Do Bees Have Lungs?

Insects are a distinct group with many interesting and alien-like features. One of the many commons questions surrounding them as a whole, concerns their breathing.

So, do bees have lungs? No, bees do not have lungs. Bees only breathe via a combination of spiracles, tracheae and small air sacs. Air is passed freely in and out of the Bee rather than being forced within a rib cage like that of a human.

Traditional Human Lungs

Core components a bee’s breathing system?

Spiracles – This is the term for the external openings that regulate air flow in and out of the bee, of which in the case of the honey bee, there are ten for example.

Tracheae – These are complex tube-like organs that divide further to form air sacs.

Air sacs – The sacs serve as reservoirs (storage) for oxygen and are an extension of the tracheae.

How do bees breathe?

Bees do not breathe using their mouths like we humans do. There are tube-like organs within their tiny bodies known as tracheae which penetrate all over. Instead of blood, these tracheae pump air throughout the body. Spiracles are the pores, in effect, through which air gets into the tracheae. They are located on either side of the bee’s abdomen.

Bees breathe via the interconnection of these tubes which branch even further into the body. Just like the bronchi-oles in human lungs, the tracheae are found in their thousands. These subdivisions come to an end at the bee’s respiring tissues. The tissues essentially pick out oxygen from the air and, concurrently, carbon dioxide is pumped into the tracheae and released from the insect’s body. 

This process is understandably slow in insects like bees and air tends to stay in their bodies for quite some time. The sluggish interchange of gases in bees is because of their meager bodies. However, larger insects like the giant beetle (which is up to 15 cm long) can speed up this process by pulsating their abdomens within set intervals.

Did you know? Bees can survive short periods in water without drowning. The spiracles contain a pair of valves which close naturally thus deterring water from entering the insect’s body.

Importantly, when air is being passed through the tracheae, its arm-like muscles widen forming sacs which can be used as reservoirs for excess air. We’ve also mentioned that larger insects have a mechanism of speeding up air interchange, but so do bees. Although not quite as efficient, they contract the air sacs at intervals thereby accelerating the rate of air exchange. When releasing carbon dioxide, the bee effectively stops receiving more air to attain a perfect balance between oxygen and the former in its body.

Here’s a step by step overview of how the bee respiratory system works:

  1. The spiracles (7 pairs on the abdomen, 3 pairs on the thorax) open to allow oxygen to be vacuumed into the tracheae.
  2. Each single spiracle has a valve that regulates flow of air.
  3. The spiracles connect directly with the tracheae arms which widen further until bags called air sacs are reached.
  4. Air sacs are usually large in volume and equally contract to hasten tissue oxidation.
  5. The air sacs branch even further to form tracheoles which penetrate as far as individual tissues.
  6. When breathing out, tissues deposit de-oxygenated air ( carbon dioxide) into the tracheoles.
  7. Tracheoles further pump out the C02 until it reaches the tracheae which release it to the outside via the spiracles

Adaptations that enable the bee to breathe

Bees are certainly well placed to adapt to effective breathing and here’s how.

• An enlarged respiratory system enables quick flow of air inward and the ventilation of CO2 outward.

• The first pair of spiracles only enables air exit and not entry.

• Valves are present in each pair of spiracles to hinder back flow of air.

• Bees can quicken their rate of oxidation by contracting muscles when needed thus considerably enhancing respiration rate.

• Width-wise movement of the abdomen by making it wider or narrower for perfect compression of air during breathing.

How do bees breathe when wet or when its raining?

Ever thought how long a typical bee would survive while submerged in water? Well, they sure can survive longer than humans. The control system of air in bees is majestically seamless. Bees can easily close and open the spiracles at a flash. Under water, utilizing the hydrophobic hair-covering on its spiracles coupled with the air sacs in its body, the bee can survive for a relatively long time. It can continually tap into its reservoirs (air sacs) without having a single breathe of air.

