Ch. 37 Insects Most diverse and largest number of species of any class of organism.

They were present on earth before the dinosaurs, over 300 million years ago.

Differences from other arthropods 1. 3 body segments head, thorax,

abdomen

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2. Head has 1 pair of antennae3. Thorax has 3 pairs of legs & 1 or 2 pair of wings.

4. No wings or legs attached to the abdomen.

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Kingdom: Animalia Phylum: Arthropoda

Class: Insecta (700,000 + species named)

What makes insect so successful? Lots of them – adapt very well Great diversity – several types Reproduce rapidly Small size & ability to fly (most)

Benefit of insects?1. Pollination – plants can’t reproduce without insects. We need plants to survive.

2. Food – for other animals. Several animals rely on insects as a source of food.

3. Industrial uses – silk & honey

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What is the study of insects called? (E.C) Entomology

Grasshopper External Structures3 Body Parts:

1. Head Labium – grasps the food ( bottom lip) Mandible – chews the food (jaws) Labrum – holds the food (upper lip) Maxilla – extra jaws

2. Thorax 3 pairs of legs (6 total) 2 pair of wings usually

3 parts to the thorax 1. Prothorax – pair of walking legs 2. Mesothorax. – pair of walking legs 3. Metathorax – pair of jumping legs Forewings are attached to the

mesothorax Hindwings are attached to the

metathorax

3. Abdomen Spiracle – for respiration Tympanum – for hearing

(eardrum) Ovipositors – holds it eggs

GrasshopperInternal StructuresDigestive System What do grasshoppers eat? What are the mouth parts? Food passage: esophaguscrop

(storage) gizzard (grind) midgut (digested) hindgut (rectum & colon) out the anus

Circulatory SystemOpen Circulatory System An aorta is a large vessel that carries the blood on the dorsal side.

2 Hearts along the aorta

Respiratory System No lungs or gills Use spiracles – openings along the

abdomen The spiracles lead to the trachea

Nervous System Brain connected to a ventral nerve

cord Has simple and complex eyes

Have antennae Tympanum for sensing sound

Reproductive System The male deposits sperm into the

seminal receptacle, which stores the sperm.

The female uses its ovipositors to deposit her eggs in the ground.

Types of MetamorphosisIncomplete Metamorphosis1. Egg2. Nymph – immature form of an adult

3. Adult – able to reproduce (wings)

Complete Metamorphosis1. Egg2. Larvae – caterpillar stage3. Pupa – cocoon protects the pupa

4. Adult – emerges from the pupa (butterfly)

Defenses of InsectsWhat ways do insects use defenses?

1. Stinger or bite – bee, wasp, ants

2. Camouflage – blend into their surroundings. Ex. Grasshopper, praying mantis

3. Warning coloration – alert other animals that the insect might be poisonous.

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Insect BehaviorDivision of Labor among Bees

1. Worker bee – female bees, most abundant. (8,000) - sterile

2. Drone – male bees (100)

3. Queen bee – the only fertile female

CHARACTERISTICS OF EACH BEE

The worker bee produces royal jelly to feed the queen beeThe worker also secretes wax to make the hive.The produces a pheromone called queen factor, which makes the other females sterile.Round Dance – tells the other bees food is within 50 metersWaggle Dance – tells the other bees food is greater than 50 meters.Video