Download No metamorphosis

METAMORPHOSIS
It is the change in
growth and development
of an insect undergoes during its
life cycle from birth to maturity
There are four basic
types of metamorphosis
in insects.
•No metamorphosis
•Gradual metamorphosis
(Paurometabola)
•Incomplete metamorphosis
( hemimetaboa)
•Complete metamorphosis
Ametabola
(No metamorphosis)
e.g. Silver fish
Life stages
Egg
young one
adult
It is most primitive type of metamorphosis.
The hatching insect resembles the adult in all
respects except for the size.
Hemimetabola
(Incomplete metamorphosis)
e.g. Dragonfly, damselfly and mayfly
Life stages
Egg
naiad
adult
The young ones are aquatic and are called naiads
They are different from adults
They breath by means of tracheal gills
The lower lip is called mask, which is hinged
and provided with hooks for capturing prey
Their habit and habitat vary.
After final moult, the insects have fully
developed wings suited for aerial life
Paurometabola
(Gradual metamorphosis)
e.g. Cockroach
Life stages
Egg
nymph
adult
The young ones are called nymphs
They are terrestrial
They resemble the adults in general body form
Their compound eyes and mouth parts are similar
to that of adults
Both nymphs and adults share the same habitat
They lack wings and external genitalia
Wing buds externally appear in later instars
The genitalia development is gradual
Later instar nymphs closely resemble the adult
with successive moults
Holometabola
(Complete metamorphosis)
e.g. Butterfly and moth
larva
pupa
Egg
adult
Majority of insects undergo complete metamorphosis
Larva of butterfly is called caterpillar
Larva differs greatly in form from adult.
Compound eyes are absent in larva
Lateral ocelli or stemmata are the visual organs.
Their mouth parts and food habit differ from adults
Wing bud development is internal
When the larval growth is completed, it is followed by
a period of in activity (prepupa) and transforms into
pupa
In the pupal stage, the larval tissues disintegrate and
adult organs are built up
Hypermetamorphosis
Blister beetle
Triangulin
Pupa
Grub
Life stages
Egg
adult
Common in hemi and holometabolous insects
More than one larval stage is common