Orchard Mason Bees on Vancouver Island, B.C.

Orchard Mason Bees, Osmia lignaria propinqua – are a proven, effective pollinator, perfectly suited for the urban gardener and commercial grower alike in improving their crop production.

 

To give a bit of background to this fascinating native species, OMBs are distributed throughout Southwestern Canada and Western United States and along with many other native species play an integral role in the pollination of plants in North America. A pollination crisis is looming in North America and many other parts of the globe due to loss of natural habitat, altering the plant-pollinator interactions that are critical for crop production. OMBs emerge only once a year as adults, usually around early March and live until early June. After mating, the female locates suitable egg-laying chambers that will be secure for her offspring.

  

 Multi-layered condo design that can be taken apart and cleaned. This shows females at the entrance of their condo where each bee takes ownership of a channel and lays her eggs. This is probably a photo from approx. 15 years ago and didn't take into account the infiltration methods of Monodontomerus wasps and mite spreading between channels.

In the wild, suitable nesting chambers consist of fissures in bark, other insect holes or hollow reeds. Around urban developments, egg-laying chambers can be found in house siding and roofing, holes where bolts have been removed, even gaps in lawn chairs and any other place that provides a blind channel. To encourage OMB females to lay their eggs in a human-designed home, OMB keepers create residences with a variety of channelled orifices called ‘condos’. Condo is a perfect description for these chambers as the OMB females come together to lay eggs but prefer to remain completely independent of one another, similar to the behavioural pattern of the Purple Martin (which some birders may be familiar with!).

 

The female creates mud divisions within each channel creating a ‘cell-like’ structure where she can provide nectar and pollen for her offspring. This is mass provisioning as all the food the developing larva requires is contained within its brood cell. Honey bees and bumble bees open up the cell to prophalactically feed their young and this is called progressive provisioning. Females are laid first so that they are deeper in the channel with the males laid at the entrance, providing the first line of defence should a predator attack the channel entrance.

 
 

Female depositing pollen and nectar from her scopa and crop respectfully, providing food source for the larva. The small white grain of “rice”, is the egg. This channel dado was a mistake on the saw and two channels came together - the beginning of the Hutchings Open Tray System developed this way. They just kept getting wider and wider.

 

The overall length and shape of the channels is an important factor in determining the ratio of females to males, as well as how efficient it is for the female to lay down her mud partitions. With the help of my father (who kick started my interest in OMBs!) combined with my research at university, I determined that the optimum length of the channels needed to be 29cm (11.5”). Both round and square channels are made but square is more efficient for the bees and easier for cocoon extraction, cleaning and easier in production when using a table saw. The clear inspection cover on each tray of the condo allowed me to observe the progress of each female in her channel.
 
Individual female scraping pollen off the venter of her abdomen, (with her hind legs) called the scopa.
 
The more females produced in these channels means a greater volume of pollination since it is the females who do the majority of flower visitations. Important discoveries and structures like the Orchard Mason Bee condo can hopefully be used as a template for other pollinating bees as critical natural habitat continues to be reduced in many important food producing areas of the world.
  

Developing larvae spinning their cocoons before they metamorphose into full adults and diapause over the winter. Winged adults emerge the following Spring.

 
Here's a male sitting on top of a condo waiting for a female to fly by. They are only here to mate and emerge a few days before the females do. They are easily told by their longer antennae, white frons, and usually an overall smaller size than the female.They have the advantage of being fully active before the females and when they emerge from their diapause state, look out.
 

The end of their flight and egg-laying season is normally around late May or early June in our region. The eggs hatch and the larvae develop within each cell, feeding on the pollen and nectar provided by the mother. When the larvae are ready for metamorphosis, they spin their cocoons and begin to transform within, to become a fully developed adult throughout the winter, diapausing until ready to emerge next Spring, beginning the cycle all over again.

 

In the depths of winter, the bee-keeper can help out their population of bees by extracting all the cocoons and cleaning off all of their associated mites, and ridding the channels of any dead bees. The use of sand is the best and safest method for this important procedure. This leaves a clean, ready-to-go brood for next year that hopefully will choose your cleaned condos ready for occupation next Spring.

 

Cocoon extraction and cleaning and close inspection for parasitoids. The best method for cleaning parasitic mites, is the sand method as seen in my video, “How To Clean Orchard Mason Bees Using Sand” at http://www.youtube.com/watch?v=KSr88h8iKQk&feature=related 

 

 

Emerging boxes and transportation containers full of cocoons. Sand cleaning method prevents the cocoons from getting wet in the bleach cleaning method, and it removes all the mites.

 
 
Some of my condos set up pointing both east and west, along the south side of my house deck. Each tray has a clear film covering the channels to view the bees and their developments within.
 
 

Our open-channel design of condo tray which has proven very successful. Can you spot the twin eggs on the one cell? It’s in the left box, on the top right corner. Also note the active female in the right chamber. The cover has been removed and flipped over for better photography.

Is this a trait of quasisocial behaviour?

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