Insects
Chapter 10 Section 3
 Arthropods
with three body
sections, six legs, one pair of
antennae, and usually one or two
pairs of wings
 Three body sections are the head,
thorax, and abdomen
Body Structure
 Insect’s
sense organs found in head
(eyes/antennae)
 Two large compound eyes
◦ Compound eyes contain many lenses,
keen at seeing movement
Body Sections: Head
 Insect’s
midsection
 Where wings and legs are
attached
 Only invertebrates that can fly
 Can travel long distances to find
mates, food, and new places to live
Body Structure:
Thorax
 Internal
organs found in the
abdomen
 Small holes outside of abdomen
allow air, which contains oxygen, to
enter the body through tubes
Body Structure:
Abdomen
“If it is living, or if it once was living,
some kind of insect will eat it.”
 Mouthparts are adapted for a highly
specific way of getting food

Obtaining Food
 Begin
life as tiny, hard-shelled,
fertilized eggs
 Either
go through…
◦Complete metamorphosis
◦Gradual metamorphosis
Life Cycle

4 different stages: egg, larva, pupa, adult
Insect begins life as a tiny, hard-shelled
fertilized egg
 The eggs hatch into larvae (usually look
like worms)
 Larva will then enter next stage and
become a pupa, insect is enclosed in a
protective covering

◦ Pupa does not eat/barely moves, but it is NOT
resting

When development is complete, adult
leaves pupal case
Complete Metamorphosis

No distinct larval stage

Egg hatches into a stage called a nymph
◦ Nymph: usually looks like the adult insect
without wings

Nymph may molt several times before
becoming an adult

Grasshoppers, termites, cockroaches,
dragonflies
Gradual Metamorphosis