Gas Exchange In Insects

Why do insects need gas exchange

  • Deliver O2 to cells

  • Remove CO2 from cells

Insect Gas exchange systems have adapted to gas exchange

  • Maximise gas exchange efficiency

  • Minimising water loss

Structure of an insects gas exchange system

  • Insects have an open respiratory system comprised of tubular systems that transport air

  • Main Structures

    • Trachea - These are air-filled tubes branching throughout the organisms body

    • Tracheoles - Fine branches of tracheae that deliver gases to cells

    • Spiracles - External openings of the tracheal system on the exoskeleton of the insects

Adaptations of Insects Gas Exchange system

  • Tracheae

    • Reinforced with chitin spirals- Prevents collapsing

    • Multiple Tracheae - Increase SA

  • Tracheoles

    • Penetrate directly into tissues - reduces diffusion distance

    • Thin Walls - Reduce gas diffusion distance

    • Highly Branch - Maximises SA

    • Tracheal Fluid - Allows oxygen to dissolve to aid diffusion and reduce water loss

  • Spiracles

    • Open and close - Control gas exchange and minimise water loss

How Gas exchange occurs

  1. Air enters tracheal system through spiracles

  2. Air moves into larger tracheae and diffuses into smaller tracheoles

  3. Tracheoles branch throughout the body transporting air directly to cells

  4. Oxygen dissolves in water in the tracheal fluid and diffuses down its concentration gradient from tracheoles into body cells

  5. Carbon dioxide diffuses down its concentration gradient out of body cells into the tracheoles

  6. Air is then carried back to the spiracles via the tracheae and released from the body

Lactate Accumulation

  • Accumulates during anaerobic respiration

  • Lactate accumulation reduces the water potential of tracheal fluid

  • Water leaves the tracheoles through osmosis

  • Higher SA is exposed to air for gas exchange