Have you ever caught a glimpse of a cockroach scurrying across your kitchen floor? Well, by the time you manage to get your hands on a roach repellent, the cockroach would have disappeared. Not surprising really, considering you are dealing with one of the greatest escape artists in the insect kingdom.
Yes, cockroaches or roaches for short, are adept at wriggling out of tight spots. Whether it is a frog lurking behind a bush, or a descending broom, these creatures have an uncanny ability to scent danger. That’s how they have survived on earth for the past 320 million years!
There are about 3,500 known species of roaches found worldwide, yes, even in the North and South poles. Of these, only 30 species have an inclination to live with people. These include the American, German, Oriental, brown-banded, and Madeira cockroaches.
But how do they sense danger? Is it with their antennae or is it something like a sixth sense? A recent study carried out by American scientists shows that roaches use something more tangible to detect danger – their hair. According to scientists, tiny hairs on a roach’s back act as sensors and are designed to bend easily. These hairs are oriented in all possible directions and can sense changes in wind movement – from all sides.
Cockroaches are very, very sensitive to minute changes in air movements. Subtle shifts in wind patterns bend the hair in a particular direction. This signal is sent to the nerve cells. The cells process the information and guide the cockroach to take evasive action. All this takes place almost instantaneously.
The cockroach differentiates between regular wind patterns and the kind of slow-moving air that signals the approach of an attacker. Normal wind flow creates mixed-up swirl patterns. However, the movement of a foot, (or the approach of a frog) generates a smoother, slower wind pattern.
For example, the moment you take aim with a shoe from behind a roach, the insect senses a slight change in the wind pattern from behind, as the hair on its back is pushed forward. It immediately darts off in the opposite direction.
However, vacuum cleaners have even smart roaches fooled. Vacuum cleaners suck in air, so when the vacuum nozzle is pointed at the back of a cockroach, the air blows from the roach’s head towards its back and into the nozzle – causing the hair to get pushed backwards. The roach thinks that the wind is blowing from the front (towards it) since the hair sensors are being pushed backwards and quickly turns around and runs straight into the nozzle!
Most roaches are sensitive to light and try to hide. However, certain Asian species and the American cockroach are attracted to light. Roaches may be winged or wingless, but not all winged species fly.
Cockroaches can live without food for a month, but can only survive a week without water. As such, a cockroach can live a whole week without its head! Without a mouth the roach can’t take in water and finally dies of thirst.
Cockroaches can eat anything, including other cockroaches. They play an important role in the decomposition of forest litter and excreta. But because they breed rapidly, soil things, and are potential disease carriers, cockroaches are the most misunderstood creatures in the insect kingdom.
So even as they continue to be targeted by shoes, brooms or vaccum cleaners, chances are that they will, finally, outlast humans. Their record proves it: they have been around a whole lot longer than us!