How Do Spiders Legs Work?
WouterThe legs of spiders are primarily composed of flexor muscles. In contrast, limbed animals such as insects have extensor muscles. Moreover, some spiders are known to have flexor-only muscles on the inside of their body.
For propulsion, spiders use a combination of hydraulic torque and muscular contraction. The hydraulic mechanism has yet to be fully understood. However, it is possible that the cephalothroax (head and middle) controls the hydraulic movement of the body.
A unique hybrid propulsion system allows spiders to move robotically. The legs are grouped into four pairs of legs and move in an alternating tetrapod pattern. The hind legs have a strong vertical force that enables spiders to lift the centre of mass off the ground.
Spiders use a complex hydraulic system to extend the legs. This is similar to the mechanism used by jumping spiders. In larger spiders, the hind legs contribute to acceleration of the centre of mass through both hydraulic and muscular mechanisms.
To prevent deflation, some spiders have valves in their legs. In some species, spiders also use dry adhesions. The structure of the hairs may also be important for sticking to the surface. Scientists have viewed the hairs with a powerful microscope and have tried to pull the hairs off with tweezers.
Spiders have a large number of proprioreceptors that give them a detailed picture of their movements. These receptors are especially useful for walking over rough terrain and capturing prey. They also play a role in fine adjustments of movement.
