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Management

Mass release of alfalfa
leaf cutter bee cocoons.

I started this article some time ago, before I had all the pictures in place.  Even though most mason bees have been set out, I think it is good to compare mason bee release systems to the commercial Alfalfa Leaf cutter bee industry mas  release system.  I think we can learn a lot from the 50 year old alfalfa leaf cutter bee industry.

How to set out bees, still in their cocoons, depends on quantity of cocoons, type of nests and whether predators exist in the area.

Leaf cutter bee nests

Alfalfa leaf cutter bee producers in the Canadian Prairies, usually mass release leaf cutter bee cocoons on trays.  Thousands of cocoons are placed on trays.  Trays are set up inside yurts or similar structures that house leafcutter bee nests. Three weeks prior to setting cocoons out, leafcutter bees are put through a warming period so that bee emergence is relatively fast.  Trays are out for less than a week.  A mere 7 days or so is little time for winds and predators to upset the trays full of cocoons.

Prairie yurt with a tray of cocoons
set on top of nests.

It is a different story with mason bees.  Emergence is often longer than a week, especially under cool spring temperatures.  The number of cocoons set out are often  less than a hundred or several hundred and less often in the thousands.

Setting out a few cocoons (less than 100) small vials with a bee size hole in the lid works well.  Plastic vials are usually rodent proof.  The space underneath the roof of the Beediverse Highrise  is a great place to place the vial full of cocoons.  This space is protected from the sun, but receives the heat through the roof.

the Highrise roof protects vials
of cocoons from
predation and sun.

Beediverse Emergence box
protects cocoons from predation
and the elements.

When setting out 100 or more cocoons, small vials are too cumbersome and too time consuming.  It would be very easy to set out cocoons in open trays.  I have tried setting cocoons out in trays, even in covered trays, but it has been less successful.  Their extended emergence becomes problematic.  Winds sometimes tip trays onto the ground  Trays also make cocoons more vulnerable to predation from animals such as spiders, squirrels, mice, and wasps.  To decrease the chance of predation a wooden box with an exit hole such as the Beediverse Emergence Shelters gives the best result.  Two are sold for $19.95.

Small and large release boxes.
Dave M.  Port Alberni BC

I find these extremely handy.  I fit about 200 cocoons into each one.  I make notes on the outside to tell me where cocoons were produced.  This is handy because after spring emergence, I can check what the emergence was the previous spring.  Emergence should be 95% or more.

David M. from Port Alberni uses a square box with a hinged lid.  Each box, with two layers of cocoons, holds about 2000 cocoons.

If you have a system you would like to share with our readers, email me a description and pictures.

In a previous blog I wrote about 6″ diameter petri dishes that are so handy for storing large numbers of cocoons.  When you have a large number of cocoons, it is  wise to keep them refrigerated.  Refrigeration keeps them away from predators and keep them relatively safe. BUT I must reiterate that humidity has to be at least 60%.  In order for cocoons to survive, there has to be at least 60% humidity.  Any thing less than that will kill the bee over time.  Use a fridge  that you manually have to defrost .  These fridges keep humidity over 50%.  As a precaution keep a container of water inside the fridge.
Petri dish for storing 100-200 cocoons
A stack of petri dishes filled with cocoons are placed inside this fridge for storage.  Cocoons are then placed into release houses ready for release.
 
This is the freezer compartment in a manual-defrost type fridge.  The stack of petri dishes are just below this compartment.
Use a thermometer to let you know when temperatures are too warm or too cold.
A container filled with water ensures a greater than 60% humidity.
Release houses filled with 100 cocoons are held in the fridge, prior to  releasing into the D27 yurt.  The cardboard straw temporarily plugs up the front entrance of the Starter Cottage.

Starter Cottages, available from my on-line Beediverse.com web site, are by far the best little box for use as a release box/emergence box.  I have tried all kinds of boxes, made from cardboard, plastic and wood.  Cardboard is too fragile and predators can get at the cocoons too easily.  Plastic sometimes overheats and is slippery for the bees to walk on while exiting.  Starter cottages are bee proof, can be washed for next year, and are relatively predator proof.  I usually place 100-200 cocoons per cottage.  One day before setting the cottage out into the field and adjacent to nests, I set the cottage out in the kitchen table. It gives the bees a head start on emergence.  I don’t want bees to fly around my kitchen, so I need a bee proof container= Starter Cottage.

