The Blue Orchard Mason Bee is a cavity-nesting solitary species of bee that is found in North America in forests and forest edges in southern Canada (BC, Alberta, Saskatchewan, Ontario, Quebec) and across the continental United States (Rust 1974). Two subspecies are recognized: 1) Osmia lignaria lignaria
(in the west) and 2) Osmia lignaria propinqua
(in the east) (Thorp pers. comm. 2012). See Rust (1974) for a North American distribution map of the species and subspecies. In British Columbia, the Blue Orchard Mason Bee is found in the southern part of the province, in coastal areas and in the southern interior (BC Ministry of Agriculture 2012
The Blue Orchard Mason Bee resembles a hairy black fly, but with the longer antennae characteristic of members of the order Hymenoptera (sawflies, wasps, bees and ants). This species looks black but is actually a dark metallic blue/green in colour. Females are 14 mm in length; males are 11-12 mm in length (BC Ministry of Agriculture 2012). Males have longer antennae and a "tuft of light colored hair in the front of the head" (BC Ministry of Agriculture 2012). The hairs on the body trap pollen.
The Blue Orchard Mason Bee is now used extensively for crop pollination, and is particularly good in urban settings because of its non-aggressive nature. Thorp (pers. comm. 2012) says: "The western subspecies is increasingly used as a managed pollinator of tree fruit crops and is commonly called the Blue Orchard Bee or BOB. BOB has been used successfully on apples and cherries in UT and is currently being reared in large numbers in CA for almond pollination".
Although this is a solitary bee species, several individuals will nest close to each other making it possible to establish colonies for pollination purposes using artificial mason bee homes. Mud is important in nest building and a source of mud is needed nearby for a colony to successfully establish..
Read the BC Ministry of Agriculture fact sheet on this species.
Read about the Environmental Youth Alliance mason bee stewardship program.