Introduction to Insects

The Study of Insects• Known as entomology

• Entomologists have described and classified more than 900,000 insect species.

• Entomologists discover from 7,000 to 10,000 new species of insects each year.

Insect Classification• Kingdom: Animalia

• Phylum: Arthropoda

• Class: Insecta

• Orders (know these): Coleoptera, Diptera, Hemiptera, Homoptera, Hymenoptera, Lepidoptera, Orthoptera, Odonata

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

Mouth Parts

•Chewing (beetles)

•Sucking (adult butterflies)

•Piercing (true bugs)

•Lapping (fly)

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.

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.

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.

Complete Metamorphosis

egg

larva

pupa

adult

Incomplete Metamorphosis

egg

nymph

bigger

nymph

adult