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Monthly Archives: January 2011

These photos are bringing back some great memories of my time on the ‘farm’ with mason bees. 

We tested various types of nests, and to duplicate these, I bought 50 small office garbage cans. 

A set up used in a mason bee trial
in blueberry field.

I set each one on  top of a fence posts. 

Unfortunately, bears could not resist going after the small amount of  pollen inside the nesting tunnels.  Several of the containers were smashed to pieces. 




Mason bee trial in a blueberry field.  Bears smashed quite a few of the containers with mason bee nests.  In the distance two other containers are visible sitting on top of a post.

  After this, I realized that bears were one of the challenges for keeping mason bees in these fields.  I knew that bears go after honey bee hives, and yes, beekeepers kept their hives surrounded by electric fences.  But I did not think that bears would go after mason bee nests.  I guess early spring bears are hungry and anything goes. 

In photos of previous posts, you can see the electric fence surrounding the nests.  It is easier to have many nests surrounded by one electric fence,  than having numerous locations each with an electric fence.   



Large mason bee nesting area surrounded by
an electric fence.



But concentrating mason bees in one area begs the question about the distance that mason bees fly.  This of course will determine the distance between mason bee houses/set-ups.  Another factor for consideration is flower density.  Distances flown will depend on flower density.  The question I find most intriguing is whether the female to male ratio changes depending on the number of cocoons set out at any one location.  If you set out say 1000 cocoons will these produce more females then when you set up 20,000 cocoons?  A good PhD project for someone.

Steve E from California, contacted me about setting out mason bees in an almond orchard.  He asked me for feedback on his idea of constructing a housing unit for mason bees out of a plastic barrel.

” I brought the two plastic tubs into my garage and took this photo of the 2 containers side by side.  You can see that the all-blue barrel is uncut, while the white one has a cut-out door of about 12″ x 16″ bordered by black tape.  Within the barrel are stacked cinder blocks.  You can make out a roll of cardboard tubes within one cinder block.  On top of the cinder blocks is a wood bee block.

So, if these barrels are only 33 inches tall (a bit less than one meter), are they too short to be effective ?  The diameters are 23″.  I could put a stack of cinder blocks out with a wood pallet on top, and elevate the barrel on the pallet to gain some height.  But that would make it more vulnerable to the wind, as well as more work and materials for multiple sites.
I can obtain these barrels quite easily, and they are simple to cut out.  The temperature within vs. without is at least 5 degrees warmer on a sunny day.  On an overcast day, at least the blocks are protected from the wind.
I can put vent holes in the top or upper edges.  But these are targeting February and March activity in an almond orchard and plum orchard, and it is generally lower to mid 50′s F in those months.
Please comment on the potential efficacy of this simple housing unit.”
COMMENTS:  The bees may behave/forage/fly differently in the blue and white unit.  Setting them side by side would make for an interesting test.  Cut a hole in the center of the top (4-6″ diam) so excessive heat can escape.  Also disoriented bees can fly out through the top and re-orient to their nesting tunnel after flying through the door.  Set cinder block against the sides, so to avoid any rain coming through the skylight hole and falling onto the nesting tubes.  Secure  from wind.  Set out in an open and sunny location.   Set up 3 thermometers: 2 inside at different heights and one on the outside north wall for comparison.  I look forward to hearing more about this housing unit.
When I started  producing mason bees, I set the mason bee houses onto a barn and shed of a blueberry farm.  This was easy.  But the farmer also wanted mason bees in his blueberry field to make sure the mason bees were pollinating his blueberry flowers far from his home and barn.  But there are usually no buildings out in these commercial fields for setting out mason bee houses.
Mason bee cocoons and their nests require a few basic essentials.  They need to stay dry and during the day need to be warm- in other words, a dry spot, in the sun and preferably out of cooling winds.
I came up with using Garbage pails, set up on its side.  Theywere secured to a post and with a few other pieces of  lath, secured to the post because some of these places can be quite windy.  It worked rather well.  The set up time though was long because no field had the same type of post. 
Tim setting up a “Mason Bee house”.

Cardboard tubes were used at the time and bundles of these were set in the back of the container.  To help the bees orient to their nesting tunnel, cotton batten and “1″ foam was interspersed amongst the layers of nesting tubes.

The middle of the container was used the most by the bees.  On some days, under sunny conditions, it became very hot in the upper section of the container.  It looked like bees were avoiding the excessively hot area of tubes.  To ”cool it down a little, I cut a small hole in the upper part of the “roof” of the container.

There usually is a lip to a garbage container so that the lid can be fastened to the garbage pail.  Unfortunately, when the container was on its side, rain pooled in the rim drowning many bees.  I cut a drainage hole so that water would not pool in the rim.

The container was set up about 4 feet above the ground to avoid the splash zone and also to avoid the cooler ground temperatures.

When we started using routered nesting trays, these stacks did not fit very easily into the round container.

We learned a lot from this trial. 

The yurt was still a few years away!

