Insects and Plants 0381999661, 9780381999667

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INSECTS

AND

Digitized by the Internet Archive in

2017 with funding from

University of Alberta Libraries

https://archive.org/details/reasonwhyseriesiOOadle

The

'‘Reason

Why”

Series

INSECTS AND

PLANTS Irving

and Ruth Adler

The John Day Company

New

York

The “Reason Why”

Series

by Irving and Ruth Adler AIR

INSECTS AND PLANTS

NUMBERS OLD AND NEW OCEANS RIVERS

SHADOWS THE STORY OF A NAIL THINGS THAT SPIN WHY? A BOOK OF REASONS YOUR EYES

(C)

1962 by Irving and Ruth Adler

must not be reproduced in any form without permission. Published by The John Day Company, 62 West 45th Street, New York 36, N.Y., and simultaneously in Canada by Longmans Canada Limited, Toronto.

All rights reserved. This book, or parts thereof,

Library of Congress Catalogue Card Number: 62-19714

MANUFACTURED

IN

THE UNITED STATES OF AMERICA

About the Authors Irving and Ruth Adler have written

more than three dozen books

about science and mathematics. Dr. Adler has been an instructor in mathematics at Columbia University and at Bennington College, and was formerly head of the mathematics department of a New York City high school. Mrs. Adler,

who

formerly taught mathematics, science, York area, recently also taught at Bennington. In addition to working with her husband writing this book,

and

art in schools in the

New

drew the illustrations. The Adlers now live in

she

the country in Shaftsbury Township, near

Bennington, Vermont.

UNIVERSITY 0080-0100

OF ALBERTA LIBRARY

Contents Insects

and Plants

4 6

Trillions of Insects

An Insect’s Body

6

Getting Too Big for

How

to Raise

Your

Its

Skin

Own

8 8

Butterflies

That Eat Plants

12

Plants That Eat Insects

14

Insects

Insects

That Keep “Cows”

16

How a Flower Makes Its Seed A Flower-Insect Team: The

An

20

Yucca and the Pronuba Moth

Another Team: The Fig and the Fig Insects

18

That Pollinate Flowers

Insects

Wasp

26

That Pay Rent

28

Air-Conditioned House

How Plants Insects

24

29

30

Protect Insects

That Harm Us

32

A Beetle That Changed Its Diet

34

The Root Louse Crosses the Ocean Some Imported Insect Pests An Australian Friend in a Time of Need

34

An All-American Pest

39

Getting Rid of Insect Pests

40

Plagues

42

Live

Weed

36 38

42

Killers

Honey, Wax, and Ink Insects for Varnish

44

and Dye

46

A Cradle of Silk

47

Word List

48

387833

Insects

This

is

It tells

sects

do

and Plants

a book about insects and plants.

about some of the things that

to plants. It also tells

of the things that insects also tells

do for

plants. It

about some of the things that

plants do to insects

shows how to

in-

about some

insects

and

for insects. It

and plants are related

each other.

You

will find out

rent to plants rent-free.

You

about insects that pay

and about

insects that

go

about

in-

will also find out

sects that live in air-conditioned houses.

You

will find out

about insects that

nice smells and bright colors. too,

about insects that

4

You

like

will

like to eat

sweets and that keep “cows” that give

them

“milk.”

You

will find

out about insects and

plants that cannot live without each other.

You

will learn

on a hunger

You

about an insect that goes

strike.

will find out

about insects that peo-

ple raise because they eat plants. will find out

And you

about insects that people

kill

because they eat plants. You will also learn about plants that eat insects.

You

will find out

about insects that sew

and spin and weave and bore.

And you that people

plants that

will learn

about useful things

make from some work

together.

5

insects

and

Trillions of Insects

There are about a million different kinds of animals. There are elephants and mice,

cats

and dogs, crabs and

earthworms, snakes and

flies

and ladybugs, and

fish,

monkeys and people. Most mals are

you

insects. If

of the different kinds of ani-

one animal of each kind marched past

in a parade, out of every

them would be Insects live

warm

hundred animals, 75

of

insects!

all

over the world. Most insects live in the

places on the earth

where most

of the other ani-

mals also live. Most insects get their food by eating plants.

Because there are so people to find out

all

many

insects,

it is

important for

Then they can help them, They can also

they can about them.

how to use insects to learn how to keep insects from harming them. learn

r

An An

insect has a

Insec fs

Body

body with a hard outside

cover protects the soft parts inside.

main

cover.

The body has

The

three

parts.

The

front part of the

body

is

the head.

On

the head

are a pair of eyes, a pair of hairy feelers called antennae

(an-TEN-ee), and mouth parts.

Some

parts that can chew. Other insects

can suck. 6

insects

have mouth

have mouth parts that

The next part of the body is called the thorax (THOREax). Three pairs of legs are attached to the thorax. The legs have joints, so they bend easily. Many insects have wings. The wings are attached to the thorax, too. The back part of an insect's body is the abdomen ab-DOE-men ) The abdomen looks something like a worm. Insects that sting have their stinging parts on the abdomen. The egg-laying parts of insects are on the ab(

domen,

.

too.

Legs

An

insect’s

7

body

Getting Too Big for

Skin

Its

All insects hatch out of eggs.

