I get frequent questions about how to monitor bees when a major industry
intends to build next to a beeyard, or a new pesticide is going to be
applied. An e-mail yesterday, got me to thinking about what a beekeeper or a
bee association can do.
Studies of bees and toxic chemicals tend to be time-consuming and pricey.
However, we often use a CHEAP brood survival assay that I pioneered in
Puget Sound in the early 1980s, working with small scale beekeepers.
This test only requires some long dressmaker pins (I usually get mine at
Wally World or K-Mart), a scoring sheet, time for an initial setup and
evaluation, and time for a followup evaluation two weeks later. Works best
with two people - one to mark and read out the data, the other to record.
Brood Survival Assay:
Pull a frame with lots of eggs or eggs and young larvae.
Mark out 6 rows of 24 cells, separated by a row. Starting at the top,
left of the patch of mostly eggs, press in a Dressmaker pin - use LONG ones.
Seat the pin so head is just above top of cell, pin sticking through the
other side. That pin marks the upper left corner. Count - pin cell, then
two cells, then 20 cells, then two cells, and then the final pin. Now, go
down frame. Skip one row of cells, mark the next - pin, 2, 20, 2, pin.
Randomize the colors of the pins. Repeat till you have 6 rows marked.
Use various colored pins and randomize them. Bees work overtime PULLING
them out. IF you use all the same color pins, and you've only a few pins
left in 2 weeks, you can't index to the original patch of cells. Also, bees
tear up the cells adjacent to the pins, so the 2 cell space is a
sacrifice area, intended to ensure that you've 20 undisturbed cells.
Don't get fancy, others have used strips of plastic, frames of plastic or
wood to mark the test brood patch - and it almost always compromises the
test. If bees have to cross anything to get to the test patch, they may
either ignore it or remove the brood. The pins seem to be less intrusive -
still some colonies really worry the pins. BE SURE to get long pins - the
ends should stick through the foundation and out to tops of the cells on the
back side - bees may back out long pins, but they usually run out of room
and give up. Short pins will all be gone in a couple of days - don't use
them. Don't be surprised if you find the occasional colony that manages to
pull all of the pins.
Now, I've a scoring sheet that we use. In practice, having marked 120
cells for the test, one person READS the life stage contents of each cell
(eggs, larval stage, pupal stage, empty, nectar, pollen) (5 rows x20 cells =
100 test cells), and another records the data on the sheet - or use a small
recorder hung around your neck. Wind, batteries dying, make the recorder a
bit problemmatic. This test is easier with a kid, spouse, neighbor.
For the final (sixth) row, take something blunt that fits down into the
cell, insert, press downward, twist to macerate the contents. You have to be
aggressive - its amazing how often an egg lays over and survives, the
idea is to destroy any brood of any stage in these cells. This is the
calibration row - in two weeks, you will know how well the queen did in relaying
by how many of these cells she refilled, and you will know the maximum AGE
of any bee life stage, since in that row the oldest brood will have had to
be from an egg laid AFTER you set up the trial.
Now, place the test frame BACK into center of brood nest, close hive, and
LEAVE it alone for 2 weeks. Approximately 14 days later (don't go too
long), go back, and READ the contents of each of the 120 cells, recording on
the data sheet.
If you can't make 14 days exactly, better to go a day early than a day or
two late - you will undoubtedly have some larvae in the initial test area -
and these may emerge before you get back, if you wait too long.
Ok, with data in hand from the first and end observations, its now a
matter of subtracting age at END from life stage at beginning. Give yourself
plus or minus a day to take into account inability to know exactly how old
an egg, larvae, or pupae was - as well as any temperature effects that might
change development rate. Look at the calibration row. You may decide
that plus or minus one might be a bit tight. Plus or minus 2 days may be a
bit loose - make your choice, then be consistent for ALL tested hives.
Again, that sixth row, it will tell you a lot about AGING and about how
good the queen is about replacing lost brood.
Since everyone on this list has a computer - you can use Excel or similar
spreadsheet to do the math for this - or get out your pencil.
From this data, you can now estimate survival or mortality. Really
healthy colonies can exceed 95%. Really bad can be as low as 40-50%. Mortality
is any life stage in a cell that is younger than would be reasonable to
expect.
This test takes one box of pins, good eyes, patience. A tray for the pans
is useful, better is a cork as a pincushion - less chance of dumping them
all on the ground or into the hvie. I also take along a card of thumb
tacks. When I replace the test frame, I push a thumb tack into the top bar, so
I can quickly spot the frame when I come back in two weeks.
, as most of us get older, reliably seeing eggs in dark comb gets harder;
especially on overcast days. I've yet to find a light system that works
well - best to see who has the best eyes, then have that person 'read' the
cell contents. Hint - kids are often great at this.
Unfortunately as we age, not only does our ability to focus at short
distances degrade, but as early as 40, vision in low light begins to drop off.
Jerry
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