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Wednesday, June 27, 2012


Stephen D. writes- I'm on a steep learning curve, what with 3 types of bees. I created havoc with my mason bees, having to move the nests several times. A few bees managed to find a home, many more took off. I believe you wrote about this, so I was prepared.  Nests are now in place permanently.  Thanks for the great service you provide.
My question, is there a plant or plants that flowers at this time, that are favored by bees? I have Japonica, heather and Siberian Bugloss. They are now out of bloom, as are wild blue bells. Please suggest some options. I would opt for perennial with low growing habit.
Also, do I put my leaf cutter cocoons out after a period of 20 degree C weather? Is there a recommended period?

Hi Stephen,  Great to hear you are having so much fun with all these
Right now in my garden poppies are seeing lots of bee activity
blueberries rhodos.
I am not a plant person, but I have got a lot of bee attractive plants on
my blog.  Once you get there, there is a search window.  Type the word <plants>
You will get a variety of blogs about plants.
Another great source is to go to a garden center when it is sunny and let
the local bees tell you which plants are bee attractive plants.
Let me know if you find some good ones

Set leafcutter bee cocoons out in June as temperatures increase into the 20C range

Thanks. I went to the nursery today and looked for the bees. I came home
with a butterfly bush.
Thanks again.  Stephen D.

Nest types- which is better?


I’ve had a problem with bees released returning to my nest tubes. Attached are two photos of my boxes. I released about 20 in the setup named “original” and only one bee nested there. I’m going to try the setup named “latest” and was wondering if you think either or both should work? Thanks Norman Z


Hi Norman,  These are beautifuly constructed homes for mason bees.  Both should work.  At some locations there are lots of nesting places for mason bees such as cedar shingles and often mason bees use these over the ones we set up.  The only way that I know to get them to use your nests is over a year or two, increase the number of mason bees that are produced.  I noticed that the 'Latest' home is set on a post.  This works fine, but in cool springs, this location would be a lot colder than a site like on a wall and be a lot less attractive than the home on a warm East facing wall.   All these facts make an impact on successful nesting of mason bees.  Sometimes it is difficult to figure out why the population is not building up and it could be as simple as a few bird predators.  Try different locations and homes and slowly build up their numbers.-Margriet

Great reports and photos

Hi Margriet...

I was fascinated with all the great reports and photos on latest blog...
thanks...and thanks to all those who share their experiences with these
little critters...However I didn't see the photo of   "red color on cell
surface"...<this story is on the next page>..I was delighted with the bumble bee story as I did enjoy daily
visits from bumbles to my plants on the little balcony and the hover fly
hunting for aphids ...learning about and watching the  Mason Bees has
encouraged me to sit quietly and was able to witness  other wonders more
carefully...including the weather...I have 3 nests filled and was awed when
the few bee I had were able to survive several cool wet days...this fall
will be my first experience harvesting and cleaning cocoons and I have a
milk carton with reeds to attached to the window frame hoping to encourage
bees hatching from my bedroom window weep hole next year (as they have done
for the past 4 years) to use reed nests.

Have a great summer


Tuesday, June 26, 2012

Beediverse DVD :)

Hi, Bee Diverse,

I work at an ecological non profit in Vancouver at which we keep mason bees.  I just finished watching your DVD, All About Mason Bees, and I wanted to thank you for making such a fantastic informative video.  The infra red footage was really spectacular.  As the video began, I thought to myself - "But what is it like IN the cell?  How does the bee pack the pollen and the mud?  What does it look like?"  And then, voila!  That footage was amazing!

Thanks so much,
Kristjanne V

Mason Bees nest under a table cloth

Close up of pollen lumps with their bee larvae. 
You can see the mud chambers at the top of the picture, still attched to the shelf -cover,
 including another pollen lump with another larvae.

Shelves with a cover where mason bees
had made their nests.

Hey Margriet:

I thought you would get a kick out of these pictures, Mom noticed a lump of something under the cover on the shelves on the back porch. When she lifted the cover up low and behold they had layed eggs under the cover that had a bulge in it. Too bad they were destroyed but at least there are good pictures of an egg developing on a ball of pollen. Feel free to use these pics if you want to. As far as my stock for this season I am keeping my fingers crossed that I will have enough to sell this coming year.

Cheers Dave 

Chickadees are predators of mason bees

Hi Margriet,

I took the images of the Quicklock trays in the Highrise that have popped open.
As you can see there are a few empty holes now that previously had been full. It must be the chickadee as you suggested.

