Build it and they will come.

Baseball's “Field of Dreams?”

No, a bee nesting block.  Think "bee condo."

It's an artificial nesting site made of wood and drilled with different-sized holes and depths to accommodate the diversity of native pollinators. Often the bee block is nailed to a fence post. Native bees, such as leafminer bees and blue orchard bees, build their nests inside the holes.

Fact is, North America is home to about 4,000 species of native bees. (The  common honey bee is not a native; colonists brought it here from Europe in the 1600s.)

Members of the Xerces Society, an international organization "dedicated to protecting biological diversity through invertebrate conservation," are keen on protecting the habitat of native bees and other native invertebrates. As part of their public outreach program, they publish books, pamphlets and fact sheets. These include  Pollinator Conservation Handbook, Farming for Bees, and the fact sheet, Bumble Bees in Decline.

As for the bee condos, thousands are sold each year in the United States, according to entomologist Mace Vaughan, pollinator program director of the Xerces Society, based in Portland, Ore. As concern for the environment grows, more and more farmers and urban gardeners want to attract and accommodate the native bees. Native bees are important crop pollinators, Vaughan says, and the work people do on behalf of the pollinators also supports other beneficial insects and wildlife.

Vaughan, who escorted a group of us on a recent Yolo County farm tour, said many of our native bee species are much more efficient than honey bees at pollinating some crops.

"For example, only 250 female orchard mason bees (genus Osmia, also called blue orchard bees) are required to effectively pollinate an acre of apples, a task that would require 1.5 to 2 honey bee hives--approximatley 15,000 to 20,000 foragers." (Source: Farming for Bees, a Xerces Society publication.)

Native bees sport such names as miner, carpenter, leafcutter, mason, plasterer or carder, reflecting their nesting behaviors.

See the bee (below) heading toward the bee block? Xerces Society member Robbin Thorp, emeritus professor of entomology at UC Davis who researches native pollinators, including bumble bees, says this is a female leafcutting bee, "probably the introduced Megachile apicalis, a specialist on Centaurea species, especially yellow starthistle."

The leafcutter bee, as its name implies, cuts leaves to form its nest.

We've all heard of the cuckoo clock.

And most of us have heard of the  cuckoo bird (Cuculus canorus), which lays its eggs in the nest of birds of other species. 

But the cuckoo bee?

Yes, there is a cuckoo bee. The female lays her eggs in the nests of other solitary nesting bees.

They resemble wasps.  You can see these slender-waisted bees hovering low to the ground, sneakily searching for burrows of other solitary nesting bees.

Like an identity thief, they try to avoid detection. They slip into a  a burrow and lay their eggs in the host's nest.  The hatched larvae then eat the host's food and parasitize (kill and eat) the host's larvae.

Some cuckoo bees are more abrupt and don't smuggle their eggs into a nest.  In Insects  of the World, Walter Linsenmaier writes how a few species of Sphecodes, invade the nests of mining bees (Halictus), and "with naked force when necessary" slaughter "everything that opposes them."

Then the cuckoo bee flings the opposition out the entrance. Did anybody say "cruel world?"

Cuckoo bees are not nice and they're not ready to make nice. If this is a world of The Givers and The Takers, then they're the takers.

I captured this image of a cuckoo bee last week. Said Robbin Thorp, emeritus professor of entomology at UC Davis:  "It's a cuckoo bee, probably the genus Triepeolus (maybe Epeolus) and probably a male."

If she were boarding an airline, she'd be charged double for baggage.

But she didn't and she wasn't.

She's a pollen-packed sunflower bee enjoying our sunflower. Not a honey bee but a sunflower bee.  A native bee.

A Svastra obliqua expurgata (Cockerell), as UC Davis native pollinator researcher RobbinThorp said.

“ I have seen them nesting in gardens in Davis--including at one of the dorms on campus--and nesting in a dirt roadway on Joyce Island (Solano County),” said Thorp, emeritus professor of entomology at UC Davis.  He's also seen the sunflower bees visiting native plants in a Sacramento cemetery.

“The males,” Thorp said, “spend much time cruising searching for females.  The males  have long antennae and thus are called ‘long-horn' bees.  The males also have greenish eyes, and bright yellow markings on the lower face.” 

 Both males and females are larger than honey bees and fly more rapidly when foraging, Thorp said.  “They are among the native bees that interact with honey bees on the male rows of hybrid sunflower fields, disturbing the honey bees and causing them to fly out of the male rows into the female rows, thus increasing the pollination efficiency of honey bees as shown in the research by Sarah Greenleaf and Claire Kremen.”

Kremen, an affiliate of the UC Davis Department of Entomology and a regular at the Harry H. Laidlaw Jr. Honey Bee Research Facility on the UC Davis campus, is a conservation biologist at UC Berkeley and the recipient of a MacArthur genius fellowship.

Thorp said Svastra females have dense brushes of hairs on their hind legs and transport pollen dry in these brushes (scopae). Honey bees carry pollen moist on concave hair-fringed pollen baskets (corbiculae).

I wonder what writer Gertrude Stein (1874-1946), known for such prose as “a rose is a rose is a rose” and “there is no there there,” would have said about bees.

Perhaps “a bee is a bee is a bee?” 

Or “a sunflower is a sunflower is a sunflower?”

It isn't and it isn't.

“I've got black bumblebees buzzing around our backyard like crazy,” the caller said. “They're loud. Very loud. They're dive-bombing and scaring the cat and dog. I've never seen anything like this before.”

The unwelcome visitors were not bumblebees. They were carpenter bees.

Carpenter bees? No, they don't know how to read blueprints or frame floors and walls. They nest in weathered wood, like your fence posts, utility poles or firewood. They tunnel into your deck, railing, shingles and shutters. 

They are pests.  But they're also pollinators. Native pollinator specialist Robbin Thorp, professor emeritus at the UC Davis Department of Entomology, fields many calls about carpenter bees.

This one pictured below is a male carpenter bee,  Xylocopa tabaniformis orpifex Smith NB, Thorp says. It is stealing nectar from the base of the flower.  They also spend a lot of time cruising around chasing everything that enters their territory.”

Contrary to popular opinion, carpenter bees don't consume wood.  If you don't want them around, paint or varnish your wood. You can also plug their (unoccupied) holes with steel wool or caulk, or screen the holes so they don't return.

The female and male carpenter bees that nectar the salvia (sage) in our bee friendly garden are about the size of bumblebees. “Robust” comes to mind.  Okay, fat. They're fat.  

Their abdomens are bare and a shiny black. If you photograph them, you'll see your own reflection. It's like seeing your reflection in a black Lamborghini.

The female carpenter bees are a solid black, while the male carpenter bees are lightly colored around the head.

In comparison, bumblebees have hairy abdomens with at least some yellow markings.

If I were a carpenter and you were a…nah, I'd rather be a bumblebee.