homework encyclopedia

Abdomen is

long and slender

to balance insect

when flying

Claspers are used by

male to hold female

during mating

Thorax (middle

section of the body)

Large compound eyes

give wide field of vision

1 BED BUG

Various insects feed on blood, including head lice, mosquitoes, and fleas.

The bed bug lives in mattresses and emerges when it feels the heat of a

body. Its mouthparts are adapted to pierce skin and suck up blood.

INSECT CLASSIFICATION

Insects

Wings held together at

rest – unlike dragonflies’

wings, which are

held open

Long, delicate

legs have

several joints

Head

WHY ARE INSECTS SO SUCCESSFUL?

The main reason for insects’ success is their variety.

There are so many species that there is almost nowhere

on land they cannot live, and almost nothing they

cannot eat. Their small size enables them to go almost

anywhere in search of food. Many insects can fly,

which makes it easy for them to colonize new places.

1 DAMSELFLY

Like all adult insects, damselflies

have three-part bodies, with a

head, thorax, and abdomen.

Damselflies and dragonflies form

a very ancient group of insects.

Giant dragonflies flew in swampy

forests 350 million years ago,

before dinosaurs existed.

• Insects have thrived on Earth
  for over 400 million years.
  The insect world is divided
  into 29 groups, called orders.


• The largest order, the beetles
  (Coleoptera), contains more
  than 370,000 species.
  
  
  • Other major orders are moths
    and butterflies (Lepidoptera,
    165,000 species), bees, wasps,
    and ants (Hymenoptera,
    198,000 species), flies (Diptera,
    100,000 species), and bugs
    (Hemiptera, 80,000 species).
  
  
  
  

The most numerous animals on Earth, insects form about

75 per cent of the animal kingdom. Around 800,000 species

have been identified, but there could be up to 10 million.

Insects are six-legged invertebrates with keen sense organs,

including. ANTENNAE. Some live in. COLONIES.

BUTTERFLY SENSES 3

Long antennae and large

compound eyes help butterflies

to sense the world around them.

ANTENNAE

Club-shaped antenna,

different from the feathery

antenna of a moth

WHAT DO INSECTS USE THEIR ANTENNAE FOR?

Insects use antennae to find food and detect enemies.

Lice, fleas, and other insects that feed on other animals

use their antennae to sense the body heat or moisture

of their victims. Some male insects have especially

sensitive antennae, which can pick up scents called

pheromones given off by females (their mates).

WHAT OTHER SENSES DO INSECTS HAVE?

Many insects have compound eyes, with dozens of lenses

that work together to form a detailed picture. Some also

have sensitive bristles on their abdomens, which detect

air currents caused by moving predators or prey. Insects’

eardrums may be on their legs or body. Some insects,

such as flies, have taste organs on their feet.

The main sense organs of most insects are the antennae (feelers)

on their heads. These often long and slender projections are covered

with tiny sensitive hairs. As well as feeling, the antennae are also

used for smelling, and sometimes for taste and hearing, too.