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 adult larva pupa

Incomplete Metamorphosis egg adult nymph bigger nymph