The German Cockroach is a secretive animal that has lived with humans and their ancestors for hundreds of thousands of years. This cockroach seek conditions that provide warmth, moisture and food. The vast majority of infestations are associated with kitchens or other food-handling areas, both domestic and commercial. Within such areas, adults and nymphs find cracks and crevices in which they hide during the day. Generally they hide during the day by all bunching together tightly in cracks and crevices mainly around food preparation areas, this is called thigmotactic behaviour.
Infestations are common in food-handling factories, warehouses, storerooms, restaurants, cafes, food bars, domestic kitchens and the catering or canteen areas of office blocks, hospitals, hotels, clubs, schools and most other types of buildings. In kitchens, pantries, storerooms and other food-handling areas, the german cockroaches are usually found under sinks and cupboards, in and under drawers, in and around water heaters and appliances such as refrigerators, stoves, dishwashers, and in wall voids adjoining kitchens and bathrooms. It will eat almost any organic material found in food handling areas, ranging from crumbs to built-up grease. Where water is available, adults may survive for up to a month without food.
Adult German Cockroaches are very poor fliers, even though they have fully developed wings. Nymphs are similar in appearance to adults except that they are smaller and lack wings. Despite their poor flying ability German Cockroaches have a very wide dispersal, this is attributable largely to human error, whereby humans transport the egg cases, nymphs or even adults to new locations in food packaging, cardboard boxes or even drink crates. Its small size facilities establishment in small cracks and crevices, and its prolific breeding capacity allows it to build up a large population over a relatively short period of time.
The juvenile cockroaches rarely leave the harbourage and survive by eating the faeces and discarded shells (exoskeletal pieces) of the other cockroaches. German cockroaches breed extremely rapidly, under ideal conditions a single pair can have as many as 3 million offspring in 2 years. If a number of German Cockroaches are observed during daylight or if cockroaches are observed in non-food-handling areas within a building (e.g. bedrooms), it is likely that the building is supporting an enormous population.
Their rapid breeding has allowed them to develop resistance to all publicly available sprays and most chemical sprays only available to pest management professionals.