Dahlias and a Sweet Baby Bee

These little bees seem to live in this dahlia plant.  They hide within the curled-up petals as though they are in a honeycomb.  Some days a flower will have 4-5 bees in it.   We have many dahlia plants, and while these bees visit all the flowers of all the dahlia plants, they live only in one of the plants.  There are also some scary-looking jumping spiders that have moved to this plant.