he United States, though a number of species of other Osmia are also cultured for use in pollination.
Orchard Mason Bee. Image Courtesy Red58bill.
The bees begin to emerge from their cocoons in the spring when the daytime temperature reaches 14°C (57°F). The males emerge first. They remain near the nesting site and wait for the females to begin their emergence, which can be several days to weeks depending on the number of days of warm weather. The first thing the females do is mate. A female will typically mate once, maybe twice. She will be absent from the nesting site for several days while she feeds and waits for her ovaries to fully mature.
When a female is ready, she seeks out a suitable nest. O. lignaria females like to nest in narrow holes or tubes, though they have been found to nest inside cedar shakes and even keyholes. Beekeepers put out pre-made nesting materials to entice the females to stay close to the orchard. Rain, wind, and free-release (the practice of putting loose cocoons out rather than letting them emerge in their natal nests) discourage females from selecting a nesting site near their natal nest. A female might inspect several potential nests before settling in. Once she has found the right nest, she flies outside of the hole and does an in-flight dance. She is orienting on major visual features in order to find her nest when she returns from foraging.
O. lignaria arrange their nest as a series of partitions, with one egg per partition. She begins the process by collecting mud and building the back wall of the first partition. Then she makes trips to nearby flowers. Unlike honey bees which visit flowers that are miles away, she prefers flowers that are nearest the nest. She can visit 75 flowers per trip, and it takes 25 trips to create a complete pollen/nectar provision. She works tirelessly during the day, only stopping once the sun has gone down. When the sun rises the next morning, she will bask in its rays until she is warm enough to fly. Then she continues where ever she left off the 