Chapter 28 Insects 28-3

I. Insects A. What is an insects? 1. Body divided into 3 parts. Head, thorax and an abdomen. A pair of antennae A pair of compound eyes – multiple lens Two pairs of wings Spiracles – holes in the abdomen attached to trachea tubes. Tracheal tubes – tube in the abdomen that transport oxygen throughout body. 3 pairs of legs attached to the thorax.

II. Responding to stimuli A. Sense organs 1. Compound eyes are made of many lenses, multiple images. 2. Chemical receptors for taste and smell on mouth and antennae. 3. Sensory hairs detect slight movement in the air and water. 4. Some have well develop ears to hear sounds far above humans.

III. Adaptation for feeding A. 3 pairs of appendages used for mouth parts. 1. Mandibles for grinding food. (ant) 2. Tube-like mouthpart used to suck nectar. (moth) 3. Sponge-like mouthpart used to lap up food. (fly) 4. Piercing-like for sucking blood or other material. (mosquito)

IV. Metamorphosis A. Growth and development of insects where the body changes shape and form. 1. Complete Metamorphosis- a. Egg b. Caterpillar- larvae c. Cocoon – becomes a moth. Pupa – covered with chrysalis, becomes a butterfly. d. Adult

B. Incomplete metamorphosis 1. Egg 2. Nymph – looks like smaller version of an adult without wings and reproductive organs. 3. Adult – after molting many types developing wings and reproductive organs.

V. Insect Communication A. Insects communicate for various reasons, mostly, it involves finding a mate. 1. Visual clues – Fireflies and their abdominal signaling. 2. Chemical signals – Pheromone chemical effect the behavior or development of other individuals.

VI. Insect Societies Example – Queen bee, drones and worker bees. A. Society – is a group of related animals of the same species that work together for the benefit of the whole group. Some may consists of more than 7 million individuals. 1. Castes – individuals that are specialized to perform particular tasks, or roles. And each castes has a body form specialized for the specific role. Example – Queen bee, drones and worker bees.

B. Communication in Societies – Each society have their special was of communicating by visual, touch, sound and chemical signals. Example – Ants will leaves a trail of pheromone on the trail to lead other ants to food they have found. Bees dance and leave pheromones that specifically leaves the type, quantities, direction and distance to the flowers.