So, we believe, that in bee's life there are two types of heat transfer Heating of the nest by the heat of their bodies produced without movement or with movement of the wings, and with the transfer of heat to the distance with the help of natural or forced convection. cooling of the nest, Using ventilation when the air outside the hive is cold enough, By vaporization of the water brought to the hive, In extreme cases, using vaporization of metabolic moisture, released by the bodies of the bees, with the help of an air streams generated by the movement of bee's wings. Let's now consider how works each of them and how this affects on the creation of sound waves and their intensity, and accordingly, on the signal peak position on the frequency scale, in the range 50-180 Hz. Consider the process of heating of the nest by the bees. We assume that during temperatures drop, heating of the nest goes through three stages: 1. The first stage - Is the stage of the silent nest heating by natural silent heating of the chest of bees and natural convection of the heat in the nest. This stage takes place throughout the whole year, as long as the temperature in the hive does not exceed the temperature required for the life of bees and brood. We can not fix this stage using monitoring of sounds of the nest. 2. The second stage - Is the heating step, which occurs, when it is not enough simply to heat the chest and gather together in the nest, for heating the nest and brood. According to our observations, this type of heating occurs when the temperature drops below + 14C and can continue, for strong, well-heat-insulated families, till -3C - 5C. On this stage bees give additional heat by flapping their wings with limited speed. And, accordingly, improves heat transfer due to air streams blowing around the body of the bees, thanks to flapping of their wings. This stage is characterized by the following factors : Finite rate of heating of the bee's body due to the finite speed of metabolic processes, generating heat. Low heat transfer coefficient of the bee's body, when the bee heating the air, through her chitinous exoskeleton. And, very importantly, the requirement of a sufficiently strong heating of the transferring medium , regardless of how much heat will eventually be removed from the body of the bee. This leads to the fact that the optimal speed of blowing of air around the body of the bee should be not high, to ensure that the air managed to be warmed, and sent further, in the places, where it will heat the nest and the brood. Thus, we assume, that intensity of the sounds produced by bees during this blowout must be not high, and signals must situates in the range from 70(50) to 100 Hz. In addition, this stage of heating is characterized by a rather passive state of the family ( passive or roughly 50\50 active / passive) . The range of the working status of the family is very similar to autumn period without honey harvest . Thus we can say that the acoustic pattern of this phase shows the presence of signals in the working area in the range of the passive state 200-240 Hz , partially active ( 270-340 Hz) and convective heating, characterized by low-speed airflow, which gives a signal in the range of 70-100 Hz. This signal may be accompanied by aeration of the nest in the range of 100-140 Hz. 3. The third stage - is the type of heating, which occurs in the "ball" of wintering bees at low temperatures, due to the heating of their chests and shakes ( vibration) of the thorax. This type of heating is characterized by active state of the bees inside the "ball", and by generating of signals within the range of 270-340 Hz under normal wintering conditions and a slight shif tof the signals to the range of 380 -400Hz due to deterioration of wintering conditions or anxiety.
beekeeping, apicultura, apicoltura, apiculture
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