LATE EVENING VENTILATION OF THE NEST BY THE BEES. What is the essence of this phenomenon.

 We all had the opportunity on summer evenings, especially with a good honey flow, to observe how a mass of bees begin to ventilate the hive. A powerful rumble fills the entire apiary and does not subside until the morning. We have always believed that this is the bees remove moisture from the nectar. Not a bad idea... But why don't they do it during the day, at the hottest time of the day, when water from nectar evaporates better? At that time we don't see strong ventilation! It would seem to be a paradox, but no. Everything is logical if we turn to the statement that bees are able to maintain optimal humidity in the hive for hatching brood. We do not know what "sensors" bees have, but we can assume that they sense humidity in conjunction with temperature, that is, they respond to effective temperature, which is the derivative of absolute temperature and humidity.

So, what is actually happening in our belief in the hive and why powerful ventilation begins only in the evening?

During the day, the bees perform their usual work of bringing nectar, which they lay out first of all near open brood. And not because it needs to be fed with fresh nectar, but because water evaporating from it, raises humidity of air around the tender young brood - eggs and young larvae. After all, it is known from the works of scientists that the best survival of eggs and young larvae is observed at a relative humidity of about 90%. At the same time, we assume that the honey collection takes place during the warmest, if not the hottest time of the summer season.

So, what is the reason for this powerful evening ventilation ... And here's what! During the day, at the hottest time, water evaporating from nectar raises the absolute humidity in the hive, but the bees do not notice this yet, since the phenomenon is that they apparently feel not absolute, but relative humidity, and the higher the temperature, the less it gets! The same amount of water vapor dissolved in the same volume of air will show different relative humidity at different temperatures! At high temperatures, it will be much lower than at low! If you cool any room containing water vapor in the atmosphere, then sooner or later dew will occur! The temperature at which this can occur at certain humidity is called the "dew point". That's what bees are afraid of!

In the evening, as the temperature drops to the cold of the night, the bees feel how the relative humidity rises, which can cause vapors to condense into dew. It is this increase in relative humidity that causes the bees to intensively remove getting colder and colder moist air from the hive. That is why there is no need to ventilate the hive during the daytime - after all, at high daytime temperatures, the relative humidity of the air in the hive is not high at all, no matter how much fresh nectar is brought by the bees!

So, it can be argued that the powerful ventilation of the hive in the evening is directly related to both the supply of significant volumes of nectar and a significant decrease in temperature in the evening and at night.