Insects

Introduction to Insects

Insects are a class of invertebrates within the arthropod phylum. They are characterized by having a three-part body (head, thorax, and abdomen), three pairs of jointed legs, compound eyes, and typically one or two pairs of wings. Insects are incredibly diverse and can be found in almost every habitat on Earth.

Anatomy of Insects

Insects have a hard exoskeleton made of chitin that provides protection and support for their bodies. Their bodies are divided into distinct segments, and they have specialized mouthparts for feeding. Insects also have a highly efficient respiratory system consisting of tracheae for gas exchange.

Life Cycle of Insects

Most insects undergo complete metamorphosis, which includes four stages: egg, larva, pupa, and adult. Other insects undergo incomplete metamorphosis, with three stages: egg, nymph, and adult. The life cycle of an insect can vary greatly depending on the species.

Ecological Importance

Insects play a crucial role in ecosystems as pollinators, decomposers, and as a food source for other animals. They also help control populations of other organisms and are involved in nutrient cycling and soil health.

Common Insect Orders

• Coleoptera: Beetles
• Lepidoptera: Butterflies and moths
• Hymenoptera: Bees, wasps, and ants
• Diptera: Flies
• Orthoptera: Grasshoppers and crickets

Study Questions

1. What are the defining characteristics of insects?
2. Describe the life cycle of an insect that undergoes complete metamorphosis.
3. Explain the ecological importance of insects in an ecosystem.
4. Name and describe three common insect orders.