees drilling the holes and robbing the nectar. This time, though, it was a male. The late Robbin Thorp, UC Davis distinguished emeritus professor of entomology, always referred to the males as "teddy bear bees," adding "boy bees don't sting."
This particular teddy bear lingered a bit, sipped some nectar, and then took flight.
That's how a "bear" outsmarts a fox.
By the way, sexual dimorphism is pronounced in X. sonorina. The male is a green-eyed blond, while the females are solid black.
In our garden, other plants popular for nectar robbing include the salvias, ‘Hot Lips' Sage (Salvia ‘Hot Lips'), and California fuchsia (Epilobium canum). Sometimes you'll see a honey bee following a carpenter bee or bumble bee around to gain easy access to the nectar. She "knows the drill."
Scientists have known about nectar-robbing for more than two centuries. German naturalist Christian Konrad Sprengel observed bumble bees perforating the corollas of flowers as early as 1793, according to Wikipedia. Sprengel recorded this phenomenon in his book, The Secret of Nature in the Form and Fertilization of Flowers Discovered. Charles Darwin observed nectar robbing (by bumble bees) in 1859 and published his observations in his book The Origin of Species.
- Author: Kathy Keatley Garvey
Professor Thorp (1933-2019), a 30-year member of the Department of Entomology and Nematology and a worldwide authority on bees, was a tireless advocate of bumble bee conservation. During his retirement, he co-authored Bumble Bees of North America: An Identification Guide (Princeton University, 2014) and California Bees and Blooms: A Guide for Gardeners and Naturalists (Heyday, 2014).
And every summer from 2002 to 2018, Thorp volunteered his time and expertise to teach at The Bee Course, an annual workshop sponsored by the American Museum of Natural History and held at the Southwestern Research Station, Portal, Ariz.
Thorp also served as the regional co-chair of the Wild Bee Specialist Group of the International Union for Conservation of Nature (IUCN) and sounded the alarm about bumble bee declines, including Franklin's bumble bee, Bombus franklini, found only in its narrow distribution range of southern Oregon and northern California. Thorp last saw it near Mt. Ashland in 2006 and it is is now feared extinct or at the brink of extinction. The bee inhabits--or did--a 13,300-square-mile area confined to five counties--Siskiyou and Trinity counties in California; and Jackson, Douglas and Josephine counties in Oregon.
Enter the California Bumble Bee Atlas (CBBA), a collaboration of the California Department of Fish and Wildlife (CDFW), Sacramento, and the Xerces Society for Invertebrate Conservation, headquartered in Portland, Ore. Launched in March 2022, the Atlas is a "collaborative community science effort to track and conserve the state's native bumble bee species," according to Dylan Winkler, bumble bee scientific aide for the CDFW's Wildlife Diversity Program.
Back in September 2021, the U.S. Fish and Wildlife Service announced that the American bumble bee, "whose populations have plummeted by nearly 90 percent, may warrant Endangered Species Act protection." The announcement kicked off a one-year status assessment of the species. (See news story)
If you're interested in bumble bee conservation, take note. Winkler will lead a "Bumble Bee Walk" from 10 a.m. to noon on Saturday, May 28 in the UC Davis Arboretum and Public Garden. The goal is to teach interested participants how to survey bumble bees. You can pre-register at https://arcg.is/0PDyO4. Organizers plan to cap attendance at 20 people. Details about this Atlas event and several more scheduled in June:
- Saturday, May 28: UC Davis Arboretum, Davis, CA (Yolo County), parking at Putah Creek Lodge Parking Lot, Garrod Drive, Davis, CA 95616. Tour of the native plant gardens and the forest along Putah Creek from 10 a.m. to noon.
- Saturday, June 4: The Gardens at Lake Merritt, 666 Bellevue Avenue, Oakland, CA (Alameda County). Tour of the gardens from 9 a.m. to 11 a.m.
- Sunday, June 5: College of Marin at Kentfield (Marin County), parking at covered Lots 6/7 off College Ave, Kentfield, CA 94904. Details: Meet at bridge over Corte Madera Creek. Tour of the campus native plants from 10 a.m. to noon.
- Saturday, June 18: Soil Born Farms, Rancho Cordova, CA (Sacramento County), parking at Soil Born Farms: American River Ranch, 2140 Chase Drive, Rancho Cordova, CA 95670. As part of National Pollinator Week, the group will tour the gardens from 10 a.m. to noon. Closed-toed shoes required.
Of the 50 species of bumble bees found in North America, an estimated 25 inhabit California. Overall, a quarter is at risk, according to the Atlas website. The decline is attributed to "loss or fragmentation of habitat, pesticide exposure, climate change, overgrazing, competition with honey bees, low genetic diversity, and perhaps most significant of all, the introduction and distribution of pathogens through commercial honey bee and bumble bee colonies used for crop pollination. All of these factors likely interact, increasing pollinator vulnerability. To support bumble bees, it is critical to protect existing habitat while creating and maintaining new habitat."
Winkler says "we will be using butterfly nets to catch bees, then move them to small vials, and chill them in coolers with ice, so we can take ID'able photographs of them before releasing." The full protocol is at https://www.cabumblebeeatlas.org/point-surveys.html
What bumble bees might you see May 28 in the Arboretum? Bombus vosnesenskii, the yellow-faced bumble bee, and B. melanopygus, the black-tailed bumble bee. "There is a record of B. crotchii at the arboretum from last year around the same date, which is rare and would be amazing to see!" Winkler said.
The project is funded by the U.S. Fish and Wildlife Service through the Wildlife and Sport Fish Restoration Fund. Funding is also provided by the Bureau of Land Management and several private foundations. Read more about the project and the list of coordinators here.
- Author: Kathy Keatley Garvey
If you've ever been to Bodega Head in Sonoma County, you may have marveled at the waves crashing and the whales surfacing.
But have you ever seen the digger bees, Anthophora bomboides stanfordiana, aka bumble bee mimics, that nest in the sandstone cliffs?
They're there. They're foraging on flowers, excavating their nests, and rearing young.
These digger bees are not easy to photograph. On our May 9th trip, we got lucky: our 200mm macro lens picked up a digger bee warming its flight muscles.
"The species name indicates that it is a bumble bee mimic," the late Robbin Thorp (1933-2019), a global authority on bumble bees and a UC Davis distinguished emeritus professor of entomology. "These bees need a source of fresh water nearby. Females suck up water, regurgitate it on the sandstone bank surface, then dig away at the soft mud. They use some of the mud to build entrance turrets, presumably to help them locate their nests within the aggregation of nests."
"The female," Thorp said, "sucks up fresh water from nearby, stores it in her crop (like honey bees store nectar) for transport to the nest. She regurgitates it on the sandstone, and excavates the moistened soil. She carries out the mud and makes the entrance turret with it."
Thorp, a 30-year member of the Department of Entomology and Nematology, studied these bees. (See his presentation at the Proceedings of the Symposium on Biodiversity of Northwestern California, Santa Rosa, delivered in October 1991.)
Today, community ecologist and associate professor Rachel Vannette from the same department, is among scientists engaged in the research of these fascinating bees.