Insect Development

• Embryogenesis – beginning of the embryo. It is when

  the fertilized egg undergoes rapid growth and

  development
• Morphogenesis- changes during the post-embryonic

  period. (after hatching (eclosion). This includes:

  growth, molting and maturation
• The molting process is triggered by hormones

  released when an insect’s growth reaches the physical

  limits of its exoskeleton
• Molting stops when the insect becomes an adult
• Metamorphosis - The radical change in insect development.
• Ametabola - (no/slight metamorphosis)
• Paurometabola - (gradual)
• Holometabola - (complete).
• Hemimetabola - (incomplete)
• Ametabolous insects undergo little or no structural change as they grow

  older.
• Paurometabolous Metamorphosis - Exhibits a simple gradual change in body form during morphogenesis. Immatures are called nymphs.
• Hemimetabolous Metamorphosis - The immatures are called naiads and are aquatic and have gills for respiration.
• Holometabolous Metamorphosis - They have immature forms called larvae which are voracious feeders.
• Egg - is the stage where most of the insect life started.
• The reproductive mode in which the developing eggs are laid and hatch externally in the environment is called oviparity
• The act of laying the egg is oviposition
• Each egg is composed of only 1 living cell which is the female

  gamete.
• Ametabolous Metamorphosis - Collembola, Thysanura, Mallophaga and Anoplura.
• Paurometabolous Metamorphosis - Hemiptera, Homoptera, Orthoptera, Thysanoptera, Psocoptera, Embioptera, Dermaptera and Isoptera
• Hemimetabolous Metamorphosis - odonata, ephemeroptera, plecoptera
• Holometabolous Metamorphosis - Neuroptera, Coleoptera, Mecoptera, Trichoptera, Lepidoptera, Diptera, Siphonaptera and Hymenoptera).