The cluster began with one, then two. (Photo by Kathy Keatley Garvey)

Just call them "snuggle bugs."

Or "snuggle bees."

After spending the day chasing the girls and defending their  patch of Mexican sunflowers or Tithonia, a cluster of  Melissodes robustior males settled down for the night.

Their bed last night: a Tithonia leaf curl. Before that, some lavender stems. Before that, a Tithonia blossom.

The occasion: Boys' Night Out.  While the girls sleep in their underground nests, the boys find a comfortable and presumably safe place to get some shut eye.

Last night a single male chose the bed, and soon half a dozen others joined him. They are territorial during the day, but at night, it's all fuzzy wuzzy, peace 'n harmony, and "brotherly love." 

Meanwhile, a European paper wasp flew by, its legs dangling, and a nearby garden spider crawled to the edge of its web and checked out the sleeping boys.

Melissodes is just one of the bees mentioned in the book, California Bees and Blooms: A Guide for Gardeners and Naturalists (Heyday). It's the work of the University of California-based team of Gordon Frankie, Robbin Thorp, Rollin Coville and Barbara Eritter, all of whom are linked to UC Berkeley, past or present  (Thorp, a distinguished emeritus professor at UC Davis, received his doctorate at UC Berkeley.)

The authors point out that there are 130 Melissodes species in the New World, "predominantly in North America, which is home to approximately 100 of these."

Fifty Melissodes species have been found in California alone. "Only (the) species, M. robustior, M. tepida timberlakei and M. lupina are widespread and common," they write.

Our Vacaville bee garden annually draws dozens of Melissodes robustior to the Tithonia. 

Widespread and common? Yes, at least in our little bee garden.

Katharina Ullmann

The excitement began when Martin Guerena, an integrated pest management (IPM) specialist with the City of Davis, encountered a native bee nesting site Wednesday in front of the U.S. Bank, corner of 3rd and F streets, Davis.

Some passersby figured they were wasps and were asking bank officials to exterminate them.

Guerena contacted UC Davis officials and learned that these particular bees were sunflower bees, Svastra obliqua expurgata, nesting underground. Native pollinator specialist Robbin Thorp, distinguished emeritus professor of entomology at UC Davis, identified them, and Katharina Ullmann, who last year received her doctorate in entomology from UC Davis and is now a crop pollination specialist with the Xerces Society for Invertebrate Conservation, circled the site with yellow caution tape today and posted an educational sign.

"This is a sunflower bee nesting site," Ullmann wrote. "These gentle bees are native and ground nesting. The females of this species are solitary bees, but like to nest near each other and often use the same nest entrance.  Their nesting tunnels lead to individual chambers below the ground. Each chamber is filled with pollen, a single egg, and then closed off. These eggs will hatch, develop underground, and emerge next summer to build their nests. This sunflower bee is one of 1600 species of native bees found in California."

The sign included a "name tag" with the common name, scientific name, favorite food (pollen and nectar), favorite place to be (3rd St., Davis), favorite colors (yellow, red and orange) and favorite saying (YOLO, You Only Live Once).

Ullmann added: "Three things you can do to help this bee: (1) protect nests, (2) plant flowers and (3) use fewer insecticides.

Sunflower bees are also nesting nearby--near the Pizza Guys restaurant and the 7-Eleven parking lot. UC Davis entomology graduate student Margaret "Rei"Scampavia identified the bees as from the same genus, and also noted the presence of cuckoo bees.

Thorp says the female cuckoo bee, Triepeolus concavus, lays her eggs in the ground nests of other bees, including the sunflower bee, Svastra. Cuckoo bees are kleptoparasites, meaning that they steal the food stores provisioned by the host bee. Cuckoos lack pollen-collecting structures (scopa). So when the cuckoo bee eggs hatch, the larva will consume the pollen ball collected by the hosts, and kill and eat the host larvae. Like human kleptomanias, they've found a way to make it in this world at the expense of others.

Ullmann, who studied with pollination ecologist Neal Williams of the UC Davis Department of Entomology and Nematology, wants to protect the sunflower bees and figures an informational sign will help.

Frankly, it's quite appropriate that the sunflowers bees are nesting near the bank. They're making their own deposits--pollen!

Two species of male sunflower bees, Svastra obliqua and Melissodes agilis, spend the day on our Mexican sunflowers (Tithonia) chasing the girls and protecting their turf.

Sometimes I wonder why they don't tire out sooner than they do. The Energizer Bunny could take lessons from them.

But a night, it's a different story.

While the female sunflower bees return to their underground nests at night, the males sleep in a tight cluster on the nearby lavender stems. These boys are s-o-o tired that they're often "in bed" by 5 or 6 p.m.

But their cousins, the honey bees, are still foraging, gathering pollen and nectar for their colony.

So what a surprise last weekend to see a worker bee doing what her name implies--working!--on a lavender blossom next to the sleeping boy bees, Melissodes agilis.  "Excuse me, boys! There's nectar here! Do ya mind? Could you move over just a little bit?"

I aimed my little pocket camera, a Nikon P340, and caught the girl on the boys' night out. 

She'll be back. So will the boys.

(Editor's Note: You can learn more about native bees in the Heyday book, California Bees and Blooms, a Guide for Gardeners and Naturalists, written by UC-affiliated authors Gordon Frankie, Robbin Thorp, Rollin E. Coville, and Barbara Ertter.)

You can tell it's summer along Yolo County roads by the acres and acres of sunflower fields.

Looking like real-life Van Gogh paintings (Van Gogh painted them in vases, Mother Nature paints them in rows), the sunflower fields are nothing short of spectacular. With tousled heads rising toward the sun and golden locks nodding in the breeze, they stand their ground.

Sunflowers (Helianthus Annuus), native to North America, are one of our most recognizable flowers. They're a good food source, a designer's dream, and dugout tradition.

Earlier this year we fielded a call from a young man from southern California who wanted to know when the sunflowers would bloom in Yolo County.  He wanted to propose to his girlfriend in a sunflower field.

This is one agricultural crop that does not go unnoticed. Not by people, not by animals, not by birds, and especially not by honey bees and sunflower bees.