Tracheal System

Lungs for Flies

Drosophila do not have what the stereotypical lungs that humans have. While human lungs develop 4-7 weeks post fertilization and they are functional at 24-38 weeks post fertilization, human lungs do not completely develop until 3+ years post birth (Schittny). In humans, lungs are thought of as a place in the body where oxygen is stored until it can get to the blood stream, however Drosophila do not have a centralized area where air is stored. Instead, flies, and other insects, have a branching system throughout their body (called the tracheal system) that allows air to move freely throughout the body where it can diffuse into the tissues that need oxygen. The tracheal system in Drosophila the tracheal system first appears as 10 pairs of tracheal placodes at stage 11. These placodes originate from the ectoderm, and are thickened areas of tissue that will then continue to invaginate quickly and develop into long tubes in stage 14, and completely finish developing at stage 16. This means that by 13.3 hours ( 800 minutes) post fertilization, the tracheal system of the fly is completely developed and functioning. 

Development of Human Lungs. By OpenStax

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Since humans develop inside their mother, their lungs become functional  closer to birth( 28 weeks). However, they do not have to use their lungs until they are born. Drosophila develop in the same environment in which they live normally (outside the mother in wet, warm temperatures). This tracheal system is finished developing hight before hatching so that the larvae has the ability to get oxygen once hatched.

To learn more about the Tracheal System in the fly, please click here for the literature used to make this website.