A

newly hatched baby grasshopper looks a

grown-up grasshopper. But

As

it

grows,

it is

gets too big for

it

skins in hayfields.

and

splitting

a

small and has no wings.

its skin.

and the baby grasshopper walks out skin behind in the grass.

lot like

Then of

it

the skin splits

and leaves the

You can find empty grasshopper

The grasshopper keeps on growing

its skin. Its

wings develop. Finally

it is

full-

grown.

Other insects change a few times before they become full-grown or adult (a-DULT). This flies,

for example.

So you can watch

own Monarch

all

true of butter-

butterflies are easy to raise.

these changes

when you

raise

your

butterflies.

How to You begin

Monarch

is

Raise Your

to see the

Own

Monarch

Butterflies

butterfly in fields

gardens in the northern part of the United States in

and

May

and June. The butterfly has brown wings with black lines on them, and rows of white dots near the edges. 8

The female Monarch butterfly always lays its eggs on the milkweed plant. The milkweed is the only food the newly hatched babies will eat. You can find Monarch eggs on the underneath side of young leaves. They are white and about the size of a pinhead. The picture shows you what they look like. Pick the milkweed leaves with the eggs on them, and

put them into a big glass of the

jar.

Make

jar.

After a few days the eggs will hatch.

Monarch baby does not look is

the cover

air holes in

The newly hatched

at all like

an adult

insect. It

a tiny caterpillar with yellow, black and white stripes.

It is

called the larva of the insect.

to eat the leaves of the

time. It

grows very

milkweed.

want

to

It

fast. It splits its

way the baby grasshopper does. two inches

The

It

long. This takes about

is

keeps eating

skin a

grows

few

until

all

the

times, the it is

about

two weeks. You

keep fresh milkweed leaves

caterpillar

caterpillar begins

will

in the jar while the

growing. You will also want to clean out

caterpillar droppings.

Egg (drawn many times larger)

Caterpillar

9

Then the of the

jar,

caterpillar stops eating. It crawls to the top

where

it

weaves a

little

mat

part of the caterpillar hooks into the silk pillar

hangs with

its

its

and becomes short and

isn’t

pupa

wiggles and twists so hard its

head.

stripes of the caterpillar

pupa (PEW-pa)

caterpillar

It pulls

together

thick. It hasn’t the yellow, black

a caterpillar any more.

into a

It

skin splits, starting at

and white

silk.

head down. Then the

begins to wiggle and twist. that

The back mat. The cater-

of

The

any more. In

caterpillar has

fact

it

changed

or chrysalis (KRISS-a-lis).

The

looks like a pea-green jewel with golden nails.

The pupa hangs from its silk mat without moving for about 10 days. You must be careful not to shove or bang the jar at this time. If you look at the pupa every day, you will notice that it is changing. First the pupa begins to turn gray. Then it becomes so clear that you can see inside it. You can see a Monarch butterfly folded up inside.

10

The

butterfly

Now

is

the adult insect.

the butterfly

ready to hatch.

is

you are lucky,

If

you will be watching when the pupa splits and the butter-

The newly hatched butterfly hangs by its legs, with its head down. Its abdomen is very fat. Its wings are very small. You can see something like a heartbeat moving in the abdomen. With each beat, the abdomen gets smaller and the wings get bigger. With each beat, blood is pumped from the abdomen into the wings. fly

comes

out.

When the to

wings are

full of

blood, the butterfly begins

walk around. You can hold

time and

it

will not fly

in

It

your hand for a long

cannot

wet. After a few hours,

wings are

still

are dry,

will fly

it

away.

it

fly,

because

when

its

its

wings

away.

After the male and female butterflies mate, the female is

ready to lay eggs. She looks for a milkweed plant. Then

you can

start raising butterflies again.

The newly hatched 11

butterfly

Cabbage worm

Cabbage

butterfly

Insects That Eat Plants

The cabbage

butterfly lays

its

plants in the cabbage family.

It

eggs on the leaves of

lays

eggs on nastur-

its

tiums, too. These plants are the only food that

the cabbage worm, will eat.

If

If

die.

larva,

cabbage worms are moved

to other kinds of plants, they will

and

its

But they can be fooled

go on a hunger

strike

into eating other plants.

the sap of cabbages or nasturtiums

leaves of other plants, the cabbage

is

rubbed on the

worms

will

begin to

eat these plants, too.

Many

plant-eating insects, like cabbage worms, are

free feeders. Free feeders can

move around

easily over

the plant on which they are feeding.

Some

plant-eating insects are trapped on the plants

on which they trapped in

this

Male adult

feed. Scale insects

and

gall insects are

way.

scale insects

The female

cannot

eat.

mouth

parts to the plants

have no mouth

parts.

adults attach themselves

on which they 12

So they

by

their

feed. Their bod-

make a scaly stuff. The scale of some The scale of other insects is cottony. The

ies

feeding insects and hides them.

It

insects

waxy.

is

scale covers the

looks like part of the

plant on which the insects are feeding.

The female

gall insect lays

in a leaf or twig.

leaf or

way.

When

her egg in a hole she makes

the egg hatches into a larva, the

twig around the larva begins to grow in a strange

It

grows into a

gall,

which looks something

round nut. As the larva grows, the

gall

grows

too.

like a

So the

larva always has plenty of food.

