Modification of Insect’s legs


Modification of Insect’s legs

1. Ambulatorial (Walking leg): e.g. Fore and middle legs of cockroach. Femur and tibia are long. Legs are well developed similar in form.

2. Cursorial (Running leg): e.g. All three pairs of legs of Ants. Femur in not swollen. All the legs are long.

3. Saltatorial (Jumping leg): e.g. Hind leg of grasshopper, field cricket, Trochanter is fused with femur. Hind femur is enlarges.

4. Scansorial (Clining leg): e.g. All three pairs of legs of head house. Tibia is stout and at one side bears a thump like process. The tarsus is single segmented. There is a single large claw that usually fits against a thumb-like process, which forms an efficient mechanism for hanging on to the hairs of host.

5. Fossorial (Digging leg): e.g. Fore legs of mole cricket. Femur is shout. Tibia is short and shout and bears distally two or three strongly printed tines. The first two segments of tarsus are also produced into strong tines. The first two segments of tarsus are also produced into strong tines. Tympanum is present on fore mantids.

6. Raptorial (Grasping leg): e.g. Fore legs of preying mantids. Fore legs are of no use in locomotion. Coxae elongated to give an extended reach to capture the prey. The femur is large and groove when it snaps down over the prey. Tarsus consists of five tarsomeres.

7. Natatorial (Swimming leg): e.g. Hind legs of water bug or water. Beetle, Femur, tibia and first four tarsomeres are all broad and flattened. Their edges are provided with flattened setae. The hind legs serve as oars.

8. Sticking leg: e.g. All the three pairs of legs of housefly.
Pretarsus consists of a pair of lateral adhesive pads called pulvilli and a pair of claw. Arolium is absent. But a median spine like structure called campodium is present. The pulvilli are covered with dense mats of tiny glandular hairs called tenant hairs. Secretions of these glandular hairs are helpful in clinging to smooth surfaces and to walk upside down on the ceiling.

9. Basket-like leg : e.g. Legs of dragonfly and damselfly
Legs are situated just being the head and are anterior in position. Legs are spiny and closely placed which are useful in seizing the prey during flight. Legs are not useful in locomotion.

10. Foragial leg: (Pollens collecting and carrying leg) e.g. legs honey bee.
a. Eye brush: Hairs on tibia useful to clean the compound eyes.
b. Antenna cleaner: Velum is a movable clasp present at distal end Tibia. Antenna c. c. comb semicircular notch lined with small spines.
d. Pollen brush: Bristles on basitarsus from the pollen brush which is useful to collect pollen from the head and mouth parts.

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