# Shallow Mason Bee holes - how bad?



## xC0000005

According to the book I have on Orchard Mason Bees the optimal hole depth is about 6 inches. I have the ability to produce 4 inch deep holes pretty easily, 5 with some work. According to the book it will work but there will be more males. Anyone know just how badly this would mess up the ratio of males to females?


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## BjornBee

I'm not sure there would be more males, just less females. The number of males, are dependent on the number of holes. So if you have 100 holes 6 inches long, or 100 holes 4 inches long, would all make the same number of males. Whats left over on the holes would now dictate how many females would be left. That number of course would be far less than what you would have if using longer holes.

A side note,

I started with drilled wood. And after one season, went to tubes. You can split them, collect them individually for refrigerator storage, and add clean tubes as need, among other things. Consider using tubes. You will be glad you did. And tubes come in nice lengths such as 6 inches or more....


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## BjornBee

Just some advice....

Here is a shot of a few cans and what tubes can do for you. This picture shows cans already prepared for this season. I have removed (split) a good number of filled tubes and replaced with new tubes. You will get about a 6 times production in a good year with adequate forage. So for every tube, you can expect at least 6 filled.

You may want to start with wood, but after you get your colony established, I'd look into tubes.

http://s186.photobucket.com/albums/x236/BjornBee/?action=view&current=Beepictures109.jpg


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## dcross

Bjorn, where do you buy the tubes?


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## BjornBee

dcross said:


> Bjorn, where do you buy the tubes?



Hello D,

I bought a bunch two years ago from Ace Paper Tube Company. (they are on the web) I bulk ordered (5000) for about 7 cents a tube. They do take smaller amounts but not sure the price, and of course the price I mention is from two years back.

What your looking for is tube .375" ID x 6" LG x .50" WL


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## dcross

Thanks Bjorn! I ended up just ordering one of these to dabble for now:

http://www.territorialseed.com/product/32/176


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## Jim Fischer

Here's what I deploy as a "survey" tube to detect what is out there:

http://www.bee-quick.com/bee_tube.jpg

Nothing more than some 2.5-inch PVC plumbing pipe with a pressure cap
on the end. It holds a dozen tubes, and could be used for small-scale deployment if fitted with two tubes filled with cocoons from last year
and 10 empty tubes.

Rather than going as fancy as Bjorn Bee for actual "production" pollinator
deployment, I use 1-gallon paint cans which one can buy shiny new from
any paint store for about $1.00 each. They hold about 70 tubes with ease,
which would imply using 6 to 8 tubes filled with cocoons from last season.

I get my tubes in bulk from Knox Cellars, and I also get the paper liners
from the same source.

For non-Osmia bees which might require tubes other than 7mm or so wide,
I use bamboo, which is easy to find in a wide range of diameters.

Drilling holes in wood is tedious, and if one uses hardwood, which one 
wants to use to get a "clean" hole and wood that will weather well, 
the drill bit wear can get expensive. I like the Knox Cellars "system"
very well, as the paper tubes allow one to inspect and disinfect the
cocoons during winter to kill off the parasites.

Osmia are cute little bees - never make any honey for humans, but never
sting either. Difficult to move the tubes out of crops like apples, as the
cocoons are not yet formed, and vibration/jarring can knock the eggs off
their piles of pollen soaked with nectar. Use extreme care if evacuating
your tubes from an orchard before they spray.


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## BjornBee

Hey Jim,

Have you (Or anyone else) seen where masons fill both ends of the tube and in between there is absolutely nothing?

I was rearranging the tubes and wanting some photo's of the cocoons, and decided to open a few. I found some tubes that were freshly sealed this past season, but completely empty. And these were new tubes, never used, with no internal marking of anything else (cavities) ever being made. They had a mud plug at the back end, and a plug closing it off in the front.

Is this a "defensive' ploy to make dummy plugs to fool predators? (I would think they could smell" their food or some other detection)

Anyone ever see this?

Now I question some of those unopened tubes I bought when I first started out. I thought some never opened. And this may be the reasoning. Just simply nothing in some tubes although sealed as they were full.

I guess the paper tubes would be easier to check than would be the cardboard ones.


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## dcross

How does one go about disinfecting the cocoons anyway? I caught a reference to washing them somewhere, but can't wrap my brain around that one...


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## Jim Fischer

> Have you (Or anyone else) seen where masons fill both ends of the 
> tube and in between there is absolutely nothing?

Nope, I've not seen that at all. 
100% clean and empty, no residue at all?
Weird.