Most plants have many

About 1,000

Some by a

of

gall.

insects that feed

different kinds of insects feed

them are

gall insects.

There are

13

on oak

The oak “apple”

insects that

Oak

on them.

is

trees.

made

even feed on poison

‘‘apples”

ivy.

Plants That Eat Insects Plants get water

and chemicals from the

soil

through

The water and chemicals help make the grow. Some plants do not have big roots. They

their roots.

plants

grow

in soil that

does not have

all

the chemicals they

need. These plants get the chemicals from insects that

they catch and

The Its

eat.

pitcher plant grows in

leaves are reddish-green.

ers.

wet places

They

Insects that crawl into the

in the

woods.

are shaped like pitch-

open pitcher cannot get

out again. There are rows of hairs on the inside, near the

open end

work side.

of the pitcher.

like a

The

hairs all face

down. They|

barbed-wire fence, and keep the insects

The insects fall to

)

in- /

the bottom of the pitcher and die. ^

Chemicals in the pitcher plant change the insects into food to make the plant grow.

The sundew sects. Its leaves

is

another plant that catches and eats

in-

look like fuzzy caterpillars at the end of

Pitcher plant

A sticky sap comes out of the fuzzy hairs Insects get caught in the sticky sap. When

long thin stems.

on the

leaves.

an insect

is

caught, the hairs

sect tightly, so that

it

The Venus’s

insects into food for the

sundew.

flytrap catches insects with the

speed of

a mousetrap. At the end of each wide leaf looks like a round box, with a hinge

The edges

in-

cannot get away. Chemicals in the

change the

sticky sap

bend over and hold the

of the trap

end

in a

row

of

is

down stiff,

There are tiny hairs on the inside of the

a trap that

the middle.

pointed hairs.

trap, too. Insects

go inside the trap because of a sweet sap they find there.

When

an insect steps on the tiny

the trap close very quickly.

together the

hands.

The

icals inside icals that

way your

insect

is

The

fingers

hairs, the

stiff,

two parts

of

pointed hairs come

do when you clasp your

trapped and cannot get out. Chem-

the trap change the insect into other chem-

the plant can use as food.

A Venus’s

flytrap catches

an insect

Insects That

People it

who park

Keep “Cows'’

their cars

on tree-lined

hard to keep their cars clean and shiny. The cars are

soon covered with tiny drops of a sticky is

streets find

honeydew.

It is

made by a

AFF-id) The aphid .

is

stuff.

This

stuff

small insect called an aphid

a sucking insect.

It

has mouth

parts that look like a drinking straw. It sucks the sap from

the leaves of the trees. aphid’s

body

into sweet

The sap

is

changed inside the

honeydew. There are two

little

openings at the back end of the aphid from which the

honeydew

flows.^Ants

come

to drink the

there aren’t enough ants to gather

all

honeydew.

If

the honeydew, the

sticky drops fall to the ground.

There are tree ants in India that take care of aphids the

way

a farmer cares for his cows.

the leaves of trees to aphids. thread.

make

They sew together

a shed in which they keep the

The ants use a live needle that makes its own The needle is one of their own larvae. The thread 16

spun by the

The

is silk

that

some

of the ants pull the edges of

is

larvae.

picture shows

two leaves

how

together.

Other ants hold the larvae in their jaws. They push the larvae back

As they do

and

this,

forth

between the edges

the larvae spin a sticky

thread sticks to the edges of the leaves. together to

make

of the leaves.

silk

It

thread.

The

sews the leaves

a dry shed for the ant “cows.”

^^There are aphids that feed on the roots of corn plants. In

many

places,

aphids to stay

who

it

gets too cold in the wintertime for the

alive.

These aphids are cared

gather their honey dew.

to places deeper in the

Then

The

for

by

ants

ants carry the aphids

ground where

it is

not as cold.

the aphids do not die. In the springtime, the ants

carry the aphids back to the corn plant.

Ants “sewing” a

17

leaf

shed

How a Flower Makes Its Many

plants have flowers that

flowers have male parts

Seed

make

and female

The

their seeds.

The male parts To make a seed,

parts.

make a fine yellow powder called pollen.

pollen must be brought from a male part to a female part.

This

is

called pollination (poll-in- A Y-shun). For

plants the

work

of pollination

The male part of a flower is men). The anther (AN-ther) of the stamen. Pollen

The female part of till). The bottom part

is

made

done by

is

called the is

a

little

some

insects.

stamen

knob

(

STAY-

at the

end

in the anther.

a flower

is

of the pistil

called the pistil (PISis

shaped

like a large,

Stigm Anther

The parts

of a flower

18

round bead. This part

is

called the ovary (O-va-ree).

The end called the stigma (STIG-ma). The stigma the ovary by a thin tube called the style. There are eggs

cells in

the ovary.

of the pistil is

is

attached to

Insects that pollinate flowers carry the pollen

from the

The Then

anther of one flower to the stigma of another flower.

stigma

is

usually sticky, so the pollen

is

held there.

the pollen grain grows a long thin tube.

down into the ovary. Some of goes down the tube into the with an egg

cell in

(FUR-till-ized).

the ovary.

The

The tube goes

the stuff inside the pollen ovary.

