Cockroaches are one among the infectious creatures existing worldwide. There are about 4000 species of cockroaches of which only about 30 are considered pests. Others live in the wild without invading the human habitat. They are nocturnal insects. They hide during most part of the day and are quite active at night. They are also one of the most successful creatures in a sense they easily adapt to the environment and reproduce so quickly that they see up to 6 generations in a year. These insects are not very easy to get rid of.
The head of a cockroach houses their eyes, antennae and mouth. Surprisingly, they can survive without their heads for more than a week. This is because they neither need their mouth to breath nor their head for blood circulation.
They breathe through holes on the sides of their body called spiracles. They have an open circulatory system. There are tubes called tracheae that deliver oxygen to organs and tissues. Also much of their nervous system activity takes place in nerve tissues Being cold-blooded they can survive without food for even a month but cannot survive without water for more than a week. A headless cockroach may finally die because of thirst.
The four most common pest species of cockroaches are – the German cockroaches, Brown banded cockroaches, American cockroaches and Oriental cockroaches. German ones are small which can fit into a hole as thin as a cent and American ones are much bigger.
The thick protective case called ootheca is where the eggs are kept protected. While German cockroaches may encase about 40 eggs in one ootheca, the American cockroaches average about 14 eggs per capsule. One female can produce multiple egg cases in her lifetime. The cockroaches get most of the nutrients from the bacteria residing inside their body and so it is not a matter of importance as to what they feed on be it a nutritious substance or even garbage.
Cockroaches can easily sense threat using changes in air flow. They have a pair of appendage called cerci at the end of their body. This part has minute hairs on them. These can detect air movements. Once they sense changes in air movements, they start to run at a very high speed and escape threats.