Why Aren't the Six Legs of an Insect Always Identical?

Some insects have modified front legs that act like claws.

As a general rule, insect legs are the same from side to side, but can vary a lot from the front to the back of the animal. Also, within the insect kingdom there is a wide variation in leg functions, but there is also some specialization of the legs within the body of one insect.

Insect Legs

Insect legs come in three pairs and are segmented into five parts. Each part has a scientific term to define it and throughout the insect population, the leg performs many different tasks such as leaping, digging, crawling, running, preying and even singing. However, more specialized functions like making auditory noises are usually only found on one pair of legs.

Front Leg Design

Differentiated front legs on an insect can serve many purposes. For example, a praying mantis has extra-long front legs that are used for capturing prey. Some other interesting examples of specialized front legs come from crickets, which have hearing mechanisms, called tympanum, which are sensitive to sound vibrations. Then there are the mole crickets, whose front legs are specially designed for digging.

Hind Leg Specialization

Though not as common as in the front, the hind legs of insects can also be specialized for various activities. This scenario is best exemplified again by the cricket, which has extra-long, spring-loaded, back legs, which assist in leaping.

References

• Washington State University: Insect Morphology:
• Purdue Extension: Not All Insect Legs Are Made for Walking
• Globio: Insects - The Most Successful Animals on Earth