It

comes together

The egg has been fertilized

fertilized

egg becomes a flower

seed.

The

pistil is in

are around the

the stamens.

the center of the flower.

pistil.

The

The

petals are

petals often

The stamens

around the

have bright

colors.

bright colors help bring insects to the flowers.

An egg

cell is fertilized

pistil

and

The

Insects That Pollinate Flowers

Flowers of different plants have different shapes, ors

and

odors.

Some

ffowers have sweet smells.

flowers smell like animal dung.

(NECK-tar) Nectar .

is

and smells

Some

Some flowers make nectar

a sweet liquid that insects gather

The

as food. Insects also gather pollen as food.

colors

eol-

shapes,

of flowers bring insects to them.

When an insect visits a flower to sticks to the insect’s

body. Then,

to another flower of the

same

get food,

when

kind,

it

some pollen

the insect

flies

carries pollen to

Bees, butterflies, wasps, moths, beetles and

flies all

on it.

carry

pollen from one flower to another.

Flowers that are pollinated by bees are usually yellow

and blue. This

is

because bees cannot see

see mostly yellow smells.

and

Bees will not

blue.

visit

They

Bee flowers have sweet

flowers with

20

all colors.

bad

smells.

Bees

fly

only during the daytime. So

many bee

open during the daytime and closed of

some bee flowers come together

The nectar

is

at the

bottom of the

flowers are

at night.

The

petals

make a thin tube. tube. The long thin

to

tongue of the bee can gather the nectar of these flowers.

Some orchids bee flowers,

are bee flowers. Peas, violets

too.

The nectar tom of a long

of butterfly

and moth flowers

tube, too. Almost

have very long tongues. There 10 inches long. Moths usually night. So

moth

and clover are

moth

is

at the bot-

all butterflies

and moths

is

a

moth with a tongue

fly in

the evening and at

flowers do not have bright colors.

flowers are closed during the daytime

in the evening. Morning-glory, tobacco,

Many

and open up

yucca and eve-

ning primroses are moth flowers. Butterflies feed during the daytime.

Red and orange

21

are colors that

some butter-

flies

can

see.

For

many butterfly flowers are and many lilies are butterfly

this reason,

red and orange. Carnations flowers.

Some

fly

flowers have very

bad

smells. Flies

with short

tongues get most of their food from dung or rotting plants

and animals. So these food they are used

flies visit

plants that smell like the

to.

Beetles visit flowers because of their smell. Beetle flowers usually have big blossoms that roses,

pond

lilies

grow

and magnolias are beetle

alone.

Wild

flowers. Bee-

are not happy just to gather nectar from flowers. They also eat the petals. Some insects are trapped for days by the flowers they tles

visit.

ing.

Hairs inside the flower keep the insect from escap-

While the

insect

ripens on the stamens.

is

inside the flower, the pollen

The trapped

22

insect gets covered

A

caught

fly

in

a milkweed flower

with pollen. After a few days, the hairs drop insect

is

able to leave the flower.

one

just like the

in

which

it

It flies to

off

and the

another flower

was trapped. Here

it

is

trapped again for a few days. So the pollen the insect rub

carries has plenty of time to

rubs

off

off.

Some

of the pollen

on the stigma and pollination takes place.

The milkweed

plant

is

it.

There are deep cracks

is

formed. Insects

gather nectar.

slip

They

unkind

to

some

in the anthers

when they

slip into

step

insects that visit

where the pollen on the ffower

the deep cracks, where their

legs get caught. Pollen sticks to their legs.

hard to get

free.

Some

to

The

insects try

insects never free themselves.

Others lose a leg in the struggle. The insects that get free then

ffy

on

to another

milkweed blossom, where the same

thing happens. While they are fighting to free themselves again, they leave

some pollen on the 23

flower’s stigma.

A

Flower-Insect Team: The Yucca and the

Pronuba Moth

The yucca flower and the Pronuba (pron-YOU-ba) moth cannot live without each other. They work together as a team.

The flowers of yucca plants open up and the Pronuba moth becomes an adult at exactly the same time. They are ready for mating at exactly the same time. Each one needs the other to help

it

mate.

The Pronuba moths come to the yucca flower because of its sweet smell. Male and female moths fly around inside the blossom and mate there. The female Pronuba moth has special mouth parts with which she can scrape. After mating, the female moth scrapes sticky pollen from the anthers of the yucca. She presses the pollen together,

and

rolls it into

way

a child carries a balloon tucked under his chin. She

a ball. She carries the ball of pollen the

carries the ball of pollen to another

makes a hole

in the

yucca flower. She

ovary of the second flower, and lays

an egg. The egg of the moth

is

now

in the

ovary of the

flower.

After the

moth has

laid her egg, she climbs

up onto the

stigma. She takes part of the ball of pollen that she carries

and pushes

it

into the

opening of the stigma. Then

she lays another egg in the ovary. After laying the second

24

egg, she pushes

some more pollen

lays about five eggs. after

each egg

laid her eggs

into the stigma.

She

She pushes pollen into the stigma

is laid.

In this

way

moth has at the same

the female

and pollinated the yucca flower

time.

