Lecture 17

Question 1

Aquatic Insects

Answer 1

• The orders with immatures always in water are Ephemeroptera, Odonata, Plecoptera, and Trichoptera
• The order with immatures who are somewhat in the water are Diptera, Hemiptera, Coleoptera, Neuroptera, and Megaloptera
• Ephemeroptera, Odonata, Plecoptera, and Hemiptera are Hemimetabolous (incomplete metamorphosis)
• Trichoptera, Diptera, Coleoptera, Neuroptera, and Megaloptera are Holometabolous (complete metamorphosis)
• Hemimetabolous has nymphs (naiads)
• Holometabolous are larvae

Question 2

Major Problem with Water?

Answer 2

• Obtaining oxygen (200,000 ppm in air but water only has 15 ppm)
• Loctic water (flowing water)
• Lentic water (standing water)

Question 3

Gas exchange

Answer 3

• Depend on diffusion which is rapid in air, and slow in water. Even slower in cuticle
  A. Closed Tracheal System
  
  • gills external/internal
  • Thoracic, abdominal, caudal, anal gills
    
    • Plecoptera stonefly naiad has thoracic gills
    • Ephemeroptera mayfly naiad has abdominal gills
    • Megaloptera Dobsonfly larva= Hellgrammite has abdominal gills
    • Neuroptera: Sisyridae Spongefly larva has abdominal gills
    • Trichoptera Caddisfly Larva has abdominal gills
    • Odonata Damselfly Naiad has caudal gills
    • Odonata Dragonfly naiad has internal anal gills
  • cutaneous respiration
    
    • Hemiptera: Heteroptera: Belotomatidae Giant water bug
    • Midges- Diptera: Chironomidae
  • Haemoglobins(high affinity for O2)
    B. Open Tracheal System (spiracles)
  • Suspension in water meniscus (caudal breathing tubes)
    
    • mosquito larvae
    • Giant water bug, Belostomatidae
  • Caudal breathing tubes
  • Compressable gills
    
    • Predacious diving beetle (Coleoptera: Dyticidae)
  • In-compressable gills (plastron)
    
    • Water boatman (Hemiptera: Heteroptera, F. Corxidae)
      HYDROPHOBIC HAIRS CALLED PLASTRON

Question 4

Lotic (Flowing) Environment

Answer 4

• Substrate type (boulders)
• High food volume in flow
• High oxygen in flow
• Insects have to be good swimmers or hang on well
• Lotic adaptations: DORSO-VENTRAL FLATTENED
  ex; Water penny (Coleoptera: Psephenidae) really flat
• Lotic adaptations: PORTABLE LARVAL CASES
  ex; Caddisfly larvae order Trichoptera
• Lotic adaptations: SUCKERS
• Lotic adaptations: Hooks and webbing
  ex; black fly larvae (Diptera: Simuliidae)