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Orchard Bees Osmia lignaria (and other species)


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Alternate name: Mason Bees

Family: Megachilidae, Megachilid Bees view all from this family

Description 3/8-1/2" (10-14 mm). Black with long black hair on thorax and sides of head. Tongue long; mandibles prominent, sharp. Female has pollen brush below abdominal segments 2-3. Legs black. Wings clear to brownish.

Warning As with all bee species, females will sting if provoked.

Food Adult drinks nectar. Larva feeds on nectar and pollen.

Life Cycle Adult bees emerge in spring; males precede females. Mating takes place as soon as females emerge; males die soon after mating. Females visit various flowers collecting nectar and pollen, which is transported to a nest. One egg is laid in each nest cell where larvae develop, feeding on pollen/nectar mixture. Larvae construct tough cocoons and pupate until following spring.

Habitat Meadows and forest edges.

Range Throughout North America; every state and Canadian province has a dozen or more distinct species, each showing more limited distribution.

Discussion Nest architecture is highly variable within this family of solitary bees. Orchard or Mason Bees convert clay into a cementlike material. Some species include plant fragments in their nest construction. Others build inside empty snail shells, and still others line each nest with snips of flower petals. Some species nest in natural cavities such as the holes created by wood-boring beetles or the hollow ends of twigs. The individual cells of this type of nest are divided by a mud partition, or in the case of those species called leafcutter bees, the partitions are made of leaf fragments that are snipped out of nearby plants. Gardeners are often puzzled when they find neat circular holes cut from leaf edges, with no evidence of leaf-eating insects nearby. Many species of solitary bees have declined sharply in North America as they have been out-competed by the introduced European honeybee. Plant specialists now realize that many native plants are specifically adapted to pollination by solitary bees; when they are visited only by honeybees they produce significantly fewer fruits and seeds.