bee biology

Do your bees have this strange condition?

Beekeepers sometimes report unusual behaviors in their bees, everything from fore-and-aft convulsions to unmitigated quaking anger. I’ve collected three of these observations below, each from a new beekeeper:

“Today a bee on the landing board was trying to vomit. Her whole body was wracked with convulsions that moved in waves. When I opened the hive, I found others pulsating in the same way. I’m worried. What should I do about these sick bees?”

“I think my bees have been sprayed with insect killer. Some of them are showing muscles spasms in their abdomens that don’t stop, and I’ve read insect poison will do that. Except for the contractions, they are acting kinda normal. What do you think?”

“Bees on the front of my hive are so angry, I ran away. They are mad, acting like they’re in labor, or having seizures of fury. It’s hard to explain but it’s like a wave of tension that flows from one end to another and it happens over and over. Should I just wait or what? What made them so furious?”

A condition with a name

Luckily for us, this well-known condition has a name. It’s called breathing.

Animals, including insects, need oxygen for survival, and complex multi-cellular animals need ways to deliver oxygen to all the cells and organs inside the body. Many different breathing systems have evolved, and each system works for the particular environment where the animal lives.

Bees, like many other insects, have a system of tracheal tubes that move oxygen throughout the body. These tubes are long with many branches that get smaller in diameter as they go further in. They start at the integument (skin) of the insect and grow inward in a complex matrix.

The tracheae deliver

The tracheae deliver oxygen to wherever it needs to go because, unlike human blood, insect hemolymph does not carry oxygen. At various places along the tracheae, thin-walled balloons or pillows fill up with oxygen, expanding and contracting as needed. In many ways, these sacs act like lungs, bringing in oxygen and pushing it where it needs to go. Honey bees have air sacs in their head, thorax, abdomen, and legs.

Muscle movements in the abdomen control the movement in and out of the air sacs. These telescoping movements have been described by scientists as “accordion-like.” The muscle contractions seem to flow along the length of the abdomen causing the abdominal plates to slide over or under one another.

The whole body appears to move because the muscles attach to the inside of the segments, not the air sacs. The bee can contract her muscles dorsoventrally (from top to bottom) or along the length of the abdomen. As the abdomen contracts, air is squeezed from the sacs and as the muscles relax, air is sucked into them, much like a bicycle pump.

The spiracle miracle

Each tracheal tube attaches to the inside of the integument at a point called a spiracle. Basically, a spiracle is just a hole through the integument that has a one-way valve so air can come in easily but cannot escape. This means when the bee contracts her abdomen, the air moves inward to the organs and not back out through the spiracle. Pretty neat. Bees have ten pairs of spiracles, three pairs on the thorax and seven pairs on the abdomen.

The spiracles connect to the widest part of the tracheal system. As you travel along the tubes, they get smaller in diameter with thinner walls. At the very ends of the tracheal branches are the smallest tubes called tracheoles. From these terminal points, the oxygen moves by diffusion into the tissues that surround them.

Spiracles are different sizes and unfortunately, the first pair, the two closest to the head of the bee, are large enough to allow other small items to enter. The worst of these other items is the tracheal mite.

Control of oxygenation

Bees can increase the amount of oxygen going to their organs by increasing the number and size of muscle contractions. This “heavy breathing” is probably the thing that beekeepers notice and become concerned about. Although you can often see bees breathe if you look closely, the movements are very slight, but at other times they are quite pronounced. The amount of movement can increase due to oxygen depletion or decrease due to carbon dioxide elevation.

But don’t read too much into these variations. Heavy breathing does not necessarily mean anger or disease or poison or fear. It just means that, for some reason, the body needs more oxygen. Breathe easy and let your bee be the judge.

Honey Bee Suite

Don't read too much into heavy breathing. It just means the bee needs more oxygen.
Don’t read too much into heavy breathing. It just means the bee needs more oxygen. Image by Myriam Zilles from Pixabay


  • This was very interesting, especially the one interpreting it as fury. My partner, possibly somewhat bee nervous, has been known to come tell me my bees are really angry about something. Every time this has happened, I’ve gone to watch them for a while, then come back to report that the bees are fine, there’s a lot of drones out today, drones are just noisy. They’re boisterous, not angry.

  • I had no idea. This planet and its beings defy description. Another lesson learned. Thanks for being such a good teacher.

  • Fascinating! If the spiracle is the one way in valve would be inhalation for us, what would be their exhalation?

    • Benjamin,

      The gases, including carbon dioxide, simply diffuse through the integument. Apparently it is easier for CO2 to diffuse out of the bee than O2. Not sure why that is but I read it in a couple of places.

  • Thanks Rusty another piece of enlightenment for the novice in me.
    I keep backyard bees in Tasmania AUSTRALIA.

  • Chilled bees will breathe rapidly to provide oxygen for rapid muscle contraction – to generate heat. I can’t remember where I read about this, but it’s commonly seen where field bees will settle on an object and heavily breathe for a while to get back up to operating temperature.

  • I also find this fascinating I am learning so much about bees since reading your posts…Before I just enjoyed the honey… I am lucky to get wild honey here of which I have just enjoyed a couple of spoonfuls. Thank you for sharing your knowledge 🙂

  • When I started beekeeping, I built my bottom boards with a large landing area. I continue to this day because it is here that I can observe a lot of the social behavior that takes place between bees. I have noticed it is usually bees returning from a foraging flight or orienting that exhibit the heavy breathing similar to what we would do after heavy exercise.

    In early spring, I notice bees returning from foraging will often not make it back to the hive. They will drop into the grass 30-40 feet in front of the hive, and sit there breathing like mad. Nothing wrong with the bees – they just aren’t in game shape yet. Later on, we don’t see this.

  • Hello everyone hope, you all are fine.

    I have found some insects about the size of varroa mite with something like horns at their head in my beehive. What should I do? Any suggestions?

    • Muzafar,

      The first thing to do is figure what they are and if they are harmful. Lots of different things live in beehives, but not all cause a problem.

  • The same tubes that transport oxygen into the insect body usher out carbon dioxide. Insects use different methods to release carbon dioxide, including opening the thoracic spiracles (the ones closest to the head) to take in oxygen while exhaling carbon dioxide through the abdominal spiracles. — The American Physiological Society (APS) annual meeting April 29 2007.

    • Thanks, Peter.

      I’ve read several different theories about the CO2; some say it goes into the spiracles and some say not. I’m working on clarifying that aspect and will add this reference into the mix.

  • Rusty,
    How to identify if they are harmful. I have clicked a picture of one. But how can I upload it here.

  • Hi Rusty,

    Thanx for the very informative “chat” on the breathing bee. We live in South Africa and do bee-awareness in pre-schools as well as our primary schools for kids and this info will come handy to the little ones!!


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