Honeybees: Why too much ventilation can be a bad thing

Would you be thinking that opening an additional ventilation entrance on a bearded hive like this would be a good idea? If your answer was yes, it would be a wrong one! If you look closer at the image, with the temperature outside at 31 C, there are very few bees that are actually ventilating the hive. That is because the colony evacuated just the right number of bees from the brood area that they can maintain the internal temperature and humidity levels with the least posible amount of work and energy needed. Usually, with the hive in this condition there is also a very limited traffic at the entrance. Why would there be much of it at 31 degrees, as most of the nectar out there dries out before the bees can get to it, even if some plant would produce it at the temperatures as high as that? So, what happens if you open the ventilation? You make the bees work hard to re-establish the nest microclimate. The beard size reduces, or it disappears completely, because the bees now need to get in the nest area and burn energy to keep the incubation temperature at it's optimum. Since with the increased ventilation the moisture levels drop too, you'll see increased traffic at the entrance, but those bees mostly bring water in, not nectar. Give yourself and your bees a break during the heat waves, don't force them to work when they don't need to, and trust them that they know what are they doing. The exception to this is when you see a clear sign of distress when the whole colony is spread over the hive walls with all the bees beating their wings, trying to cool down the hive.