Introduction to Insects

1
Introduction to Insects

• August 21st, 2008

2
The Study of Insects

• Known as entomology
• Entomologists have described and classified more
  than 700,000 insect species.

3
Insect Classification

• Kingdom Animalia
• Phylum Arthropoda
• Class Insecta
• Orders (know these) Coleoptera, Diptera,
  Hemiptera, Homoptera, Hymenoptera, Lepidoptera,
  Orthoptera, Odonata

4
Insect Anatomy

• A hard exoskeleton protects a soft interior.
• Divided into head, thorax, abdomen
• Most have wings of some type
• No Lungs breathes through spiracles and trachea
• insect anatomy web page

5
Mouth Parts

• Chewing (beetles)
• Sucking (adult butterflies)
• Piercing (true bugs)
• Lapping (fly)

6
Insect Growth

• The exoskeleton limits the potential size of
  insects, but provides valuable protection.
• To grow and become an adult, young insects shed
  or molt their exoskeleton.

7
Molting

• A new, flexible exoskeleton forms beneath the old
  exoskeleton.
• By taking in extra air, the insect expands itself
  and splits the old skin.
• The new, soft exoskeleton starts to harden in
  minutes.
• Once an insect becomes an adult it stops growing.

8
Life Cycles Metamorphosis

• Complete Metamorphosis
• For butterflies, the caterpillar is very
  different from the adult.
• Incomplete Metamorphosis
• In grasshoppers, the young resemble the adults.
  The younger stages are called nymphs.
• No Metamorphosis
• The young are identical to adults, except for
  gonads.

9
Complete Metamorphosis
egg
adult
larva
pupa
10
Incomplete Metamorphosis
egg
adult
nymph
bigger nymph