This website is concerned with “small scale” raising of Orchard Mason Bees. The objective of the site:

1. Present ideas for Housing the nests, both for aesthetic and functional purposes.
2. Suggest alternative Nest cavities.
3. Address the Pests that influence the Mason bee.

Quotes from “Managing Alternative Pollinators”

The Mason Bee Life Cycle

The following is a “typical” life-cycle timeline that might occur given a specific set of circumstances. Details are from the U.S. agricultural handbook “How to Manage the Blue Orchard Bee” by Bosch & Kemp. This scenario assumes “average” temperatures, but in the real world they would vary widely under garden conditions and various temperature regimes. If temperatures are cooler, timelines will become longer and development may cease altogether for a time if it is cool enough.

The cocoons have been stored in a cool place (better yet a fridge) over the winter and are set out in a hatching box when the Maximum daily temperature for the past few days have ranged from the mid to high 50’s. (13-15C).

A year in the life of an Orchard Mason Bee

May 6: Cocoons are set out in a hatching box adjacent to nests.

May 9: First male chews out of its cocoon and emerges. Finds a local eatery for a meal of nectar. Starts to look around the nest area for a date.

May 12: First female emerges. While she is observing this new environment, a male spots her and they mate. She then sets off for a meal and to allow her body to get set for laying eggs..

May 14: Female finds a nesting place, hopefully near the hatching box. She cleans up a channel of any debris, plugs the rear of the nest with mud, and deposits a scent to warn off other females from that channel. It is now her channel, although occasionally another female will “usurp” the channel.

May 15: She makes many trips to flowers to gather pollen & nectar. She forms a “pollen ball” at the back of the channel, and lays an egg on it, which she has decided will be a female. She then forms another wall of mud to protect that cell. She will repeat this until the channel is full. Midway through the channel she will switch from fertilized eggs (females) to unfertilized egg (males). After the last egg has been deposited she will mud off that cell, then create an oversize cell that will remain empty. This is called a vestibule. She then muds off this empty cell. At the entrance to the nest she creates a double wall which is visible from the outside. Having completed the entire nest she will find a new one and start all over. On average she will complete 2-3 nests in her lifetime of 4-6 weeks or so.

This narrative now switches to the newly laid egg.

May 15: The first egg has just been laid, the mother bee has sealed off the compartment with mud. The egg is on its own, sitting atop a large pile of food. The mother is out of its life forever. The egg goes through several changes over the next few days while feeding on the eggs resources.

May 22: The egg hatches and is now a larva. The larva starts to eat its store of food. During the next 2-3 weeks or so it finishes its food while going through several developmental stages.

June 8: Having consumed the pollen ball, it starts to spin a cocoon around itself. All debris such as bee poop and pests are isolated outside of the cocoon.

June 11: The cocoon is now complete, and the larva has become pre-pupa. It undergoes a dormant period.

July 9: The pre-pupa molts into a pupa. It changes slowly into a white pupa and then a fully developed bee.

Aug 20: Development over, the fully developed bee enters a state of diapause until it emerges in spring.

In the Spring of the following year the cycle repeats.

The following is another description of the life of a Blue Orchard Mason Bee. It is quite similar to the above but was developed as a handout to use for various functions.

The Blue Orchard Mason Bee life cycle

The life cycle of the Orchard Mason Bee is most conveniently told from the view of the female.  The male does have a story of course, but his is one of consuming some nectar, doing limited pollination, and never contributing to raising a family.  His only job is to mate,  which he does with gusto. The female on the other hand does everything necessary to ensure the continuation of the species, and works her butt off until her final breath.  

Through winter and early spring Mason bees remain encased in their cocoon.

The Blue Orchard Mason bees are programmed to emerge from their cocoons when the temperature in spring reaches about 13C. or 55F for  a few days. The male bees are mostly at the front of the nest and emerge first, followed by females a few days later. The males are often waiting, and will try to mate with her immediately.  After mating she will spend a short time soaking up a bit of heat and then fly off to find a nearby meal of nectar.  In the next couple of days she will build up some body strength and allow her ovaries to mature so she will be capable of producing eggs.   

She then either returns to the same nest or finds a new one.  Once she has found a promising nest she will lay down a scent that tells other females that the nest is now taken, and not to intrude.  Her next chore is to bring in several loads of mud to place at the back end of the nest.  She then provisions a food supply for her first offspring, consisting of many trips collecting pollen and nectar which she piles at the end of the nest.  Once she has a pile about the size of a pea, she will lay an egg on the food.  She has the ability to determine whether this will be a male or a female, and normally she will lay females at the rear of the nest.  She then creates another wall of mud, sealing in the egg and food supply.  

The mother bee continues to provision cells with pollen & nectar until the nest is full, averaging 5-8 cells for a 6 inch nest.  Halfway through a nest she will start laying eggs that produce male bees.  As the nest is completed she muds off an empty cell to provide additional protection from pests.  This is called a vestibule. She then builds an extra strong mud cap to finish the nest.

It is while gathering food that the female Orchard Mason bee incidentally provides a huge service to nature.  Her body is covered with hair that pollen adheres to, and she rolls around in each flower to gather as much as she can.  She has an impressively long tongue which can suck up nectar, and stores it in a second stomach until she gets back to her nest.  As she goes from one flower to another, some of the pollen from her body will stick to the new flower, thus providing pollination.  This is her gift both to the flower and to mankind.

The female mason bee is capable of laying about 35 eggs, but will average closer to 15 if she lives a full life.  Under ideal conditions she may lay 2-4 eggs a day. After 3 to 4 weeks  of hard work, time and age will catch up, and she dies.

To continue the saga of her life cycle, we now go back to that first eqq she laid.  

Being at the back of the nest the egg will be that of a female, and it sits on an enormous pile of pollen and nectar, called a pollen loaf. The time is around mid spring.  The egg will go through several changes over the next week as it feeds on the resources of the egg. After about a week the egg will hatch, and the bee is now a larva.  The larva begins to eat the pollen loaf, which it will consume over the next few weeks.  The larva continues to change, going through several distinct phases.  With her food supply gone, the larva will spin a silky cocoon around herself, creating a safe place to spend the winter.  This takes about 3 days.  The cocoon is very strong and water resistant.

The larva, inside her cocoon, is now a “pre-pupa” and will rest for a few weeks.  In summer she will start the process of becoming a fully adult bee.  Her body changes in many ways from a pre pupa to a fully adult bee, growing legs, wings, antenna etc.  The process is complete by the end of summer, when she is a fully developed Mason bee.  She now enters a state of diapause, which will slow her body metabolism down in order to conserve body fat through the winter.  She will emerge from the cocoon in spring when the temperature permits by using her mandibles (claws) to chew out of her cocoon.  And the cycle repeats.

It should be noted that the 24 hour temperature average will determine the length of time all stages of development will take.  Cooler than normal temperatures will significantly slow her development. At the larval stages the bee is sometimes in a race with different pests for survival, and warmer temperatures will enhance her chances to prevail. After the cocoon stage, an ideal environment would be in your house at normal room temperatures until late summer.