- Author: Kathy Keatley Garvey
But have you ever seen the digger bees?
They're out there.
The sand cliffs are the home of the digger bee, a bumble bee mimic known as Anthophora bomboides stanfordiana. This bee builds turrets in the sand cliffs.
Last Thursday we watched several digger bees warm their flight muscles, take flight, and forage on the lupine, wild radish, and seaside daisy. Then we saw the females zipping in and out of their turrets: their cozy castles in the sand.
As the late Robbin Thorp, a global authority on bumble bees and a UC Davis distinguished emeritus professor of entomology, told us several years ago: "The species name indicates that it is a bumble bee mimic. 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."
As part of a National Science Foundation grant, community ecologist Rachel Vannette, assistant professor, UC Davis Department of Entomology and Nematology, is teaming with other colleagues, including pollination ecologist Stephen Buchmann, to research these digger bees and their nests.
It's a big beautiful bee world out there.
- Author: Kathy Keatley Garvey
There's more to Sonoma County's Bodega Head than the stunning views, crashing waves, nesting seabirds, and bursts of flora and fauna.
The sand cliffs are also the home of a digger bee, a bumble bee mimic known as Anthophora bomboides stanfordiana.
"The species name indicates that it is a bumble bee mimic," the late Robbin Thorp, a global authority on bumble bees and a UC Davis distinguished emeritus professor of entomology, told us several years ago. "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."
On multiple trips to Bodega Bay over the years, we watch in fascination as the bees excavate their homes, zip in and out of their turrets, and nectar on nearby flowers.
This time (June 24) we photographed an ant and bee encounter on a turret. The ant? Formica transmontanis, according to ant specialists Phil Ward, professor of entomology at UC Davis, and UC Davis alumnus Brendon Boudinot, who recently received his doctorate from UC Davis, studying with Ward.
"The species nests on the bluffs," Ward told us.
And about that bee-ant encounter? Commented Boudinot: "I suspect the little lady was alarmed by the big bee. These ants and their relatives are rather passive scavengers except during the brooding season, when fresh meat is an order. Most entomeat for Formica tend to be free-walking insects than barricaded larvae, as probably for the bee. For these reasons I think that the encounter may be coincidental!"
Scores of UC Davis entomologists have engaged in research at Bodega Bay. Rachel Vannette, assistant professor, UC Davis Department of Entomology and Nematology, is currently researching Anthophora bomboides stanfordiana and its nests as part of a National Science Foundation grant. Her project on solitary bee provision microbiome includes investigating the diverse community of bacteria and fungi in the provisions and brood cells.
While COVID-19 mandates and precautions hamper her research team's efforts (she's done some preliminary sampling this year and the entire team is planning to do research next year), the digger bees of Bodega Head keep digging, crafting turrets, nectaring on the nearby flora--and encountering ants.
They're all in this together.
- Author: Kathy Keatley Garvey
But there's one thing they don't do. They don't check out the sand dunes, home of the bee villages.
Tiny holes are everywhere, yet nobody seems to notice.
They're the work of digger bees, aka faux bumble bees. These are Anthophora bomboides stanfordiana, researched by native pollinator specialist Robbin Thorp, emeritus professor of entomology at UC Davis.
"The (female) bees suck up water nearby and then regurgitate on the (faces of the) sandstone cliffs to moisten and excavate soil for the tunnels, construct their turrets, and finally to seal the nest tunnel," Thorp says. The bees use some of the soil from the base of the turret to plug the entrance.
The bee turrets are somewhat like our gated communities! Keep out!
The digger bees have "grocery stores" all around them. You'll see the males and females foraging on the wildflowers, which include yellow and blue lupine, California golden poppies, wild radish, mustard, dandelions, and seaside daises.
If you crouch next to the bee villages, a nearby hiker is likely to ask "Lose something?"
No, we found something!
- Author: Kathy Keatley Garvey
They can fool you.
Just like replica designer bags, shoes and sunglasses meant to look like the real thing (think Louis Vuitton, Jimmy Choo and Prada), those digger bees on Bodega Head, overlooking Bodega Bay, look like bumble bees.
Especially the females.
Native pollinator specialist Robbin Thorp, emeritus professor of entomology at the University of California, calls them "faux bumble bees."
They're Anthophora bomboides stanfordiana. "The females are the ones that build the neat turrets in front of their nests on the cliff faces," Thorp says. "The females are even better mimics of bumble bees and they do not sting!"
So, if you're visiting Bodega Head to watch the whales, the waves, the birds or the boats, be sure to check out the sand cliffs for the bee villages.
If you want to capture their images, you'll want to lie flat and motionless on the ground, position your trigger finger, and frame them flying in and out of their turrets.
Soon you'll be visiting Bodega Head to see the whales, the waves, the birds, the boats AND the bees.
- Author: Kathy Keatley Garvey
They're populating the sandy cliffs of Bodega Head, Sonoma County. A sure sign of their presence: dense clusters of turrets.
When they're not foraging among the wild radish (genus Raphanus), lupine (genus Lupinus) and other plants, these ground-dwelling bees are digging nests and rearing their young.
"The female sucks up fresh water from nearby, stores it in her crop--like honey bees store nectar--for transport to the nest," said native pollinator specialist Robbin Thorp, emeritus professor of entomology at the University of California, Davis.
"She regurgitates it on the sandstone, and excavates the moistened soil," he said. "She carries out the mud and makes the entrance turret with it."
The digger bees are sometimes referred to as "alternative pollinators," but they're all members of the Apidae family, which includes honey bees (the super pollinators), bumble bees, carpenter bees, sunflower bees, orchid bees, cuckoo bees and the like.