I used this plastic container to carry 5 Starter cottages to the field site.   Each has about 100 cocoons.  The door to the cottage is secured with a pin, sometimes two.  The entrance hole is temporarily plugged with a cardboard straw until the starter cottages are set up in the yurt or other structure.  These Cottages have been out of the fridge and into a kitchen environment for 24 hours.  This means that some of the males will have emerged.

The D27 Yurt is set up with 9 Highrises in the upper part of the yurt.  Each Highrise has Eco-Corn Quicklock nesting trays with 72 nesting holes.  Note these Highrises do not have a cedar roof.

Starter cottages are set on top of each Highrise.
This is a Charly- Yurt containing many different
nesting trays, wood, plastic and eco-corn.

Once Starter cottages have been set in place,
the cardboard tube is removed.
Three males have emerged and are examining their new abode.   Note their long antennae- nearly as
long as their wings.
They now have to wait for the girls to appear.

“Hi Margriet,

I called you yesterday from the 16th/Oak community garden about a strange pest we found in our mason bee hive. They looked like larva with little red heads and were crawling over the cocoons in one of the trays. Do you have any idea what they might be from the attached images?
By the way I’ve read your book cover and cover and if I may be so bold I’d like to offer a small suggestion. Being a novice mason bee keeper I found it really hard to imagine and identify the pests you were talking about with the black and white drawings. Perhaps in future additions if budgets permit you could include actual photographs of the critters you describe? I’m sure the community at large would offer many for your book :) In all other respects that book was invaluable! 
I’ve also recently heard of people not using the bleach/water solution to clean cocoons but to use sand instead as an abrasive to remove mites. Have you or others ever tried the technique? 
Many Thanks,
Maria”
Hi Maria, 
Thank you for your pictures and comments.  
 Scavenger type beetle larvae.  Note size in comparison with 
mason bee cocoon in upper right hand side of picture.



Cscavenger type  Beetle larvae are reddish brown and can be recognized by their long bristles on each larval segment.



  • This pest is a carpet beetle (Page 90 Pollination with Mason Bees by M.D Dogterom.  These beetles feed on pollen provisions and nest debris.   
  • Yes, a book in colour would be awesome.  Like you mentioned, budget permitting.  It is definitely in the works for a future edition.
  • Yes, I have heard about the sand/abrasive technique to remove mites.  I have not used it myself.  I use a metal mesh as an abrasive surface to remove mites, and do a final rinse in bleach to remove any molds and parasitic fungi.  Using an abrasive surface like a metal screen works very well.  The sand is also used as an abrasive technique to scour mites from the cocoons.  I prefer not to deal with sand and find this a definite advantage.

Margriet

The reason for setting out cocoons within the protection of a house that shelters nesting tunnels, is to provide the cocoons, and the mason bees inside, a place that is protected from predators like mice, protected from the sun and protected from rain and snow.

It depends on the design of the house whether cocoons can simply be set within the house, like underneath the roof of the Highrise or whether space needs to be created for the vial like in the Starter Cottage.
Royal house with predator guard

Temporarily remove predator guard from the front of the Royal house,
and set vial on its side, with tab removed,  underneath peaked roof.
 Replace predator guard.
The Royal house is similar to the Highrise.  Simply remove predator guard, and set vial on its side underneath the peaked roof.
If you have a Lodge- without the predator guard, or the Chalet with a predator guard, space needs to be created for the vial containing cocoons.  Remove one set of trays, insert vial above trays and replace vial with tray when all bees have emerged.
Lodge without predator guard.
Chalet with predator guard.
Unwrap bundle of nesting trays by removing electricians tape.  Remove
one set of trays, and re-tape remaining nesting trays.
The vial can now be inserted under the roof and adjacent to the nesting tunnels.

Replace the predator guard of the Chalet after vial has been set
inside the house.  When all bees have emerged- about 2 weeks
after first bees emerge, remove vial, tape up the individual tray
 and set above other trays.
If you buy a vial of Beediverse Mason Bee cocoons
from a store, the cocoons need to be set it out adjacent to mason
bee nesting tunnels.  Cocoons are
washed, screened and candled before packaging them into vials.
If you have a Starter Cottage
 with cardboard tubes it is best to set the vial of
cocoons inside the cottage amongst the nesting tubes.

Temporarily remove front door to access
cardboard tubes.

Remove a few cardboard tube to make room for one vial
containing mason bee cocoons.
Remove red tab covering the exit hole of the vial, and place
vial amongst tubes.

Replace front door and hang Starter Cottage on an East facing wall,
 in the sunshine and out of the rain.  This cottage can also be
 set down on a shelf.  Make sure it is secure so the wind
or predators do not knock it off the shelf.

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