Mason bees are solitary bees but they also prefer to live close to each other. The females each nest in their own tubes and do not help each other. They only raise one generation a year.
The life cycle of a Mason bee according to Our Native Bees, A day or two after mating the females begin searching for new nest sites, such as insect holes bored in wood, plant canes, gaps in siding, masonry weep holes and, of course, Plan Bee Houses, if they’re lucky enough to find one!
Each female constructs her own brood cells using mud (Orchard Mason Bees) or leaf pieces (Leafcutter Bees) to partition each brood cell. She forages for pollen and nectar, and makes a pollen-nectar loaf upon which she deposits one egg. She then seals the cell with either mud or leaf pieces, and begins the process again, normally making 6 – 7 brood cells in a 6″ deep hole or nesting straw. About one week later the eggs hatch and the larvae feed until they’ve eaten all their food supply, which takes approximately six weeks. By late June the larvae spin cocoons around themselves and have developed into pupae, or fully-formed adult bees, by late summer. From September to April they remain dormant in a state of ‘diapause’ until the warm spring temps awaken them and the amazing cycle repeats itself.
By comparison, honeybee worker development is 21 days, egg to adult.
Fun facts from Kym Pokorny of The Oregonian…
Females decide whether to lay a female or male egg. A female lays about three to four male eggs for every two females because males emerge from the nest first and are more likely to end up as dinner for a predator. Since the males have no other job except to fertilize the females, they stick around the entry waiting for a female to emerge.
It takes the female about 15 to 35 trips – with 75 flower visits per trip — to collect enough pollen and nectar to feed one larva. She lays approximately 30 eggs in her lifetime.
Keeping mason bees is one of the easiest method of beekeeping. What is so amazing about them? 200 mason bees will out-pollinate 2000 honey bees, they will fly at cooler temperatures than honeybees, and rain doesn’t bother them. Mason bees rarely sting.
How do Mason bees pollinate so well? Their pollen is gathered ‘dry’ on the underside of their abdomen. It’s more easily transferred than the wet pollen of the honeybee.
It’s November now. The adult bee is fully formed and it’s the time of year to inspect for Chaetodactylus mites, (not Varroa mites, common on honeybees). Some people advise to wash the cocoons in a sieve with warm water. I hesitate to do that, it seems like it might be too rough. I opt to unroll the tube and gently brush off the debris.