American cockroaches will move indoors when they experience a food shortage or a significant change in the climate. In general, American cockroaches prefer warm, moist and dark environments with temperatures between 70-80 degrees Fahrenheit. They often enter structures by being brought in on human belongings, coming up from the sewer system via drains or occasional mass migration from other structures, dumps, etc., during warm weather.

American cockroaches are especially common in larger commercial buildings such as restaurants, bakeries, grocery stores, food processing plants, hospitals, etc., where they usually infest food storage and food preparation areas, boiler rooms, steam tunnels and basements.

Source & Photo Credit: Pest World

Oriental cockroaches are believed to be of North African origin, despite their name. Oriental roaches are sometimes called “waterbugs” because they come out of drains, and “black beetle cockroaches” because of their smooth, dark bodies. They are known for their strong, unpleasant, “roachy” odor. 

The Oriental cockroach feeds on all kinds of food, especially decaying organic matter and starchy foods. This species of cockroach can survive outdoors in freezing temperatures for long periods of time.

Outside, Oriental cockroaches are often found in sewers and under debris, leaves, stones and firewood. They will enter structures through door thresholds, under sliding glass doors, along utility pipes and through floor drains. Once indoors, Oriental cockroaches find harborage in basements and crawl spaces.

Source & Photo Credit: Pest World