When formed

the eggs hatch into larvae, seeds have already

in the ovary of the yucca.

the seeds. This help. After a

is

how

month

The

larvae eat

the yucca pays the

some

moth

for

of its

of eating seeds, the larvae eat their

way out of the ovary. They fall to the

ground. They grow

up to be adult moths. They become adults at exactly the same time that the yucca flowers bloom again.

25

Another Team: The Fig and the Fig

Sweet Italy,

figs

grow on the Smyrna

and Spain.

tries. It is also

It is

fig trees of

warm and sunny

warm and sunny

Wasp Turkey,

in all these coun-

in southern California.

So fruitgrowers decided to raise Smyrna

figs in

southern

California.

At that

first

the

fig

growers were disappointed. The

grew on California Smyrna

sour. Fig

growers wanted

fig trees

figs

were small and

to find out the reason for this.

Their search for the answer was like a detective story.

The clue to the answer was a tiny little wasp. The Smyrna fig is a thick, soft shell shaped

The

flow-

fertilized, a

seed

There are hundreds of flowers inside the ers are all female.

forms.

When

a flower

Each flower makes only one

26

is

like a pear.

shell.

seed.

A

fig will

be

very sweet

sweet is

if it

many

if

has a

lot of

of

flowers have

its

seeds in

So a

it.

fig will

been pollinated. Here

where the mystery begins. The Smyrna

pollen.

How

There figs

do

its

a wild

is

do not

be very

fig

makes no

flowers get pollinated?

fig called

taste good.

with plenty of pollen.

But

A

the caprifig (CAP-ri-fig).

flowers are male flowers,

its

little

Its

wasp

lives in the caprifig.

It develops inside a wild fig and feeds on it. The male wasp has no wings and never leaves the caprifig. It mates

with the female wasp while she

is still

inside the

fig.

After

mating, the female crawls out of the caprifig. As she does so,

she gets covered with pollen.

The female wasp has wings. She lay her eggs. If she lands

on a

and new wasps develop.

If

walks around inside the

fig

flies

to another fig to

caprifig, she lays

she lands on a

her eggs

Smyrna

fig,

she

looking for a place to lay her

eggs. She does not lay her eggs there, because the eggs will not

develop inside a Smyrna

fig.

But something

happens. Pollen from the caprifig rubs the female flowers of the flowers are fertilized

Smyrna

fig

figs.

her body onto

In this

way

the

and seeds develop, making sweet

figs.

When Smyrna

Smyrna

off

else

the

figs

wasps

fig

growers of California found out

were pollinated, they brought

to the

sweet Smyrna

United

States.

figs.

27

Now

caprifigs

how and

California grows

Pay Rent

Insects That

There are plants that give insects, in turn,

pay rent

insects a place to live.

The

to the plants for their safe

homes. They pay the plants by keeping away other sects that

in this

might harm the

plant.

Many

in-

ants help trees

way.

There are long hollow thorns on the hull-horn acacia tree that

grows

in Brazil

live in these thorns.

and Central America. Tiny ants

They

get inside

the pointed end of the thorn. a fine

home in which the

their food

insects

The hollow

inside

ants raise their young.

in

makes

They

get

They suck a sweet sap from the acacia leaves. The ants keep leaf-eating

from the

the stems of

by making a hole

away from

tree, too.

the tree. So the ants always have

plenty of leaf sap for food. At the same time, the ants protect the acacia tree.

An

Air-Conditioned House

You can see lumps of ‘‘spit” on the stems of grass and weeds in the springtime and summertime. If you take away the spit carefully, you will find out what has made You will find a small insect that looks like a tiny frog. It is a young froghopper. The froghopper uses sap that it sucks from the plants for making the spit. Its abdomen is built so that it works like a bicycle pump. The froghopper pumps air into the sap. Air bubbles are trapped in the sap. This makes the sap look like spit. The insect stays inside the lump of spit. It is cool and wet inside. The young froghopper is safe from the hot sun in his air-conit.

ditioned house.

A froghopper making 29

“spit”

How Plants Protect Insects The

color or shape of an insect

or death.

The

them from

The

color

their

and shape

is

of

often a matter of

many

some

insects

is

shape of the plant on which the insect insect

on the

is

plant, the insect

bird enemies do not attack It isn’t

like a twig. It

like the

is

cannot be seen

lives.

hard to

When

see.

the

Then,

its

hop around.

name because it looks easily among dead twigs. its

a caterpillar that looks like a twig, too.

twig of the birch

home on

like the color or

easy to see a grasshopper in the green grass

walking-stick insect gets

There

is

birds.

it.

until the grasshopper begins to

The

insects protect

most dangerous enemies,

color or shape of

life

tree.

the birch tree where

A

It

looks

This caterpillar makes it is

hard to

walking-stick insect

see.

its

The thorax

of the thorn treehopper

is

pointed.

It

looks

like a

big thorn. So the thorn treehopper cannot be seen

when

it

rests

Anglewing ragged.

on thorn

trees.

butterflies

The underneath

ish-gray.

When

have wings that look torn and side of the anglewing

the anglewing

is

at rest in the

ragged brownish-gray wings look

just like

is

brown-

woods,

dead

its

leaves.

There are some insects that are protected by colors that

make them

bar) caterpillar

The cinnabar-moth (SIN-aan example. The caterpillar has bright

easy to see. is

yellow and black

stripes.

