Honey bees have no lungs or diaphragm, nor do they bring air in and out through the mouth…. and there is no “nose” at all.  Instead, air is exchanged through a set of ten pairs of tiny “portholes” called spiracles – three pairs on the thorax and seven the abdomen.

Fresh air flows through each spiracle into a tube (trachea) that connect to thin-walled sections, which form air sacs (atria) at various points along the tracheae. These can expand like balloons for temporary storage of air. From these atria, air travels through branches of ever-smaller dimensions (tracheoles) to carry oxygen to all parts of the body: to the head, thorax, abdomen, and legs.

Every tube of the tracheal system has a strong framework made of chitin in the form of a coil, something like a spring that keeps it open, stretchable, and flexible.

A bee contracts the abdomen to expel carbon dioxide out through the spiracles, and as it relaxes, oxygen-rich fresh air is pulled in through the same openings. Because the muscles attach to the inside of the rigid abdomen and not directly to the atria, the entire abdomen moves in a rolling contraction from top to bottom or from front to back as the bee pumps air through the system.

You can SEE this movement, yourself, if you observe a forager that has paused from flight to rest or clean itself. New beekeepers are sometimes upset to note what might appear to be a “spasm,” as if the bee were unwell—but no worries! It is normal breathing for a bee.¹

The waves of muscle contractions control the flow of air into and out of the sacs to wherever it is needed by the body’s tissues.  To maintain the necessary air pressure in this system, every spiracle has a valve that shuts tightly between breaths of air in and out, preventing backflow.

Safety Valves. The spiracle valves can sometimes save a bee from drowning if it falls into a pond, a birdbath, or a swimming pool, because they can be effectively held shut for at least a brief time—possibly up to 5 minutes²—before they give way and are flooded, suffocating the struggling insect. 

However, a bee has one chance for survival (short of rescue by a kindly human hand). That is, even though water adheres to the super-thin, membranous wings so that it is impossible to take off and fly, the bee can nonetheless still beat its wings as if in flight, though not as rapidly.

In so doing, the bee creates tiny waves in the water on which it can “surf” (hydrofoil) toward safety, making use of the hydrodynamic thrust thus generated.³  It’s a race against time…

Moving the O₂.  Meanwhile, back in the tracheal system under normal circumstances, the smallest tracheoles, analogous to the capillaries in a mammalian circulatory system, transfer oxygen directly to the cells and tissues and remove the respiratory waste product, carbon dioxide.

However, unlike in the mammalian system, this transport and transfer of oxygen occurs without binding and carrying the gases within a blood-like liquid. That is, “bee blood” (hemolymph) does NOT carry gases. Instead, this liquid system distributes nutrients along with immune- and defense-substances throughout the bee’s body, whereas the tracheal system carries only air.

Epilogue. Perhaps the mindful bees in a colony might be aware that “every breath we take is a gift of life.” Well, perhaps not….… but in any case, they have evolved to employ a perfectly successful respiratory system that has worked well for them for 120 million years so far—spiracles and all.