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