Insect Leg: Structure and Modifications

INSECT LEG:
STRUCTURE &
MODIFICATIONS
Created and edited by:-
Vikas Kumar
Student of B.Sc
(Agriculture)

2
What are Legs?
“An insect usually bears three
pairs of legs which are located
on the ventral surface of
thoracic segments. They are
primary organs for running or
walking, but according to the
habit and habitat of insects they
are modified for different
purposes.”

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Structure of Insect Leg
A typical leg consists of the following parts:-
a) Coxa:- It is the basal segment and joint the leg with thorax.
b) Trochanter:- It is the small second division of the leg which
articulates with coxa but is usually fixed with femur.
c) Femur:- It is the largest and most powerful division of the leg.
d) Tibia:- It is the slender, usually quite long.
e) Tarsus:- It is the fifth divisional segment and generally sub
divided into 2-5 segments.
f) Pretarsus:- It is the last terminal segment of the leg which
represented of the leg which is represented by a complex set
of claws.

5
Modifications of Leg
1. Ambutorial or Walking Type:-
It is generalized form of insect
leg, which is usually adapted
for walking.
Example:- Cockroach and
Bugs

6
2. Cursorial or Running Type:- It is
almost similar to walking type
of leg, but it is differentiated by
the tarsus which is
comparatively longer and
touches the ground while
running.
Example:- Ants, Blister Beetle
and wasps.

7
3. Saltatorial or Jumping Type:-
Such type of legs are present
in grasshopper, crickets and
flea beetle where the femur
of the hind leg get enlarged
and accomodates the
powerful tibial muscles.
Example:- Hind leg of
Grasshopper

8
4. Scansorial or Clinging Type:-
This type of legs are smaller
and flat. The coxa are widely
separated and tarsi bears a
single claw.
Example:- Head Louse

9
5. Fossorial or Digging Type:- This
type of legs are modified for
the purpose of digging. These
are powerful, broad and small
in size. Tibia and tarsus short
and broad with teeth like
projections.
Example:- Mole crickets and
Dung rollers.

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6. Raptorial or Grasping Type:-
Such legs are adapted for
catching the prey and are
found in Mantids. Coxa of fore
leg is more elongated whereas
the trochanter is small. Tibia is
spinous and fits along the
femur.
Example:- Preying Mantids

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7. Natatorial or Swimming Type:-
These type legs are found in
insects which lives in the water
and help them to swim. The
femur, tibia and tarsus are
flattened and posses the long
rows of hairs.
Example:- Dytiscus and Jaint
water bug.

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8. Foragial or Pollen Collecting
Type:- This type of legs are
found in worker honey bees
which is mainly adapted for
carrying the pollen from the
flowers. Tibia of the hind leg is
dialated and covered with longs
dense hairs which forms a
pollen basket.
Example:- Hind leg of Woker
Honey Bee.

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9. Stridulatorial or Sound
Producing Type:- These legs
are typically adapted for
producing sound wherein the
femur of hind leg is provided
with the row of pegs on its
inner side. These femoral pegs
work against the outer surface
of each tergum or coastal
margin of the fore wing,
thereby producing a sound.
Example:- Male Grasshopper
and cricket.

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10. Sticking Type:- In such type of
legs the pretarsus is highly
modified in a pair of claws and
a pair of pad like structure
known as pulvilli (found at the
base of claws). Hollow and
tubular hairs secrets a sticky
substance. These are also
known as Adhesive type of
legs.
Example:- House fly.

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11. Clasping Type:- This Such type
of legs are modified for
reproduction purposes. Coxa
and Trochater is comparatively
smaller while the Femur is
thick. The tibia is slender,
tarsus is one segmented and
arched. This adaptation helps
male to holds the female
during reproduction.
Example:- Chleredryinus
(Parasite of Sugarcane Pyrilla)

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12. Suctorial or Sucking Type:- This
type of legs are also modified
for the purpose of
reproduction in which coxa and
trochanter of fore legs are
small while femur is thick and
small. They are also helpful in
sticking with grasses and leaves
against the water flow.
Example:- Male Dytiscus.

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13. Antennal Cleaning Legs:-
This type of legs are
modified for the purpose of
cleaning antennae in which
tibia possess a movable
spine and the first tarsal
segment with a semi-circular
notch.
Example:- Front legs of
Honey Bees.

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14. Wax Pick Legs:- This type of
legs are modified for the
purpose of picking of wax
plate in which Tibia possess a
spine called wax pick for
removing the wax plates
from the ventral side of the
abdomen.
Example:- Middle legs of
Honey Bees.

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15. Prehensile:-
This type
of legs are modified
for the purpose of
catching prey and
basket forming.
Example:- Dragon
Flies.

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For any questions or doubts you can find
me:
Twitter:- @vikaskashyap__
Email:- Vikas Kashyap
THANKS!

Insect Leg: Structure and Modifications

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