Ventilating a hive is not a science, but you need to know how
What you will learn here
- When and how to ventilate a bumblebee hive
- What to follow
- How sensitive are bumblebees to ventilation and when?
Last updated: 6/4/2024
In a nutshell
- When placing bumblebees in the hive, the ventilation hole must be closed
- Ventilation with sensitivity: air belongs in the hive, not drafts
- CO2 also bothers bumblebees : in a closed hive, a strong nest can produce excessive CO2
- The humidity of the nest is generally not a problem: high humidity in the hive is not a big problem. The air supply for the nest is more important.
- Light in the hive is confusing : if the ventilation is open, it interferes with settling - bumblebees will try to find their way to the light
- Don't rush: start aerating only when the bumblebees have learned to go through the flap.
- Observe the behavior of bumblebees: if bumblebees are short of air or have an excess of CO2, they will try to ventilate by flapping their wings.
- Blocked ventilation: bumblebees sometimes cover their ventilation hole with padding, this is an instinctive thing to do. If they are not ventilating at the same time, there is no need to deal with this. Alternatively, remove some of the padding when checking them and uncover the ventilation hole.
English Abstract
- When settling bumblebees into the nest box, the ventilation opening must be closed
Ventilation with feeling: air, not draughts, belongs in the hive - CO2 also bothers bumblebees : in a closed hive, a strong nest can produce too much CO2
- Humidity does not bother the nest so much: high humidity in the hive is not a big problem. The air supply for the nest is more important
- Light in the hive is confusing: if there is open ventilation, it bothers the settling – bumblebees will try to find a way to the light
- Don't rush: only start ventilating when the bumblebees have learned to walk through the flap
- Observe bumblebee behavior : if the bumblebees are short of air or have too much CO2, they will try to ventilate the scare by swirling their wings
- Clogged ventilation : bumblebees sometimes cover the ventilation hole with a lining, they do this instinctively. If they do not ventilate on the comb at the same time, there is no need to deal with it. Alternatively, remove some of the lining and uncover the vent when checking them.
Contents
Introduction
Ventilating the hive during and after the queen settles
in Ventilating the hive after the queen settles in and while you are teaching her to pass through the flap
Ventilating the hive after the queen reliably passes through the flap
Ventilating the hive after the first generation of workers is born
Ventilating when the first and second generations of workers are in the hive
Ventilating when the hive has a strong nest
Ventilating when there are new queens and males
Ventilating the hive after you have placed a bumblebee nest in it
Ventilation and parasites
Workers and their behavior - an important indication of the need for hive ventilation
Other tips and texts on hive ventilation
Conclusion
Introduction
Every hive for bumblebees must be equipped with a ventilation hole . The ventilation hole ensures air circulation in the hive - oxygen supply, CO2 removal, moisture removal. Sometimes a moderate air circulation is appropriate so that excessive mold does not form .
A healthy bumblebee nest can handle mold if there is enough lining . The workers keep the mold away from the wax work. The workers can clean it with their mandibles. Draughts are more damaging to the nest , so only one ventilation hole is enough. Sometimes the bumblebees will cover that with lining if they feel the need.
The ventilation opening of the hive is equipped with a cap/closure so that the size of the ventilation opening can be regulated.
In the following text you will find instructions on how to regulate ventilation in the hive and what to follow.
The temperature in the hive varies greatly depending on where and how you measure it. In the core of the nest you can measure 30°C and at the same time only 10°C on the surface. Measuring temperatures is therefore problematic. Therefore, if you measure the temperature in your hives, measure it in the same place so that you can compare the measured values. It is optimal to measure the air temperature above the lining , preferably in the middle of such a space.
Measuring the temperature in the lining is pointless. The lining is thermal insulation and you do not know what you are measuring. It is like measuring the temperature in a bedroom, but the thermometer is placed under the duvet. 🙂
Unless otherwise stated, in the instructions we therefore state the air temperature outside the enclosure – the outside air temperature.
