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Insect Morphology and SystematicsInsect Morphology and Systematics
Mechanism of respiration
Oxygen enters the spiracle and passes through the length of the tracheae to the
tracheoles and into the target cells by a combination of
ventilation and diffusion
along a
concentration gradient, from high in the external air to low in the tissue. Where as the net
movement of oxygen molecules in the tracheal system is inwards (
Inspiration
), the net
movement of CO
2
and water vapour molecules is outwards, (
Expiration
).
Respiration in aquatic insects
1.
Closed tracheal system
In some aquatic and many endoparasitic larvae spiracles are absent and the tracheae
divide peripherally to form a network. This covers the body surface, allowing cutaneous gas
exchange. e.g. Gills : Tracheated thin outgrowth of body wall.
Lamellate gills - mayfly naiad
Filamentous gills - damselfly naiad
Rectal gills - dragonfly naiad
Insect Morphology and Systematics
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