Favorite sites for nesting include tubes of lawn furniture or boring into urethane foam roofing material. Once the female has built her nest, she provisions it with a mixture of pollen and nectar. She lays her egg on the food. The egg hatches into a tiny grub that consumes the food over the period of a week or two, and then pupates. Depending on the time of year and the species of bee, the newly emerged adult bees may fly out of the nest to start new nests, or may stay underground protected in the nest until the following spring.
Carpenter bees are another common example of a solitary bee.
The hairy, bluish-black bees you see visiting flowers or hear buzzing by each spring are female carpenter bees. They are over one inch long and about as wide as your thumb. Female carpenter bees are capable of stinging, but are not normally aggressive. They do not sting unless trapped, stepped on or otherwise endangered. Male carpenter bees are similar in size to females, but are blond or tan-colored.