Cockroaches are closely related to termites and are representatives of a primitive and highly successful group of insects whose origins go back as far as 300 million years.
There are around 3,400 species of cockroach worldwide, however only some 10 species have seriously exploited buildings and human dwellings. These 10 species are very successful scavengers that now cohabit with people in most of the human communities around the world.
It is thought that most if not all species of cockroach originated from tropical and sub-tropical Africa, dispersed across the world via ships, carriages, trains, planes and automobiles. Adults may live for up to a year in some species, during which period 5 to 30 egg-cases may be produced by the females. Egg-cases may contain 12-40 eggs depending on the species involved.
If one does the maths it becomes evident just how quickly large populations of cockroaches may develop in “no time at all”.