1 Class Insecta BIO 2215 Oklahoma City Community College Dennis Anderson

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Class Insecta

BIO 2215

Oklahoma City Community College

Dennis Anderson

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Subphylum UniramiaClass Insecta (Hexapoda)

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Most Abundant and DiverseAnimal Class

• 1,000,000+ species identified– May be as many as

30,000,000

• More than all other animals combined

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Distribution of Insects

• Air• land• In the soil• Parasites

– Plants– Animals

• Freshwater• Not marine???

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Characteristics of Insects

• Three body regions– Head– Thorax– Abdomen

• Three pair of legs• Open circulatory

system

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Characteristics (cont)

• Two pair of wings– One pair in flies– Absent in some

• Pair of compound eyes

• Spiracles for respiration

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Centipede and Symphyla

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Insect Evolution

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12Chewing Mouthparts

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Piercing Mouthparts

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Siphoning Mouthparts

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Sponging Mouthparts

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Insect abdomen

TergumTergum

SternumSternumPleuralPleuralmembranemembrane

OvipositorOvipositor

CercusCercus

SpiracleSpiracle

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Insect Excretion

Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

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Internal Anatomy

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Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

Complete Metamorphosis

From Raven/Johnson, Biology, 3rd ed., Copyright © 1999 The McGraw-Hill Companies.

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Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

Incomplete Metamorphosis

From Hickman/Roberts/Larson, Integrated Principles of Zoology, 11th ed., Copyright © 2001 The McGraw-Hill Companies.

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Digger Wasp

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Paralyzes Prey

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Social Insects

• Live in colonies• Queen• King• Soldiers• Workers

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Insect Societies

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Casts in a Bee Hive

• Queen– Lays eggs– Queen substance

• Worker– Builds hive– Takes care of eggs– Attends to queen– Royal jelly

• Drone– Fertilizes queen

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Become a Queen!

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Swarm

• New queen • Leaves with part

of the hive to start a new colony

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Honey

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Ant Colony

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Casts in an Ant Colony

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Ant Pheremones

• Alarm• Food trail

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Beneficial Insects

• Honey bee– Honey– Pollinates crops

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Beneficial Insects

• Lady bug• Eats harmful insects

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Beneficial Insects

• Silkworm moth• Lava produces silk

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Beneficial Insects

• Breakdown dung

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Beneficial Insects

• Blow fly• Decompose dead bodies

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Beneficial Insects

• Ichneumonid wasps• Kill harmful insects

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Fruit Fly

• Drosophila• Genetics research

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Harmful Insects

• Tent catepillar• Pest of many trees and shrubs

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Harmful Insects

• Boll weevil• Destroys cotton

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Harmful Insects

• Mosquitos• Vector

– Malaria– Yellow fever– Encephalitis– West Nile virus

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Harmful Insects

• Flea• Vector for

– Plague

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Xenopsylla cheopis

• Rat flea• Vector for plague

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Black Death

• 1357-1350 killed 25,000,000 in Europe

• 1900’s killed 20,000,000 in India

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Bubos

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Plague Survivor

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Alexandre Yersin

• Discovered bacterium• Yersinia pestis

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Insect Orders

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Order Collembela

• Springtails• 5mm long• Furcula for jumping• No wings

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Order Thysanura

• Firebrats• No wings

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Order Odonota

• Dragon flies• Damsel flies• Two pair of large

wings

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Order Orthoptera

• Grasshopper• Cockroach• Praying mantis• Cricket

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Order Dermaptera

• Earwigs• Forceps-like cerci• Short wings

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Order Isoptera

• Termites• White• Broad waist• Winged and wingless

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Order Homoptera

• Cicada• Aphids• Leaf hoppers• Roof-like wings

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Order Hemiptera

• True bugs• Front wing

– Basal portion is leathery

– Apical portion of wing is membranous

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Order Coleoptera

• Beetles• 350,000+ species• Hard front wings meet

midline• Back wings

membranous

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Order Lepidoptera

• Butterflies– Knobbed antennae

• Moths• Scales on wings• Larva are catepillars

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Order Diptera

• Flies• Mosquitoes• One pair of wings

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Order Hymenoptera

• Bees• Wasps• Ants• Four membranous

wings• Narrow waist

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Order Anoplura

• Lice• No wings• Single claw• Sucking mouth parts• parasites

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Order Siphonaptera

• Fleas• Flattened laterally• Spines on legs and

body• Parasites

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The End