Inside: You can frequently find male mason bees, Osmia lignaria, hanging around near the nests of females.
Male mason bees emerge before the females
After being holed up for about ten months, this male mason bee (Osmia lignaria) pushed the mud plug out of his paper straw and luxuriated in the sunshine. Then, within twenty minutes, he was out of the house and sipping at the Siberian squill in the back garden.
Male mason bees always emerge first and have distinctive behavior. After a brief stretch, they sip some nectar and then find a warm place to rest—usually on a rock or on the sunny side of the house. They repeat this process over and over, sipping and resting, sipping and resting. Sounds like typical male behavior, right?
Look for pairs mating in the flowers
Once the females emerge, eating and mating replace eating and resting…at least that’s how it appears. Like most male bees other than honey bees, the males can mate many times, usually in the flowers or on the ground.
We can distinguish male mason bees from the females by their dense “moustache” and long antennae. They are also smaller than their female counterparts. The females have large mandibles and carry pollen in an abdominal scopa.
Because Osmia lignaria are particularly good at pollinating orchard crops, and because they glint blue in the sunshine, they are often called “blue orchard bees.” A perfect name.