Many

of these caterpillars feed

together on ragwort, a plant with small leaves. So the caterpillar It it

is

not hidden by the plant on which

it

feeds.

can be seen very easily from quite far away. Because can be seen

mies. to eat

The it.

easily, its color protects

caterpillar has a

So,

when

bad

it

taste.

from

its

bird ene-

Birds do not like

birds see the caterpillars feeding to-

gether, they stay away.

The thornhopper looks 31

like

a thorn

Insects That

Some

insects are

Harm Us

harmful because they damage or

even wipe out plants that people food for animals that people

food for people.

Then there is Then there is also

use.

raise.

And there are less

cotton,

and other things that people get from Only a few

of the

many

is

less

wood, tobacco

plants.

kinds of insects are harmful.

These insects weren’t always harmful. One way

become harmful

less

insects

by being moved from a place where

they have always lived to a place where they have never lived.

Insects that

have been

in a place for a long, long time

have made enemies. Their enemies may be diseases that kill

may be birds or other insects Their enemies kill many of them. So, when

them. Their enemies

that eat them. insects

have been

are usually not so

in a place for a long, long time, there

many

them

of

that they can

do much

harm.

When

insects are

moved

never lived before, they the

number

The

insects

to a place

may

find

where they have

no enemies

there.

So

of insects of that kind gets bigger very fast.

may

still

cause there are so

eat the

many

same kind

insects,

of plant.

But be-

they can eat up

all

the

plants.

When

insects are

moved

to another place they

32

may

begin to eat plants that they never ate before. Then the

new

some

plants are in danger of being eaten up. In

become harmful when new plants are brought to the place where the insects live. The insects may take a liking to the new plant. Then the insects will cases insects

begin to go to

new

places looking for the

new

plant.

Since the insects have no natural enemies in the places, they

become an

insect pest there.

Cockroach

Some

Clothes moth insect pests

33

new

A

A

Beetle That

The Colorado potato beetle.

States

Changed

Its

Diet

beetle wasn’t always a potato

At first it lived only

on a

potato beetle

diet of weeds.

in the southwest of the

When

United

the early American set-

moved west to California they carried potato plants with them. The Colorado beetle liked the taste of potatlers

toes very

much. Wherever potatoes were planted, the

beetles found their

way

to them. In this

spread across the United States. eat their

way from

California to

It

way

the beetles

took them 15 years to

New York.

The Root Louse Crosses the Ocean For a long time American grape growers tried

to

grow

grapes from vines brought from France. The vines

ways louse,

died.

They had been

which spent part of

killed

its life

by an aphid, the

United States were not damaged by

American vines were very tough. 34

root

eating the roots of the

grapevine. Grapevines that had always

of

al-

grown

this insect.

in the

The

roots

About 100 years ago, some American grapevines were brought into France. The root louse came into France on the roots of the vines. In just a few years, all

it

killed almost

the vines in France and in other parts of Europe, too.

The French grape growers found out how they could grow healthy plants. They attached French vines to the tough roots of the American plant. They did this by grafting. The new vines grew grapes with the fine flavor of French grapes. They were not attacked by the root louse because they had the strong roots of American plants.

Some good came out

of this terrible experience.

These new vines were brought back States

where they could grow,

too.

to the

United

Now American grape

growers can grow French grapes in the United States.

A

slit is

stem

made

of an

in

the

American

vine

.

.

.are put

in

the

slit.

The

graft

covered with wax to protect

Grafting of grape vines

is

Some Imported Most

of the insects that

Insect Pests

have become pests

in the

United States have been brought in from other countries

where they were not harmful. They became

pests in the

United States because they found no natural enemies to

keep them from spreading.

The gypsy moth was brought into Massachusetts about 100 years ago by a French scientist who was trying to make silk. Some caterpillars escaped from his laboratory. The caterpillars discovered quickly that they liked eating the leaves of American shade trees. They spread to other states and even to Canada.

People have learned spreading.

how

They spray

to

trees

Many trees were killed.

keep the gypsy moth from with poisons. They also

in-

spect plants that are shipped from one state to another to

make

sure there are no gypsy moths on them.

A Japanese 36

beetle

The Japanese States in 1916. It

beetle

was

was

living

first

on some fancy Japanese

New Jersey.

in a tree nursery in

noticed in the United

People didn't

harmful the beetle could be, so they beetle spread quickly because

it

found

dreds of other trees and bushes, too. control. It has

know how

left it alone. it

It

liked to eat hun-

has been hard to

is

the larva of a moth.

It

has always

lived in

Europe and Asia where there was no

found

liked corn

from America. In else.

when

fact,

From the time

its

a nice, comfortable their

way

have

lots of

in

dead

The

even been found in airplanes.

The corn borer it

trees

it

corn was brought to Europe

likes

corn better than anything

eggs hatch in July, the larvae have

home

all

cornstalks.

They bore the plant. They

in the corn plant.

into tight, dark places inside

food

corn. It

the time.

