The German cockroach is very successful at establishing an ecological niche in buildings and is resilient in the face of many pest control measures.

Reasons include:

• - Lack of natural predators in a human habitat
• - Prolific reproduction
• - Short reproductive cycle
• - The ability to hide in very small refuges
• - Sexual maturity attained within several weeks
• - They prefer confined spaces
• - Females carry oothecal of 18-50 eggs (average about 32) during incubation until just before hatching