Entomology Basics

Entomology

• Hexápodos (Hexapoda) is a subphylum of arthropods that includes insects and their closest relatives.
• Entomology is the study of insects, including their behavior, ecology, evolution, and classification.
• Hexápodos are a key focus of entomology due to their diversity and importance in ecosystems.

Arthropod Evolution

• Hexápodos evolved from a common ancestor with crustaceans (Crustacea) around 400-450 million years ago.
• The evolution of hexápodos is characterized by the development of:
  • Three main body parts: head, thorax, and abdomen.
  • Six legs (hexapodous) attached to the thorax.
  • Wings (in most insects) that arise from the thorax.
• Hexápodos have undergone significant evolutionary adaptations, such as the development of compound eyes and antennae.

Insect Anatomy

• Hexápodos have a three-part body consisting of:
  1. Head: contains eyes, antennae, and mouthparts.
  2. Thorax: contains wings and legs.
  3. Abdomen: contains digestive organs and reproductive organs.
• Insect body structure is characterized by:
  • Exoskeleton: a hard outer covering that provides support and protection.
  • Segmentation: the body is divided into repeating parts or segments.

Insect Classification

• Hexápodos are classified into several classes, including:
  • Insecta (true insects): includes most familiar insects, such as beetles, flies, and bees.
  • Entognatha (hidden-mouth insects): includes springtails and bristletails.
  • Archaeognatha (ancient jaw insects): includes jumping bristletails.
• Insect classification is based on characteristics such as:
  • Body structure and morphology.
  • Wing development and venation.
  • Mouthpart structure and function.

Hexapod Morphology

• Hexápodos exhibit a range of morphological adaptations, including:
  • Body shape and size: varies greatly between species, from tiny fairyflies to large beetles.
  • Leg structure: adapted for walking, running, jumping, or swimming.
  • Wing shape and structure: adapted for flying, gliding, or other forms of locomotion.
  • Sensory structures: such as compound eyes, ocelli, and antennae.