Bees don't have lungs!

Bees don’t have lungs! [1] So how do they breathe?

Well, through 20 separate air holes all over their bodies of course [1,2]

These holes are called spiracles, and they’re connected to a network of tubes called trachea and air sacs that the bee can use to draw in and expel air by expanding and contracting her entire abdomen. [3]

Oxygen and carbon dioxide move directly between the air in these tubes and the bee’s cells through diffusion.

This is much less efficient than our system of gas being exchanged in the lungs and carried around the body by our blood.

The bigger an insect is, the greater the fraction of their body that needs to be composed of air tubes, which is partly why we don’t see any giant bugs roaming around in today’s low oxygen environment. [4]

References:
Snodgrass RE. Anatomy of the honey bee. Cornell University Press; 1956.

Kovac H, Stabentheiner A, Hetz SK, Petz M, Crailsheim K. Respiration of resting honeybees. Journal of insect physiology. 2007 Dec 1;53(12):1250-61.

Bailey L. The respiratory currents in the tracheal system of the adult honey-bee. Journal of Experimental Biology. 1954 Dec 1;31(4):589-93.

Kaiser A, Klok CJ, Socha JJ, Lee WK, Quinlan MC, Harrison JF. Increase in tracheal investment with beetle size supports hypothesis of oxygen limitation on insect gigantism. Proceedings of the National Academy of Sciences. 2007 Aug 7;104(32):13198-203.