Mason Bees are a native bee that is very common about the United States. They have proved hardier at resisting disease, pesticides than the honeybee. They get their name for their nesting habit of laying their eggs in a cavity of woodpecker holes, insect holes and hollow stems and sealing off the cavity with an application of mud. The males to not have a stinger and the females will only sting if trapped or squeezed. Mason bees are excellent pollinators. Two or three females can pollinate a mature apple tree. Weather is not a problem for Mason bees they will work in cool and damp weather when honeybee may stay in the hive.