Do you think it is too risky for me to try to tape it tight again? I dont want to squish them but they are completely exposed now.

Your bee-loving friend, Eve

Hi Eve, I would not try and tape the nesting trays at this stage.  When they are done flying turn the trays so they are facing inwards- then the chickadees can't get at the larvae.

Quicklock Trays in a HIghrise showing tape has loosened
around nesting trays.

That's why you have a Phd  and I don't. :-)

Interesting observations

There are so many neat observations by folks...keep them coming.

John's Field Shelter with a blue tarp

Hi Margriet , here are photos of this years Hutch/Field Shelter at home. Thought that you may be interested in the design. Will sent pictures of another unit I have in White Rock when I get a chance to get out there. Note that I am using a blue tarp , it absorbs more heat than other colors. Bees do not care. John
Outside view of John's Field Shelter
Inside view of John's Field Shelter
Tarp is kept tight by nailing a piece of lath over the tarp.

Parasitic wasps of Mason Bees?

From Norm Z.
Can you ID these insects for me? If so what are it’s nesting habits? Thanks

Here they are-lovely photos- any body know what species these wasps are?  Probably parasitic types, since they are hanging around the mason bee nests.-Margriet

Bombus melanopygus bumble bees using Mason Bees nesting tunnels

From MB

I've been keeping mason bees for four years now and earlier this month I came across something I have never seen/read/heard about before.
One afternoon I noticed a big bumblebee — a big bugger, about twice the size of a mason bee with a tiger-striped orange abdomen — hanging around my mason bee houses and fussing about at the end of one of the tubes. I later observed the same bumbler entering already occupied tubes on more than one occasion. I figured the bumbler was simply stealing the pollen already gathered by the mason bees — you know: working smarter, not harder.

Then one evening I was checking the mason bee house with a flashlight and noticed that in four of the tubes, there was a thick, viscous liquid inside. The taste test doesn't lie — it was honey.
I emailed Margriet and asked some of the questions running through my mind: Is this common? Do bumblebees hijack mason bee tubes for themselves?
I already have 20 tubes filled up so I have more than enough mason bees for next year. I'm no interest in killing the bumbler but its behaviour was fascinating.

Since then I did some research and, combined with my observations, I have concluded the bumbler in question is an orange rump bumblebee queen (Bombus melanopygus) who has apparently made an odd choice for a nesting site (image: Queen). She had taken possession of a row of four mason bee tubes, each of which contains globs of honey. If you look inside the tubes in image: honey, the little gleams of light are actually the blobs of honey. (I have a better shot of the honey but I can’t get my email to work on my iphone right now).

She goes in and out of the tubes but has to back out of them because she is too big to turn around inside like a mason bee can.
One evening when I returned home from work I was lucky enough to watch as the queen used her wings to fan the entrance to one of the tubes (image: bumbler1A). I’ve read about honeybees doing this at the entrance to a hive so it was interesting to see. When she was finished, I was able to get the second shot (image: bumbler 2).

There are also now a couple of worker orange rumped bumblebees on site and one of them has taken possession of another tube. They are much smaller — but still bigger than a mason bee — with just a dab of orange on the end of their butts.

I have two mason bee houses located side by side but the bumblers show no interest at all in the other house. The bumblers are now very active as you can see by the heavily stained appearance around the end of their tubes (image: tubes). I believe this is caused by dirt and pollen tracked through the honey by the busy bumblebees. They are still producing honey.

From all appearances, the bumblebees have set up shop in the empty mason bee tubes for the remainder of the summer. I have 10 empty ones left so there still room for expansion.

Thanks Michael B.  for some great photos and some neat observations.-Margriet
Bumbler IA

Bumbler 2


Honey on base of tubes

Osmia californica bees and nests

Michael emailed me with a question on setting out new nests when the old nests are getting filled.  He asked if adding a nest close to the others would disorientate the bees already nesting at the location.  

I suggested that additional nests are best set out in the visual range and clustered close to the original nests. 

Michael also noted that his bees headed for the tubes first.  Yes mason bees prefer round holes, especially when the substrate is wood or carboard.  Unfortunately the bees' choice is not always the best for eaze of management. 

