W9: Invertebrate Physiology (Physiology Overview 2) [Dr. Blair] Flashcards
(38 cards)
If there are no blood vessels or haemoglobin, how do insects get O2?
Insects take in O2 through the spiracles which lead to the tracheal system (trachea & tracheoles), which then go directly to the tissues and cells.
Spiracle?
= an opening to the tracheal system of insects found along the abdomen of insects.
No lungs? Without actual lungs, wouldn’t body size influence insect respiration?
Yes.
What’s the world’s smallest insect?
Fairy flies/wasps.
Fairy flies/wasps attributes? (2)
- Parasitic wasps.
- ~0.1mm in size.
What’s the world’s largest insect?
Depends on if you mean in terms of size or weight.
2 views to consider when indicating the world’s largest insect? (2)
- Size.
- Weight.
World’s largest insect in terms of size?
Elephant beetle.
World’s largest insect in terms of weight?
Gaint weta/Wetapunga (New Zealand cricket).
Insect respiration in smaller insects attributes? (3)
- Use passive diffusion.
- Limits body size as increased size lowers efficiency of gas exchange.
- Small body size = Passive diffusion/”energy free”
Insect respiration in larger insects attributes? (5)
- Passive diffusion is problematic.
- Highly efficient.
- Larger tracheae.
- Large air sacs.
- Active ventilation.
How do larger insects overcome the problematic nature of passive diffusion? (30
- Larger tracheae (increases volume of air).
- Air sacs (provide air stores & increased ventilation).
- Active ventilation.
How does active ventilation help larger insects overcome passive diffusion problem?
The contraction of muscles coupled with activity increases circulation.
Efficiency of insect respiration?
Enables sustained flight (open spiracles: aerobic).
What about aquatic insect respiration?/Aquatic insect respiration attributes? (2)
- Difficult to take O2 in without taking inhaling water as well.
- No spiracles in technical positions to prevent taking in water while breathing.
Ways to get O2 in but not water & allow CO2 out in aquatic insects?/What about aquatic insect respiration? (4)
- “Physical” gills/Plastrons.
- Cutaneous respiration.
- Air bubbles.
- Tracheal gills.
Explain “Physical” gills/Plastrons?
Plastrons trap a thin layer of air & allow O2 from the water to diffuse into the trapped air layer, and then into the insect’s tracheal system, while CO2 diffuses out.
Explain Cutaneous respiration?
O2 from the water diffuses across the insect’s thin body surface into the haemolymph, where it is transported to the insect’s tissues. CO2 is similarly released back into the water.
Explain Air bubbles?
When aquatic insects trap air bubbles from the surface & carry them underwater (bubbles act as temporary oxygen reservoirs). As the insect consumes oxygen, more oxygen diffuses into the bubble, keeping it oxygenated for a time.
Explain Tracheal gills?
Oxygen diffuses from the water through the tracheal gills into the tracheal system, where it is transported directly to the tissues, while carbon dioxide diffuses out.
Egs of aquatic insect that uses “Physical” gills? (2)
- Backswimmers (Notonecta).
- Some water bugs.
Eg of aquatic insect that uses Cutaneous respiration?
Larvae of some stoneflies.
Eg of aquatic insect that uses Air bubbles?
Water beetles.
Eg of aquatic insect that uses Tracheal gills?
Mayflies.
