1. The most critical part is gathering
a representative sample.
This is done by pouring the bags or boxes of bees from one
container to another and
while they are flowing, gathering a sample from the
stream of bees.
This sample will most likely still be
too large, so, to get a representative sample from this collection,
place all these bees in a sampling tray with removable
bottom slides.
If a sample box is not available, make
sure you pour the sample and take another smaller sample by
gathering bees from the beginning of the pour to the
end.
This is the sample you will weigh and
cut.
DO NOT take a set weight, like 10, 20 or 30 grams, because
as you try to arrive at a specific weight
it is very difficult to add or take away and keep the sample
representative. This is the reason why we
use the sample tray, weigh the entire sample that falls out
of the slide drawer when pulled.
It is usually between 20 and 30 grams.
2. Once you have your sample, cut all the cocoons and
count the live larvae, parasites, pollen,
and whatever else you want to keep track of e.g. dead, damaged,
2nd generation, etc.
3. Measure all of our samples in grams. The following is an example of the calculations to use:
e.g. Sample size 31.8 grams, or .0318 kg and from cutting this sample, we obtained,
296 live larvae
0 parasites
Calculations are as follows:
1000 grams = 1 kg
31.8 grams ÷ 1000 = .0318 kg
To get bees/kg 296 ÷ .0318 = 9308.2
To convert bees/kg to bees/lbs use the conversion factor of 2.2045
(9308.2 ÷ 2.2045 = 4222.4 bees per pound)
4. Now add up the total weight of bees and subtract the
weight of the containers they are in
to get the net bee weight. Then multiply by the number
of bees per kilogram, or the number of
bees per pound whichever measurement you choose.
We most often talk in terms of "gallons
of bees" in sales. One gallon simply refers to 10,000 live larvae.
To get the number of gallons of bees, just divide
the total number of bees by 10,000.
Formula for the number of gallons of bees...
No. of gallons = net weight in lbs. x no.
of bees/lb ÷ 10,000
or metric no. of gallons = net weight in kgs. x no. of bees/kg
÷ 10,000
For our example, say we have 428 lbs or
194.1 kgs of bees net weight-
No. of gallons = 428 lbs.(total bee net weight) x 4222.4(no.
of bees /lb.) ÷ 10,000 = 180.7 gallons
Or using metric measurement of kgs.
no. of gallons = 194.1kgs.(Total bee net weight) x 9308.2(no. of
bees/kg.) ÷ 10,000 = 180.7 gallons
1. Again the most critical part
is obtaining a representative sample and cutting the sample immediately.
-if all of the styro blocks are full, we assume they
are fairly consistent in quality and quantity.
2. Obtain a 20-30 gram sample, and depending on the size
of the lot,
in order to get this we punch a hole in every block
or every 3 blocks, or whatever it takes.
Never mix samples from different
kinds of blocks that are from the different manufacturers,
keep samples separate.
Choose a hole in the block trying to
vary the place you obtain the sample from,
from one block to another, in other words, don't choose
the same hole in every block you sample.
3. Collect ALL the material, (don't tumble or modify
the sample in any way).
Then weigh all the material as soon as possible. Some
of the cocoons will crush and become damp,
and weigh the sample before they dry out.
4. Then cut the sample taking care to count everything,
including the cells that were crushed.
They are easy to separate and count accurately while
they are still damp. Count them as good live larvae.
5. Then calculate the bees per pound, or bees per kilogram,
the same way as you calculate the loose cell count.
The net weight of the particular lot(s) we have sampled
must now be obtained. First we weigh the total lot,
then subtract the weight of the blocks.
6. Weigh a few stripped out of the blocks and get an
average weight of a block, and use this for the calculation.
It is important that you weigh a block that was full,
then stripped out, not a new one that has never been used.
The block weights vary with the different manufacturers
and can vary slightly if the manufacturer has changed
the density of the foam at all.
When we weigh the block that was
full and stripped, we are careful to weigh it with the leaves and trash in it,
that must be included in the weight. We are careful
not to bang this out of the block before weighing.
We use Plastifab block, and most
of the bees we buy in block are in Plastifab, so the calculations below
are based on the Plastifab block. However, we do buy
and sell bees in other manufacturers block, and
together with the buyer or seller, we determine the
stripped block weights for those.
Example of the sample data, and calculations to obtain the number of bees in a particular lot:
We weighed out a few blocks and found that
they varied in weight from 1.9 to 2.2 lbs so we used
an average of 2 lbs. per block for our calculations, and
the following calculations are in pounds only.
Average weight of full, stripped out block = 2 lbs.
Total lot weight = 1688 lbs.
Total no. of blocks = 238
Total block weight 238 x 2 = 476 lbs.
The net bee weight is, 1688 - 476 = 1212 lbs.
When we cut this sample, we found 4200 live bees/lb. then, 1212 lbs x 4200 bees/LB = 5,090,400 total bees
To convert to gallons, divide by 10,000
So, 5,090,400 ÷ 10,000 = 509.04 gal.
509.04 total gal ÷ 238 total blocks = 2.1388 or, an average of 2.14 gallons per styro block in this particular lot.
Sampling or Grinding drilled boards is more difficult and time consuming than for loose cells or styro blocks.
We have been grading wood boards for more than 20 years now,
and have found the fairest method of
obtaining samples, is to use a template.
We designed a template to fit over the board. Ours is made out
of a piece of metal and it has three holes
drilled in it, about 1/2 inch in diameter. The template is placed on top of
the board exposing three holes.
The template removes any prejudice that may occur when picking which hole to
probe.
We then use a bee probe to pull each of the three holes, and
count the number of live cocoons.
Sometimes the cocoon at the bottom of the hole is missed by the probe and you
need to go into the same hole
a second time to make sure you haven't missed any.
If the boards are all full, we randomly select about 25% of
them, making sure that we sample at least 100 boards
and probe those using the template.
If the boards are partially full we grade every board, and only
buy/sell in full pallets of approximately 100 boards.
So, neither the buyer or the seller can pick through and buy only a few. This
is because using the template method
a large sample is needed to be statistically valid.
Example of calculation to determine number of bees in boards, in particular lot of wood
First, and very important, you must know how many holes you
have in the drilled boards.
This can vary quite a bit from one manufacturer to another. Some we've seen,
have as few as 1500 holes,
and some have 2100, or anywhere in between.
100 boards with 2100 holes per board
1320 bees were found (by probing 3 holes per board in each of the 100 boards)
Ttotal bees in probes ÷ total holes probed = no. of bees per hole, or 1320 ÷ 300 = 4.4 bees per hole then,
Avg. no. of bees per hole x no. of holes per board x no. of boards = total of bees, or
4.4 x 2100 x 100 = 924,000 total bees
to convert to gallons divide by 10,000
So, 924,000 ÷ 10,000 = 92.4 gal. and,
92.4 ÷ 100 = .924 avg. gal per board in this lot.
Any information contained on this web site is only to be used with strict permission
from JWM Leafcutters or Mennie Bee Farms.
Contact by E-Mail:jan.mennie@yourlink.ca