I have had some questions about candling mason bee cocoons.  Joe Sadowski from Burnaby, BC thought of this idea- and it works.  Candling is just like candling eggs.  In a dark room you shine a bright light under the cocoon.  With some experience, you can see the adult mason bee in a fetal position inside the cocoon.  You can also see empty cocoons or non- viable cocoons, where the larva has died and not developed into a adult bee. 

Here is a batch of mason bee cocoons.  Mud has been washed off, and mites have been removed.  After washing them, cocoons take about an hour or so to dry and then candling can be done.

Place dry cocoons on a petri dish or similar container,over a 6 Volt flashlight.  It is easiest to do the candling in a room without windows.

Turn the lights off in the room and look at the cocoons.  You will be able to see right through empty cocoons.  In normal light, these cocoons look like normal viable cocoons.

You can also see the viable cocoons with the bee inside the cocoon.

Rock, move and rotate petri dish over the light.  The light scatters and allows you to see the non- viable cocoons.

All cocoons sold at Beediverse are candled and non-viable cocoons removed.

I’m writing to tell you briefly about our 2010 harvest, and also am sending some images of weird and wonderful things that we encountered in the process.
As for the harvest itself, I’m not going to send you all the data but will simply summarize.
I had 13 people in the group this year.  Altogether we set out 3110 cocoons, and  we harvested 3124.  Not a banner year by any means, but at least sustainable.  
Here are some photos.  I’d be pleased to receive any comments or suggestions about these, Margriet.  It seems that every year we find something more weird and more wonderful than ever.  
I should also mention that I’m using the stainless-steel-screen technique to remove additional mites after washing.  I did it the first time an hour or so after washing and drying, with very good results, I’ll do it again this month while they’re in storage, and a final time when I take them out of storage to distribute to the members of our group..
This photo (below) is of a group of 15 strange rusty coloured cocoons that we found in just one tray from a nesting box on Galiano Island. They seem to be covered with sticky pollen or something that stains the fingers.  Image 009 shows how the cocoon material itself is sort of layered.  When I tried to open some of them I found that there was an outer layer that peeled away, with some sort of cocoon-like structure underneath.  Inside that I found only a thick creamy coloured fluid that oozed out.  Any ideas? 
COMMENTS:  This is a species of summer mason bees, that uses masticated leaf materials for its chamber construction.  I have never opened one, so it is interesting to note that the content is still in the pupal stage of development.  The final stage of development would occur when warmer weather begins in spring.
This photo (below) shows a gallery with eight compartments constructed from pine resin, for goodness sakes!!.  Four of them have tiny caterpillars in them.  They look superficially like the ones in Image 002 but they are much smaller.  There is no doubt about the pine resin (or some conifer), because it was sticky to remove and as I worked it I could smell the familiar fragrance.  Again, any ideas?
COMMENTS:  This looks likes some resin bees in the pupal stages of development.  They would develop into an adult resin bees and emerge in the summer when the resin is soft.
This photo (below) shows wiry brown frass completely filling a compartment.  There were two or three of these compartments. The entomologists at the Museum thought it might be fly frass.  Never seen it before.
COMMENTS:  Does anyone have any ideas on this one?
The photo below shows how easily the mites can travel from one gallery to another.  
COMMENTS: The brown-reddish granules are the pollen feeding mites.  One or two or more land in the chamber in spring and mites consume the pollen.  What you get is a million mites and no bee.
This photo (below) shows another type of caterpillar.
COMMENT:  It could be a beneficial wasp pupae. 
This shows (below) a cocoon completely covered with dark brown rods of frass.  The question is .. whose frass is it and how could it have been placed while the cocoon was completely enclosed by mud and the overlying tray??  I’ve cropped the image so you can see it better.
COMMENTS:  When a mason bee spins its cocoon, it leaves its frass on the outside of the cocoon.  The different colours of pollen indicates that multiple species of plants were visited when collecting the pollen.
This photo (below) shows large creamy coloured ‘caterpillars’. 
COMMENTS:  This compartment contains no bee, although it is the compartment made by a mason bee.  These grubs were laid in the compartment while the female mason bee was completing the construction of the compartment.  The brown stringy frass may belong to this insect.

 NOTE:  Usually I would not disturb the cocoons and the pupae like the resin bees, but close up the nest and set the nest outside.  The reddish frass and the multiple pupae in one cell, looks like it came from a predator of some kind and I would remove it from the nesting tunnels.

Photo #1.  Joe S. from Burnaby, BC showed me this interesting occupant of his Beediverse Quicklock nesting trays. The photo above shows 2 nesting tunnels.  The upper tunnel shows a common sight.  It looks like sawdust, but actually is a collection of pollen feeding mites amongst pollen. The lower tunnel contains a mason bee cocoon on the left hand side and a group of pupae on the right hand side.  The whole cell with the pupae was very sticky.  It looks like these insects have consumed a lot of the pollen/ nectar mixture that the female mason bee had collected for her offspring.
We have never seen this inside a mason bee nesting tunnel, and we are wondering what it is. 

 

Photo #2 is a collection of fruit flies.  Joe has never seen such persistant fruit fly activity as last year (2010).  The question is whether these fruit flies are the same as the pupae in photo number one.  If anyone knows if this is the new Cherry fruit fly, please let us know.

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