The Red Mason Bee has a very different life cycle than other bumblebees because it is a solitary bee. This means it has no queen or workers.

Around March and April, the males first become active. They wait at nest tunnels until the females emerge and then mate immediately. After mating, the females begin searching for suitable nesting sites—small holes in wood, reeds, holes in walls, or special bee hotels. In each nest tunnel, the female builds several cells in a row. She provides pollen and nectar as a food supply. She lays an egg on top of this supply. Then she seals the cell with a wall of clay or mud. Hence the name Red mason bee. A single nest tunnel often contains multiple cells, arranged from back to front.

After a few days, the larvae hatch from the eggs and feed on the pollen and nectar supply. Once the food runs out, the larvae pupate in sturdy cocoons. Inside these cocoons, they develop into adult Red Mason Bees.

The Red mason bees are fully developed for winter, but they remain safely in their cocoons. This way, they sleep through the cold months. During the first warm days of March and April, the adult red mason bees gnaw their way out of the cocoons. The males emerge first and wait near the nest tunnels for the females. Then the whole cycle begins again.