Insect Leg: Structure and Modifications

This ppt include brief introduction about the Insect leg, thier structure and their modifications accroding to insect's habit and habitat.

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

2. 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.”

3. 3 Structure of Insect Leg A typical leg consists of the following parts:- Coxa :- It is the basal segment and joint the leg with thorax . Trochanter :- It is the small second division of the leg which articulates with coxa but is usually fixed with femur . Femur :- It is the largest and most powerful division of the leg. Tibia :- It is the slender , usually quite long . Tarsus :- It is the fifth divisional segment and generally sub divided into 2-5 segments . Pretarsus :- It is the last terminal segment of the leg which represented of the leg which is represented by a complex set of claws.

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

6. 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. 7 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. 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. 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.

10. 10 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

11. 11 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.

12. 12 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.

13. 13 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.

14. 14 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 .

15. 15 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 )

16. 16 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 .

17. 17 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.

18. 18 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.

19. 19 15. Prehensile :- This type of legs are modified for the purpose of catching prey and basket forming . Example:- Dragon Flies .

20. 20 For any questions or doubts you can find me: Twitter:- @ vikaskashyap __ Email:- Vikas Kashyap THANKS!