Ventilation of the beehive by honey bees

Fan at the edge of the honeycombs

Do honeybees form ventilation lines for effective cooling, dehumidification or gas exchange? In a natural beehive in a tree cavity there are no significant natural air changes. Ventilation with the aim of gas exchange, cooling or dehumidification must be actively performed by the bees. It is known that honey bees start fanning when air temperature, … Read moreVentilation of the beehive by honey bees

Theory of Torben Schiffer on the propolis of bees

No Goretex effect

Do bees put holes in the propolis layer on purpose to achieve the effect of functional clothing?

Torben Schiffer says so. He presents in the name of HOBOS electron microscopic images of holes in the propolis layer online among a theory of their formation and effect. It is stated that bees create these holes on purpose to ensure the removal of moisture by water vapor diffusion. Supposedly, they achieve an effect such as that of functional clothing (like Gore-Tex) by this means that allows water vapor diffusion but prevents the permeability to water in its liquid form. Several questions arise from the article.

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Upgrade of the Infrared Camera System

Biene mit Varroa Milbe

In the last weeks I spent a lot of time to upgrade my system for recording infrared videos. I replaced the old 0.4MP camera with a 3MP camera with a wide-angle lens. The illumination is now via 9 infrared LEDs (previously one LED) and is now recorded at a frame rate of 60fps (previously 25fps).

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Effect of high humidity in the beehive on the water content of honey

test specimens

A balance is established between the water content of the honey and the surrounding air humidity. The balancing moisture content of honey at a relative humidity of 55% is about 17.5%. At a relative humidity of 80%, honey has a water content of over 30% (source: The hygroscopic properties of different dilutions of Honey, Doull & Mew 1977).

The wax capping of the honey cells slows down the speed of these water transports, but does not prevent diffusion. The wax layer is so thin that the resistance of this cap to water vapour diffusion is just as high as that of a 3.3 cm thick layer of air. The experimental setup for determining the diffusion density is explained below.

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Effect of outer thermal insulation on moisture in the beehive


The evolution of honeybees has taken place over many millions of years in tree hollows with a respectable thermal insulation of the surrounding wood. It is to be expected that they have adjusted perfectly to this climate inside the tree cavities, which is much influenced by the thermal insulation. Only in modern beekeeping did they have to forgo the advantages of such thermal insulation.

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Bee hive Gruibert


The instructions for a new hive are now available under hive building: The Gruibert hive. The idea was born together with Gabi and Norbert Dorn. The goal was a hive with the following characteristics:

  • Thermal insulation comparable to tree cavities inhabited by bees
  • Entrance tunnel and volume of the brood chamber comparable to tree cavities inhabited by bees
  • Operation with top beams
  • Geometry based on tree cavities inhabited by bees higher than wide
  • Inserting of a common frame size possible
  • Access to the brood chamber from above and below possible
  • Hanging in the tree
  • Varroa screen board
  • Hive can be reconstructed with simple means and without special previous knowledge

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Tom´s Tree

Toms Tree

In the fall of 2017, I made Thomas Seeley an offer he couldn’t possibly refuse. I offered him 10 of my just finished Beeloggers to use in the Arnot Forest in the natural tree cavities he knows. I wrote him an e-mail with all the information about the data loggers and offered to climb into the trees with him. Thomas Seeley answered quickly and firmly: Unfortunately no time.

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Rodeo bee drops Varroa mite!

Rodeo Biene

A bee tries to free itself from a Varroa mite for minutes, with powerful and very fast shaking movements. Presumably she cannot distinguish the mite from disturbing pollen residues at all, I have often been able to observe this shaking movements. Often bypassing bees then take these shaking movements to help the troubled bee, just as here at the end of the video (social or mutual grooming). In this case, however, the mite has already been thrown off. In a shaking phase with a very high frequency it obviously can no longer hold. Maybe she’ll fall to the ground and be received by book scorpions 🙂

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The diffusion lid works!

Temperature under the Diffusion Lid

Average temperature difference

In December 2017 I took measurements on a beehive with a Diffusion-lid for 2 weeks to get an overview of the average temperature below the lid. For this purpose, 7 temperature sensors were installed as shown. The values given are the average temperature difference between the sensor and the outdoor temperature. The average temperature difference to the outside air is 5.5°C in the 2 weeks considered (the average outside temperature in the period was 0.4°C). The temperature difference is much smaller than expected, especially since the hive is provided with an additional external insulation, a closed floor and only 3 small entrances. But the bees do not heat the hive, but only their bee cluster :-).
Because of this rather small temperature difference, I had some doubts if I was right with my theories…

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Thermal insulation of honeycombs


When considering the thermal insulation of bee hives, we also have to consider the honeycomb construction with its air layers in between. These layers themselves act as thermal insulation. The more honeycombs between the bee cluster and the side wall, the higher the insulation. I.e. with regard to the side thermal insulation, the broad constructions of the modern hives are quite helpful.

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