Dear Bee-Liners
 
As a newcomer to BEE-L I apologise in advance if this subject has
been recently covered.
 
When I first became interested in bees and read about the subject,  I
was interested to find references describing how experienced
beekeepers can detect whether a colony is queenless or queenright by
tapping the hive and listening to the response.
 
I also wondered whether sound might yield other information about the
state of the colony.
 
Several years later I was lucky to come across an article by an UK
beekeeper called Rex Boys.  It described the work of a beekeeper and
BBC sound engineer called Eddie Woods from the late thirties to the
late fifties.  Rex (who was a colleague of Eddie Woods and who still lectures
about his work) very kindly sent me some articles about Eddie Woods'
work.
 
Eddie discovered that a colonies state,  particularly in relation to
swarming condition,  could be ascertained by measuring the sound
frequencies within a hive after tapping on the hive sufficient to
disturb its occupants.  He described two sounds in particular that he
called 'hiss' and 'warble'.  He described 'warble' as a bubbling
noise with a pitch round about middle C,  always present in a healthy
colony but sometimes almost inaudible.  He found that the warble is
produced by young bees and that the volume of 'warble' increases
during the period of 10-15 days before the appearance of queen cells.
About 7 days before the issue of a swarm the volume of warble becomes
relatively very loud.
 
The 'hiss'  he described as a much higher frequency,  the noise we
can most readily hear if we rap the side of a hive.  He found that as
swarming approaches 'warble'  increases and 'hiss' diminishes.
 
Eddie was obviously very clever as well as having a finely tuned ear,
for he produced 3 devices which he called 'Apidictors'. The idea was
that you could rap your hive and measure the relative 'warble/hiss
components from the sounds and predict (amongst other things)
whether the colony was likely to swarm.
 
He found that an apiary of 30 colonies could be 'measured'  in about 3
minutes
 
Most of the development of the Apidictors was carried out in the late
forties and early fifties and although I know little about
electronics I reckon this was pretty clever stuff.  The Apidictor was
produced in small numbers on a commercial basis,  but the price and
the attitude of beekeepers prevented it from becoming a success.
 
My guess is that today an improved Apidictor could be produced in
quantity for little more than a couple of jars of honey.  I have
copies of the technical descriptions of the Apidictor if anyone is
interested.  Surely there must be a subscriber to Bee-Line who knows
about electronics!
 
Eddie also had an article published in New Scientist in the fifties
describing the frequency of the worker's wingbeat.  As he describes
it,  previous measurements had been made by measuring the wingbeat of a
fanning worker or by mechanically restraining the bee (pinnning?!).
These give a figure of about 180 beats per second.  Because Eddie had
such a fine ear he could tell when playing keys on the piano and
comparing the sound with the buzz of a bee flying in his room that
this was incorrect.  He explained that the centre of motion of a bee
in flight changes and hence the frequency is about 250 beats per
second.  He later confirmed this with an oscilloscope.
 
IBRA have copies of Eddie's work and the BBKA have put together a
tape made from rather aged recordings of  'Sounds from the Beehive'
including one called something like 'Murder in the Apiary'  which is
a recording of the emergence and battle of young queens and their
piping.
 
I would be happy to forward any information that I have
available about the work of Eddie Woods to who anyone shares my rather
esoteric interest in the noises made by bees!
 
Best wishes
 
Joe Hemmens