Insect Life Cycles

• Most adult female insects are oviparous
  • Lay eggs which hatch after deposition

• Some adult female insects are viviparous
  • Lay larvae or nymphs
  • Eggs rupture in female reproductive tract

Simple Metamorphosis

• Hemimetabolous

• Nymph emerges from the egg which resembles the adult but is sexually immature

• Nymph grows and undergoes several ecdyses (moults)

• Nymph becomes an adult (imago)

• E.g. Lice

Complex Metamorphosis

• Holometabolous

• Larva emerges from the egg and does not resemble the adult

• Larva feeds, grows and undergoes several ecdyses

• Larvae undergoes a quiescent stage where the outer cuticle hardens to form a pupa
  • Some species have a silken cocoon

• Adult develops inside the pupal case before emerging

• E.g. Fleas and dipteran flies