If you're in the right spot at the same time, you may get a double bonus: a non-native bee and a native bee on a native plant.

We took this photo in Healdsburg last week of a non-native bee (the common European or Western honey bee, Apis mellifera) and a native sweat bee (Halictus ligatus) sharing a plant native to the Americas: the sunflower. 

A golden moment.

Squatters' rights.

A dandelion poking through the rocks near Nick's Cove on Tomales Bay, in Marshall, Sonoma County, seemed an unlikely host for squatters' rights.

It first drew a tiny bee, barely a quarter-inch long. It was a female sweat bee, family Halictidae, genus Lasioglossum, subgenus Dialictus.

She claimed the dandelion all to herself.

Not for long.

Another insect shadowed the dandelion and swooped down to feed.

It was a hover fly, family Syrphidae. (Probably a Eristalinus aeneus, observed UC Davis pollinator specialist Robbin Thorp, emeritus professor of entomology at UC Davis.)

So on one dandelion: a fly and a bee.

The fly is bigger. But the bee can sting. The sting, however, is rated only 1.0 on the Schmidt Sting Pain Index compiled by (now retired) entomologist Justin O. Schmidt at the Carl Hayden Bee Research Center, Tucson, Ariz.

Fight or flight?

Flight.

The dandelion blossom belongs to the fly.

Seems like many folks assume that all bees are "honey bees."

They're not.

If you look around you, you'll see bees of all shapes, colors and sizes nectaring flowers.

And they're not all honey bees (Apis mellifera)!

The one below, as identified by native pollinator specialist Robbin Thorp, emeritus professor of entomology at UC Davis, is a medium-sized striped sweat bee, Halictus ligatus. It's a ground-nesting bee. It's also a native bee (unlike honey bees which arrived here from Europe in 1622 with the colonists).

This particular sweat bee took an avid interest in the Agapanthus in our yard.

The Xerces Society has compiled a wealth of information on native bees. You'll want to check out their Web site and read about the $458,000 grant the society recently received to study native pollinators and protect their habitat.

Okay, everybody in the pool!

That means bees, too?

It does.  Sweat bees.

You may have noticed the tiny bees--common name “sweat bees” from the family Halictidae--in your swimming pool or pollinating your flowers.

They're attracted to perspiring skin (thus the name “sweat bees”). Sometimes when you're splashing around in the pool, you'll feel a sharp but harmless sting.

UC Davis emeritus professor Robbin Thorp, who researches native pollinators, identified this one (below) as a Lasioglossum  (Dialictus) sp. female. 

A dull metallic gray, brown or blackish in color, they're found throughout California. They nest in ground burrows.  

If you want an excellent book on providing native habitat for these native bees,  you'll want to obtain a copy of Farming for Bees: Guidelines for Providing Native Bee Habitat on Farms, written by Mace Vaughan, Matthew Shepherd, Claire Kremen and Scott Hoffman Black and published by the Xerces Society for Invertebrate Conservation, an international, nonprofit, member-supported organization dedicated to preserving wildlife habitat through the conservation of invertebrates.  For more information, contact the Xerces Society  4828 SE Hawthorne Blvd., Portland, Ore. 92715 or access the Xerces Web site.

They write: "North America is home to about 4000 species of native bees, most of which go overlooked. These insects are not the familiar European honey bee, nor are they wasps or other aggressive stinging insects."

With the decline of honey bees, expect to see more reliance on native bees.

Excerpts from Farming for Bees:

• If enough natural habitat is close by, native bees can provide all of the pollination necessary for many crops
• Fifty-one species of native bees have been observed visiting watermelon, sunflower or tomato in California
• Native pollinators have been shown to nearly triple the production of cherry tomatoes in California