Leaf Cutter Bees

I watched these weird looking bees and I wasn't actually sure they were bees. They moved so fast, like wasps, but yet went deep into the digitalis plants. One fatter bee, guarded the towers of pink blooms in the pot near my pathway. It darts at other bees, then humps certain bees that go into the flower. Other bees are chased away. He also darts over to the other digitalis and guards those too. He burns a lot of energy going back and forth. He even chases off bumble bees. After a bit of research I found out these are leaf cutter bees. These are Megachile Brevis, and they are probably living nearby. It can't be far. These bees are not social. They don't have a hive or honey. They come out in spring and frolic. The female lays eggs in a little tunnel shaped like a straw. She deposits something like a ball of nutrients, an egg, then puts a little leaf disk to separate the layers of eggs. As evidenced from the roses, they cut small circles. I don't know if they deposit eggs every now and then or all at once, but once those egg babies are laid, nothing more is needed of the ladies and they die. The larvae eat all the sustenance and incubate into bees. It isn't very romantic. The male in my yard latches right onto the girl and does a few seconds of pushing then flies off. He uses the plants as his chick magnet, chasing off all others that might threaten his copulation zone. The honey bees are all over the butterfly bush. I will look into their little habitat tomorrow. I will try to add pictures of the carpenter bees, but for now, all I get is a blur.