One way

They have a winter home

to control corn borers

planting corn at just the right time.

is

by

An

Australian Friend in a

The cottony-cushion eats the sap, leaves It

was

fruit

first

is

and twigs

of

Need

a small scale insect that of citrus (SIT-rus) trees.

in California orange,

lemon and grape-

orchards about 100 years ago. Within 15 years

citrus trees

their

found

scale

Time

had been

whole crop of

killed

by the

scale

many

and farmers

lost

citrus fruits.

Some people thought

that the scale

was brought

into

came from Australia. They thought this because they knew that the cottony-cushion scale had lived in Australia for a long time. They also knew that it was not an insect pest in Australia. So they went to Australia to find out why. They found their answer in a little reddish-brown lady California on fruit trees that

beetle, the vedalia beetle. This beetle

and

its

larvae ate

the larvae and eggs of the cottony-cushion scale and

nothing

else.

About 500 vedalia

beetles

fornia from Australia. There

were brought

was plenty

A

38

into Cali-

of food for them.

vedalia beetle

so there

were many

of

two years there were

them so

in a short time. In less

many

than

vedalia beetles in Cali-

fornia that the cottony-cushion scale stopped being a pest.

An

All-American Pest

The boll weevil is a little black bug with a long snout. It came from Mexico. It likes to eat only the cotton plant. The adult eats the leaves of the cotton plant. With its snout, the female bores holes in the plant.

buds of the cotton

She lays her eggs inside the buds. Larvae hatch

from the eggs. The larvae eat the inside of the bud. Then the

bud never grows

into a cotton boll.

in the cotton bolls, too.

the boll, so that

The

it

growing

It

larvae spoil the cotton inside

cannot be used.

boll weevil

Texas in 1892.

The

She lays her eggs

came

into the

can be found

states in the South.

United States through

now

in all the cotton-

Cotton farmers can keep

it

under control by using good seed and taking good care of their land.

39

Getting Rid of Insect Pests

They

Insect pests do a lot of harm. trees.

They damage houses and

get rid of

all

insect pests.

eat crops

clothing.

We

and hurt

can never

But we can learn how to control

them.

One way

to control insect pests

by finding

is

their

natural enemies. Chinese citrus-fruit growers controlled insect pests this

way

for a long time.

China are bothered by a small black the natural enemies of the citrus

put these ants into their citrus “ant bridges” out of

bamboo

The

Certain ants are

fly.

fly.

trees.

poles, to

citrus trees of

The fruitgrowers They even make make it easier for

the ants to go from one tree to another. There are people

who make Germs

a living raising ants for the fruitgrowers.

are sometimes natural enemies of insects. So

germs that hurt

insects

but do not hurt animals or people

are sometimes sprayed on plants

Another way

which

to control insect pests

plants that insects like

insects eat.

is

to stop

growing

and grow instead another plant

the same kind that insects do not

like.

used to be a pest on American wheat. So

The Hessian scientists

of fly

looked

They found such a wheat plant in southern Europe. They brought this plant to the United States. The European for a

wheat that the Hessian

wheat grew well

in the

sian fly did not like

United

it.

40

fly

would not

States,

eat.

because the Hes-

Another way

to control insect pests

on the plants on which

insects live. This

gerous. It can be dangerous,

food plants.

is

when

The poisons can hurt

to spray poison

way can be

poisons are used on

people.

gerous, too, because the poisons can

kill

It

can be dan-

the natural ene-

mies of the insect pests at the same time. Then, insect pests It

come back

dan-

if

the

again, they spread very quickly.

can be dangerous because the poisons can go into the

soil

and poison the streams. This happened

when pest.

in Florida

a poison was used to control the sand-fly, an insect

Not only were the

fish in

sand-flies killed,

but

all

of the

the area were killed, too.

Another way

to control insects

is

to

keep them from

spreading from one country to another. This can be done

by making sure

that

all

plants that

come

into a country

have no insects on them.

USDA photograph

Plagues It is

a bright sunny day. There are fields of grain as far

as the eye

can

The wind makes the

see.

grain ripple, so

that the fields look like a great golden sea.

Suddenly

it

becomes very dark. The sun

hind a black cloud. But

this

is

is

hidden be-

not a storm cloud.

The

cloud moves very quickly, and makes a loud buzzing noise. It

made up

a cloud

is

looking for a

new place to

of millions of grasshoppers

live.

After the grasshoppers have passed, the fields are bare.

The

trees are bare.

The grasshoppers have eaten

every-

thing.

When rible.

this

happened a long time

eaten ‘it

all.

Thousands

grasshopper pZague

Grasshoppers ally don't die all

ago,

it

was very

ter-

People had no food because the grasshoppers had

still

when

of people died. This

(PLAYG) do a

was what a

did.

lot of

damage. But people usu-

grasshoppers eat their crops. People

over the world try to help each other.

If

people in one

part of the world do not have enough food, people in

other parts of the world often help

them

them by sending

food.

Live

Weeds

Weed

are plants that

Killers

grow where they are not

wanted. They grow in gardens and 42

fields

crowding out

plants that are raised for food.

We usually don’t think of the It is

a pretty desert plant in the United States.

keep

it

The

as a

We even

house plant.

became a weed in Australia. It was Australia by accident in 1787. But the cac-

cactus plant

brought into tus

cactus plant as a weed.

had no natural enemies in

quickly.

