How Does A Bee Get Oxygen?

How does a bee get oxygen? In this article, we show that bees do not have lungs, but look at how they breathe. Bee respiration is critical to bee flight and operation, hence we also look at how different bees have adapted to be efficient in different environments.

How We Breathe

If we look at how we get oxygen, we breathe air into our lungs. Oxygen transfers into the blood and gets bound to hemoglobin in red blood cells. This blood then gets pumped around to parts of the body where it is needed. The blood then brings used oxygen – in the form of Carbon dioxide, back to the lungs where this is released into the air and fresh oxygen is absorbed into the blood.

How Bees Breathe

How does a bee get oxygen? Well, bees use a completely different system. They do not have lungs. They have spiracles – small holes in their hard exoskeleton. A bee can be loosely divided into major sections based on the shape of the exoskeleton.

The major segments are the head, thorax, and abdomen. Major segments are further divided into smaller segments – for example, the abdomen has multiple segments. Each section of the bee needs an oxygen supply.

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Spiracles

Spiracles provide openings into these segments. There are three pairs of spiracles in the thorax and seven in the abdomen. Spiracles are connected to pipes that look a bit like vacuum cleaner pipes.

Trachea

These reinforced pipes or trachea form a network that spreads into the body of the bee. Every now and then, an air sack forms in the tracheal network. This helps with breathing – we will get to that shortly.

The trachea eventually branches to the point where they are very small, at which point they are called tracheoles. These have a very large surface-to-volume ratio which allows rapid exchange of oxygen to the cells, and removal of carbon dioxide from the body of the bee.

Air Sacks

Hence so far we can see bees do not have lungs in the sense that we do. They do however have an ability to pump air in and out of their bodies using the air sacks we mentioned earlier. These air sacks will expand if the bee extends her abdomen, and they will contract if she contracts her abdomen.

To pump air in and out of her respiratory system, a bee will lengthen and shorten her abdomen. Watch a bee land on a flower – if she is a bit tired from a long flight you will actually see her just sitting on the flower and her abdomen gets longer and shorter as she “catches her breath”. Then once she has reoxygenated herself, she will go and get nectar and go about her business.

How Does Bee Respiration Work?

If we ask ourselves how bee respiration works, it is now clear they have a system to pump air in and out of their bodies through a tracheal network with airbags to ensure airflow. Unlike us, bees do not have a well-developed circulator system to pump blood around. In fact, they don’t even have hemoglobin.

Hemolymph

Bees have an alternative to our blood. This is called hemolymph and it is circulated around in a so-called open circulatory system. It just sloshes around inside the bee basically and is moved around by a heart that runs from the tip of the bee’s abdomen to its head.

The Bee Heart

The bee heart is long and acts as a pump to suck hemolymph from the abdomen to the head segment. Remember a bee does not have spiracles in its head, so this is how oxygen gets to its powerful little brain.

From the head, the hemolymph then spills through the thorax to the abdomen, and the cycle repeats. The part of the heart in the thorax is called the dorsal aorta, and the part in the abdomen is called the dorsal heart. This part has little holes in it called Ostia that let hemolymph into the heart and then pump it to the aorta, which, much like our aorta gives it a strong pulse to propel it on its journey.

Malate Dehydrogenase and Miles Per Gallon Of Honey

Now that we know how bees breathe let us have a closer look at how this system is fine-tuned. Oxygen is provided to all parts of the bee’s body via this respiration system. Malate dehydrogenase is a crucially important enzyme in the wing muscle of the bees. Depending on how well these enzymes work determines the rate at which bees can react oxygen with glucose to produce energy and fly.

In the evolution of bees, African bees have evolved more powerful malate dehydrogenase enzymes, meaning that their “fuel efficiency” and “performance” are better per unit sugar metabolized. This has a huge impact on the efficiency of a beehive, as the actual miles per gallon of honey that the bees are getting is greater, meaning the entire hive is more efficient.

What Can Go Wrong?

We have answered the question of how a bee gets oxygen. As with all systems, there are ways that the way bees breathe can malfunction. Tracheal mites – Acarapis woodi – are small mites that crawl into the spiracles of bees and multiply. They puncture the trachea and feed on hemolymph. This has the effect of weakening the bee and also reducing the rate of oxygen flow into the bee.

With time, the bee will basically drown or suffocate as the tracheal mites make it impossible for the bee to breathe. Interestingly, some bees have evolved to repel tracheal mites – their spiracles have different shapes and sizes which stop mites from entering.

We hope you have enjoyed this article and next time you see a bee flop down on a flower and expand and contract her abdomen, point out to your friends that she is breathing.  If you found this article helpful, please share with others who are interested to know how bees breathe.

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