Why we should all Encourage Mason Bees
to Live in our Back Yards
About Mason Bees
WHY WE SHOULD ALL ENCOURAGE MASON BEES TO LIVE IN OUR BACK YARDS
PHOTOS OF MASON BEES
also known as Blue Orchard Bees
The bees are flying towards and entering a bee house. You can see the white parchment liners inside the holes, and the yellow on their tummies is masses of pollen that they are taking in to the holes to heap up in front of each egg. The young will eat this for food when they hatch. The bees are actually black, as in the last photo, although they glint dark blue when the sunlight hits them.
Why Mason Bees
Many of the regular honey bees where I live in Canada are being wiped out by a small mite. Elsewhere, all over continental North America, they are disappearing in record numbers. Our crops still need to be pollinated and one alternative is to encourage mason bees to come and nest in your garden or small orchard. Mason bees are solitary bees that do not make a communal nest, and are therefore less likely to transmit diseases, and they only sting when their lives are threatened. They are much better than honey bees at pollinating your crops and they are doing it unknowingly as they gather pollen to feed their young.
The bees' life cycle
The bees emerge from their cocoons in the early spring when the temperatures get to about 10ºC (55ºF). They mate and start laying eggs in small holes in wood, so if your nesting boxes are in the right place at the right time, they will (hopefully) lay their eggs in there. The females lay their eggs, one in front of the other, in a hole, each with a small heap of pollen for food for the larva and a plug of mud to separate it from the next egg. Once the hole is full they move on to the next hole. While they are gathering a supply of pollen for food for their larvae to eat when they hatch, they incidentally pollinate your fruit trees. When the adults have finished laying eggs for the year, they die (probably form sheer exhaustion!), usually in late May or early June. The larva stay in the nesting box all year until they emerge the following spring as an adult bee, ready to begin the cycle all over again.
- A supply of mud close by - a puddle of water near some fine soil should work.
- An East, preferably, or South-East facing wall.
- Shelter from the noon-day sun and the rain. My nest box went mouldy where it got wet from the rain, so keeping the bee house out of the rain is a must. Under the eaves of your house or a under the eaves of a shed is good.
- Keep an eye out for ants, and put tanglefoot in their path if necessary.
- You may have to protect the larvae from woodpeckers with some wire mesh across the front of the nesting box.
Tubes for holes
You can either buy tubes, or make your own, to line the holes for easier cleaning in the spring time. Cut strips of parchment paper 2.5in to 3in wide and roll into narrow tubes. You find the parchment paper in the baking section of a grocery store. Push the parchment tubes into the holes, leaving about 0.5in sticking out of the back if you have a removable back on your nesting box as mine do. Squash the ends flat when you put the back on. This makes it easy to remove the liner tubes in the spring when the bees have left the block. If you do not have a removable back, you will have to make the tubes just flush with the back, and then they will be more difficult to remove.
Cleaning the holes
The easiest way to clean the holes is to remove the liners, if you use them, and replace them with fresh ones. If you do this in mid'winter, you can unroll, or slit open, the liners and remove the bee cocoons. Store the cocoons in a cool, dry shed over the winter in a box with a hole in it for them to emerge in the spring. Put the box out beside your cleaned bee block when the temperature is around 10ºC, just before your fruit trees blossom. If you don't have liners you can get a 5/16in drill bit and re-drill the holes to clean out all the gunk, obviously waiting until the bees are no longer in the holes!
You have to time the cleaning correctly if you want to clean out the nesting holes after the bees emerge in the spring. You will have to be very quick before they have had time to start laying eggs in the holes again.
Rotating the boxes
I like the idea of rotating the nesting boxes. As the bees are emerging, you put out boxes you have already cleaned and then clean the dirty ones, once they have all emerged, and save them for next year.