Michael's original question was:
If I need to set out more nesting sites for the Mason bees should I put them next to existing sites, or, put them a bit away from the one's I originally set out?  The reason I ask is that I am getting many more bees to nest so far this spring compared to last year but I do not want to mess up the bees visual cues to the old sites.  I also know they like to be near each other.  Your thoughts?

Michael's follow up notes are:

As I mentioned before I was particularly surprised by what happened this spring when most of the O. lignaria emerged at once with a very low dispersal rate.  This activity was in contrast to the last two springs where the dispersal rate was high and emergence rates were very sporadic.

In my nesting set-ups, which I have two of them around my house (see the BEFORE photo), I put 40 cocoons in the wooden house, and 20 cocoons in each of the tube units (80 total of O. lignaria).  There was also 20 of your O. californica cocoons in the wooden nursery house.

I set out all of my bees on April 20 and to my astonishment, almost all of O. lignaria had emerged by April 22, and the first mud nests were made in the tubes on April 24.

The second surprise was that all of the bees decided to move to the tube units (reeds and paper filled tubes).  This is where I was beginning to get concerned that I would not have enough nesting sites.  We had a week of very good weather, and then we had four-five days of cool and damp weather which I then decided to put another tube unit below the existing two tube units (see AFTER photo).

During this cool period of weather, I noticed that all the O. lignaria bees were resting in the tubes, so I kept track of what bees were in what tubes and how far they had gotten along in building their mud nests.  The good news is that when the good weather returned last weekend that all of the existing bees resumed their normal activity and were not deterred by the NEW unit below!  It seems that putting a new nesting house nearby did not distort their visual cues (at least under my conditions).

Also, in taking the pictures of my nesting sites last weekend I noticed the O. californica I purchased from you were beginning to emerge.
I just managed to snap a photo of a O. californica male and female bee doing what a pair of bees are supposed to do .
It might also be my imagination but it appears that the O. californica seem a bit larger than the O. lignaria, and so far all the O. californica bees are headed for the tubes.
Maybe it is some kind of social communication or interaction, but who knows what the bees are really thinking!

Best wishes,


Mating Osmia californica


Bright orange pollen in Observation nest-update


An interesting observation from Diane.

"This morning I peaked into small observation nest purchased some years ago
 and noted a bright red color on top surface of one edge of two you know what this might be?


Ohh how lovely.  The bee has collected pollen from two sources, one flower
with yellow pollen and the other flower with orange pollen.

By touching the anthers of flowers you can see there is quite a lot of
pollen colors out there.  One flower that has bright orange pollen is theTiger lily.


This is a picture of a 3 nesting tunnel observation/viewing nest.  The lowest tunnel is empty.  The middle tunnel contains 3 completed chambers with pale yellow pollen.  Two cells ( of the four) in the upper channel have bright orange and yellow pollen as part of the pollen lump.  There is even a bee in the upper nesting tunnel.
 Thanks so much...another bit of learning...this is fun!   Diane
Here is a picture of the same nest taken about a month later. 
Cocoons are fully formed  with adult bees inside.

Sunday, June 24, 2012

Osmia californica

Osmia californica comes out late in spring, often their emergence overlaps the latter end of the Osmia lignaria (early spring mason bee) season.

However very little is known about them.  If you'd like to share your photos of Osmia californica, please email them to me and I will get them on this blog.

Its late June 2012

It is the 3rd week of June and Osmia lignaria the early spring mason bees, and of course Osmia californica have stopped flying.  They have left their offspring behind, and hopefully few parasites and predators will get to the developing larvae by next spring.

I have received a lot of interesting emails with photos that I want to share with you.

People are sending more detailed notes of their observations - all very interesting.

I have had relatively good news from the majority of mason bee producers.  It seems there was enough reasonable good weather for good production along the west coast of NA.  Of course, raccoons, flickers and ants have taken their toll.  But overall, production will be adequate for replenishing their nests next year.

People are trying out different types of nests, bee attractants and different ways of setting out bees and protecting them from the weather.

I find this bee attractant very interesting although I have not heard whether it has been properly tested by scientists (as yet).

Here in BC rain and cool weather has been a large part of June.  I am curious whether, there has been enough warmth for bee larvae to feed and develop into adult bees.  In the fall when I open nests and examine the contents, I will be looking for the proportion of pollen lumps.  If the percent pollen lumps is greater than  5%, it usually indicates  cold  and damp weather.  Bee larvae have died of starvation because they were too cold to feed.