Download Insect Metamorphosis Notes

TEKS 5.10C Describe the differences between complete
and incomplete metamorphosis of insects.
What is complete metamorphosis?
In complete metamorphosis, an insect goes through four stages:
egg, larva, pupa, and adult. Look at the diagram below. The
process begins when eggs hatch into larvae. A larva usually looks
something like a worm. Caterpillars are the larvae of butterflies.
Other larvae include the grubs of beetles and the maggots of
flies. Larvae eat and grow for some time. Then, a larva becomes
a pupa (PYOO puh), which is the next stage of the process. A
pupa has a covering that protects it.
Insect Metamorphosis
What is an insect?
Moths, caterpillars, dragonflies, ants, cockroaches, and bees are all
insects. You can identify insects by counting their body sections and
legs. Insects have three body sections and six legs. The three body
sections are the head, thorax, and abdomen. Insects also have one pair
of antennae. Most insects have one or two pairs of wings.
Insects have a tough outer covering called an exoskeleton. It protects
the animal. An exoskeleton cannot grow with an insect. So, an insect
must shed its exoskeleton and make a new one to grow. This process is
called molting.
Like all living things, insects have life cycles. They begin life as tiny,
hard-shelled eggs. Insects hatch from the eggs and begin a process of
body changes and growth. This process is called metamorphosis.
Metamorphosis produces adult insects. There are two types of
metamorphosis. They are called complete metamorphosis and
incomplete metamorphosis.
The pupa does not eat. It grows very little. But major changes
take place in the insect’s body as it becomes an adult. Beetles,
butterflies, flies, bees, and ants all undergo complete
metamorphosis.
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What is incomplete metamorphosis?
In incomplete metamorphosis, an insect has no distinct larval
stage. Instead, an egg hatches into a stage called a nymph
(NIMF). A nymph usually looks like the adult insect without
wings.
A nymph may molt several times before becoming an adult.
Grasshoppers, termites, cockroaches, and dragonflies go through
incomplete metamorphosis. You can see the process in the
diagram below.
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