I had an opportunity to get a good look at one of our native pollinators during our camp-out last weekend. Fellow campers discovered the nest of this colorful little ground bee in the lawn at the campground.
The bees were coming and going from a small hole in the ground. The bees seemed to like the easy-digging soil, and made quite a little mound around their entrance. Judging from the amount of dirt removed and the bee traffic, there was a small colony of perhaps 1-2 dozen bees in the ground. Most of the time there was a bee “on guard” at the top of the hole.
The bees were coming back with a bright yellow pollen on their legs. They were amazingly quick at entering the hole when they came flying in. The guard bee would back out of the way and in a flash the incoming bee was in the hole and out of sight.
A little internet research reveals that this is most likely Agapostemom melliventris. The bee is common in the western United States.
Sweat bees often nest in the ground with several females tending their own brood in nest side-chambers off the main tunnel. Unlike honey bees, there is little communication between individuals.
Squash Practice 
Hi Gary! I am an entomology PhD student working on some lesson plans with high school biology teachers. Would it be possible to use one of your images for a lesson plan on pollinators? I am needing an image of an Agapostemon nesting in the ground and yours fits the bill! The lesson plan will eventually be published on the Ag in the Classroom website for public use and I would credit you as the image source. Let me know if this is a possibility! Thanks!
Hi Gary,
I am giving a presentation about native bees and would love to include your pic of a sweat bee living in the ground. May I use it (with proper photo credits of course!)?
Sincerely,
Laura