These are the comments I promised on the last three years Bee-L
postings about the electronic swarm predictor invented by the
late E.F.Woods and which he called the Apidictor. With 3 years
to cover, it is not surprising that there are about 1700
thought-provoking words here and I suggest you print it out and
settle down in an armchair to read it. The items are more or less
in reverse date order.
On 4th Jan. Chris Slade mentioned that he had heard the queen
pipe when he nearly squashed her or otherwise put her in danger.
I, too, once heard a pipe on September 30th when the brood box
cover came off with a snap. Normally piping is an indication
that she has detected the proximity of another queen, but maybe
it is also a general sense of danger. Eddie Woods had an unusual
method of finding the queen. He would break open a queen cell,
get some of the contents on his finger and move it across the
frames. When his finger got near the queen, she piped. Of course,
people who breed and package queens hear piping all the time.
Several people have been wondering how to calibrate their
home-made apidictors. Unfortunately there is nothing in Eddie's
papers to indicate how he did it and I suggest the answer is to
suck it and see.
Whichever method of indication is used, calibration is necessary.
You can use a constant gain amplifier driving a meter with a
calibrated scale or you can use a constant level indicator with a
calibrated gain control. Ideally, it would be nice if you could
calibrate it in 'days until swarm' but colonies vary so much that
predictions can only be approximate. That is why you have to use
coloured bands. An indication in the red area means that the
warble is loud, you must open up and look for queen cells. The
green area means that the warble is quiet, there is no need to
inspect because they will not yet have started queen cells.
Between these two, there is a mushy, uncertain area where you
should come back in a few days and expect to find a red
indication; I have a feeling that in later models Eddie put a
band of yellow paint in this area.
Bear in mind that it is no good trying to calibrate on a single
hive; you must have as many measurements as you can get in order
to get a sensible average.
Under Murphy's law, you then find that the meter (or gain) is at
the top end of the scale a week before the swarm, you have to
make an adjustment to the preset and start all over again. The
swarming season is short and you run out of time until next year.
Remember that Eddie had access to an apiary with 1,000 hives.
For these he would have used a microphone on a stick, through the
hive entrance but for permanent use, the best place is a hole in
the hive wall, near the top of the frames, covered on the inside
with black polythene.
Back in November, somebody wondered about microphones getting
propolised. Of course, this would only happen if you left it in
the hive for long periods but a piece of black polythene sheet,
renewed every year would let the sound through all right. Eddie
used crystal microphones because they were cheap (used in all
hearing aids) and had a high output with no need for great
fidelity. Also, they did not need a battery like the modern
electret ones do.
Mention has been made of the bee tone analyser made in Sweden by
Mr. Vancata. I have to be careful what I say about this because
he is a Bee-L subscriber! One beekeeper wrote to him for
details, only to be told that since it is a commercial item
offered for sale, they could not expect to receive information
that would allow them to make their own. Quite right too! In the
ABJ article he explained that the frequency filter was
continuously tunable and to me this makes it sound more like a
laboratory instrument used for spectrum analysis. However, he
must have misunderstood the apidictor which he claimed tuned to
only 3 frequencies. In fact it had a 3-position switch which
allowed you to listen to:-
1) The complete hive noise, i.e. all frequencies at once.
2) All the frequencies between 225 and 285Hz, covering just the
warble and blotting out everything else.
3) Only those frequencies above 3,000 Hz, thus separating out the
hiss.
Thus it was a simple instrument for doing a quick check of
whether or not the colony was planning to swarm within the next 3
weeks.
The Bee Tone Analyser, on the other hand, tunes from 180 -550Hz
but only lets you hear one note at a time. Hence, you cannot
listen to the hiss at all and you have to twiddle the knob to
cover the spectrum of the warble. Undoubtedly the modern active
filters are smaller and more efficient than the old passive ones
but do they come in band pass and high pass versions which are
what you need for this job? (Being long retired I am out of touch
with such matters) If I have got anything wrong here, I hope Mr.
Vancata will post an enlightening contribution.