Got any photos? Send 'em off to Rosalyn James at USDA.
Send some to me too, as I wanna see that.

> Is this a "defensive' ploy to make dummy plugs to fool predators?

No, I don't think so, as the main "defense" offered is to lay "male"
eggs toward the front of the tubes, so that predators only get the
males. (For those who don't play with mason bees, one can loose a 
lot of males and still have a successful spring mating, as males can
mate more than once, and are quite happy to mate with every female
that emerges. Not very picky, those fellows.)


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## solitaryb

Jim Fischer said:


> > ...the main "defense" offered is to lay "male"
> eggs toward the front of the tubes, so that predators only get the
> males.


I thought the sex issue might have been regulated by a temperature variation thing - the ones nearest the outside being colder and thus males. So does it work by the female actually choosing to lay male eggs? Wow! Can you explain the mechanism or point me to some source for this?
Cheers, Paul.


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## Keith Benson

Jim Fischer said:


> Here's what I deploy as a "survey" tube to detect what is out there:
> 
> http://www.bee-quick.com/bee_tube.jpg
> 
> Nothing more than some 2.5-inch PVC plumbing pipe with a pressure cap
> on the end. It holds a dozen tubes, and could be used for small-scale deployment if fitted with two tubes filled with cocoons from last year
> and 10 empty tubes.


let me see if I have this right: that is a PVC pipe, inside there are a dozen cardboard tubes, inside that there are other paper liners?

Keith


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## dcross

That's what I think it is. I'm just trying the paper tubes.


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## MichaelW

solitaryb,
They do it just like honey bees and all other Hymenoptera.
As a general rule,with exceptions, the queen decides the sex of 
the offspring by choosing to fertilize the egg with sperm from the spermatheca, 
or she can choose not to. If she does not the egg will develop into a 
Haploid male, if she does fertilize, it will be a diploid female.

With the honey bee, the size of the comb cell influences her decision
to fertilize. There is probably similar considerations with stick depth
and diameter in Osmia. 'They' say that smaller diameter sticks will yield
more males too. Or is it the other way around?

here is a write up on haplodiploidy on Wikipedia
http://en.wikipedia.org/wiki/Haplodiploid_sex-determination_system


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## BjornBee

Other way round....


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## Jim Fischer

> let me see if I have this right: that is a PVC pipe, inside there 
> are a dozen cardboard tubes, inside that there are other paper liners?

Yes, exactly. The paper tubes are clamped into the cardboard tubes
with little plastic plugs that snap into the "back" end of the tube.

> I'm just trying the paper tubes.

The reason for the cardboard tubes is to prevent various species of
predatory wasps from sticking their egg-laying "syringe" into the
Osmia cocoon from outside the tube. They can poke through some
reeds and such, but the cardboard tube stops this. 

> How does one go about disinfecting the cocoons anyway?

In very early spring (never in summer or fall) one can remove the paper
tubes from the cardboard tubes, slit open the paper with a razor blade
(taking care to not nick the cocoons) and wash them in a very 
dillute solution of bleach in water, 1 tablespoon of Chlorox (5% hypochlorite) 
per gallon of water. This will kill multiple things, but mostly it will kill the tiny mites
that infest Osmia. To the naked eye, the mites look like mold growing in the
entrance of the tubes. Under a microscope at 10x, the "mold" can be seen to
move. At 100x, you can see that these are mites. Lots and lots of mites.

Another thing to do is to hold each paper tube up to a strong light before cutting
them, and look for cells that appear to contain more than the typical cocoon.
This would be any one of a number of parasites that have infested the cocoon.
Destroy these cocoons to prevent, or at least help your next generation in staying
pest-free.


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## solitaryb

MichaelW said:


> solitaryb,
> They do it just like honey bees and all other Hymenoptera.
> As a general rule,with exceptions, the queen decides the sex of
> the offspring by choosing to fertilize the egg with sperm from the spermatheca,
> or she can choose not to. If she does not the egg will develop into a
> Haploid male, if she does fertilize, it will be a diploid female.
> ...
> here is a write up on haplodiploidy on Wikipedia
> http://en.wikipedia.org/wiki/Haplodiploid_sex-determination_system


Thanks for clearing that up with the wiki reference. 
My tubes are 8mm in diameter and 900mm (c.3") long and it seems a bit more than a quarter are females, but apart from that I am not sure what is influencing these ratios - I have yet to figure out if there are any mite attacks.


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## dcross

Thanks, jim!


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