What's this bee up to digging around in the mud?

This blue orchard bee is a mason, a builder.

Her material is - you guessed it - mud.

And she works alone.

In fact, unlike those honeybee hives you might think of, most of the 4,000 types of bees in North America are solitary.

See how she scrapes the wet earth?

She collects it with two huge pincer-like tools on her face called mandibles.

She's gathering mud to make her nest.

The nest is long and thin.

In nature, she goes into places like hollow twigs.

At the University of California, Davis, she uses a six-inch-long paper straw provided by researchers.

In this nest without a straw you can see how she builds a wall of mud.

Then she gathers food from spring flowers, but not only to feed herself.

See the pretty purple pollen on the anther of this flower?

She grabs the anthers with her legs and rubs the pollen onto hairs on her abdomen called scopa.

And while she's at it, she sips a little nectar from the blooms.

When she climbs back into her nest, she turns the pollen and nectar into a sweet morsel next to the mud wall.

On this purple ball she lays a single egg.

She repeats this several times in her narrow nest.

Egg.

Wall.

Egg.

Wall.

When she's done, she seals it all up with more mud.

A cross-section of the nest shows her incredible craftsmanship: it looks like a piece of jewelry.

Soon, the eggs hatch.

The hungry larvae feed on their pollen provision, the purple lunchbox their mom packed for them.

Still in the safety of the nest, the well-fed larva spins a cocoon.

The following spring, the adult bee chews its way out.

Just like their name says, blue orchard bees love orchards: fields of almonds and sweet cherries.

And they're really good at pollinating them: A few hundred females can pollinate as many almonds as thousands of honeybees.

And their tube nest means they're portable.

That makes it easy to distribute them to farmers.

So why haven't they taken over the fields?

Well, they reproduce slowly.

They only have 15 babies a year.

A queen honeybee has 500 ... a day.

So there just aren't that many blue orchard bees around.

But some farmers are enlisting them anyway, hoping they can provide some relief to their struggling honeybee cousins.

If you look carefully, you might just spot a blue orchard bee foraging out in a field, helping keep fruits and nuts on our plates.