Australia. So

it

spread very

By 1925 millions of acres of land were

filled

with the weed. Nothing else could grow in them.

came to America to see if they could find the natural enemy of the cactus plant. They brought many different insects back with them. The inAustralian scientists

sects kept the cacti

them

from spreading, but did not wipe

out. Finally, after ten years of searching, the right

insect-enemy was found. Argentina. Billions of

seven years

all

its

It

was a moth

that lived in

eggs were sent to Australia. In

of the cactus plants

were wiped

out.

Then

the land could be used again for crops and pasture. Cactus plants before ...

... and after the moths came.

Dept, of Public Lands, Queensland, Australia

i

Cells in a

honey comb

A honey bee

A bee

hive

Honey, Wax, and Ink

Some

when we take things from them. when we make things from them.

insects help us

Other insects help us

44

We take honey and wax from bees. and wax from the nectar they

The wax forms making gether

in small scales

abdomen. The wax

of the bee’s

little

make

six-sided

Bees make honey

gather.

on the underneath side is

used by the bees for

rooms called

Many

cells.

a comb. Eggs are laid in the

cells to-

cells.

Some

of the

nectar the bee swallows goes into the honey sac.

Chem-

The bee makes honey icals

in

its

honey

sac.

change the nectar into honey. Then

honey up.

the bee spits the

the honey into the cells of the comb.

It spits

The honey is food for the larvae that hatch from Beekeepers fool the bees into making extra

the eggs. cells

and

them with honey, even though no eggs have been in these cells. Special machines remove the honey

filling

laid

from these

cells.

This

is

the honey that the beekeepers

sell.

They

get beeswax

Beeswax makes a

We

make

by melting down old honeycombs.

fine polish.

a very good writing ink with the help of a

small wasp. These

little

wasps feed on oak

trees in the

western part of Asia, near the city of Aleppo. These

wasps are

gall insects.

They make Aleppo

galls.

A very fine black ink is made from Aleppo galls. Under the laws of Massachusetts, this ink must be used for writing

all

public records.

45

A

Insects for Varnish

Varnish

is

often used on

varnish has lac in lives in the

Many

it.

Lac

is

cochineal insect

and Dye

wood instead of paint. Good made from a scale insect that

Far East.

lac insects live together

on the twigs of

trees.

The female has a pointed beak. She sucks sap through her beak. Most of the sap passes out of her body. It forms a scale of lac on her back. Because the insects are

crowded together on the to

make

a sheet.

The

twig, the scales

insects

come together

keep feeding under

this

sheet of lac.

Lac-covered twigs are then cut from the scale

and

insects are separated

the twigs in hot water.

Lac

The

from the wood by putting

for varnish

is

scale. Artists' colors called “lakes" are

dead

trees.

made from made from

the the

insects.

Beautiful red dye

(KOTCH-i-neel)

is

made from

insect, a scale insect

the cochineal

found

in Mexico.

abdomen is dark red. Most cochineal insects are female. Dye is made from female insects that are filled with eggs. The female is very large then. It takes 70,000 insects to make a pound of dye. It lives

on cactus

plants. Its

46

A silkworm ...

...

A There are

Cradle of

caterpillars that

times to

pillar spins

make

its

cocoon

Silk

make

silk.

The

caterpillar

wraps the thread around

spins a silk thread. It

many

and

(kuh-KOON). The

a cocoon

about a half mile of thread to make

This caterpillar

is

called the silkworm. It

a large white moth.

It eats

is

its

itself

cater-

cocoon.

the larva of

the leaves of mulberry trees.

Silkgrowers gather the cocoons and heat them to the caterpillars inside.

cocoons and wind

it

Then they unwind

on

reels.

the

silk of

Several strands of

silk

kill

the are

make thread for weaving and sewing. It takes about 3,000 cocoons to make 1 pound of silk. Silk is not used very much today. Man-made fibers like

twisted together to

rayon and nylon have taken

Most

silk

its

place.

comes from China and Japan. 47

WORD — The

Adult (a-DULT)

full-grown insect.

— An

Antennae (an-TEN-ee)

They

like stiff hairs.

Anther (AN-ther)

LIST They look

insect’s feelers.

are attached to the insect’s head.

— The

male part of a

flower. It

makes

pollen.

— What

Chrysalis (KRISS-a-liss)

Later the chrysalis changes into an adult insect.

into.

— The

Cocoon (kuh-KOON) which some

pupa

of

some

Larva (LAR-va) is

— In

cell to

— It

is

the

a flower, the joining of pol-

make

a seed.

hatches from an insect’s egg.

A

— A sweet syrup made by some flow-

gathered by insects as food.

Ovary (O-va-ree)

— The

bottom part of the

made in the ovary. Pistil (PIS-till) — The female part of a flower. Pollen POLL-en — A yellow dust made by egg

It

a larva.

Nectar (NECK-tar) ers. It is

thread in

silk

insects.

and an egg

caterpillar

blanket of

wrap themselves.

caterpillars

Fertilize (FUR-till-ize)

len

a caterpillar changes

pistil.

The

cells are

(

)

of a flower. It

flower to

make

the anther

comes together with the egg

cell of

a

a seed.

Pupa (PEW-pa) — Same as chrysalis. Stigma (STIG-ma) — The top part of ceives the pollen.

48

the

pistil.

It re-

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