The slow transition to spring has affected pest insects and their predators, but a discussion of beneficial insects is always relevant. Solitary bees are not often the subject of scrutiny or even interest, the concern over the health and decline of pollinator population seems to be solely focused on hive bees while those solitary species in the families of Megachilidae (mason bees) and Colletidae (plasterer bees) are equally important.
Mason bees are solitary bees which nest in the hollow galleries abandoned by other wood-boring insects. So-called for their compartmentalizing of galleries made of mud, these early season bees usually first become active around St. Patrick’s Day. This year and last were especially slow to warm and bee activity and bee emergence has yet to be recorded.
Mason and plasterer bees are incredibly beneficial insects as they are the first pollinators of the season to emerge. Mason bees display protandry, which is where male bees emerge first followed by the females a few days later. Females are a commodity and it seems the earlier the males are to emerge and survive the more likely they are to secure a mate. Mated female mason bees spend hours each day collecting pollen and nectar and developing it into little cakes or balls, which they use to fill the hollow stems and galleries where they live. She will deposit eggs on the pollen cakes, seals that compartment with mud and repeats the process until the nesting tube is filled with egg compartments. Eggs in the back of the tube will become females and those in the front will be males. During summer and into fall the eggs will become larvae and eat their way out of the nest. They will completely pupate into adults late in the fall, settle in for winter and emerge early spring.
Mason bees provide ecosystem services widely valuable to human, wildlife and plant populations; they pollinate native and non-native flowering plants including many fruits and vegetables cultivated for popular consumption, ornamental flowering plants and many species which provide habitat and forage material for wildlife.