How Do Cockroaches Lose Their Legs?

WouterSeptember 30, 2022

Cockroaches lose their legs in a couple of ways. Firstly, the leg is detached from the femur joint (also called the trochanter joint) nearest the cockroach’s torso. This leaves a small stump. The cockroach regenerates this limb in stages over the course of about five weeks. However, the regeneration of the nerves takes a little longer.

Secondly, cockroaches can be born with four or five joints in each “foot.” Cockroaches can also have four joints in one or two feet, making them have six legs in total. This variation is often seen in cockroaches that molt and re-grow their legs.

Cockroaches have a large genome, allowing for more information to be stored in their DNA. This helps them build a complex biological network. They also possess signaling pathways in their limbs that instruct their nerves to regenerate limb tissue. This allows cockroaches to regrow their legs even if they are in an unfavorable environment.

Another way roaches lose their legs is when they are killed. When a cockroach is killed by humans or by another animal, it is often inflicted with a toxin that is meant to kill any disease vectors on their legs. Most bug sprays damage the roach’s nervous system and internal circuitry.

In addition, when a cockroach is poisoned, it instinctively turns its back to protect its airways. This is due to the large legs and the center of gravity on its back. Since the legs tuck underneath the body, a roach can’t always get itself back into a balanced position. Alternatively, a roach can hang onto a natural object to stabilize itself.