Have you ever thought about how honey bees breathe-do bees have lungs? They fly through the garden at fast speeds-for such a small insect. If we used that much energy to run up a hill – we might be huffing and puffing afterwards. Like us, honey bees need oxygen to survive. In fact, honey bees have a remarkable respiration system that allows gas exchange – but they don’t use lungs to get the job done.
A look into the intricate respiratory system of bees reveals a remarkable process. As a beekeeper, I am continually amazed at honey bee anatomy. For each job, bees have special body parts to assist in everyday life. Their system for obtaining oxygen and expelling carbon dioxide – is no exception.
The Respiratory System of Honey Bees
The respiratory system of honey bees consists primarily of spiracles and tracheal tubes. Bees do not have large lungs that inflate and deflate. Rather, oxygen is distributed throughout their bodies using a tube network.
Air enters the body through valve-like opening in the exoskeleton called “spiracles”. These openings appear laterally along the body – most insects have 10 pairs.
In bees, the first 3 pairs are located on the thorax and the last 7 pairs are on the sides of the abdomen. If you look closely at bee larvae, those little dark dots on the sides are the developing spiracles.
Spiracles play a major role in how honey bees breathe. These tiny openings can open and close as needed.
Tracheal Tubes: Breathing Pathways
Each spiracle opens into a tube called a trachea. Trachea have round rings of chitin giving the appearance of a ringed vacuum hose.
This strong material is arranged in a spiral on the outside of the trachea – making the tubes very flexible and kink resistant.
These tubes work similar to the plumbing in your house delivering water to several rooms. Instead, tracheal tubes deliver oxygen throughout the bee’s body.
As the tube network gets farther and farther from the spiracle opening, they branch out and divide into smaller and smaller tubes.
At the very end, they become so small they attach directly to the cellular tissues – these are the tracheoles.
This is where the gas exchange takes place – oxygen moves into the tissue and carbon dioxide wastes move out.
Instead of lungs, bees have air sacs located at various places along the tracheal tubes. They are located in all sections of the bee’s body with the largest ones in the abdomen.
These thin-walled sacs help move oxygen to where it is needed. Muscles in the abdomen cause the sacs to expand or contract depending on the bees need for oxygen.
Have you ever seen a honey bee – pumping her abdomen? Now you know why – she is working hard to get oxygen where it is needed.
The movement is barely noticeable under normal conditions, but if she is experiencing a lack of oxygen, you can easily see the pumping action.
Oxygen Exchange – Carbon Dioxide Out
Oxygen helps cells break down the foods bees eat and turn it into energy. Energy is needed to perform all the tasks necessary for hive survival.
Whether the forager bees are traveling a long distance for food, or defending the colony against attack – they need energy.
This all sounds great but, just like humans, bee bodies produce wastes. No, I’m not talking about bee poop – though they do that as well.
As cells use up oxygen, they produce carbon dioxide. To prevent carbon dioxide from building up in the body, the tracheal system works in reverse.
It carries the carbon dioxide back through the tubes and spiracles to get it out of the body.
In normal situations, this system works well. However, if something is wrong and the tracheal tubes don’t deliver enough oxygen, the bee’s body will not function properly. She may appear tired or sick.
When bees are flying or working hard, they need more oxygen – just like us. As she takes a breath, the spiracles open allowing fresh air to enter. Fresh oxygen helps the bee feel better and is used to create energy.
But, if the bees are sleeping or resting, they don’t need as much energy or gas exchange. They can regulate air intake by closing the spiracle to a smaller opening. This balance helps the bee save energy and provides a metabolism balance.
Factors Affecting Bee Respiration
Other than activity level, there are other factors that affect breathing in bees:
Bees are cold blooded insects that are sensitive to temperature changes. Cold temperatures cause their bodies to slow down – it becomes harder for them to breathe or move.
Likewise, in very hot weather, they attempt to cool down. They may flap their wings (called fanning) to attempt cooling down the hive. This extra ventilation can result in a lose of moisture which makes breathing more difficult.
Humidity is a tricky thing for a bee colony. Too much humidity can be a serious problem for a colony – especially in the winter beehive.
However, air that is very low humidity can dry out the inside of their tracheal tubes making breathing more difficult. Thankfully, the colony has systems in place to help control these issues.
Optimal Hive Conditions
We can’t control the weather – thank goodness. But, if you are a beekeeper, there are things you can do to help your bees to breathe well and be more comfortable
Ensure good hive ventilation to allow fresh air to move in and stale air to move out. This helps maintain an oxygen/carbon dioxide balance.
In some locations, insulating the hive (especially in winter) may help keep the temperature steady. This prevents stressing the bees during times of extreme cold.
Be sure to put your beehive in a good location that’s not too damp. Boggy locations can produce excessive humidity in the hive.
But, be sure they have access to a nearby bee safe water source-they need water for several purposes.
Keep your colonies healthy by controlling varroa mites and other pests. Varroa may not be the threat to bee respiration that tracheal mites were – but sick stressed bees are not as healthy – regardless of the reason.
Yes, air enters the bee through spiracles and travels along the tracheal tubes into the tracheoles. Here gas exchange takes place with oxygen moving in and carbon dioxide moving out of the cells and into the tubes to be expelled from the body.
Seeing a honey bee rapidly pumping its abdomen means it needs more oxygen. Muscles in the abdomen pump to change the pressure in internal air sacs and get oxygen to where it is needed.
Bees do not breath in and out through their mouth or nostrils. They have openings on their body called spiracles that allow air to enter and leave the body.
Bees can survive a short time without oxygen. They can close their spiracles to protect themselves from drowning but carbon dioxide continues to build up inside their body.
Bees do not have lungs but the air sacs located inside the tracheal tubes help get oxygen rich air to where it is needed. Once there, tiny tracheoles create the gas exchange within the cells.
So, now you know – honey bees do not have lungs. But, they do have an interesting respiration systems that works well to get oxygen-rich air to every cell in their body. In some ways, that is the same thing that lungs do for us – just a different way to get it done.