While I think of it, I have a feeling that the warble and the
queenless moan are the same thing, the moan being the warble
taken to the limit. There's a highly significant thought that
deserves a discussion on its own!
While I am in this mode, I'll deal with the other group of people
who got excited about using computer software to analyse the
sound. The phrase that comes to mind here is about the tail
wagging the dog. It's all very well but it means recording the
sound and taking it back to the computer, doesn't it? By the
time you know whether the colony is going to swarm, they've gone.
Does the computer software include band pass and high pass
filters?
Another consideration was the viability of the instrument and
what price people would pay. Eddie always stressed that the time
saving factor applied mainly to commercial beekeepers. In the
swarming season, brood box inspections have to be done every 8
days taking about 15 minutes each, but 90% of these are wasted
because no swarm preparations are found. Also, colony
disturbance results in a sizeable loss of honey, I am told. An
apidictor check takes 30 seconds so you save 14.5 minutes x 90%
of your hives every 8 days. I gave a more detailed calculation in
my posting on this site dated 10th January where the answer came
out at a saving of 217 man hours per year for somebody with100
hives. Multiply this by the wage rate in the country where you
live and you can judge how worthwhile it is. Even for a one-man
business who does not have to pay wages, it would mean he could
keep that many more hives.
Back in March, Tom Barrett questioned my figure of 4,000 for the
number of nurse bees in a hive but here again it is a question of
simple arithmetic. We are talking about the time of year when
activity is at its peak. There are 60,000 bees in the colony
working themselves to death in 6 weeks; let's call it 40 days.
Divide 60,000 by 40 and it is obvious that there are 1,500 1-day
old bees, 1500 2-day old bees............1500 39-day old bees and
1500-40 day old bees and, of course, the queen is laying 1,500
eggs a day. The period when a bee's body is producing food is
from 4.5 to 6days old; these are the nurse bees. With 1,500 at 6
days old, 1,500 at 5 days old and 750 at 4.5 days old this adds
up to 3,750 which I reckon is near enough 4,000. QED.
Several contributors regarded the apidictor as a flop, which it
was, because beekeepers were too conservative and non-technical.
The professional entomologists of the day were offended by this
upstart engineer who started telling them how bees functioned and
they didn't really have the technical knowledge to understand
what he was talking about. One, who shall be nameless because he
is a Bee-L subscriber, persuaded a queen to pipe while breathing
helium in an experiment which actually proved that her breathing
tubes were less than 10 inches long! Even if the apidictor was
a flop then, it was taken up with enthusiasm by more far-sighted
beekeepers, some are still using it today and only last year I
was instrumental in getting two repaired for desperate users.
Quite a number went to Australasia, I understand and I'd like to
contact a discussion group in that continent if anybody knows of
one. Bee-L is clearly made up of Northern Hemisphere folk.
Well done Chris Slade for finding that 1965 Kimpton Bros. letter.
I wrote to them 20 years ago but there was nobody left in the
firm who remembered the existence of the apidictor. The
manufacturers had lost their identity in a series of takeovers
and there was no way of getting technical information.
Eddie's widow passed me on to their son in Yorkshire who gave me
what papers still existed and a few artefacts which I passed on
to IBRA. It was because I felt that his name deserved to be
kept alive that I wrote the book 'Listen to the Bees' which you
can get from Northern Bee Books, Scout Bottom Farm, Mytholmroyd,
Hebden Bridge, Yorkshire, HX7 5JS, UK. Tel:01422 882751,
Fax:01422 886157, e-mail [log in to unmask] Postage
paid price is £1.50 in the UK and $3.00 to the USA. It's not
just about the apidictor but about all the sounds made by bees
and it includes my own revolutionary theory that the buzzing
sound actually contributes to the bee's aerodynamics.
Thanks to the kindness of Barry Birkey of Chicago, the circuit
diagram and other data on the apidictor can now be downloaded
from his web site on www.beesource.com using Adobe Acrobat Reader
version 3 or above.(which you can also get from the site)
Rex Boys.
19.1.00
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