A drizzle will most likely not perturb bees’ normal breathing as they can just close their spiracles until it ceases for them to take an extra gasp of air. However, during a heavy downpour, the swarm of bees tends to stay together in a shelter to stay warmer. This is partially due to the fact that they may not necessarily survive individually in such a pelting. 

Please see our other article here: https://schoolofbees.com/can-bees-fly-in-the-rain/

Do other insects breathe like bees?

Bees breathe via a combination of tracheae and air sacs. Insects primarily breathe the same way. However, some insects fly while some do not. Does this affect how they breathe? Well, let’s get into it here.

Just like a bee, a grasshopper makes use of its abdomen to aid it in breathing. The spiracles open when the abdomen expands and close when the abdomen contracts. When flying, the spiracles on either side of the thorax take charge of breathing. The thoracic spiracles draw air into the body whereas the spiracles at the abdomen releases it. Why so? In essence, a suction drawing air into the tracheae is created when the insect is flying due to thorax expansion. The thoracic muscles tend to expand because of the frantic movement of wings. When vice versa occurs, air is pushed to the abdomen for release.

As opposed to bees, some insects may have more spiracles than others purely owing to the size of the insect and its family. Larger insects like the grasshopper must actively engage in breathing by moving their abdominal muscles in pulses. In contrast, smaller insects do not have to move a muscle when breathing. A fly’s breathing system is virtually some ventilation. They open their valves (or pores) and sit lazily waiting for air to drift in and out. It is a passive activity in the very tiny insects.

Are bee lungs like humans?

Bees and any other insects alike do not have lungs. They have a respiratory system that works on the principle of exchange of gas (draw in oxygen, release carbon dioxide). The dense network of tracheae branching all over the bee’s tiny body help it to “breathe”.  

Do bees control their own breathing?

Simply put, bees can take charge of how they breathe to some extent. Muscle contractions enable the spiracles to open or close depending on the action of breathing. They can also forcibly pump air through the tracheae to effectively quicken oxygen delivery. Additionally, environmental conditions can dictate how bees need to breathe.

In arid areas, a bee tends to keep its spiracles (air openings) closed to minimize moisture loss. Furthermore, in cases of strenuous heat conditions, this insect can adeptly contract its muscles to maintain balanced breathing and vent carbon dioxide. 

Which species of bees can breathe submerged in water?

Bees are a species that exist in their thousands (approximately 20000). Unsurprisingly, none of the known bee species can breathe underwater. It is vital to note that they can survive in water for some time but not necessarily breathe in it. The small size means opening the spiracles to let in air would be catastrophic since they can’t withstand the added pressure of water. They only stay alive underwater as long as their air sacs can release enough oxygen into the tissues. Once the reserved oxygen is depleted, they die immediately.

Please see our other article for more information: https://schoolofbees.com/can-bees-breathe-underwater/

How does a bee’s respiratory system contrast to humans’?

Bees breathe when oxygen typically streams through the spiracles as part of the normal air mixture, drifts into further branches of the tracheae, via the air sacs and completes the short journey by being deposited at the bee cells. In humans, the process is much more physical. Blood is pumped by the heart to fetch oxygen from the lungs and ends the cycle by depositing it to the cells in a secondary process. That’s a complex flow in itself. In contrast, bees barely move a muscle as oxygen streams or floats in effortless motion right up to the cells.

Conclusion

Bees breathe via a simple yet slow process. They utilize three key micro organs which are namely spiracles, tracheae and air sacs. It is impossible for the human eye to observe how the bee’s respiratory system works. However, scientific research has consistently given evidence to the absence of lungs in all species of bees that have ever been observed. This substantially discards any claim of possibility of lungs in bees unlike in the Arachnid species.

It is fair to say that speculation regarding the general existence and life of bees will only escalate with unfounded stories taking shape each day. However, bees, like any other insect, do not have “lungs”.

References

https://lifeofbreath.org/2019/03/mysterious-breathers-how-insects-breathe/
http://sciencing.com/functions-spiracles
https://saburchill.com/chapters/chap0021

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