ACOUSTIC CONTROL IN THE PROCESS OF WINTERING - the Peculiarities

Our three-years study of bees' life, using the Apivox Auditor and Apivox Smart Monitor acoustic control devices, led us to conclude that some statements, made by Professor Eskov about acoustic signals of bees during the wintering period, which were considered to be fundamental and not subject to doubt, today look somewhat untenable. We would like to conduct a comparative analysis and allow you to see the reasons why we came to this conclusion.

So, let's talk about bees signals in winter ...

Prof. Eskov writes: * ... "components in the range of 210-330 Hz are generated by processes associated with the heat production of bees  This conclusion is based on the following: 1) the intensity of the components in the range of 210-330 Hz is directly dependent on the amount of heat released by the bee family; 2) this range is constantly present in the sound background of the hive, and bees, as it is well known, support a certain thermal regime in the nest, and as a result have constant heat production ; 3) a decrease in temperature in the peripheral zone of the nest is reflected in a decrease in intensity of bees' sounds in the range of 210-330 Hz 4) Bees are capable to produce sound in the range of these frequencies, exclusively by vibration of thorax, under the action of indirect-acting wing muscles. In the process of this vibrations heat is generated ... "

  * Sources  - Eskov EK 'Honeybee Behavior' - Moscow: Kolos, 1981 - p.184

                   - Eskov E.K. "Acoustic control of the state of bees"

   

We disagree with almost all statement. Heat production, according to all authoritative scientists, under normal conditions, practically does not cause any generation of sound signals. Bees, like all living creatures, first of all follow the path of minimizing of energy losses, and therefore, pay more attention to the conservation of energy, than to its creation. In addition, this statement does not take into account the breed characteristics of the behavior of bees, associated with generation of vibro-acoustic signals.

We believe that appearance of an incorrect interpretation of the behavior of bees during wintering, is associated with a radical difference in the behavior of the Russian breed of bees during wintering, from  breeds of bees, whose homeland were the mountains.

According to scientists, the bees of mountains, to which Caucasian mountain bee belongs, as well as apparently Carnica, require a temperature of 5-6 degrees lower for normal vital activity, than, and this is surprisingly, more thermophilic bees of Russian breed.

That is why Russian bees are forced to spend more strength and energy on wintering, almost constantly engaged in the distribution of food and active heating. That is why they consume more feed and have a large winter waste of bees. That is why their acoustic signals are always loud and always contain peaks in the area, corresponding to the performance of various in-hive works.

We could observe such effect during winter control of two families - the family with the F1 queen of the Carnica breed, and the family, which was a crossbreed between Russian bees and

some other. The bees of the Russian breed could be  heard even at close distance from the hive. Carnica breed bees could not be heard, even when the hive was open, and the microphone was placed on the upper bars of the frames among the bees.

This breed phenomenon, as it seems to us, served as the basis for the incorrect statements of prof. Eskov .... After all, heat production up to a certain point is generally not accompanied by any significant sound signals, and is not always accompanied by the vibration of the bee's thorax. But the amount of works, performed by the family, is directly related to the temperature in the hive and in the nest, and, accordingly, to the generation of sound and vibration signals.

In addition, another observation speaks in our favor ... We observed signals from bees, whose hives were located on open air, and at a total air temperature of about -10C, were heated by the spring sun.... The heating of the hives by the sun activated all signals dramatically, and after sunset,  and accordingly,  after return of the temperature in the hive to negative values, all signals subsided to almost complete inaudibility. And this contradicts the statement of prof. Eskov that these signals are the signals emitted by the bees during heating process, because in this case, they should increase in accordance with a drop in temperature, and not vice versa.

One more data, it seems to us, is confirming our idea. It was obtained this year when working with an observational hive. As we have already written, the family in the observant hive was brought from the cold yard into the cold room.

One side was opened, and we started measurements. The picture on the screen of Apivox Smart Monitor showed a very low level of acoustic signals. This, in our opinion, corresponds to the mode of maintaining the optimal temperature in the nest, in the period of not very low outdoors temperatures. After that, we started heating of the observational hive using a fan heater.  At some intervals, the heating was stopped and measurements were taken. The result showed an increase in the activity of bees in the process of heating the hive.  Accordingly, the level of acoustic background also increased. The cluster of bees became more friable, the bees began to do their usual works.

It should be noted, that after a while, the activity of bees continued only around the queen. The

overall level of background signals decreased, remaining, however, higher than when they were in hibernation. The reason for this could be the apparently complete lack of works, that could be continued to be done, after the first needs of bees were met.

So, this experiment also speaks about the inverse relationship of the acoustic background of the bee family, to the cold in winter. This means, the colder the weather, the lower the acoustic background of the hive at small negative or slightly positive temperatures, when the bees shifts to the phase of passive heating and heat preservation. As the temperature increases, the bees become more active and begin to work and ventilate the nest. This leads to an increment in the acoustic background of the hive.

Basing on our own observations and data of scientific works of American scientists on the topic of thermoregulation in bee colonies (  Honeybee Colony Thermoregulation – Regulatory Mechanisms and Contribution of Individuals in Dependence on Age, Location and Thermal Stress, metabolism-and-upper-thermal-limits-of-apis-mellifera-carnica-and-a-m-ligustica ),  it can be concluded, that there may be times, when the active heating phase may be accompanied by generation of sounds on the lowerest frequencies of the range, indicated by prof. Eskov, as the diapason of signals of working bees.

We have developed our own theory, where we present a group of evidence, which states, that this is possible. No doubt, that  additional researches will be required, in order to confirm this statement.

It cannot be denied, that at extremely low temperatures, bees may still have to spend more energy for heating and, accordingly, this requires more feed, which in its turn, can cause an increase in the amount of works in the warm part of the nest, and a corresponding increase in acoustic background. But the rise of background sounds occurs mainly in the low-frequency part of diapason, which was mentioned by prof. Eskov.

Thus, in the process of conducting our own observations of wintering bees, we clearly noticed the dependence of acoustic signals on temperature and time of day!  Acoustic background of the family fully corresponds to the works, with which bees are currently busy, differs by nothing, from the sound background of the family in summer. This is a very important result, indicating, that the "vocabulary" of bees stay unchanged in summer and winter.

As a result, it can be argued, that the strong sound background of the hive in winter in the high-frequency region is not directly related to heating, and says, apparently, about possible problems in the family.

On the other hand, strong sound background in the low-frequency region, indicates the attempt of the bees to heat the hive. It is possible that the family needs to heat the hive and move to a new frame with food, or about external intervention, because of which, the family must shift to the active state, in spite of the winter cold.  In this case, while beehive is heated, the growth of high-frequency component in working diapason will be associated with the implementation of in-hive works.

At the same time we believe that there is no strictly established relationship, between the reasons that caused this event and the frequency components of the acoustic background. This can be hunger, mice, excessive concentration of CO2. We just see the attempt of bees, in spite of the cold around, to correct the situation in which they found themselves, and save the family.

----------------Copyright Glebskij ------------------