Important note
- Our instructions are based on the assumption that a 12-14l nest box is filled 2/3 full or up to the ventilation hole with quality lining. The lining acts as thermal insulation.
- Small hives, insufficient lining, or poor quality lining is a serious handicap for the hive both in low and high temperatures.
A hive with an open ventilation hole
Photo O. Hercog (2019)
Ventilation of the hive during and after the queen settles in
It is necessary to keep the ventilation hole closed!
When placing a queen bee in a hive (bumblebee), it is necessary to keep the hive ventilation closed, see the procedure HERE
If the mother sees light coming through the ventilation hole , she may try to leave the hive that way.
This may also be one of the reasons why the queen bee does not leave the hive and why she becomes "frozen" in the hive . This is often forgotten and it is enough to close the opening or tape it over to make the hive completely dark.
Hive with closed ventilation hole after introduction of queen
Photo O.Hercog (2019)
Deformed vent cover of a commercially available beehive (bumblebee hive)
Photo O. Hercog (2020)
Deformed vent cover of a commercially available beehive (bumblebee hive)
Mop solution
Photo: Petr Gebls Groebl
Ventilating the hive after the queen has settled in and while you are teaching her to go through the flap
It is necessary to keep the ventilation hole closed!
Once the mother has settled down, she needs to be taught to go through the protective flap, see the procedure HERE.
Until the mother reliably learns to go through the protective flap and sees light coming through the ventilation, she may try to leave the nest this way .
This may also be one of the reasons why training the mother to pass through the flap is not successful .
Mother bumblebee (Bombus terrestris) on a protective flap
Mother's name Bobina
Photo B. Klimešová (2019)
Ventilation of the hive after the queen passes reliably through the flap
We recommend keeping the ventilation hole closed unless the outside temperature exceeds 20°C.
The ventilation can be slightly opened, but you do not need to ventilate until the temperature exceeds 20°C.
Some keepers ventilate at temperatures of 15 °C, which is fine too. If there is enough lining in the hive, the queen copes just fine.
In the solitary phase (the mother is alone) the mother's air consumption is low and, unless the nest is hermetically sealed , sufficient oxygen enters it.
The mother's CO2 production is not high either and ventilation is not necessary.
Ventilating the hive after the first generation of workers is born
We recommend keeping the ventilation hole closed unless the outside temperature exceeds 15 - 20°C.
Once the first worker is born, it is a good idea to keep the vent closed. It is necessary to wait a day or two until the workers learn to go through the protective flap .
If the workers in the hive see light shining through the vent, they may try to leave the hive this way .
But this does not last long - once the workers start going through the flap, you do not need to take this into account and then you should be guided primarily by the temperature and, if necessary the behavior of the workers .
about the next generations of workers , they will follow the path of their older sisters.
If you have modified the ventilation of the hive using pipe extensions and have an elbow (bend) there, the light will not shine through into the hive. So you don't have to worry about it bothering the workers.
I wrote about this solution HERE .
Awning with ventilation from a HT pipe
Photo O. Hercog (5/2020)
Ventilation when there are first and second generation workers in the hive
We recommend keeping the ventilation opening open unless the outside temperature drops below 10 - 15°C.
The nest with workers already produces a sufficient amount of heat and is not as sensitive to a drop in external temperatures.
On the contrary, it is necessary for fresh air to flow , so that the CO2 produced does not accumulate there and mold does not form there.
Ventilation when there is a strong nest in the hive
We recommend keeping the ventilation open unless the outside temperature drops below 5-10 °C.
If the temperature drops below 5 °C, it is a good idea to close the ventilation, but not hermetically.
The nest with workers already produces a sufficient amount of heat and is not as sensitive to a drop in external temperatures .
On the contrary, it is necessary for fresh air to flow into the hive and for the CO2 produced to not accumulate there. In a strong nest, the amount of CO2 produced is quite significant.
