How can an insect deliver air without lungs like ours?

Most insects take in air through small openings along the body called spiracles. These openings connect to branching air-filled tubes called tracheae. The tubes carry air close to tissues that need oxygen.

The branches become finer toward the working cells. Oxygen moves from the air through short final distances into tissues, while carbon dioxide moves outward. In many insects, body movements also help ventilate parts of the tube system.

Unlike human circulation, insect blood generally does not carry most oxygen between a lung and the tissues. The airway network provides a more direct route. Opening and closing spiracles can help regulate gas exchange and water loss.

This arrangement works within the insect’s body size and activity demands. It is not simply a miniature human breathing system. The same need for cellular oxygen can be met through a different relationship between openings, branching passages and short diffusion distances.