Is there a readily available species of colonial bee that requires no care?

Yes, there is a Native North American Bee called a Mason Bee or sometimes called a Cutter Bee because it cuts little round shapes out of leaves to cover it's eggs instead of producing wax.

A Mason Bee will pollenate approximately 300 times the number of plants that a Honey Bee will pollinate during it's life. Once started in your garden, they will require no maintenance what so ever.

Mason Bees do not live in colonies like Honey Bees. They prefer to find small holes in wood and lay their eggs inside the hole. Then they fill the hole with pollen from your veggies and flowers, and finally cut little round pieces from leaves to seal up the hole.

To attract Mason Bees, Get a 4 inch by 6 inch Untreated wooden block and drill a series of holes 5/16 inch in diameter. Then mount the post in your garden. Or as one person I know did, get a 6 x 6 Untreated wooden post and set it as a post in the middle of the garden and drill holes all over it. This takes a lot of time to drill holes in a tall post.

Or you can get 5/16 inch diameter straws, bundle them together and tie the bundle to a fence post.

Do not confuse Mason Bees with Carpenter Bees that eat holes in your homes structure. Carpenter Bees look like huge all black Bumble Bees. Mason Bees are honey bee size and black with yellow stripes around the abdomen.

There are wild bees. If you can get the queen into your beehive, they take care of themselves.

Except you have to remove the excess honey once in a while. Contact a beekeeper, they can set you up.