The blue orchard bee (Osmia lignaria), is a solitary bee, native to North America. It is an extremely effective pollinator and has been domesticated for the pollination of fruit and berry orchards. This bee has the potential of replacing honeybees as the most important fruit tree pollinator.

These dark metallic blue/green bees are gentle and easy to manage. They will forage for nectar and pollen, and pollinate in poor weather conditions, such as cloudy skies, and cooler temperatures. They nest inside wooden holes, but only use pre-existing ones. Although the bees are solitary and go through their life cycle alone, they are gregarious, meaning that they nest close together. It is this gregarious behaviour that has provided the opportunity to domesticate them.

The mated females lay their eggs in holes in wood and seal off the entrance with a rough mud plug. Inside the hole, each egg is laid in an individual mud sealed cell with a food supply of pollen and nectar for the resulting larva. When the adults are grown, they break out their cells and then break out of the mud plug at the entrance of the hole. The eggs near the entrance hatch into male bees so they come out first and wait for the females to emerge so that mating can begin. The female bee lives for about one month in the spring time and will lay about one or two eggs per day.

Females are larger than the males. The males are more slender and can be identified by their longer antennae and a patch of light coloured hair on their heads. Both male and female blue orchard bees have bodies that are covered in hair. This makes them good pollinators because they can carry pollen grains in their hair from flower to flower.