As the CO2 content increases the humidity in the nest also increases , sometimes even above 95%. Humidity in itself is not harmful if you ventilate the hive. Ventilation is therefore necessary for a small air circulation and moisture removal to prevent the formation of mold .
Read more about removing moisture from the hive HERE (we are preparing).
Ventilation during the time of new mothers and males
Follow the same rules as for a nest with workers . If the male cannot find a way out, it is better to keep the ventilation closed. Pay attention to the need for ventilation in temperatures above 20 °C and in a strong nest, air supply and CO2 ventilation.
Young mothers will find their way out of the hive and return to it.
Males sometimes take longer to find their way and can be found sitting on the lining. If there is light shining through the ventilation , males may sit there and wait. The light sometimes activates them and they may try to mate with young queens. Hives where light does not penetrate through the ventilation have an advantage – preferably thanks to a curved ventilation system (elbow).
Ventilating the hive after placing a bumblebee nest in it
We recommend keeping the ventilation hole closed unless the outside temperature exceeds 20°C.
Once you have placed a new nest in the hive (purchased or evacuated nest see HERE ), you need to wait for the workers to start going through the protective flap . If they see light shining through the ventilation hole in the hive, they may try to leave the hive this way.
But this doesn't last long and once the workers start walking through the hive, you don't need to take this into account and just focus on the temperature and behavior of the workers.
Ventilation and parasites
In a strong nest, it is advisable to leave the ventilation ajar even at night, and not only for the sake of air supply. Especially where the ventilation hole is equipped with a sticky parasite trap, it is a good idea to leave the ventilation ajar.
This will distract the parasites from the protective flap and other places through which the parasites may try to penetrate the hive.
It makes sense to do this at a time when such parasites appear. We are referring to the ectoparasitic fly (Aphomia sociella) . It appears only on warm nights in May.
The condition is of course to have a ventilation hatch prepared according to the instructions, see HERE
Ventilation with a sticky trap at night
Photo: O. Hercog (5/2020)
Worker bees and their behavior – an important indication of the need for hive ventilation
It is usually sufficient for the beekeeper to monitor the external temperature, but the behavior of the workers is also an important indicator .
If you see a worker bee sitting on the top of a hive , or sitting on the lining and flapping its wings , it could mean the following:
- The temperature in the hive is high
- There is high humidity in the hive
- there is an excessive amount of CO2 in the hive
listen to the workers and open the ventilation until this behavior stops.
Hive ventilation - external protection with sticky trap - cover created on a 3D printer
Photo O.Hercog (2018)
Ventilation modification of commercially available hives – example
Photo O. Hercog (2019)
Hive ventilation cover
Photo O. Hercog (5/2021)
Hive ventilation protection – 3D printed cover
Photo O. Hercog (5/2021)
Hives (bumblebees) with ventilation attachment
Pay attention to the rules for using attachments
Photo O. Hercog (5/2020)
Conclusion
If your hive is empty and you are just getting ready to settle the queen, air it out and dry (in the sun, or remove the roof at home). After you have started trying to settle the hive, do not open it unnecessarily .
Bumblebees are sensitive to micro-drafts , especially the queen bee when she is guarding the nest or when she is settling in the hive. Therefore, a hive with one ventilation hole where there is no draft is recommended.
When you are placing the queen bee, no light should shine into the hive . Some commercial products do not meet this requirement and it is therefore necessary to seal the ventilation hole, for example by covering it with opaque adhesive tape.
For a hive with a queen in the solitary phase, you can leave the vent closed as long as the outside temperatures do not exceed 20° C.
Ventilation during the hatching of the first generation of workers should be addressed when they find their way out. It is no longer necessary to address this for subsequent geberating workers.
For a hive with a thicker nest, you don't need to completely close the ventilation until temperatures drop significantly.
If your hive is equipped with a sticky trap (recommended), it is necessary to keep the ventilation ajar even at night , otherwise the sticky trap is ineffective.
If the workers on the garlic or on the lining are fluttering their wings, it is necessary to ventilate .