Let’s Learn About Insects!

All photos and text by Kris H. LightCopyright 2008

All rights reserved

What is the difference between an insect and a spider?

• Insects: • have 3 body parts• have 6 legs• can have antennae • can fly (if they have wings) • have compound eyes

• Spiders:• have 2 body parts• have 8 legs• do not have antennae • never have wings • have 6 - 8 simple eyes

Which of these animals are insects?

No -

TickNo -

Ant-mimicspider

Yes -

PleasingFungus Beetle

No -

Scorpion

Yes -

Thread-legged Assassin Bug

No -

MillipedeYes -

Scorpionfly No -

Slug

Insects have 3 body parts

Head - Mouth, compound eyes, simple eyes, may have antennae

Thorax - 6 legs; 0, 2 (flies) or 4 wings; flight muscles

Abdomen - spiracles for breathing, digestive system, circulatory system, reproductive system; fireflies have light segments

Firefly (male)

Head

Thorax

Abdomen

Do Caterpillars have 3 body parts too?

Head

Thorax(with 6 true legs)

Abdomen(with 10 prolegs)

Yes!

Insects have compound eyes

• Insects have many to thousands of tiny eyes, called “compound eyes” (ocelli) to detect movement and find food.

• Some insects have three simple eyes to detect light and dark.

CompoundEyes

3 SimpleEyes

Insect Mouths The type of mouth an insect has determines what it can eat

Chewing

- solids(leaves, wood, meat, other insects)

Piercing

-

liquids(plant sap, blood)

Sponging

-

liquids(plant juice, blood, body fluids)

Coiled tube

- liquids (nectar);flies and butterflies taste with their feet!

Insect antennae - used for hearing, smelling, feeling

Male mosquitoes and midgeshear the females’

wingbeats with their antennae

Ants smell and follow chemical trails with theirantennaeMale moths

can smell afemale moth’spheromonesover many mileswith theirfeathery antennae!

Some beetles have unusual-shaped antennae

Why are insects important?• Insects:• Are a food source for other animals• Eat pests that damage crops• Pollinate flowers and make honey• Turn dead plants and animals into soil

(decomposers)• Can make silk, shellac, and natural “food

coloring” (cochineal bugs)• Are fun to watch and learn about!

Bumblebee onSquash flower

Lacewing larva eating an aphid

What Do Insects Eat?

PlantsOther insects

Blood

Pollen and Nectar

Dead AnimalsWood

Dung!

Insect life cycles: Metamorphosis

Complete metamorphosisinvolves 4 stages:

1. Adult Adult Adult -

lays eggs, can have wings2. EggEggEgg3. Larva Larva Larva -

looks nothing like adult;the eating and growing stage;molts 5 times (“instars”); never have wings and can’t lay eggs4. PupaPupaPupa

-

resting, changing stage;adult emerges (chrysalis, cocoon)

Insects that go throughcomplete metamorphosisinclude: butterflies and moths,beetles, flies, bees, ants, and wasps

Incomplete metamorphosisinvolves 3 stages:

1. AdultAdultAdult

-

lays eggs, can have wings2. EggEggEgg3. Nymph Nymph Nymph - looks similar to adult; the eating and growingstage; molts 5 times (“instars”);never have wings and can’t lay eggs

Insects that go throughincomplete metamorphosisinclude: grasshoppers, roaches,true bugs, leafhoppers, dragonflies and damselflies

Complete Metamorphosis: Life Cycle of a Ladybug

1. Eggs

2. Larva3. Pupa

4. Adult

Incomplete Metamorphosis Life Cycle of a True Bug

1. Adultlays eggs

2. Nymphs hatchfrom eggs

3. After last molt,nymph grows wings and becomes adult

Insect “babies”

“Doodlebug”

-Antlion

larvaLadybug larva Mosquito

larva

Aphid givingbirth to nymph

Ants with pupaHellgramite

-

Dobsonflylarva

Webworm Moth caterpillar

Ways insects protect themselves:

Mimicry

-Looking like something else!

The Io moth surprises predators with “fake eye spots”

This Moth looks like bird poop!

This Fly looks like a bee

This Moth looks like a Bumblebee

This Fly looks like a wasp

This leafhopperlooks like a thorn

Camouflage

A Loopercaterpillar with flowers onits back

Lacewing larva with fuzz Ambush Bug

MothChrysalis Beetle

Bad smell or taste (brightly-colored insects often

have a bad taste!)

Aphid releasingdefensive liquid when bitten by lacewing larva 4-eyed Milkweed

BeetleStinkbug

Red-banded Leafhopper Grasshopper spitting“tobacco juice”

Ladybug

Stinging or Biting (bright colors can be a warning that insects are

dangerous)

BitingStinging

Ant

Saddlebackcaterpillar

Io Moth Caterpillar

Shieldbug Wasp Flannel Moth caterpillar

Where do insects live?

Fields, gardens, forests In the soil

On treesIn the water Plants and

Flowers

How many different kinds of insects are there?

It has been estimated there are about1,017,018 species of insects in the world!

The biggest group of insects is Beetles.

How many different kinds of insects can you think of?

Whirligigbeetle

4-eyed Milkweedbeetle

Hercules beetle Tiger beetle

There Are Many Different Kinds of Insects

Beetles

True bugs

Wasps, bees, ants

Flies

Mantids

CricketsDragonflies

Fleas

Cicadas

Leafhoppers

Butterflies and moths

Follow-up questions:

1.

What is the difference between an insect and a spider?2.

What kinds of mouths do insects have? Give examples

3.

Explain the 2 different kinds of metamorphosis4.

What are some ways insects protect themselves?

5.

Name some insects that live in your area6.

What is your favorite insect?

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