Like many other insects, cockroaches have a total of six legs that come in pairs. The legs are segmented, and all of them are attached to the middle part of the roach’s body. This central part is known as the thorax, after which the pair of legs are named. The first pair of legs are the shortest, back legs being the longest. These strong back legs are the primary source of movement.
The Three Pair Of Legs
- The first pair is the prothoracic legs, which are closest to the cockroach’s head. These are the shortest legs in length and act as brakes when the insect runs. Another pair is the mesothoracic legs, which are the middle legs. They help in speeding or slowing down the cockroach by moving back and forth.
- The last pair is the metathoracic legs, which are the long, back legs of a cockroach, and they help in the forward movement of the cockroach.
The Leg Anatomy of a Cockroach
The three pairs of legs have different lengths and functions, but they are constituted of the same parts and move likewise. The Coxa, upper portion of the leg, attaches the leg to the thorax.
The other parts of the leg bear a resemblance to components of a human leg.
- The trochanter acts like a knee and lets the cockroach bend its leg.
- The femur and tibia resemble thigh and shin bones.
- The segmented tarsus acts like an ankle and foot.
- The hook-like tarsus also helps cockroaches climb walls and walk upside down on ceilings.
- There are two short protrusions called cerci at the back of the abdomen, which function like rear antennae. They are connected to the legs by the abdominal nerve ganglia. This allows their legs to start moving when they sense any vibrations, often before their brain even processes a threat. That is also why it can be hard to sneak up on a roach.
Fun Facts about Cockroach’s Legs
- When all three pairs of legs are in motion, a cockroach can run at very high speed, and they’re elusive, too, with the ability to turn on a dime while at full pace.
- The fastest start-time clocked by a roach was just 8.2 milliseconds after it felt a puff of air on its rear end.
- Observations of the insect’s stride on sand and wire meshes have indicated that they help in locomotion on steep terrain. This is also used as inspiration for robotic legs.
- They are also able to traverse walls and ceilings since their legs have short, spiky projections that stick to surfaces.
- Cockroach legs can grow back if they’re lost in any case. Cockroaches molt or shed their exoskeletons to grow. They sometimes delay a molt until a lost leg has fully grown back.
- Cockroach legs have tiny hairs that can detect movements of air. These hairs provide them with a sense of touch.
- Cockroach legs are susceptible when touched.
- Cockroaches were found to have near-circular cross-sections that come close to breaking when the insects jump.